WO2018230737A1 - アンモニアの分離方法およびゼオライト - Google Patents
アンモニアの分離方法およびゼオライト Download PDFInfo
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- WO2018230737A1 WO2018230737A1 PCT/JP2018/023042 JP2018023042W WO2018230737A1 WO 2018230737 A1 WO2018230737 A1 WO 2018230737A1 JP 2018023042 W JP2018023042 W JP 2018023042W WO 2018230737 A1 WO2018230737 A1 WO 2018230737A1
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- Prior art keywords
- ammonia
- zeolite
- gas
- zeolite membrane
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- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 title claims abstract description 1086
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 title claims abstract description 897
- 239000010457 zeolite Substances 0.000 title claims abstract description 855
- 229910021536 Zeolite Inorganic materials 0.000 title claims abstract description 852
- 229910021529 ammonia Inorganic materials 0.000 title claims abstract description 448
- 238000000926 separation method Methods 0.000 title claims abstract description 251
- 239000012528 membrane Substances 0.000 claims abstract description 637
- 239000007789 gas Substances 0.000 claims abstract description 340
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 198
- 238000000034 method Methods 0.000 claims abstract description 192
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 135
- 229910001873 dinitrogen Inorganic materials 0.000 claims abstract description 76
- 239000002131 composite material Substances 0.000 claims description 180
- 238000004519 manufacturing process Methods 0.000 claims description 109
- 229910052757 nitrogen Inorganic materials 0.000 claims description 104
- 230000008859 change Effects 0.000 claims description 48
- 150000001340 alkali metals Chemical class 0.000 claims description 37
- 238000004833 X-ray photoelectron spectroscopy Methods 0.000 claims description 36
- 229910052783 alkali metal Inorganic materials 0.000 claims description 25
- 239000012466 permeate Substances 0.000 abstract description 51
- 230000001747 exhibiting effect Effects 0.000 abstract description 8
- 239000013078 crystal Substances 0.000 description 158
- 125000004429 atom Chemical group 0.000 description 99
- 239000011148 porous material Substances 0.000 description 84
- 229910052739 hydrogen Inorganic materials 0.000 description 82
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 71
- 229910001868 water Inorganic materials 0.000 description 71
- 238000001027 hydrothermal synthesis Methods 0.000 description 69
- 239000000203 mixture Substances 0.000 description 68
- 239000001257 hydrogen Substances 0.000 description 64
- 238000011282 treatment Methods 0.000 description 59
- 125000004433 nitrogen atom Chemical group N* 0.000 description 51
- 238000006243 chemical reaction Methods 0.000 description 49
- 239000002994 raw material Substances 0.000 description 47
- 229910052710 silicon Inorganic materials 0.000 description 46
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 44
- -1 alkali metal salt Chemical class 0.000 description 41
- 230000035699 permeability Effects 0.000 description 41
- 238000010438 heat treatment Methods 0.000 description 40
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 38
- 239000007864 aqueous solution Substances 0.000 description 37
- 229910000323 aluminium silicate Inorganic materials 0.000 description 35
- 238000005259 measurement Methods 0.000 description 35
- 238000005342 ion exchange Methods 0.000 description 34
- 230000008569 process Effects 0.000 description 33
- 239000011541 reaction mixture Substances 0.000 description 31
- 229910002651 NO3 Inorganic materials 0.000 description 28
- 229910004298 SiO 2 Inorganic materials 0.000 description 28
- 229910052782 aluminium Inorganic materials 0.000 description 28
- 239000006185 dispersion Substances 0.000 description 28
- 230000002829 reductive effect Effects 0.000 description 26
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 25
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 25
- 238000001179 sorption measurement Methods 0.000 description 24
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 23
- 150000002500 ions Chemical class 0.000 description 23
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 22
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 22
- 150000001768 cations Chemical class 0.000 description 22
- 241000894007 species Species 0.000 description 21
- IUVCFHHAEHNCFT-INIZCTEOSA-N 2-[(1s)-1-[4-amino-3-(3-fluoro-4-propan-2-yloxyphenyl)pyrazolo[3,4-d]pyrimidin-1-yl]ethyl]-6-fluoro-3-(3-fluorophenyl)chromen-4-one Chemical compound C1=C(F)C(OC(C)C)=CC=C1C(C1=C(N)N=CN=C11)=NN1[C@@H](C)C1=C(C=2C=C(F)C=CC=2)C(=O)C2=CC(F)=CC=C2O1 IUVCFHHAEHNCFT-INIZCTEOSA-N 0.000 description 20
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 20
- 238000001035 drying Methods 0.000 description 20
- 239000011734 sodium Substances 0.000 description 20
- 239000002904 solvent Substances 0.000 description 18
- 239000003513 alkali Substances 0.000 description 17
- 239000004809 Teflon Substances 0.000 description 16
- 229920006362 Teflon® Polymers 0.000 description 16
- 238000001816 cooling Methods 0.000 description 16
- 239000010703 silicon Substances 0.000 description 16
- 238000005406 washing Methods 0.000 description 16
- ZMANZCXQSJIPKH-UHFFFAOYSA-N Triethylamine Chemical compound CCN(CC)CC ZMANZCXQSJIPKH-UHFFFAOYSA-N 0.000 description 15
- 239000002253 acid Substances 0.000 description 14
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 14
- HUCVOHYBFXVBRW-UHFFFAOYSA-M caesium hydroxide Inorganic materials [OH-].[Cs+] HUCVOHYBFXVBRW-UHFFFAOYSA-M 0.000 description 14
- 239000000126 substance Substances 0.000 description 14
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical group [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 13
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 13
- 230000015572 biosynthetic process Effects 0.000 description 13
- 125000002091 cationic group Chemical group 0.000 description 13
- 230000007423 decrease Effects 0.000 description 13
- 230000000694 effects Effects 0.000 description 13
- 238000011156 evaluation Methods 0.000 description 13
- BNGXYYYYKUGPPF-UHFFFAOYSA-M (3-methylphenyl)methyl-triphenylphosphanium;chloride Chemical compound [Cl-].CC1=CC=CC(C[P+](C=2C=CC=CC=2)(C=2C=CC=CC=2)C=2C=CC=CC=2)=C1 BNGXYYYYKUGPPF-UHFFFAOYSA-M 0.000 description 12
- 239000003054 catalyst Substances 0.000 description 12
- 239000003795 chemical substances by application Substances 0.000 description 12
- 230000007246 mechanism Effects 0.000 description 12
- 229910052760 oxygen Inorganic materials 0.000 description 12
- 239000001301 oxygen Substances 0.000 description 12
- 239000000377 silicon dioxide Substances 0.000 description 12
- 238000003786 synthesis reaction Methods 0.000 description 12
- 229910052751 metal Inorganic materials 0.000 description 11
- 239000002184 metal Substances 0.000 description 11
- PAYRUJLWNCNPSJ-UHFFFAOYSA-N Aniline Chemical compound NC1=CC=CC=C1 PAYRUJLWNCNPSJ-UHFFFAOYSA-N 0.000 description 10
- ROSDSFDQCJNGOL-UHFFFAOYSA-N Dimethylamine Chemical compound CNC ROSDSFDQCJNGOL-UHFFFAOYSA-N 0.000 description 10
- QUSNBJAOOMFDIB-UHFFFAOYSA-N Ethylamine Chemical compound CCN QUSNBJAOOMFDIB-UHFFFAOYSA-N 0.000 description 10
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 10
- BAVYZALUXZFZLV-UHFFFAOYSA-N Methylamine Chemical compound NC BAVYZALUXZFZLV-UHFFFAOYSA-N 0.000 description 10
- JGFZNNIVVJXRND-UHFFFAOYSA-N N,N-Diisopropylethylamine (DIPEA) Chemical compound CCN(C(C)C)C(C)C JGFZNNIVVJXRND-UHFFFAOYSA-N 0.000 description 10
- NQRYJNQNLNOLGT-UHFFFAOYSA-N Piperidine Chemical compound C1CCNCC1 NQRYJNQNLNOLGT-UHFFFAOYSA-N 0.000 description 10
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical compound C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 description 10
- WGQKYBSKWIADBV-UHFFFAOYSA-N benzylamine Chemical compound NCC1=CC=CC=C1 WGQKYBSKWIADBV-UHFFFAOYSA-N 0.000 description 10
- 238000002425 crystallisation Methods 0.000 description 10
- 230000008025 crystallization Effects 0.000 description 10
- NAQMVNRVTILPCV-UHFFFAOYSA-N hexane-1,6-diamine Chemical compound NCCCCCCN NAQMVNRVTILPCV-UHFFFAOYSA-N 0.000 description 10
- 150000002431 hydrogen Chemical class 0.000 description 10
- 239000002245 particle Substances 0.000 description 10
- 239000000243 solution Substances 0.000 description 10
- GETQZCLCWQTVFV-UHFFFAOYSA-N trimethylamine Chemical compound CN(C)C GETQZCLCWQTVFV-UHFFFAOYSA-N 0.000 description 10
- 230000008602 contraction Effects 0.000 description 9
- 230000007547 defect Effects 0.000 description 9
- 238000001612 separation test Methods 0.000 description 9
- 229910052708 sodium Inorganic materials 0.000 description 9
- 230000009471 action Effects 0.000 description 8
- 229910052792 caesium Inorganic materials 0.000 description 8
- 238000004364 calculation method Methods 0.000 description 8
- 238000010304 firing Methods 0.000 description 8
- 239000000047 product Substances 0.000 description 8
- 238000006884 silylation reaction Methods 0.000 description 8
- XEZNGIUYQVAUSS-UHFFFAOYSA-N 18-crown-6 Chemical compound C1COCCOCCOCCOCCOCCO1 XEZNGIUYQVAUSS-UHFFFAOYSA-N 0.000 description 7
- 150000001412 amines Chemical class 0.000 description 7
- 239000000919 ceramic Substances 0.000 description 7
- 238000013461 design Methods 0.000 description 7
- 239000010410 layer Substances 0.000 description 7
- 239000002002 slurry Substances 0.000 description 7
- 238000002336 sorption--desorption measurement Methods 0.000 description 7
- PAWQVTBBRAZDMG-UHFFFAOYSA-N 2-(3-bromo-2-fluorophenyl)acetic acid Chemical compound OC(=O)CC1=CC=CC(Br)=C1F PAWQVTBBRAZDMG-UHFFFAOYSA-N 0.000 description 6
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 6
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 description 6
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 6
- 238000002441 X-ray diffraction Methods 0.000 description 6
- ANBBXQWFNXMHLD-UHFFFAOYSA-N aluminum;sodium;oxygen(2-) Chemical compound [O-2].[O-2].[Na+].[Al+3] ANBBXQWFNXMHLD-UHFFFAOYSA-N 0.000 description 6
- 150000001450 anions Chemical class 0.000 description 6
- IWOUKMZUPDVPGQ-UHFFFAOYSA-N barium nitrate Chemical compound [Ba+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O IWOUKMZUPDVPGQ-UHFFFAOYSA-N 0.000 description 6
- ZCCIPPOKBCJFDN-UHFFFAOYSA-N calcium nitrate Chemical compound [Ca+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ZCCIPPOKBCJFDN-UHFFFAOYSA-N 0.000 description 6
- 239000008119 colloidal silica Substances 0.000 description 6
- 238000005336 cracking Methods 0.000 description 6
- YIXJRHPUWRPCBB-UHFFFAOYSA-N magnesium nitrate Chemical compound [Mg+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O YIXJRHPUWRPCBB-UHFFFAOYSA-N 0.000 description 6
- 239000002808 molecular sieve Substances 0.000 description 6
- 229910001388 sodium aluminate Inorganic materials 0.000 description 6
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 description 6
- VILCJCGEZXAXTO-UHFFFAOYSA-N 2,2,2-tetramine Chemical compound NCCNCCNCCN VILCJCGEZXAXTO-UHFFFAOYSA-N 0.000 description 5
- RPNUMPOLZDHAAY-UHFFFAOYSA-N Diethylenetriamine Chemical compound NCCNCCN RPNUMPOLZDHAAY-UHFFFAOYSA-N 0.000 description 5
- KWYHDKDOAIKMQN-UHFFFAOYSA-N N,N,N',N'-tetramethylethylenediamine Chemical compound CN(C)CCN(C)C KWYHDKDOAIKMQN-UHFFFAOYSA-N 0.000 description 5
- AFBPFSWMIHJQDM-UHFFFAOYSA-N N-methylaniline Chemical compound CNC1=CC=CC=C1 AFBPFSWMIHJQDM-UHFFFAOYSA-N 0.000 description 5
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 description 5
- 150000003863 ammonium salts Chemical class 0.000 description 5
- 239000012298 atmosphere Substances 0.000 description 5
- 230000000903 blocking effect Effects 0.000 description 5
- 238000001354 calcination Methods 0.000 description 5
- 125000004432 carbon atom Chemical group C* 0.000 description 5
- 150000001875 compounds Chemical class 0.000 description 5
- 238000009833 condensation Methods 0.000 description 5
- 230000005494 condensation Effects 0.000 description 5
- HPNMFZURTQLUMO-UHFFFAOYSA-N diethylamine Chemical compound CCNCC HPNMFZURTQLUMO-UHFFFAOYSA-N 0.000 description 5
- 229910052742 iron Inorganic materials 0.000 description 5
- 229910052744 lithium Inorganic materials 0.000 description 5
- RIWRFSMVIUAEBX-UHFFFAOYSA-N n-methyl-1-phenylmethanamine Chemical compound CNCC1=CC=CC=C1 RIWRFSMVIUAEBX-UHFFFAOYSA-N 0.000 description 5
- 230000036961 partial effect Effects 0.000 description 5
- 229920005597 polymer membrane Polymers 0.000 description 5
- 239000011164 primary particle Substances 0.000 description 5
- UMJSCPRVCHMLSP-UHFFFAOYSA-N pyridine Natural products COC1=CC=CN=C1 UMJSCPRVCHMLSP-UHFFFAOYSA-N 0.000 description 5
- 150000003839 salts Chemical class 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 4
- 239000004115 Sodium Silicate Substances 0.000 description 4
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 4
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 4
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 4
- 229910001860 alkaline earth metal hydroxide Inorganic materials 0.000 description 4
- VXAUWWUXCIMFIM-UHFFFAOYSA-M aluminum;oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Al+3] VXAUWWUXCIMFIM-UHFFFAOYSA-M 0.000 description 4
- 229910001593 boehmite Inorganic materials 0.000 description 4
- 229910052796 boron Inorganic materials 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 238000007598 dipping method Methods 0.000 description 4
- 238000005265 energy consumption Methods 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 229910021485 fumed silica Inorganic materials 0.000 description 4
- 230000006870 function Effects 0.000 description 4
- 229910052733 gallium Inorganic materials 0.000 description 4
- CHPZKNULDCNCBW-UHFFFAOYSA-N gallium nitrate Chemical compound [Ga+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O CHPZKNULDCNCBW-UHFFFAOYSA-N 0.000 description 4
- FAHBNUUHRFUEAI-UHFFFAOYSA-M hydroxidooxidoaluminium Chemical compound O[Al]=O FAHBNUUHRFUEAI-UHFFFAOYSA-M 0.000 description 4
- 239000011261 inert gas Substances 0.000 description 4
- 239000004816 latex Substances 0.000 description 4
- 229920000126 latex Polymers 0.000 description 4
- KVKFRMCSXWQSNT-UHFFFAOYSA-N n,n'-dimethylethane-1,2-diamine Chemical compound CNCCNC KVKFRMCSXWQSNT-UHFFFAOYSA-N 0.000 description 4
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen(.) Chemical compound [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 4
- 239000003960 organic solvent Substances 0.000 description 4
- 229910052700 potassium Inorganic materials 0.000 description 4
- 230000035484 reaction time Effects 0.000 description 4
- 230000000630 rising effect Effects 0.000 description 4
- CPRMKOQKXYSDML-UHFFFAOYSA-M rubidium hydroxide Chemical compound [OH-].[Rb+] CPRMKOQKXYSDML-UHFFFAOYSA-M 0.000 description 4
- 239000000523 sample Substances 0.000 description 4
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 4
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 4
- 229910052911 sodium silicate Inorganic materials 0.000 description 4
- 230000002269 spontaneous effect Effects 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- IATRAKWUXMZMIY-UHFFFAOYSA-N strontium oxide Chemical compound [O-2].[Sr+2] IATRAKWUXMZMIY-UHFFFAOYSA-N 0.000 description 4
- LFQCEHFDDXELDD-UHFFFAOYSA-N tetramethyl orthosilicate Chemical compound CO[Si](OC)(OC)OC LFQCEHFDDXELDD-UHFFFAOYSA-N 0.000 description 4
- 229910052718 tin Inorganic materials 0.000 description 4
- 239000010936 titanium Substances 0.000 description 4
- 238000009623 Bosch process Methods 0.000 description 3
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 3
- 239000011575 calcium Substances 0.000 description 3
- 239000001569 carbon dioxide Substances 0.000 description 3
- 229910002092 carbon dioxide Inorganic materials 0.000 description 3
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 3
- 229910052736 halogen Inorganic materials 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 3
- 230000001771 impaired effect Effects 0.000 description 3
- 230000002401 inhibitory effect Effects 0.000 description 3
- 230000007774 longterm Effects 0.000 description 3
- 239000011777 magnesium Substances 0.000 description 3
- 238000000691 measurement method Methods 0.000 description 3
- 229910000000 metal hydroxide Inorganic materials 0.000 description 3
- 150000004692 metal hydroxides Chemical class 0.000 description 3
- 229910052863 mullite Inorganic materials 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 230000000737 periodic effect Effects 0.000 description 3
- 229920000642 polymer Polymers 0.000 description 3
- 238000010298 pulverizing process Methods 0.000 description 3
- 238000004064 recycling Methods 0.000 description 3
- 229910052701 rubidium Inorganic materials 0.000 description 3
- 238000007789 sealing Methods 0.000 description 3
- 230000002194 synthesizing effect Effects 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- 229910052725 zinc Inorganic materials 0.000 description 3
- 239000011701 zinc Substances 0.000 description 3
- GHOKWGTUZJEAQD-ZETCQYMHSA-N (D)-(+)-Pantothenic acid Chemical compound OCC(C)(C)[C@@H](O)C(=O)NCCC(O)=O GHOKWGTUZJEAQD-ZETCQYMHSA-N 0.000 description 2
- MFGOFGRYDNHJTA-UHFFFAOYSA-N 2-amino-1-(2-fluorophenyl)ethanol Chemical compound NCC(O)C1=CC=CC=C1F MFGOFGRYDNHJTA-UHFFFAOYSA-N 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- XURCIPRUUASYLR-UHFFFAOYSA-N Omeprazole sulfide Chemical compound N=1C2=CC(OC)=CC=C2NC=1SCC1=NC=C(C)C(OC)=C1C XURCIPRUUASYLR-UHFFFAOYSA-N 0.000 description 2
- 229910052581 Si3N4 Inorganic materials 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- 150000001242 acetic acid derivatives Chemical class 0.000 description 2
- 238000010306 acid treatment Methods 0.000 description 2
- 230000032683 aging Effects 0.000 description 2
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- RQPZNWPYLFFXCP-UHFFFAOYSA-L barium dihydroxide Chemical compound [OH-].[OH-].[Ba+2] RQPZNWPYLFFXCP-UHFFFAOYSA-L 0.000 description 2
- 229910001863 barium hydroxide Inorganic materials 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 2
- 239000000920 calcium hydroxide Substances 0.000 description 2
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 150000007942 carboxylates Chemical class 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 230000002950 deficient Effects 0.000 description 2
- 238000003795 desorption Methods 0.000 description 2
- PPQREHKVAOVYBT-UHFFFAOYSA-H dialuminum;tricarbonate Chemical compound [Al+3].[Al+3].[O-]C([O-])=O.[O-]C([O-])=O.[O-]C([O-])=O PPQREHKVAOVYBT-UHFFFAOYSA-H 0.000 description 2
- RSIHJDGMBDPTIM-UHFFFAOYSA-N ethoxy(trimethyl)silane Chemical compound CCO[Si](C)(C)C RSIHJDGMBDPTIM-UHFFFAOYSA-N 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 229940044658 gallium nitrate Drugs 0.000 description 2
- 229910001679 gibbsite Inorganic materials 0.000 description 2
- 229910001849 group 12 element Inorganic materials 0.000 description 2
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- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 2
- 239000000347 magnesium hydroxide Substances 0.000 description 2
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
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- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 2
- 229910010271 silicon carbide Inorganic materials 0.000 description 2
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 229910001415 sodium ion Inorganic materials 0.000 description 2
- 239000004317 sodium nitrate Substances 0.000 description 2
- 235000010344 sodium nitrate Nutrition 0.000 description 2
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 2
- LPSKDVINWQNWFE-UHFFFAOYSA-M tetrapropylazanium;hydroxide Chemical compound [OH-].CCC[N+](CCC)(CCC)CCC LPSKDVINWQNWFE-UHFFFAOYSA-M 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- RUDFQVOCFDJEEF-UHFFFAOYSA-N yttrium(III) oxide Inorganic materials [O-2].[O-2].[O-2].[Y+3].[Y+3] RUDFQVOCFDJEEF-UHFFFAOYSA-N 0.000 description 2
- ONDPHDOFVYQSGI-UHFFFAOYSA-N zinc nitrate Chemical compound [Zn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ONDPHDOFVYQSGI-UHFFFAOYSA-N 0.000 description 2
- 229910052726 zirconium Inorganic materials 0.000 description 2
- BQCIDUSAKPWEOX-UHFFFAOYSA-N 1,1-Difluoroethene Chemical compound FC(F)=C BQCIDUSAKPWEOX-UHFFFAOYSA-N 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical group [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- 229910000906 Bronze Inorganic materials 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 229910000503 Na-aluminosilicate Inorganic materials 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 239000004695 Polyether sulfone Substances 0.000 description 1
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- 239000004642 Polyimide Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 1
- 229910008051 Si-OH Inorganic materials 0.000 description 1
- 229910006358 Si—OH Inorganic materials 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- HDYRYUINDGQKMC-UHFFFAOYSA-M acetyloxyaluminum;dihydrate Chemical compound O.O.CC(=O)O[Al] HDYRYUINDGQKMC-UHFFFAOYSA-M 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000000274 adsorptive effect Effects 0.000 description 1
- 229910001413 alkali metal ion Inorganic materials 0.000 description 1
- 229910001420 alkaline earth metal ion Inorganic materials 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- 150000001336 alkenes Chemical class 0.000 description 1
- 150000004703 alkoxides Chemical class 0.000 description 1
- HIGRAKVNKLCVCA-UHFFFAOYSA-N alumine Chemical compound C1=CC=[Al]C=C1 HIGRAKVNKLCVCA-UHFFFAOYSA-N 0.000 description 1
- ILRRQNADMUWWFW-UHFFFAOYSA-K aluminium phosphate Chemical compound O1[Al]2OP1(=O)O2 ILRRQNADMUWWFW-UHFFFAOYSA-K 0.000 description 1
- 229940009827 aluminum acetate Drugs 0.000 description 1
- 229940118662 aluminum carbonate Drugs 0.000 description 1
- 229940024545 aluminum hydroxide Drugs 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000004760 aramid Substances 0.000 description 1
- 229920003235 aromatic polyamide Polymers 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- 239000002585 base Substances 0.000 description 1
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- 229910001423 beryllium ion Inorganic materials 0.000 description 1
- 239000010974 bronze Substances 0.000 description 1
- TVFDJXOCXUVLDH-UHFFFAOYSA-N caesium atom Chemical compound [Cs] TVFDJXOCXUVLDH-UHFFFAOYSA-N 0.000 description 1
- 229910001417 caesium ion Inorganic materials 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
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- 238000003889 chemical engineering Methods 0.000 description 1
- 238000001311 chemical methods and process Methods 0.000 description 1
- UFMZWBIQTDUYBN-UHFFFAOYSA-N cobalt dinitrate Chemical compound [Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O UFMZWBIQTDUYBN-UHFFFAOYSA-N 0.000 description 1
- 229910001981 cobalt nitrate Inorganic materials 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- KUNSUQLRTQLHQQ-UHFFFAOYSA-N copper tin Chemical compound [Cu].[Sn] KUNSUQLRTQLHQQ-UHFFFAOYSA-N 0.000 description 1
- XTVVROIMIGLXTD-UHFFFAOYSA-N copper(II) nitrate Chemical compound [Cu+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XTVVROIMIGLXTD-UHFFFAOYSA-N 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
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- 239000011521 glass Substances 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- MVFCKEFYUDZOCX-UHFFFAOYSA-N iron(2+);dinitrate Chemical compound [Fe+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MVFCKEFYUDZOCX-UHFFFAOYSA-N 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
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- 238000012986 modification Methods 0.000 description 1
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- KBJMLQFLOWQJNF-UHFFFAOYSA-N nickel(ii) nitrate Chemical compound [Ni+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O KBJMLQFLOWQJNF-UHFFFAOYSA-N 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 239000012188 paraffin wax Substances 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 231100000572 poisoning Toxicity 0.000 description 1
- 230000000607 poisoning effect Effects 0.000 description 1
- 229920002492 poly(sulfone) Polymers 0.000 description 1
- 229920002239 polyacrylonitrile Polymers 0.000 description 1
- 229920006393 polyether sulfone Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
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- 230000009467 reduction Effects 0.000 description 1
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- IGLNJRXAVVLDKE-UHFFFAOYSA-N rubidium atom Chemical compound [Rb] IGLNJRXAVVLDKE-UHFFFAOYSA-N 0.000 description 1
- VSZWPYCFIRKVQL-UHFFFAOYSA-N selanylidenegallium;selenium Chemical compound [Se].[Se]=[Ga].[Se]=[Ga] VSZWPYCFIRKVQL-UHFFFAOYSA-N 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
- 125000005372 silanol group Chemical group 0.000 description 1
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- 230000003068 static effect Effects 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 238000001308 synthesis method Methods 0.000 description 1
- JBQYATWDVHIOAR-UHFFFAOYSA-N tellanylidenegermanium Chemical compound [Te]=[Ge] JBQYATWDVHIOAR-UHFFFAOYSA-N 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 150000003568 thioethers Chemical class 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/22—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion
- B01D53/228—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion characterised by specific membranes
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
- C01C1/00—Ammonia; Compounds thereof
- C01C1/02—Preparation, purification or separation of ammonia
- C01C1/12—Separation of ammonia from gases and vapours
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/22—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0039—Inorganic membrane manufacture
- B01D67/0051—Inorganic membrane manufacture by controlled crystallisation, e,.g. hydrothermal growth
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/10—Supported membranes; Membrane supports
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/10—Supported membranes; Membrane supports
- B01D69/108—Inorganic support material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/02—Inorganic material
- B01D71/028—Molecular sieves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/02—Inorganic material
- B01D71/028—Molecular sieves
- B01D71/0281—Zeolites
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B39/00—Compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites; Their preparation; After-treatment, e.g. ion-exchange or dealumination
- C01B39/02—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof; Direct preparation thereof; Preparation thereof starting from a reaction mixture containing a crystalline zeolite of another type, or from preformed reactants; After-treatment thereof
- C01B39/46—Other types characterised by their X-ray diffraction pattern and their defined composition
- C01B39/48—Other types characterised by their X-ray diffraction pattern and their defined composition using at least one organic template directing agent
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
- C01C1/00—Ammonia; Compounds thereof
- C01C1/02—Preparation, purification or separation of ammonia
- C01C1/04—Preparation of ammonia by synthesis in the gas phase
- C01C1/0405—Preparation of ammonia by synthesis in the gas phase from N2 and H2 in presence of a catalyst
- C01C1/0458—Separation of NH3
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/40—Nitrogen compounds
- B01D2257/406—Ammonia
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/22—Thermal or heat-resistance properties
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
Definitions
- the present invention relates to a method for separating ammonia by selectively permeating ammonia gas from a mixed gas composed of a plurality of components including ammonia gas and hydrogen gas and / or nitrogen gas using a zeolite membrane.
- the present invention also relates to a zeolite membrane that effectively separates ammonia from a mixed gas composed of a plurality of components including ammonia gas and hydrogen gas and / or nitrogen gas even under high temperature conditions.
- the polymer membrane has the technical problem that it is easy to swell and has low heat resistance, while having a feature that it is excellent in processability to, for example, a flat membrane or a hollow fiber membrane.
- the polymer membrane has low resistance to reactive chemicals, and there remains a technical problem that easily deteriorates due to adsorptive components such as sulfides.
- the polymer membrane is easily deformed by pressure, and thus the separation performance is lowered, it is not practical in the separation of ammonia under high temperature conditions, which is one of the problems of the present invention.
- the zeolite membrane has regular sub-nanometer pores and functions as a molecular sieve, so that it can selectively permeate specific molecules and has a wider temperature range than the polymer membrane. It is expected as a highly durable separation membrane that can be separated and concentrated in a range.
- a zeolite membrane is usually used as a zeolite membrane composite in which zeolite is formed into a membrane on a support made of an inorganic material.
- zeolite membranes such as A-type membranes, FAU membranes, MFI membranes, SAPO-34 membranes, and DDR membranes are known as gas separation zeolite membranes, which separate gases emitted from thermal power plants, petrochemical industries, etc.
- gas separation zeolite membranes which separate gases emitted from thermal power plants, petrochemical industries, etc.
- gases emitted from thermal power plants, petrochemical industries, etc.
- gases emitted from thermal power plants, petrochemical industries, etc.
- a zeolite membrane composite for separation has been proposed (for example, Patent Document 4).
- the separation of the ammonia gas of the present invention from hydrogen gas and nitrogen gas is also applied to membrane separation, for example, the membrane separation is applied to an ammonia production process by the Harbor Bosch method, which is one of industrially important processes. Is expected in recent years.
- this ammonia generation reaction is an equilibrium reaction, and the reaction under high pressure and low temperature conditions is preferred thermodynamically, but in order to ensure the catalytic reaction rate, In general, high-pressure and high-temperature production conditions are imposed.
- unreacted hydrogen gas and nitrogen gas coexist with ammonia gas in the mixed gas to be generated, in the step of recovering ammonia gas as a product from the generated mixed gas, ⁇ 20 ° C.
- Non-Patent Documents 1 and 2 the ammonia gas concentration contained in the product mixed gas inevitably becomes low due to the above-mentioned reaction equilibrium restrictions, so in the ammonia cooling separation process from the product mixed gas, the cooling efficiency is poor, There is a feature that consumes a lot of energy. In this process, it is necessary to separate a large amount of mixed gas of hydrogen gas and nitrogen gas from the produced mixed gas and recycle it as a raw material gas into the reactor. Since it is necessary to increase the pressure to a predetermined pressure and the reaction temperature, the actual situation is that the energy consumption at the time of production is further increased.
- Patent Documents 7 and 8 As a method of separating a mixed gas containing a high concentration of ammonia gas from a mixed gas of hydrogen gas, nitrogen gas and ammonia gas, 1) Select hydrogen gas and / or nitrogen gas from the mixed gas using a separation membrane. 2) a method of selectively permeating ammonia gas from the mixed gas using a separation membrane.
- Patent Document 5 As the former method for selectively permeating hydrogen gas and / or nitrogen gas, a method using a polycrystalline layer of various zeolites (Patent Document 5) and a method using a molecular sieve film (Patent Document 6) have been proposed. ing. Patent Document 7 describes a method of selectively permeating hydrogen gas and / or nitrogen gas and a method of selectively permeating ammonia gas, using a separation membrane in which a silica-containing layer is laminated on a ceramic substrate. Thus, a separation method for separating at least one component of hydrogen gas, nitrogen gas, and ammonia gas from a product gas that is a mixture of hydrogen gas, nitrogen gas, and ammonia gas has been proposed.
- Patent Document 7 as a schematic flow chart in which a separation membrane is applied to the production of ammonia, hydrogen gas selectively permeates through a silica membrane under high temperature conditions. Hydrogen gas is separated to the permeate side by the second stage separation membrane, and ammonia gas is separated to the permeate side by the second stage separation membrane from the nitrogen gas and ammonia gas that have not permeated by the first stage separation membrane. It is shown.
- the conditions for separating the ammonia gas from the mixed gas of hydrogen gas and ammonia gas must be a low temperature condition such as 50 ° C., and the ammonia gas concentration in the mixed gas may exceed 60 mol%. It is shown that it is necessary.
- Patent Document 8 As a method for selectively allowing the latter ammonia gas to permeate, in addition to Patent Document 7, using a specific zeolite having an oxygen 8-membered ring, ammonia from a mixed gas of ammonia gas and hydrogen gas and / or nitrogen gas is used.
- An efficient ammonia separation method for separating gas has been proposed (Patent Document 8).
- a method is proposed in which a specific zeolite membrane composite is designed and ammonia gas is separated by molecular sieve action utilizing the pore diameter of the zeolite.
- ammonia is used as a probe molecule that adsorbs to acid sites in a temperature-programmed desorption method that measures the acid amount of zeolite.
- Patent Document 8 discloses that the permeation performance of ammonia gas can be controlled by controlling the adsorption ability of ammonia to zeolite by ion exchange of zeolite. .
- Patent Document 8 clogging of zeolite pores by ammonia during permeation of ammonia gas is cited as a problem, and a technique that avoids this is disclosed in Examples.
- the zeolite is used to suppress the adsorption of ammonia, and the ammonia gas is permeated by the molecular sieving action utilizing the pore diameter of the zeolite while suppressing the clogging of the ammonia pores. It is proposed that the technique of making it effective.
- JP 2011-121040 A JP 2011-121045 JP 2011-121854 A JP 2012-066242 A Japanese National Patent Publication No. 10-506363 Special Table 2000-507909 JP 2008-247654 A JP 2014-058433 A International Publication No. 2015/129471
- Patent Document 7 when the technique of Patent Document 7 is adopted, in order to complete an economical process, a high-concentration hydrogen mixed gas containing ammonia gas permeated through the first-stage separation membrane, and not permeated. A step of separating the ammonia gas from the mixed gas of nitrogen gas and ammonia gas is essential. That is, this method is not only a complicated process for separating ammonia gas from a mixed gas of hydrogen gas, nitrogen gas and ammonia gas in at least two stages, but also to complete an economical process, A process for recovering ammonia from both the mixed gas permeated in the first stage and the non-permeated mixed gas is required, and the process becomes more complicated.
- the separation membrane according to one embodiment of the present invention is formed.
- the raw material gas permeates, so the reaction becomes disadvantageous due to the above-mentioned reaction equilibrium limitation, and high-concentration ammonia gas cannot be produced.
- the method of selectively permeating hydrogen gas and / or nitrogen gas from a mixed gas of hydrogen gas, nitrogen gas, and ammonia gas using such a separation membrane is the energy at the time of production.
- Patent Document 8 ammonia gas is separated from a mixed gas of nitrogen and ammonia gas at 140 ° C., but when comparing the permeance of various gases before and after permeation of ammonia gas, any gas after permeation The permeance value is increasing, and there remains a problem that the durability of the zeolite membrane is impaired even under a relatively low temperature condition of 140 ° C.
- the composition of the supply gas mixture and the temperature at which it is separated are used because ammonia essentially has the ability to adsorb to zeolite. Need to be combined appropriately.
- Patent Document 8 there is no description about the proper separation conditions and no proposal has been made, and a mixed gas of hydrogen gas, nitrogen gas, and ammonia gas, hydrogen gas, and ammonia gas are not included. A method for separating ammonia from a mixed gas has not been demonstrated.
- Patent Document 9 in recent years, a highly active ammonia production catalyst process has been reported even under low temperature and low pressure conditions, and is expected as a process for reducing energy consumption during production.
- this innovative manufacturing process alone it is not possible to generate a mixed gas containing high-concentration ammonia gas exceeding the equilibrium composition due to the limitation of reaction equilibrium because the ammonia generation reaction is an equilibrium reaction as described above. Inherently, it is not possible to solve the problems such as reduction of energy consumption during production including the recovery of the generated ammonia and the recycling process of the raw material gas.
- the present invention has been made in view of the above-described conventional situation, and ammonia gas is selected from a mixed gas composed of a plurality of components including ammonia gas and hydrogen gas and / or nitrogen gas with high permeation. It is an object of the present invention to provide a method for separating ammonia, which can separate ammonia by passing through a zeolite membrane at a high degree, and is excellent in high-temperature separation stability and long-term operation stability.
- the present inventors have further investigated the separation of ammonia using a zeolite membrane.
- concentration of ammonia gas in the mixed gas of hydrogen gas, nitrogen gas, and ammonia gas was specified. It has been found that the permselectivity of ammonia gas permeating the zeolite membrane is remarkably improved when the amount exceeds the above range. Further, it has been found that when one embodiment of the present invention is used, ammonia gas separation performance can be stably maintained even under temperature conditions exceeding 200 ° C.
- Patent Document 8 proposes a method for separating ammonia by designing an ammonia gas separation / permeation membrane that avoids the clogging because the permeating ammonia gas becomes a clogging factor for the pore diameter of zeolite.
- the present invention it has been found that if a method of actively adsorbing ammonia on zeolite is used, the ammonia gas separation performance is remarkably improved and the separation stability is improved, and the present invention is completed. It came.
- invention A The first embodiment of the present invention (Invention A) has been achieved based on such findings and provides the following.
- [A1] A method of separating ammonia by selectively permeating ammonia gas from a mixed gas containing at least ammonia gas, hydrogen gas, and nitrogen gas using a zeolite membrane, the mixed gas A method for separating ammonia, in which the ammonia gas concentration is 1.0% by volume or more.
- [A2] The method for separating ammonia according to [A1], wherein a volume ratio of hydrogen gas / nitrogen gas in the mixed gas is 0.2 or more and 3 or less.
- [A3] The method for separating ammonia according to [A1] or [A2], wherein the temperature at which ammonia is separated is higher than 50 ° C. and 500 ° C. or lower.
- [A4] The method for separating ammonia according to any one of [A1] to [A3], wherein the zeolite constituting the zeolite membrane is RHO zeolite or MFI zeolite.
- [A5] including a step of producing ammonia from hydrogen gas and nitrogen gas, and separating the ammonia from the mixed gas containing ammonia gas obtained in the production step by the separation method according to any one of [A1] to [A4] Ammonia separation method.
- the present inventors have further studied the separation of ammonia gas using a zeolite membrane in order to solve the above-mentioned problems.
- the existing zeolite membrane for ammonia gas separation is more highly selected than the existing silica membrane.
- the separation performance is that the permeance ratio (ideal separation factor) of ammonia gas and nitrogen gas is only about 14 at most, whereas X-ray photoelectron spectroscopy ( It has been found that when a zeolite membrane having a surface in which the molar ratio of nitrogen atoms to Al atoms determined by XPS is in a specific range is used, ammonia gas separation performance is significantly improved.
- ammonia gas separation performance can be stably maintained even under high temperature conditions. That is, in order to separate ammonia gas with high selectivity and high permeability from a mixed gas composed of a plurality of components including ammonia gas and hydrogen gas and / or nitrogen gas even under high temperature conditions, various zeolite membranes are used. Among these, it has been found that it is necessary to use a zeolite membrane having a surface containing nitrogen atoms having a specific molar ratio with respect to Al atoms, and the present invention has been completed.
- the second embodiment (Invention B) of the present invention has been achieved based on such findings, and provides the following.
- [B4] The zeolite membrane according to any one of [B1] to [B3], wherein the zeolite is an RHO type zeolite.
- [B5] The zeolite membrane according to any one of [B1] to [B4], wherein the zeolite membrane is for ammonia gas separation.
- [B6] Ammonia gas separated from a mixed gas containing at least ammonia gas and hydrogen gas and / or nitrogen gas by permeating ammonia gas using the zeolite membrane according to any one of [B1] to [B5]. Separation method.
- [B7] A method for separating ammonia, wherein ammonia obtained in the step of producing ammonia from hydrogen gas and nitrogen gas is separated by the separation method described in [B6].
- the present inventors have further studied the separation of ammonia gas using a zeolite membrane in order to solve the above-mentioned problems.
- the existing zeolite membrane for ammonia gas separation is more highly selected than the existing silica membrane.
- the separation performance is that the permeance ratio (ideal separation factor) of ammonia gas and nitrogen gas is only about 14 at most, and under relatively low temperature conditions such as 140 ° C.
- the zeolite having a surface in which the molar ratio of Si atoms to Al atoms determined by X-ray photoelectron spectroscopy (XPS) is in a specific range It was found that when a membrane is used, remarkable ammonia separation performance is exhibited and separation stability under high temperature conditions is improved. That is, in order to separate ammonia gas with high selectivity and high permeability from a mixed gas composed of a plurality of components including ammonia gas and hydrogen gas and / or nitrogen gas even under high temperature conditions, various zeolite membranes are used.
- a zeolite membrane having a surface containing a specific molar ratio of Si atoms to Al atoms, and the present invention has been completed.
- the third embodiment (Invention C) of the present invention has been achieved based on such knowledge, and provides the following.
- [C1] A zeolite membrane, wherein the molar ratio of Si atoms to Al atoms determined by the following measurement conditions using X-ray photoelectron spectroscopy is 2.0 or more and 10 or less.
- the zeolite membrane has a molar ratio of nitrogen atoms to Al atoms determined by the following measurement conditions using X-ray photoelectron spectroscopy is 0.01.
- [C6] The zeolite membrane according to any one of [C1] to [C5], wherein the zeolite is an RHO type zeolite.
- [C7] The zeolite membrane according to any one of [C1] to [C6], wherein the zeolite membrane is for ammonia separation.
- [C8] Ammonia gas separated from a mixed gas containing at least ammonia gas and hydrogen gas and / or nitrogen gas by permeating ammonia gas using the zeolite membrane according to any one of [C1] to [C7]. Separation method.
- [C9] A method for separating ammonia, wherein ammonia obtained in the step of producing ammonia from hydrogen gas and nitrogen gas is separated by the separation method according to [C8].
- the present inventors have further investigated the separation of ammonia gas using a zeolite membrane in order to solve the above-mentioned problems, and as a result, alkali metal atoms relative to Al atoms determined by X-ray photoelectron spectroscopy (XPS). It was found that the permeation performance can be improved while maintaining high ammonia gas separation selectivity when a zeolite membrane having a surface in which the molar ratio is in a specific range is used. Further, it has been found that when the present invention is used, ammonia gas separation performance can be stably maintained even under high temperature conditions.
- XPS X-ray photoelectron spectroscopy
- [D1] A zeolite membrane, wherein the molar ratio of alkali metal atoms to Al atoms determined by the following measurement conditions by X-ray photoelectron spectroscopy is 0.01 or more and 0.070 or less.
- X-ray source for measurement Monochromatic Al-K ⁇ ray, output 16 kV-34 W Background determination method for quantitative calculation: Shirley method
- the molar ratio of nitrogen atoms to Al atoms determined by the X-ray photoelectron spectroscopy under the following measurement conditions is 0.01 or more and 4 or less.
- [D5] The zeolite membrane according to any one of [D1] to [D4], wherein the zeolite membrane is a zeolite membrane treated with an ammonium salt and then treated with an alkali metal salt.
- [D6] The zeolite membrane according to any one of [D1] to [D5], wherein the zeolite is an RHO type zeolite.
- [D7] The zeolite membrane according to any one of [D1] to [D6], wherein the zeolite membrane is for ammonia gas separation.
- [D8] Ammonia gas separated from a mixed gas containing at least ammonia gas and hydrogen gas and / or nitrogen gas by permeating ammonia gas using the zeolite membrane according to any one of [D1] to [D7] Separation method.
- [D9] A method for separating ammonia, wherein ammonia obtained in the step of producing ammonia from hydrogen gas and nitrogen gas is separated by the separation method described in [D8].
- the present inventors have further studied the separation of ammonia gas using a zeolite membrane composite in order to solve the above-mentioned problems.
- the zeolite membrane is more selectively and efficiently ammonia than the existing silica membrane.
- gas can be separated, as described in Reference Example E1 of the present invention, the rate of change in thermal shrinkage at 200 ° C. and 300 ° C. with respect to 30 ° C. is 0.13% and 0.30% (c-axis direction).
- ammonia can be efficiently and selectively separated under high temperature conditions exceeding 200 ° C. That is, ammonia gas is separated with high selectivity and high permeability from a gas mixture composed of a plurality of components including ammonia gas and hydrogen gas and / or nitrogen gas under high temperature conditions, which is one of the problems of the present invention.
- the present inventors have found that it is necessary to apply a zeolite membrane composite in which a zeolite exhibiting a rate of change in thermal expansion in a specific temperature region is applied among various zeolite membrane composites, thereby completing the present invention. It came to.
- the rate of change of the coefficient of thermal expansion is the rate of change of the coefficient of thermal expansion in the axial direction where the rate of change of the coefficient of thermal expansion is maximized.
- CHA-type zeolite has different thermal expansion / contraction rates in the a-axis and c-axis directions, but the rate of change is larger in the c-axis. Therefore, the rate of change of the coefficient of thermal expansion of CHA is the rate of change of the coefficient of thermal expansion in the c-axis direction.
- MFI-type zeolite has different thermal expansion / contraction rates in the a-axis, b-axis, and c-axis directions, but the rate of change is larger in the c-axis.
- the change rate of the thermal expansion coefficient of MFI in this specification is the change rate of the thermal expansion coefficient in the c-axis direction.
- RHO-type zeolite is cubic and all crystal axes are equivalent, so the rate of change of thermal expansion coefficient is constant regardless of the axial direction.
- the fifth embodiment (Invention E) of the present invention has been achieved based on such knowledge, and provides the following.
- [E1] A zeolite membrane composite for ammonia separation containing zeolite, wherein the change rate of the thermal expansion coefficient at 300 ° C. with respect to the thermal expansion coefficient at 30 ° C. of the zeolite is within ⁇ 0.25%, and the heat at 30 ° C.
- a zeolite membrane composite for ammonia separation wherein the rate of change of the coefficient of thermal expansion at 400 ° C. with respect to the coefficient of expansion is within ⁇ 0.35%.
- the rate of change of the thermal expansion coefficient at 400 ° C. relative to the coefficient of thermal expansion at 30 ° C. is within ⁇ 120% of the rate of change of the thermal expansion coefficient at 300 ° C. with respect to the coefficient of thermal expansion at 30 ° C.
- [E4] The zeolite membrane composite for ammonia separation according to any one of [E1] to [E3], wherein the zeolite has a SiO 2 / Al 2 O 3 molar ratio of 6 or more and 500 or less.
- Ammonia is separated from a gaseous mixture containing at least ammonia gas and hydrogen gas and / or nitrogen gas using the zeolite membrane composite for ammonia gas separation according to any one of [E1] to [E4].
- [E6] A method for separating ammonia, wherein ammonia obtained in the step of producing ammonia from hydrogen gas and nitrogen gas is separated by the separation method according to [E5].
- the second to fifth embodiments are technologies related to an ammonia gas separation membrane that contributes to the completion of an energy-saving production process for ammonia, and also to a reaction separation type ammonia production process that is one aspect of the present invention. This technology can be expected to be applied.
- ammonia gas can be efficiently separated to the permeate side with high selectivity continuously from a mixed gas composed of a plurality of components including ammonia gas, hydrogen gas, and nitrogen gas.
- the ammonia gas can be used stably even at high temperatures exceeding 50 ° C. and even 200 ° C., so that the ammonia gas permeability is high, and as a result, the membrane area required for separation is reduced. Therefore, it is possible to separate ammonia at low cost with a small-scale facility.
- the zeolite membrane of the present invention in an ammonia production process represented by the Harbor Bosch process, etc., a mixture comprising ammonia gas recovered from a reactor, a plurality of components including hydrogen gas and nitrogen gas is used.
- ammonia separation can be performed more efficiently than the conventional cooling condensation separation method, so that the cooling energy for ammonia condensation can be reduced.
- the zeolite membrane of the present invention can efficiently and efficiently permeate ammonia gas from a mixed gas composed of a plurality of components including ammonia gas, hydrogen gas and nitrogen gas even under high temperature conditions.
- ammonia gas is continuously increased from a mixed gas composed of a plurality of components including ammonia gas and hydrogen gas and / or nitrogen gas, even under high temperature conditions. It can be separated efficiently and selectively on the permeate side. Further, since the zeolite membrane of the present invention can be used stably even under higher temperature conditions, the ammonia gas permeability is high, and as a result, the membrane area required for separation can be reduced, and small-scale equipment can be used.
- the zeolite membrane of the present invention in an ammonia production process typified by the Harbor Bosch process, etc., a plurality of components including ammonia gas and hydrogen gas and / or nitrogen gas recovered from the reactor are used.
- the ammonia can be separated more efficiently than the conventional cooling condensation separation method, so that the cooling energy for ammonia condensation can be reduced.
- the zeolite membrane of the present invention is stable and efficient even at high temperatures, with high permeability of ammonia gas from a mixed gas comprising a plurality of components including ammonia gas and hydrogen gas and / or nitrogen gas.
- reaction separation type ammonia production process in which the zeolite membrane of the present invention is installed in a reactor, and ammonia gas generated at the same time is recovered while ammonia gas is generated.
- the application of the first to fifth embodiments to the reaction separation type ammonia production process is not only expected to lower the reaction pressure during ammonia production, but also has a remarkable conversion rate of raw material gas to ammonia gas. It can be expected to improve and reduce the amount of recovered gas recycled to the reactor during production. That is, the reaction separation type ammonia production process adopting the zeolite membrane of the present invention makes it possible to suppress the energy consumption during production, and makes it possible to produce energy-saving ammonia excellent in economy.
- Example 2 it is a schematic diagram which shows the structure of the apparatus used for the ammonia gas separation test. It is a measurement result of the thermal expansion coefficient according to temperature of the zeolite concerning Example E4.
- the zeolite in this specification is a zeolite defined by International Zeolite Association (IZA). Its structure is characterized by X-ray diffraction data. Further, in this specification, “a porous support-zeolite membrane composite in which a zeolite membrane is formed on a porous support” may be referred to as “zeolite membrane composite” or “membrane composite”. is there.
- the “porous support” may be simply abbreviated as “support”, and the “aluminosilicate zeolite” may be simply abbreviated as “zeolite”.
- “hydrogen gas”, “nitrogen gas”, and “ammonia gas” may be simply referred to as “hydrogen”, “nitrogen”, and “ammonia”, respectively.
- the ammonia separation in the present invention means obtaining a mixed gas containing a higher concentration of ammonia gas from a mixed gas containing ammonia gas.
- the first embodiment of the ammonia separation method of the present invention is a high permeability of ammonia using a zeolite membrane from a mixed gas comprising a plurality of components including at least ammonia, hydrogen, and nitrogen. It is a method of performing separation stably and continuously on the permeate side with high selectivity, and selectively permeating ammonia from a mixed gas of hydrogen and nitrogen containing a specific amount or more of ammonia. It is a feature.
- a specific zeolite membrane is contacted with a mixed gas comprising a plurality of components including ammonia and hydrogen and / or nitrogen, and ammonia is selected from the mixed gas. It is characterized in that it is transmitted through and separated. Details will be described below.
- the ammonia separation method according to the present embodiment can be effectively used when efficiently separating ammonia from a mixed gas containing at least ammonia, hydrogen, and nitrogen. It is effective to use in combination with a method for producing ammonia from which a gas is obtained. That is, the first step of producing ammonia from hydrogen and nitrogen, and the second step of separating the ammonia obtained in the first step by the ammonia separation method described later, In addition to the ammonia production method in which ammonia is separated in the process, an ammonia production method in which the first step and the second step proceed in one reactor is also a preferred embodiment of the present invention. The first step and the second step proceed in one reactor means that the first step and the second step proceed simultaneously.
- ammonia gas is produced from hydrogen gas and nitrogen gas in a container, and ammonia is efficiently produced in the container while separating ammonia from the mixed gas containing the produced ammonia gas.
- a container ammonia gas is produced from hydrogen gas and nitrogen gas in a container, and ammonia is efficiently produced in the container while separating ammonia from the mixed gas containing the produced ammonia gas.
- the industrial production method of ammonia but the Harbor Bosch method can be mentioned.
- iron oxide is used as a catalyst, and nitrogen and hydrogen gas are reacted on the catalyst at a high temperature and high pressure of 300 to 500 ° C.
- ammonia production industrial catalysts are generally roughly classified into iron-based catalysts and Ru-based catalysts.
- the first embodiment of the ammonia separation method of the present invention uses a zeolite membrane to bring a mixed gas comprising a plurality of components including ammonia, hydrogen and nitrogen into contact with the zeolite membrane, and selectively selects ammonia from the mixed gas. It is characterized by being separated by permeation. Further, the ammonia separation method of the present invention uses a specific zeolite membrane to bring a mixed gas composed of a plurality of components including ammonia and hydrogen and / or nitrogen into contact with the zeolite membrane, and from the mixed gas, ammonia is removed. It selectively permeates and separates. As described above, according to the present invention, ammonia gas is produced from hydrogen gas and nitrogen gas in the reactor, and the ammonia gas produced using the zeolite membrane is allowed to efficiently pass through the reactor. Ammonia can be produced and recovered.
- the ammonia separation by the zeolite membrane is mainly based on the hopping mechanism of ammonia in the zeolite pores, but separation as a molecular sieve is also utilized by controlling the pore diameter of the zeolite membrane by adsorbed ammonia, ammonium ions or the like. Due to the former action, ammonia having high affinity with the zeolite membrane can permeate the zeolite membrane with high selectivity, and the latter action makes the size larger than the effective pore diameter of the zeolite membrane to which ammonia is adsorbed. In order to efficiently separate the gas molecules having and the gas molecules below it, ammonia can be more effectively separated.
- water is adsorbed on the zeolite as described above, and is characterized by the separation of ammonia based on the hopping mechanism of ammonia in the zeolite pores.
- the ammonia gas concentration in the supply gas containing gas, nitrogen gas, and ammonia gas needs to be controlled to a specific amount or more.
- the concentration is important to be 1.0% by volume or more as the concentration of ammonia gas in the supply gas. This is because the ammonia adsorbed on the zeolite has an adsorption equilibrium relationship with the ammonia gas in the gas phase, and the adsorption ability of ammonia on the zeolite greatly depends on the ammonia gas concentration in the supply gas.
- the ammonia gas concentration in the mixed gas is set to 1.0% by volume or more, the ammonia is added under the condition that the ammonia gas concentration in the mixed gas obtained when producing ammonia is 1.0% by volume or more. What is necessary is just to manufacture.
- the ammonia gas concentration in the supply gas is preferably 2.0% by volume or more, more preferably 3.0% by volume or more, and particularly preferably 5.0% by volume or more.
- the upper limit is not particularly limited, but as the ammonia gas concentration in the supply gas is higher, the separation performance is improved. Therefore, the upper limit is usually less than 100% by volume, but generally 80% is necessary because of the necessity of separating ammonia.
- the volume% or less preferably 60 volume% or less, more preferably 40 volume% or less.
- the concentration of ammonia in the supply gas is considered to be the same as volume% in terms of the molar fraction of ammonia by collecting the supply gas and analyzing its components. Similarly, the volume% of other gases is also regarded as volume% with a molar fraction.
- the ammonia concentration is less than or equal to that produced under the production process conditions.
- the ammonia separation technique using the present invention separates ammonia from a supply gas in contrast to a known method of selectively permeating hydrogen gas and / or nitrogen gas from a mixed gas of hydrogen, nitrogen and ammonia.
- Patent Document 7 has a feature that ammonia separation performance is remarkably improved, and that separation stability during high-temperature operation or long-term operation is high.
- the ammonia gas concentration in the mixed gas of hydrogen, nitrogen, and ammonia exceeds a specific amount, the factor that the permeation selectivity of ammonia that permeates the zeolite membrane is not yet clear, but the mixed gas
- the ammonia gas concentration in the medium is increased, adsorption to the zeolite is likely to occur due to the above-described adsorption equilibrium between the ammonia gas and the zeolite, and first, a zeolite membrane in which ammonia is adsorbed in the pores is formed.
- the zeolite membrane adsorbed with ammonia thus produced can reduce the permeation rate of hydrogen having a small molecular size in order to narrow the pore diameter in the zeolite membrane.
- the present invention first actively adsorbs ammonia on the zeolite and controls the pore diameter of the zeolite membrane to enhance the separation selectivity of ammonia, while the adsorption / desorption of ammonia in the pores.
- the temperature during the ammonia separation is the long-term durability of the zeolite membrane used. This is one of the important design factors because it greatly affects the ammonia separation performance of the zeolite membrane and the production energy balance of the entire process when combined with ammonia production equipment. From these viewpoints, in the present invention, when separating the product gas in ammonia synthesis, the temperature during ammonia separation is usually the same as or lower than the synthesis temperature of ammonia.
- the temperature at that time is the temperature in the separator that performs ammonia separation, that is, the temperature of the mixed gas used for the separation, and the temperature of the separated ammonia gas. Further, the temperature of the separation membrane can be regarded as substantially the same as the temperature in the separator. From the design of the ammonia production process, it is preferable to perform separation at the same temperature as the synthesis temperature because it is not necessary to raise the temperature of hydrogen and nitrogen to be recycled to the reactor. For this reason, although the preferable temperature in the ammonia separation depends on the reaction temperature in the ammonia synthesis reaction, it is usually 500 ° C. or lower, preferably 450 ° C. or lower, more preferably 400 ° C. or lower.
- the zeolite membrane When ammonia is separated under these temperature conditions using the zeolite membrane of the present invention, the zeolite membrane is not only stable but also capable of continuous operation over a long period of time. Selectivity develops.
- the lower limit is usually a temperature exceeding 50 ° C., preferably 100 ° C. or higher, more preferably 150 ° C. or higher, particularly preferably 200 ° C. or higher, preferably 250 ° C. or higher, and particularly preferably 300 ° C. or higher.
- the energy required for raising the temperature of hydrogen and nitrogen is reduced, and therefore ammonia separation under higher temperature conditions is preferable.
- the lower limit is preferably 250 ° C. or higher, more preferably 300 ° C. or higher.
- the speed can be controlled by controlling the molar ratio of the alkali metal atom to the Al atom in the zeolite pore to be less than the saturation amount ratio. Control of the molar ratio is important, and may be preferable in combination with a technique for controlling the molar ratio to 0.01 or more and 0.070 or less as in the fourth embodiment of the present invention.
- the other gas composition in the supply gas is not particularly limited, but the volume ratio of hydrogen gas / nitrogen gas contained in the supply gas is usually 3 or less, more preferably 2 or less.
- the volume ratio of hydrogen gas / nitrogen gas contained in the supply gas is usually 3 or less, more preferably 2 or less.
- Ru-based ammonia production with a low volume ratio of hydrogen gas / nitrogen gas in the raw material gas is used.
- the lower limit thereof is not particularly limited because ammonia separation selectivity is improved as it is smaller, but is usually 0.2 or more, preferably 0.3 or more, and more preferably 0.5 or more.
- the upper limit and the lower limit are valid values within the range of significant figures, that is, the upper limit of 3 or less is 2.5 or more and less than 3.5, while 0.2 or more is 0.15 or more. Less than 0.25 and 1.0 or more mean 0.95 or more and less than 1.05.
- the pressure of the supply gas is a preferable embodiment because the higher the pressure, the better the separation performance of the zeolite membrane and the reduced area of the zeolite membrane to be used.
- the pressure may be adjusted to a desired pressure by adjusting the pressure appropriately.
- the pressure can be increased with a compressor or the like.
- the pressure of the supply gas is usually atmospheric pressure or larger than atmospheric pressure, preferably 0.1 MPa or more, more preferably 0.2 MPa or more.
- the upper limit is usually 20 MPa or less, preferably 10 MPa or less, more preferably 5 MPa or less, and may be 3 MPa or less.
- the pressure on the permeate side is not particularly limited as long as it is lower than the pressure of the gas on the supply side, but is usually 10 MPa or less, preferably 5 MPa or less, more preferably 1 MPa or less, more preferably 0.5 MPa or less, and sometimes atmospheric pressure or less.
- the pressure may be reduced to When separating until the concentration of ammonia in the supply gas becomes a low value, it is preferable that the permeate side is at a low pressure, and when the pressure is reduced to a pressure below atmospheric pressure, the concentration of ammonia gas in the supply gas is lower It is possible to separate ammonia until the concentration is reached.
- the differential pressure between the gas on the supply side and the gas on the permeate side is not particularly limited, but is usually 20 MPa or less, preferably 10 MPa or less, more preferably 5 MPa or less, and even more preferably 1 MPa or less. Moreover, it is 0.001 MPa or more normally, Preferably it is 0.01 MPa or more, More preferably, it is 0.02 MPa or more.
- the differential pressure refers to the difference between the partial pressure on the gas supply side and the partial pressure on the permeate side.
- the pressure [Pa] indicates an absolute pressure unless otherwise specified.
- the flow rate of the supply gas is such that it can compensate for the decrease in the permeated gas, and the concentration in the vicinity of the membrane of the gas having a low permeability in the supply gas matches the concentration in the entire gas.
- the flow rate is sufficient to mix the gas.
- the linear velocity is usually 0.001 mm / sec or more, preferably 0.01 mm / sec or more, more preferably.
- the upper limit is not particularly limited, and is usually 1 m / sec or less, preferably 0.5 m / sec or less. It is.
- a sweep gas may be used.
- the sweep gas means a gas supplied to efficiently recover ammonia permeated through the separation membrane, and is a gas supplied to the permeation side of the separation membrane, not a gas introduced to the supply gas side before the separation permeation. is there. That is, the sweep gas is a gas that is supplied separately from the supply gas before separation and permeation, and a gas of a different type from the supply gas is allowed to flow on the permeation side to recover the gas that has permeated through the membrane.
- the sweep gas used in the present invention refers to, for example, the gas 9 supplied from the line 12 shown in FIG.
- the pressure of the sweep gas is usually atmospheric pressure, but is not particularly limited to atmospheric pressure, and is preferably 20 MPa or less, more preferably 10 MPa or less, further preferably 1 MPa or less, and the lower limit is preferably 0.09 MPa. As mentioned above, More preferably, it is 0.1 MPa or more. In some cases, the pressure may be reduced.
- the flow rate of the sweep gas is not particularly limited, but the linear velocity is usually 0.5 mm / sec or more, preferably 1 mm / sec or more, and the upper limit is not particularly limited, usually 1 m / sec or less, preferably 0.5 m / sec. sec or less.
- the apparatus used for gas separation is not particularly limited, but usually a zeolite membrane composite is used as a membrane module (hereinafter referred to as “separation apparatus using zeolite membrane composite and / or zeolite membrane composite” simply “membrane module”). ”).
- the membrane module may be, for example, an apparatus as schematically shown in FIG. 1, and for example, a membrane module exemplified in “Gas Separation / Purification Technology”, page 22 of Toray Research Center 2007, etc. is used. May be. The separation operation of the mixed gas in the apparatus of FIG. 1 will be described in the section of the example.
- membrane modules When performing membrane separation of ammonia from a mixed gas, membrane modules may be used in multiple stages.
- the separation gas may be supplied to the first-stage membrane module, and the non-permeate side gas that has not permeated the membrane may be further supplied to the second-stage membrane module. It may be supplied to the second stage membrane module.
- the concentration of the low-permeability component on the non-permeation side can be further increased
- the concentration of the high-permeability component in the permeated gas can be further increased.
- the method which combined these methods can also be used conveniently.
- the pressure of the supply gas may be adjusted with a booster or the like as necessary when supplying the gas to the subsequent membrane module.
- membranes with different performance may be installed in each stage.
- a membrane performance a membrane having high permeation performance has low separation performance, whereas a membrane having high separation performance tends to have low permeation performance.
- a membrane having a high permeability reduces the required membrane area, while a component having a low permeability is easily transmitted to the permeation side. Therefore, the concentration of highly permeable components in the permeate side gas tends to be low.
- permeation of a component with low permeability to the permeation side is unlikely to occur.
- the concentration of the component with high permeability in the permeation side gas is high, but the required membrane area increases. Tend.
- the relationship between the required membrane area and the permeation / non-permeation amount of the concentration or separation target gas is difficult to control, but the use of membranes with different performances makes the control easier.
- the membrane can be installed so that the relationship between the optimum membrane area and concentration, the permeation amount and the non-permeation amount of the separation target gas can be established, and the overall merit can be maximized.
- the gas on the non-permeation side can be further separated by several stages of membranes.
- the separation of ammonia / hydrogen in the membrane is not sufficient in one stage of membrane separation, and a large amount of hydrogen is contained together with ammonia on the permeate side, the permeate gas must be separated with a membrane having high ammonia and hydrogen separation performance. You can also.
- the zeolite membrane used in the present invention has excellent chemical resistance, oxidation resistance, heat stability, pressure resistance, high ammonia permeation performance, separation performance, and excellent durability.
- the high permeation performance here indicates a sufficient throughput, for example, the permeance (Permeance) of the gas component that permeates the membrane [mol / (m 2 ⁇ s ⁇ Pa)], for example, ammonia at a temperature of 200 ° C.
- Permeance permeance of the gas component that permeates the membrane
- it is usually 1 ⁇ 10 ⁇ 9 or more, preferably 5 ⁇ 10 ⁇ 9 or more, more preferably 1 ⁇ 10 ⁇ 8 or more, further preferably 2 ⁇ 10 ⁇ 8 or more, especially Preferably it is 5 ⁇ 10 ⁇ 8 or more, particularly preferably 1 ⁇ 10 ⁇ 7 or more, and most preferably 2 ⁇ 10 ⁇ 7 or more.
- the upper limit is not particularly limited, and is usually 3 ⁇ 10 ⁇ 4 or less.
- the permeance [mol / (m 2 ⁇ s ⁇ Pa)] of the zeolite membrane composite used in the present invention is usually 5 ⁇ 10 ⁇ 8 or less, preferably 3 ⁇ when nitrogen is permeated under the same conditions. 10 ⁇ 8 or less, more preferably 1 ⁇ 10 ⁇ 8 or less, particularly preferably 5 ⁇ 10 ⁇ 9 or less, most preferably 1 ⁇ 10 ⁇ 9 or less, and ideally the permeance is 0.
- the order may be about 1 ⁇ 10 ⁇ 10 to 1 ⁇ 10 ⁇ 14 .
- permeance also referred to as “permeability” is obtained by dividing the amount of substance to be permeated by the product of the membrane area, time, and the partial pressure difference between the permeate supply side and the permeate side.
- Mol / (m 2 ⁇ s ⁇ Pa)] is a value calculated by the method described in the section of the examples.
- the selectivity of zeolite membrane is expressed by ideal separation factor and separation factor.
- the ideal separation factor and the separation factor are indicators that represent the selectivity generally used in membrane separation.
- the ideal separation factor is a value calculated as follows by the method described in the section of the embodiment.
- ⁇ (Q′1 / Q′2) / (P′1 / P′2) [In the above formula, Q′1 and Q′2 represent the permeation amounts [mol / (m 2 ⁇ s ⁇ Pa)] of the gas having high permeability and the gas having low permeability, respectively, and P′1 and P ′ '2 indicates the partial pressure [Pa] of the gas having high permeability and the gas having low permeability in the supply gas, respectively. ]
- the separation factor ⁇ can also be obtained as follows.
- C′1 and C′2 indicate the concentration [volume%] of the highly permeable gas and the low permeable gas, respectively, and C1 and C2 are respectively in the supply gas. The concentration [volume%] of the highly permeable gas and the low permeable gas is shown. ]
- the ideal separation factor is usually 15 or more, preferably 20 or more, more preferably 25 or more, and most preferably 30 or more when ammonia and nitrogen are permeated at a temperature of 200 ° C. and a differential pressure of 0.3 MPa. Further, when ammonia and hydrogen are permeated at a temperature of 200 ° C. and a differential pressure of 0.3 MPa, it is usually 2 or more, preferably 3 or more, more preferably 5 or more, further preferably 7 or more, particularly preferably 8 or more, particularly preferably. 10 or more, most preferably 15 or more.
- the upper limit of the ideal separation factor is a case where only ammonia is completely permeated. In this case, the upper limit is infinite, but in practice, the separation factor may be about 100,000 or less.
- the separation factor of the zeolite membrane used in the present invention is usually 2 or more, preferably 3 when a mixed gas of ammonia and nitrogen in a volume ratio of 1: 1 is permeated at a temperature of 50 ° C. and a differential pressure of 0.1 MPa. As mentioned above, More preferably, it is 4 or more, More preferably, it is 5 or more.
- the upper limit of the separation factor is a case where only ammonia is completely permeated. In that case, the separation factor is infinite, but in practice, the separation factor may be about 100,000 or less.
- the zeolite membrane used in the present invention is excellent in chemical resistance, oxidation resistance, heat stability, pressure resistance, high permeation performance, separation performance, and excellent durability.
- the ammonia separation method of the present invention using such a zeolite membrane can be applied to the separation of ammonia from the product of ammonia synthesis.
- the ammonia separation method of the present invention provides a zeolite membrane in an ammonia synthesis reactor and selectively permeates and separates ammonia in the reactor to separate hydrogen gas, nitrogen gas and ammonia in the reaction system. It can also be used as a membrane reactor that shifts the equilibrium with gas and efficiently synthesizes ammonia at a high conversion rate.
- the zeolite constituting the zeolite membrane is an aluminosilicate.
- the aluminosilicate is mainly composed of Si and Al oxides, and may contain other elements as long as the effects of the present invention are not impaired.
- the cationic species contained in the zeolite of the present invention is preferably a cationic species that easily coordinates to the ion exchange site of the zeolite, for example, Group 1, Group 2, Group 8, Group 9, A cationic species selected from Group 10, Group 11, and Group 12 elements, NH 4 + , and two or more cationic species thereof, more preferably, Group 1 of the Periodic Table; A cationic species selected from the group 2 element group, NH 4 + , and two or more cationic species thereof.
- the zeolite used in the present invention is an aluminosilicate.
- the SiO 2 / Al 2 O 3 molar ratio of the aluminosilicate is not particularly limited, but is usually 6 or more, preferably 7 or more, more preferably 8 or more, and usually 500 or less, preferably 100 or less, More preferably, it is 80 or less, More preferably, it is 50 or less, Especially preferably, it is 45 or less, More preferably, it is 30 or less, Most preferably, it is 25 or less.
- Use of such a specific region of the SiO 2 / Al 2 O 3 molar ratio zeolite is preferable because the denseness of the zeolite membrane and durability such as chemical reaction resistance and heat resistance can be improved. .
- the acid point of the Al element becomes an adsorption site for ammonia.
- the SiO 2 / Al 2 O 3 molar ratio of the zeolite can be adjusted by the reaction conditions of hydrothermal synthesis described later.
- the SiO 2 / Al 2 O 3 molar ratio is a numerical value determined by scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX). In this case, in order to obtain information only on a film having a thickness of several microns, measurement is usually performed with an X-ray acceleration voltage of 10 kV.
- the structure of the zeolite used in the present invention can be expressed by a code defined by International Zeolite Association (IZA), for example, ABW, ACO, AEI, AEN, AFI, AFT, AFX, ANA, ATN, ATT, ATV, AWO , AWW, BIK, CHA, DDR, DFT, EAB, EPI, ERI, ESV, GIS, GOO, ITE, JBW, KFI, LEV, LTA, MER, MON, MTF, OWE, PAU, PHI, RHO, RTE, RWR , SAS, SAT, SAV, SIV, TSC, UFI, VNI, YUG, AEL, AFO, AHT, DAC, FER, HEU, IMF, ITH, MEL, MFS, MWW, OBW, RRO, SFG, STI, SZR, TER , TON, TUN, WEI, MFI, MON, PAU, PHI, M
- zeolite having a framework density of 18.0 T / nm 3 or less is preferable, more preferably AEI, AFX, CHA, DDR, ERI, LEV, RHO, MOR, MFI, FAU, and more preferably AEI, CHA.
- zeolite membrane composite E zeolite membrane composite E of the present invention
- a zeolite having a framework density of 18.0 T / nm 3 or less is preferable, more preferably AFX, DDR, ERI, LEV, RHO, MOR. , MFI and FAU, more preferably DDR, RHO, MOR, MFI and FAU, most preferably RHO and MFI.
- the framework density (unit: T / nm 3 ) means the number of T atoms (atoms other than oxygen among atoms constituting the skeleton of the zeolite) present per unit volume (1 nm 3 ) of the zeolite. However, this value is determined by the structure of the zeolite. The relationship between the framework density and the structure of zeolite is shown in ATLAS OF ZEOLITE FRAMEWORK TYPES Sixth Revised Edition 2007 ELSEVIER.
- the membrane separation of ammonia and hydrogen and nitrogen according to the present invention utilizes the adsorption of ammonia to zeolite and is characterized by the separation of ammonia based on the hopping mechanism of ammonia within the zeolite pores, but is not particularly limited.
- zeolite having a pore diameter close to the molecular diameter of ammonia may be preferable because ammonia separation selectivity is improved.
- the zeolite has a structure having oxygen 8-membered ring pores. preferable.
- pores having a size larger than that of the oxygen 8-membered ring are preferable in that the ammonia permeability is high, but the separation performance from hydrogen and / or nitrogen may be lowered.
- the effective pore size of the zeolite used for membrane separation greatly affects the pore size of the zeolite membrane to which ammonia is adsorbed, and thus is one of important design factors.
- the effective pore diameter of zeolite can also be controlled by the metal species introduced into the zeolite, ion exchange, acid treatment, silylation treatment, and the like.
- the separation performance can be improved by controlling the effective pore diameter by other methods.
- the pore diameter of the zeolite is slightly affected by the atomic diameter of the metal species introduced into the zeolite skeleton.
- a metal having a smaller atomic diameter than silicon specifically, for example, boron (B) or the like
- the pore diameter becomes smaller
- a metal having a larger atomic diameter than silicon specifically, for example, tin (Sn ) Etc.
- the pore diameter increases.
- the pore diameter may be affected by desorbing the metal introduced into the zeolite skeleton by acid treatment.
- the effective pore size becomes small.
- the effective pore size is reduced. Is a value close to the pore diameter of the zeolite structure.
- the separation function of the zeolite membrane composite used in the present invention is not particularly limited, but is manifested by controlling the affinity and adsorbability of gas molecules to the zeolite membrane by controlling the surface physical properties of the zeolite. That is, by controlling the polarity of the zeolite, the adsorptivity of ammonia to the zeolite can be controlled to facilitate permeation.
- the affinity of ammonia for the zeolite can be controlled to facilitate permeation.
- the permeation speed can be controlled by controlling not only the pore diameter of zeolite but also the adsorption performance of molecules by ion exchange.
- the zeolite membrane in the present invention is a membrane-like material composed of zeolite, and is preferably formed by crystallizing zeolite on the surface of a porous support.
- an inorganic binder such as silica or alumina, an organic substance such as a polymer, a silylating agent for modifying the zeolite surface, or the like may be included as necessary in addition to zeolite.
- the preferred zeolite contained in the zeolite membrane used in the present invention is as described above, but the zeolite contained in the zeolite membrane may be one kind or plural kinds.
- an amorphous component etc. may be contained besides the zeolite which is easy to produce
- zeolite membrane B is a zeolite membrane containing zeolite, wherein the molar ratio of nitrogen element to Al element determined by X-ray photoelectron spectroscopy is 0.01 or more and 4 or less. It is a zeolite membrane characterized by being.
- the zeolite membrane B is particularly preferably used in the ammonia separation method of the first embodiment.
- the zeolite membrane B is preferably a zeolite membrane having a surface in which the molar ratio of nitrogen atoms to Al atoms determined by X-ray photoelectron spectroscopy (XPS) is in a specific range.
- XPS X-ray photoelectron spectroscopy
- the surface of the zeolite membrane in this specification means the surface of the zeolite membrane on the side of supplying a mixed gas composed of a plurality of components including ammonia and hydrogen and / or nitrogen in order to separate ammonia.
- the zeolite membrane composite is used in the form of a film formed on the porous support, it means a surface that is not in contact with the porous support.
- the molar ratio of nitrogen atoms to Al atoms contained in the zeolite membrane is a numerical value determined by X-ray photoelectron spectroscopy (XPS) under the following measurement conditions.
- the content of nitrogen atoms contained in the zeolite membrane surface determined by the XPS measurement is usually 0.01 or more in terms of molar ratio with respect to Al atoms on the zeolite membrane surface.
- it is 0.05 or more, more preferably 0.10 or more, still more preferably 0.20 or more, particularly preferably 0.30 or more, and particularly preferably 0.50 or more.
- it is not particularly limited because it depends on the structure of the cation species containing nitrogen atoms in the zeolite contained and the amount of nitrate ions remaining when performing the nitrate treatment of the zeolite membrane as necessary, it is usually 4 or less, preferably 3 Hereinafter, more preferably, it is 1 or less.
- the zeolite having such a specific nitrogen / Al atomic ratio surface composition By using a zeolite having such a specific nitrogen / Al atomic ratio surface composition, it is possible to improve the denseness of the zeolite membrane and durability such as chemical reaction resistance and heat resistance, as well as ammonia and Ammonia can be separated with high permeability and high selectivity from a mixed gas composed of a plurality of components including hydrogen and / or nitrogen.
- the stated values for the upper limit and the lower limit are valid within the range of significant figures. That is, the upper limit of 4 or less means less than 4.5, while 0.01 or more means 0.005 or more.
- nitrogen atoms contained in the zeolite membrane are ammonium ions (NH 4 + ), methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, dimethylethylenediamine contained in the zeolite described later.
- a nitrogen atom derived from a cationic species protonated with an organic amine having 1 to 20 carbon atoms such as piperidine, or an organic containing a nitrogen atom when producing a zeolite membrane Plates (structure directing agent) nitrogen atoms derived from the organic template when using a nitrogen atom derived from nitrate ions remaining when nitrate treatment of the zeolite membrane to be carried out as necessary to be described later.
- the effective pore diameter of zeolite used for membrane separation is controlled by using adsorption of ammonia to zeolite, and the inside of the zeolite pores is controlled. It is characterized in that ammonia is separated based on an ammonia hopping mechanism.
- ammonia is mainly separated by utilizing the hopping mechanism in the pores accompanying the adsorption / desorption of ammonia to the zeolite, first, the ammonia in the supply mixed gas containing ammonia and the surface of the zeolite membrane It is an important design factor how to increase the adsorption affinity with respect to that of other gases such as hydrogen and nitrogen contained in the mixed gas.
- zeolite membrane C is a zeolite membrane containing zeolite, wherein the molar ratio of Si element to Al element determined by X-ray photoelectron spectroscopy is 2.0 or more, It is a zeolite membrane characterized by being 10 or less.
- the zeolite membrane C is preferably used in the ammonia separation method of the first embodiment.
- the zeolite membrane C used in the present invention is a zeolite membrane having a surface in which the molar ratio of Si atoms to Al atoms determined by X-ray photoelectron spectroscopy (XPS) is in a specific range.
- XPS X-ray photoelectron spectroscopy
- the molar ratio of Si atoms to Al atoms contained in the zeolite membrane is a numerical value determined by X-ray photoelectron spectroscopy (XPS) under the following measurement conditions.
- the content of Si atoms contained in the zeolite membrane surface determined by the XPS measurement described above is the molar amount relative to the Al atoms on the zeolite membrane surface.
- the ratio is 2.0 or more, preferably 2.5 or more, more preferably 3.0 or more, and the upper limit is usually 10 or less, preferably 8.0 or less, more preferably 7.0 or less, Especially preferably, it is 6.7 or less.
- the molar ratio of Si atoms to Al atoms in the zeolite membrane is a method for controlling the SiO 2 / Al 2 O 3 ratio of zeolite in the zeolite membrane, and the zeolite membrane is treated with an aluminum salt. It can control by the method to do.
- a zeolite film having a specific Si atom / Al atomic molar ratio it is clear from this example that ammonia is separated from a mixed gas composed of a plurality of components including ammonia and hydrogen and / or nitrogen.
- the content of Si atoms on the surface of the zeolite membrane is controlled, and if necessary, the content of nitrogen atoms contained in the surface of the zeolite membrane determined by XPS measurement is determined in a specific region.
- the content of nitrogen atoms contained in the surface of the zeolite membrane determined by XPS measurement is determined in a specific region.
- the nitrogen atom content is usually 0.01 or more, preferably in terms of molar ratio with respect to Al atoms on the zeolite membrane surface.
- zeolite having such a specific nitrogen atom / Al atomic ratio surface composition When a zeolite having such a specific nitrogen atom / Al atomic ratio surface composition is used, it is possible to improve the denseness of the zeolite membrane and durability such as chemical reaction resistance and heat resistance, as well as ammonia and hydrogen and It is preferable because ammonia can be separated with high selectivity from a mixed gas composed of a plurality of components containing nitrogen.
- the above described upper limit and lower limit values are valid within the range of significant figures. That is, the upper limit of 4 or less means less than 4.5, while 0.01 or more means 0.005 or more.
- nitrogen atoms when the zeolite membrane contains nitrogen atoms are ammonium ions (NH 4 + ), methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, dimethyl contained in the zeolite described later.
- organic template structure directing agent
- Li, Na, and Cs are preferable, and Na is more preferable because it is excellent in ammonia separation performance and is a general-purpose alkali metal.
- These alkali metal atoms are present in the form of cations as ion pairs of Al sites in the zeolite constituting the zeolite membrane, and usually, as will be described later, in the zeolite by ion exchange treatment of the synthesized zeolite membrane. be introduced. If necessary, the content of alkali metal atoms in the case where alkali metal atoms are present on the zeolite membrane surface is 0.01 or more, preferably 0.02 in terms of molar ratio with respect to Al atoms on the zeolite membrane surface.
- the upper limit is usually 0.10 molar equivalent or less, preferably 0.070.
- the molar equivalent or less more preferably 0.065 molar equivalent or less, still more preferably 0.060 molar equivalent or less, and particularly preferably 055 molar equivalent or less. Controlling the content of alkali metal atoms within the above range is preferable because the ammonia permeability tends to be improved while the ammonia separation selectivity is increased.
- the molar ratio of alkali metal atoms to Al atoms in the zeolite membrane can be controlled by adjusting the ion exchange amount during the ion exchange treatment of the zeolite, as will be described later. In this embodiment, it is not yet detailed and is not particularly limited. As described later, the effective pore diameter of zeolite used for membrane separation is controlled by using adsorption of ammonia to zeolite, and the inside of the zeolite pores is controlled. It is characterized in that ammonia is separated based on an ammonia hopping mechanism.
- ammonia in the supply mixed gas containing ammonia and the surface of the zeolite membrane It is an important design factor how to increase the adsorption affinity with respect to that of other gases such as hydrogen and nitrogen contained in the mixed gas. From this point of view, if more Al atoms are present on the zeolite membrane surface, the polarity of the zeolite membrane surface changes, and the adsorption affinity with ammonia in the supply gas increases, so that the ammonia separation performance is improved.
- the content of Al atoms on the zeolite membrane surface is controlled by the SiO 2 / Al 2 O 3 ratio of the zeolite constituting the zeolite membrane, the aluminum salt treatment after the zeolite membrane is formed, etc.
- the latter aluminum salt treatment also has an effect of sealing fine defects present on the surface of the zeolite membrane, and can improve the durability of the zeolite membrane, such as denseness and chemical reaction resistance and heat resistance, This greatly contributes to the improvement of the heat stability of the zeolite membrane at high temperatures, which is one of the problems of the present invention.
- zeolite membrane D is a zeolite membrane containing zeolite, wherein the molar ratio of alkali metal element to Al element determined by X-ray photoelectron spectroscopy is 0.01 or more. 0.070 or less.
- the zeolite membrane D is particularly preferably used in the ammonia separation method of the first embodiment.
- the zeolite membrane D used in the fourth embodiment of the present invention is a zeolite membrane having a surface in which the molar ratio of alkali metal atoms to Al atoms determined by X-ray photoelectron spectroscopy (XPS) is in a specific range. It is preferable.
- the molar ratio of alkali metal atoms to Al atoms contained in the zeolite membrane is a numerical value determined by X-ray photoelectron spectroscopy (XPS) under the following measurement conditions.
- examples of the alkali metal atoms contained in the zeolite membrane surface determined by the XPS measurement include Li, Na, K, Rb, Cs, and two or more kinds of these metal atoms. Among them, Li, Na, and Cs are preferable, and Na is more preferable because it is excellent in ammonia separation performance and is a general-purpose alkali metal.
- These alkali metal atoms are present in the form of cations as ion pairs of Al sites in the zeolite constituting the zeolite membrane, and usually, as will be described later, in the zeolite by ion exchange treatment of the synthesized zeolite membrane. be introduced.
- the molar ratio is 0.01 or more, preferably 0.02 or more, more preferably 0.03 or more, further preferably 0.04 or more, particularly preferably 0.05 or more, and the upper limit thereof. Is usually at most 0.10 molar equivalents, preferably at most 0.070 molar equivalents, more preferably at most 0.065 molar equivalents, even more preferably at most 0.060 molar equivalents, particularly preferably at most 055 molar equivalents. .
- the ammonia permeability can be improved while improving the ammonia separation selectivity, as is apparent from this example and the reference example.
- the molar ratio of alkali metal atoms to Al atoms in the zeolite membrane can be controlled by adjusting the ion exchange amount during the ion exchange treatment of the zeolite, as will be described later.
- a zeolite membrane having a specific alkali metal atom / Al atomic ratio high permselectivity can be obtained when ammonia is separated from a mixed gas composed of a plurality of components including ammonia and hydrogen and / or nitrogen.
- the ammonia permeability can be improved as compared with the zeolite membrane not containing the alkali metal atom.
- the content of alkali metal atoms on the zeolite membrane surface is controlled, and if necessary, the content of nitrogen atoms contained in the zeolite membrane surface determined by XPS measurement is specified.
- the separation selectivity when ammonia is separated from a mixed gas comprising a plurality of components including ammonia and hydrogen and / or nitrogen tends to be remarkably improved, alkali metal atoms and nitrogen atoms on the zeolite membrane surface It is preferable to coexist and to control their content appropriately.
- the nitrogen atom content is usually 0.01 or more, preferably 0.05 or more, in terms of molar ratio with respect to Al atoms on the zeolite membrane surface. More preferably, it is 0.10 or more, more preferably 0.20 or more, particularly preferably 0.30 or more, particularly preferably 0.50 or more, and the upper limit is in the zeolite contained in the zeolite membrane. Although it is not particularly limited because it depends on the structure of the cation species containing nitrogen atoms and the amount of nitrate ions remaining when performing the nitrate treatment of the zeolite membrane as necessary, it is usually 4 or less, preferably 3 or less, more preferably 1 or less.
- zeolite having such a specific nitrogen atom / Al atomic ratio surface composition When a zeolite having such a specific nitrogen atom / Al atomic ratio surface composition is used, it is possible to improve the denseness of the zeolite membrane and durability such as chemical reaction resistance and heat resistance, as well as ammonia and hydrogen and It is preferable because ammonia can be separated with high selectivity from a mixed gas composed of a plurality of components containing nitrogen.
- the above described upper limit and lower limit values are valid within the range of significant figures. That is, the upper limit of 4 or less means less than 4.5, while 0.01 or more means 0.005 or more.
- the nitrogen atom when the zeolite membrane contains nitrogen atom is ammonium ion (NH 4 + ), methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, dimethylethylenediamine contained in the zeolite described later.
- the effective pore diameter of zeolite used for membrane separation is controlled by using adsorption of ammonia to zeolite, and the inside of the zeolite pores is controlled. It is characterized in that ammonia is separated based on an ammonia hopping mechanism.
- ammonia is separated by mainly utilizing the hopping mechanism in the pores accompanying the adsorption / desorption of ammonia to / from the zeolite in the present invention, a mixture comprising a plurality of components including ammonia and hydrogen and / or nitrogen is used.
- Ammonia separation selectivity from gas is improved by the blocking effect due to the adsorption of ammonia to the Al sites in the zeolite pores.
- the permeation performance (permeability) is high due to the high adsorption power of ammonia to the Al sites. It tends to be damaged.
- the alkali metal atom of the present invention is present in a specific amount in the form of a cation as an ion pair of the Al site in the zeolite constituting the zeolite membrane, the adsorption amount of ammonia on the Al site can be controlled.
- the separation selectivity of ammonia can be maintained depending on the size of the alkali metal cation.
- permeation performance can be enhanced while maintaining ammonia separation selectivity. That is, it is important to control the content of alkali metal atoms with respect to Al atoms in the zeolite in a molar ratio of 0.01 or more and 0.070 or less.
- the ammonia permeability decreases due to the adsorption of, and if the amount exceeds 0.20, the blocking effect due to the adsorption of ammonia to the Al site is diminished and the ammonia separation selectivity is considered to decrease.
- zeolite membrane composite E is a zeolite membrane composite for ammonia separation comprising a porous support and a zeolite membrane containing zeolite on the surface thereof.
- the rate of change of the thermal expansion coefficient at 300 ° C. relative to the thermal expansion coefficient at 400 ° C. and 400 ° C. is within a specific range.
- the zeolite membrane composite E is preferably used in the ammonia separation method of the first embodiment. Specifically, the change rate of the thermal expansion coefficient at 300 ° C. with respect to the thermal expansion coefficient at 30 ° C. of the zeolite is within ⁇ 0.25%, and the change rate of the thermal expansion coefficient at 400 ° C. with respect to the thermal expansion coefficient at 30 ° C.
- the coefficient of thermal expansion that defines the zeolite of the present embodiment is a numerical value calculated under the following conditions. In this specification, when the numerical value of the thermal expansion coefficient is a positive number, it indicates that the zeolite has expanded, and when it is a negative number, it indicates that the zeolite has contracted.
- the rate of change of the coefficient of thermal expansion at a predetermined temperature relative to the coefficient of thermal expansion of 30 ° C. of the zeolite is the crystallite constant measured at 30 ° C. and the predetermined temperature by a temperature rising XRD measurement method under the following conditions: It can obtain
- Measurement atmosphere Air temperature rising condition: 20 °C / min
- Measurement method Perform XRD measurement after holding at measurement temperature for 5 minutes. The measurement data is subjected to fixed slit correction using a variable slit.
- Change rate of thermal expansion coefficient (crystal lattice constant measured at a predetermined temperature) ⁇ (crystal lattice constant measured at 30 ° C.) ⁇ 1 (1)
- the change rate of the thermal expansion coefficient at 300 ° C. with respect to the thermal expansion coefficient at 30 ° C. of the zeolite of the present invention is 0.25% or less, preferably 0.20% or less, more preferably 0.15% or less as its absolute value. Particularly preferably, it is 0.10% or less, and most preferably 0.05% or less. That is, the change rate of the thermal expansion coefficient at 300 ° C. with respect to the thermal expansion coefficient at 30 ° C. of zeolite is within ⁇ 0.25%, preferably within ⁇ 0.20%, more preferably within ⁇ 0.15%, Particularly preferably, it is within ⁇ 0.10%, and most preferably within ⁇ 0.05%.
- the change rate of the thermal expansion coefficient at 400 ° C. with respect to the thermal expansion coefficient at 30 ° C. of the zeolite is 0.35% or less, preferably 0.30% or less, more preferably 0.25% or less as an absolute value. Particularly preferably, it is 0.20% or less, particularly preferably 0.15% or less, and most preferably 0.10% or less. That is, the change rate of the thermal expansion coefficient at 400 ° C. with respect to the thermal expansion coefficient at 30 ° C.
- zeolite is within ⁇ 0.35%, preferably within ⁇ 0.30%, more preferably within ⁇ 0.25%, Particularly preferably, it is within ⁇ 0.20%, particularly preferably within ⁇ 0.15%, and most preferably within ⁇ 0.10%.
- a zeolite membrane composite in which a zeolite exhibiting a low rate of change in the thermal expansion coefficient is formed on a porous support, allows ammonia to permeate from a gas mixture composed of a plurality of components including ammonia and hydrogen and / or nitrogen.
- the non-linear thermal expansion / contraction behavior with respect to temperature is a behavior that does not monotonously thermal expansion or contraction with respect to temperature, that is, for example, shows thermal expansion or thermal contraction behavior in a certain temperature range.
- the reverse behavior that is, the thermal contraction in the former case and the thermal expansion behavior in the latter case.
- the change rate of the thermal expansion coefficient at 400 ° C. with respect to the thermal expansion coefficient at 30 ° C. relative to the change rate of the thermal expansion coefficient at 300 ° C. with respect to the thermal expansion coefficient at 30 ° C. of the zeolite of this embodiment is The value is usually 120% or less, preferably 115% or less, more preferably 110% or less, particularly preferably 105% or less, and most preferably 103% or less.
- the zeolite membrane composite of the present embodiment is prepared through a step of attaching a zeolite having a change rate of the coefficient of thermal expansion within a specific range as a seed crystal on the porous support when the membrane is synthesized.
- ammonia can be separated stably and with high selectivity under high temperature conditions, which is preferable.
- the rate of change of the coefficient of thermal expansion of zeolite used as a seed crystal for the preparation of such a zeolite membrane composite is 0.25% as an absolute value of the rate of change of the coefficient of thermal expansion at 300 ° C. with respect to the coefficient of thermal expansion at 30 ° C.
- the change rate of the thermal expansion coefficient at 400 ° C. with respect to the thermal expansion coefficient at 30 ° C. is usually 0.30% or less, preferably 0.25% or less, more preferably 0.20% or less, as its absolute value. Particularly preferred is 0.15% or less, and most preferred is 0.10% or less.
- the rate of change of the coefficient of thermal expansion at a specific temperature of the zeolite can be controlled by appropriately selecting the cation species of the zeolite to be used as will be described later.
- the cation species of RHO type zeolite and the coefficient of thermal expansion, see Chemical, Communications, 2000, 2221-2222. It is known that the coefficient of thermal expansion varies depending on the cationic species contained in the zeolite. Therefore, in order to obtain a zeolite membrane complex that stably separates ammonia with high selectivity even under the high temperature conditions of this embodiment, it is particularly important to select a specific cation species among the RHO type zeolites.
- the zeolite membrane exhibiting the characteristics of the present embodiment by selecting an appropriate cation species in the zeolite as in the case of the RHO zeolite.
- a composite can be produced.
- the cationic species contained in the zeolite of the present embodiment is preferably a cationic species that easily coordinates to the ion exchange site of the zeolite.
- the first group, the second group, the eighth group, the ninth group of the periodic table Cation species selected from Group 10, Group 11 and Group 12 element group, NH 4 + , and two or more cation species thereof, more preferably Group 1 of the periodic table Cation species selected from the group 2 element group, NH 4 + , and two or more cation species thereof.
- the zeolite used in this embodiment is an aluminosilicate.
- the SiO 2 / Al 2 O 3 molar ratio of the aluminosilicate is not particularly limited, but is usually 6 or more, preferably 7 or more, more preferably 8 or more, further preferably 10 or more, particularly preferably 11 or more, particularly preferably 12 Above, most preferably 13 or more.
- the upper limit is usually an amount such that Al is an impurity
- the SiO 2 / Al 2 O 3 molar ratio is usually 500 or less, preferably 100 or less, more preferably 90 or less, still more preferably 80 or less, and particularly preferably 70. Hereinafter, it is more preferably 50 or less, most preferably 30 or less.
- zeolite having such a specific region SiO 2 / Al 2 O 3 molar ratio it is possible to improve the density of the zeolite membrane and durability such as chemical reaction resistance and heat resistance.
- the thickness of the zeolite membrane used in the present invention is not particularly limited, but is usually 0.1 ⁇ m or more, preferably 0.3 ⁇ m or more, more preferably 0.5 ⁇ m or more, and still more preferably 0.8 ⁇ m. It is 7 ⁇ m or more, more preferably 1.0 ⁇ m or more, and particularly preferably 1.5 ⁇ m or more. Moreover, it is usually 100 ⁇ m or less, preferably 60 ⁇ m or less, more preferably 20 ⁇ m or less, further preferably 15 ⁇ m or less, further preferably 10 ⁇ m or less, and particularly preferably 5 ⁇ m or less. If the thickness of the zeolite membrane is at least the above lower limit, defects are unlikely to occur and the separation performance tends to be good. Further, if the thickness of the zeolite membrane is equal to or less than the above upper limit value, the permeation performance tends to be improved. There is a tendency that a decrease in selectivity can be suppressed.
- the average primary particle diameter of the zeolite forming the zeolite membrane is not particularly limited, but is usually 30 nm or more, preferably 50 nm or more, more preferably 100 nm or more, and the upper limit is the thickness of the membrane or less. If the average primary particle size of the zeolite is equal to or greater than the above lower limit, the grain boundary of the zeolite can be reduced, so that good permeation selectivity can be obtained. Therefore, it is most preferable that the average primary particle diameter of the zeolite is the same as the thickness of the zeolite membrane. In this case, the grain boundary of zeolite can be minimized.
- a zeolite membrane obtained by hydrothermal synthesis described later is preferable because the particle size of the zeolite and the thickness of the membrane may be the same.
- the average primary particle diameter is determined by measuring the primary particle diameter of 30 or more particles arbitrarily selected by observing the surface or fracture surface of the zeolite membrane composite of the present invention with a scanning electron microscope. And obtained as an average value.
- the shape of the zeolite membrane is not particularly limited, and any shape such as a tubular shape, a hollow fiber shape, a monolith type, and a honeycomb type can be adopted.
- the size of the zeolite membrane is not particularly limited.
- the zeolite membrane is formed as a zeolite membrane composite formed on a porous support having a size described later.
- the zeolite membrane is preferably formed on the surface of a porous support.
- the zeolite is crystallized in the form of a film on the porous support.
- porous support used in the present invention preferably has chemical stability such that zeolite can be crystallized into a film on the surface.
- Suitable porous supports include gas permeable porous polymers such as polysulfone, cellulose acetate, aromatic polyamide, vinylidene fluoride, polyether sulfone, polyacrylonitrile, polyethylene, polypropylene, polytetrafluoroethylene, and polyimide.
- Ceramic sintered body such as silica, ⁇ -alumina, ⁇ -alumina, mullite, zirconia, titania, yttria, silicon nitride, silicon carbide; sintered metal such as iron, bronze, stainless steel, etc .;
- An inorganic porous material such as a carbon molded body can be used.
- ceramic sintering is preferable because of its excellent mechanical strength, deformation resistance, thermal stability, and reaction resistance at high temperatures.
- An inorganic porous support such as a body, a sintered metal body, glass, or a carbon molded body is preferable.
- the inorganic porous support is preferably obtained by sintering ceramics, which is a solid material whose basic component or most of the inorganic support is composed of an inorganic nonmetallic substance.
- Preferred ceramic sintered bodies include, as described above, ceramic sintered bodies containing ⁇ -alumina, ⁇ -alumina, silica, mullite, zirconia, titania, yttria, silicon nitride, silicon carbide, and the like.
- the sintered body may be used, or a plurality of sintered bodies may be mixed and sintered. Since these ceramic sintered bodies may be partially zeoliticized during the synthesis of the zeolite membrane, this increases the adhesion between the porous support and the zeolite membrane. Durability can be improved.
- the inorganic porous support containing at least one of alumina, silica, and mullite is easy to partially zeolitize the inorganic porous support, so that the bond between the inorganic porous support and the zeolite is strong. This is more preferable because a dense zeolite membrane with high separation performance is easily formed.
- the porous support used in the present invention preferably has an action of crystallizing zeolite formed on the porous support on the surface thereof (hereinafter also referred to as “porous support surface”).
- the surface of the porous support preferably has a controlled pore size.
- the average pore diameter of the porous support in the vicinity of the surface of the porous support is usually 0.02 ⁇ m or more, preferably 0.05 ⁇ m or more, more preferably 0.1 ⁇ m or more, more preferably 0.15 ⁇ m or more, and further preferably 0. 0.5 ⁇ m or more, particularly preferably 0.7 ⁇ m or more, most preferably 1.0 ⁇ m or more, usually 20 ⁇ m or less, preferably 10 ⁇ m or less, more preferably 5 ⁇ m or less, and particularly preferably 2 ⁇ m or less.
- the surface of the porous support is preferably smooth, and the surface may be polished with a file or the like as necessary.
- the pore diameter of the portion other than the vicinity of the surface of the porous support is not limited and need not be particularly controlled, but the porosity of other portions is usually 20%. % Or more, more preferably 30% or more, usually 60% or less, preferably 50% or less.
- the porosity of the portion other than the vicinity of the surface of the porous support affects the permeation flow rate when separating the gas or liquid, and the permeate tends to diffuse by being above the above lower limit, and below the above upper limit value. Then, there exists a tendency which becomes easy to prevent the intensity
- a porous support in which porous bodies having different porosities are combined in layers may be used.
- the shape of the porous support used in the present invention is not limited as long as it can effectively separate a mixed gas or liquid mixture.
- the shape of the porous support is flat, tubular, cylindrical, or many through holes.
- Honeycomb-shaped materials or monoliths having Further, the size and the like of the porous support are arbitrary, and may be appropriately selected and adjusted so as to obtain a desired zeolite membrane composite.
- the porous support may have a tubular shape in some cases.
- the length of the tubular porous support is not particularly limited, but is usually 2 cm or more, preferably 4 cm or more, more preferably 5 cm or more, particularly preferably 10 cm or more, and particularly preferably 40 cm or more. Preferably, it is 50 cm or more, while it is usually 200 cm or less, preferably 150 cm or less, more preferably 100 cm or less.
- the length of the porous support is equal to or more than the above lower limit value, it is possible to increase the separation processing amount of the mixed gas per one, so that the equipment cost can be reduced.
- the production of the zeolite membrane composite can be simplified, and further, it is possible to prevent problems such as easy breakage due to vibration during use.
- the inner diameter of the tubular porous support is usually 0.1 cm or more, preferably 0.2 cm or more, more preferably 0.3 cm or more, particularly preferably 0.4 cm or more, usually 2 cm or less, preferably 1.5 cm or less, More preferably, it is 1.2 cm or less, and particularly preferably 1.0 cm or less.
- the outer diameter is usually 0.2 cm or more, preferably 0.3 cm or more, more preferably 0.6 cm or more, particularly preferably 1.0 cm or more, usually 2.5 cm or less, preferably 1.7 cm or less, more preferably Is 1.3 cm or less.
- the wall thickness of the tubular porous support is usually 0.1 mm or more, preferably 0.3 mm or more, more preferably 0.5 mm or more, further preferably 0.7 mm or more, more preferably 1.0 mm or more, particularly preferably. Is 1.2 mm or more, usually 4 mm or less, preferably 3 mm or less, more preferably 2 mm or less. If the inner diameter, the outer diameter, and the wall thickness of the tubular porous support are each equal to or higher than the lower limit value, the strength of the support can be improved to make it difficult to break.
- the inner and outer diameters of the tubular support are each equal to or less than the above upper limit values, the size of the equipment accompanying the separation of ammonia can be reduced, which can be economically advantageous. Further, if the thickness of the tubular support is not more than the above upper limit value, the transmission performance tends to be improved.
- the change rate of the thermal expansion coefficient at 300 ° C. with respect to the thermal expansion coefficient at 30 ° C. of the porous support used in the fifth embodiment is 0.25% or less, preferably 0.20% or less as an absolute value. It is preferably 0.15% or less, particularly preferably 0.10% or less, and most preferably 0.05% or less. That is, the change rate of the thermal expansion coefficient at 300 ° C. with respect to the thermal expansion coefficient at 30 ° C. of the porous support of the zeolite membrane composite E is within ⁇ 0.25%, preferably within ⁇ 0.20%, It is preferably within ⁇ 0.15%, particularly preferably within ⁇ 0.10%, and most preferably within ⁇ 0.05%.
- the change rate of the thermal expansion coefficient at 400 ° C. with respect to the thermal expansion coefficient at 30 ° C. of the porous support of the zeolite membrane composite E is usually 0.30% or less, preferably 0.25% or less as its absolute value. More preferably, it is 0.20% or less, particularly preferably 0.15% or less, and most preferably 0.10% or less. That is, the rate of change of the thermal expansion coefficient at 400 ° C. relative to the thermal expansion coefficient at 30 ° C. of the porous support is within ⁇ 0.30%, preferably within ⁇ 0.25%, and more preferably ⁇ 0.20%. Within 0.1 ⁇ 5%, particularly preferably within ⁇ 0.15%, and most preferably within ⁇ 0.10%.
- the zeolite membrane composite formed on the porous support exhibiting such a low coefficient of thermal expansion is, for example, ammonia, hydrogen, and hydrogen under a temperature condition exceeding 200 ° C. and even a temperature condition exceeding 300 ° C.
- the rate of change of the thermal expansion coefficient at 400 ° C. with respect to the coefficient of thermal expansion of 30 ° C. relative to the rate of change of the coefficient of thermal expansion at 300 ° C. with respect to the coefficient of thermal expansion at 30 ° C. of the porous support used in the fifth embodiment is
- the absolute value of the ratio is usually 120% or less, preferably 115% or less, more preferably 110% or less, particularly preferably 105% or less, and most preferably 103% or less.
- Zeolite membrane composites formed on porous supports exhibiting a specific coefficient of thermal expansion ratio between specific temperatures are also used when, for example, heterogeneous heat generation occurs in the reactor during ammonia production. Because it can suppress the cracking of the zeolite membrane following the local thermal expansion (shrinkage) of the porous support, it can stably separate ammonia into the permeate side with high permeability and stability even under high temperature conditions. Can do.
- the zeolite membrane is preferably used as a zeolite membrane composite comprising at least zeolite and a support.
- the zeolite membrane composite is a membrane in which the above zeolite is fixed in the form of a membrane, preferably crystallized, on the surface of the above porous support, etc.
- the thing fixed in the inside of a support body is preferable.
- the zeolite membrane composite for example, a zeolite membrane crystallized into a membrane form by hydrothermal synthesis on the surface of a porous support is preferable.
- the position of the zeolite membrane on the porous support is not particularly limited.
- the zeolite membrane may be formed on the outer surface, or may be formed on the inner surface. Depending on the case, it may be formed on both sides. Further, it may be formed by being laminated on the surface of the support, or may be crystallized so as to fill the pores of the surface layer of the support. In this case, it is important that there are no cracks or continuous micropores inside the crystallized film layer, and it is preferable to form a so-called dense film from the standpoint of improving separability.
- the zeolite and the support constituting the zeolite membrane composite there is no particular limitation on the zeolite and the support constituting the zeolite membrane composite, and it is preferable to use any combination of the above-mentioned zeolite and the support.
- particularly preferred zeolite and porous the combinations of the supports include MFI type zeolite-porous alumina support, RHO type zeolite-porous alumina support, DDR type zeolite-porous alumina support, AFI type zeolite-porous alumina support.
- CHA type zeolite-porous alumina support AEI type zeolite-porous alumina support, CHA type zeolite-porous alumina support, MFI type zeolite-porous alumina support, RHO type zeolite -Porous alumina support, more preferably MFI type zeolite- Porous alumina support, RHO type zeolite - a porous alumina support.
- MFI type zeolite-porous alumina support preferably, MFI type zeolite-porous alumina support, RHO type zeolite-porous alumina support, more preferably RHO type zeolite-porous An alumina support.
- the method for forming the zeolite membrane composite is not particularly limited as long as it can form the above-mentioned zeolite membrane on the porous support, and can be produced by a known method. For example, (1) a method of crystallizing zeolite in a film form on a support, (2) a method of fixing zeolite to the support with an inorganic binder or an organic binder, and (3) a support in which a polymer in which zeolite is dispersed is supported.
- Any method can be used, such as a method of adhering to a support and (4) a method of impregnating a support with a slurry of zeolite and optionally adsorbing the zeolite to the support by suction.
- a method of crystallizing zeolite on a porous support in a film form is particularly preferable.
- the support is placed in a reaction mixture for hydrothermal synthesis used for zeolite production (hereinafter sometimes referred to as an “aqueous reaction mixture”) and directly hydrothermal synthesis is performed.
- a method of crystallizing zeolite on the surface of the support is preferred.
- the zeolite membrane composite is, for example, sealed in a heat-resistant pressure-resistant container such as an autoclave in which a porous support is placed in an aqueous reaction mixture whose composition has been uniformized and heated for a certain period of time. Can be manufactured.
- the aqueous reaction mixture contains a Si atom source, an Al atom source, an alkali source and water, and further contains an organic template (structure directing agent) as necessary.
- an organic template structure directing agent
- the RHO type zeolite used in the present invention is a code that defines the structure of the zeolite defined by International Zeolite Association (IZA), and indicates an RHO type.
- RHO type zeolite has a structure characterized by having three-dimensional pores composed of 8-membered oxygen rings having a diameter of 3.6 ⁇ 3.6 mm, and the structure is characterized by X-ray diffraction data.
- the framework density of the RHO type zeolite used in the present invention is 14.1 T / 1000 kg.
- the framework density means the number of atoms constituting a skeleton other than oxygen per 1000 3 of the zeolite, and this value is determined by the structure of the zeolite.
- the relationship between the framework density and the structure of zeolite is shown in ATLAS OF ZEOLITE FRAMEWORK TYPES Fifth Revised Edition 2007 ELSEVIER.
- MFI type zeolite membrane The MFI type zeolite used in the present invention is a code that defines the structure of zeolite defined by International Zeolite Association (IZA) and indicates an MFI type.
- MFI-type zeolite has a structure characterized by having three-dimensional pores consisting of oxygen 10-membered rings having a diameter of 5.1 ⁇ 5.5 mm or 5.3 ⁇ 5.6 mm, and the structure is X-ray diffraction. Characterized by data.
- the framework density of the MFI type zeolite used in the present invention is 17.9 T / 1000 kg.
- the framework density means the number of atoms constituting a skeleton other than oxygen per 1000 3 of the zeolite, and this value is determined by the structure of the zeolite.
- the relationship between the framework density and the structure of zeolite is shown in ATLAS OF ZEOLITE FRAMEWORK TYPES Fifth Revised Edition 2007 ELSEVIER.
- the silicon (Si) atom source used in the aqueous reaction mixture is not particularly limited.
- silicon such as aluminosilicate zeolite, fumed silica, colloidal silica, amorphous silica, sodium silicate, methyl silicate, ethyl silicate, and trimethylethoxysilane.
- Examples include alkoxide, tetraethylorthosilicate, aluminosilicate gel, and preferably aluminosilicate zeolite, fumed silica, colloidal silica, amorphous silica, sodium silicate, methyl silicate, ethyl silicate, silicon alkoxide, aluminosilicate gel. . These may be used alone or in combination of two or more.
- the Si atom source is used so that the amount of other raw materials used with respect to the Si atom source is within the above-mentioned or later preferred range.
- the aluminum (Al) atom source used for the production of the porous support-RHO type zeolite membrane composite is not particularly limited, but aluminosilicate zeolite, amorphous aluminum hydroxide, aluminum hydroxide having a gibbsite structure, Bayerlite structure Examples include aluminum hydroxide, aluminum nitrate, aluminum sulfate, aluminum oxide, sodium aluminate, boehmite, pseudoboehmite, aluminum alkoxide, aluminosilicate gel, aluminosilicate zeolite, amorphous aluminum hydroxide, sodium aluminate, boehmite , Pseudoboehmite, aluminum alkoxide, aluminosilicate gel are preferred, aluminosilicate zeolite, amorphous aluminum hydroxide, alumine Sodium, aluminosilicate gel is particularly preferred. These may be used alone or in combination of two or
- Aluminosilicate zeolite may be used alone or in combination of two or more.
- an aluminosilicate zeolite is used as the Al atom source, it is preferable that 50% by mass or more, particularly 70 to 100% by mass, particularly 90 to 100% by mass of the total Al atom source is the above-mentioned aluminosilicate zeolite.
- an aluminosilicate zeolite is used as the Si atom source, it is preferable that 50% by mass or more, particularly 70 to 100% by mass, particularly 90 to 100% by mass of the total Si atom source is the above-mentioned aluminosilicate zeolite.
- the RHO type zeolite membrane has a high Si atom / Al atom molar ratio, and the zeolite membrane is excellent in acid resistance and water resistance and has a wide application range.
- the preferred range of the usage amount (Al atom / Si atomic ratio) of the Al atom source (including the aforementioned aluminosilicate zeolite and other Al atom sources) with respect to silicon (Si atoms) contained in the raw material mixture other than the seed crystal is , Usually 0.01 or more, preferably 0.02 or more, more preferably 0.04 or more, further preferably 0.06 or more, usually 1.0 or less, preferably 0.5 or less, more preferably It is 0.2 or less, more preferably 0.1 or less.
- the amount of silicon atom source used relative to the aluminum atom source may be reduced.
- the silicon atom source relative to the aluminum atom source may be reduced. Just increase the amount used.
- the resulting RHO type zeolite membrane has low water resistance and acid resistance, and the zeolite Use as a membrane may be limited.
- the Al atom / Si atomic ratio is smaller than 0.01, it may be difficult to obtain an RHO type zeolite membrane.
- the aqueous reaction mixture includes other atom sources such as gallium (Ga), iron (Fe), boron (B), titanium (Ti), zirconium (Zr), tin ( An atomic source such as Sn) or zinc (Zn) may be included.
- the type of alkali used as the alkali source is not particularly limited, and alkali metal hydroxides and alkaline earth metal hydroxides can be used.
- the metal species of these metal hydroxides are usually sodium (Na), potassium (K), lithium (Li), rubidium (Rb), cesium (Cs), calcium (Ca), magnesium (Mg), strontium (Sr), Barium (Ba), preferably Na, K, Cs, more preferably Na, Cs.
- Two or more metal species of the metal oxide may be used in combination, and specifically, Na and Cs are preferably used in combination.
- Specific examples of metal hydroxides include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, cesium hydroxide; calcium hydroxide, magnesium hydroxide, water Alkaline earth metal hydroxides such as strontium oxide and barium hydroxide can be used.
- an alkali source used in the aqueous reaction mixture a hydroxide ion of a counter anion of an organic template described below can be used.
- an organic template (structure directing agent) is not necessarily required, but by using an organic template of a type corresponding to each structure, It is preferable to use an organic template because the ratio of silicon atoms to aluminum atoms increases and crystallinity improves.
- the organic template may be of any type as long as it can form a desired zeolite membrane. Further, one type of template or a combination of two or more types may be used.
- organic template suitable for the reaction varies depending on the zeolite structure to be synthesized, and an organic template that provides a desired zeolite structure may be used. Specifically, for example, 18-crown-6-ether may be used for the RHO structure.
- the organic template When the organic template is a cation, it is accompanied by an anion that does not harm the formation of the zeolite.
- anions include halogen ions such as Cl ⁇ , Br ⁇ and I ⁇ , hydroxide ions, acetates, sulfates, and carboxylates.
- hydroxide ions are particularly preferably used. In the case of hydroxide ions, they function as an alkali source as described above.
- the ratio of the Si atom source and an organic template in the aqueous reaction mixture is usually 0.005 or higher, preferably at least 0.01, more preferably 0 0.02 or more, more preferably 0.05 or more, particularly preferably 0.08 or more, most preferably 0.1 or more, usually 1 or less, preferably 0.5 or less, more preferably 0.4 or less, It is preferably 0.35 or less, particularly preferably 0.30 or less, and most preferably 0.25 or less.
- the organic structure directing agent described later can be easily coordinated with aluminum in a suitable state, so that a crystal structure can be easily formed.
- the molar ratio (R / Si atom) between the alkali metal atom source (R) and silicon (Si atom) contained in the hydrothermal synthesis raw material mixture other than the seed crystal is usually 0.1 or more, preferably 0.15. Or more, more preferably 0.20 or more, further preferably 0.25 or more, particularly preferably 0.30 or more, particularly preferably 0.35 or more, usually 2.0 or less, preferably 1.5 or less, More preferably, it is 1.0 or less, more preferably 0.8 or less, particularly preferably 0.6 or less, and most preferably 0.5 or less.
- the molar ratio of alkali metal atom source to silicon (R / Si atom) is larger than the above upper limit, the produced zeolite is likely to be dissolved and the zeolite may not be obtained or the yield may be significantly reduced. If the R / Si atom is smaller than the above lower limit, the raw material Al atom source and Si atom source are not sufficiently dissolved, a uniform raw material mixture for hydrothermal synthesis cannot be obtained, and RHO type zeolite is difficult to produce. There is a case.
- the amount of water in the raw material mixture for hydrothermal synthesis is usually 10 or more, preferably 20 or more, more preferably 30 or more, and still more preferably 40 in terms of a molar ratio to silicon (Si atoms) contained in the raw material mixture other than seed crystals. Above, especially preferably 50 or more, usually 200 mol or less, preferably 150 or less, more preferably 100 or less, still more preferably 80 or less, particularly preferably 60 or less. If it is larger than the above upper limit, the reaction mixture may be too dilute to make it difficult to form a dense film without defects. If it is less than 10, since the reaction mixture is thick, spontaneous nuclei are likely to be generated, and growth of RHO-type zeolite from the support may be inhibited, making it difficult to form a dense membrane.
- a seed crystal may be used as one component of the “zeolite” production raw material (raw material compound).
- raw material compound raw material compound
- hydrothermal synthesis it is not always necessary to have a seed crystal in the reaction system.
- the presence of the seed crystal can promote crystallization of the zeolite on the porous support.
- the method of making the seed crystal exist in the reaction system, and a method of adding the seed crystal to the aqueous reaction mixture as in the synthesis of the powdered zeolite, or attaching the seed crystal on the support.
- a method etc. can be used, in this invention, it is preferable to make a seed crystal adhere on a support body. By attaching a seed crystal in advance to the support, a dense zeolite membrane with high separation performance can be easily formed.
- the seed crystal to be used is not particularly limited as long as it is a zeolite that promotes crystallization, but in order to efficiently crystallize, it is preferably the same crystal type as the zeolite membrane to be formed.
- a seed crystal of RHO type zeolite when forming a zeolite membrane of RHO type aluminosilicate, it is preferable to use a seed crystal of RHO type zeolite.
- the seed crystal particle size is desirably close to the pore size of the support, and may be used after pulverization if necessary.
- the particle size is usually 20 nm or more, preferably 50 nm or more, more preferably 100 nm or more, further preferably 0.15 ⁇ m or more, particularly preferably 0.5 ⁇ m or more, most preferably 0.7 ⁇ m or more, and usually 5 ⁇ m or less, preferably Is 3 ⁇ m or less, more preferably 2 ⁇ m or less, and particularly preferably 1.5 ⁇ m or less.
- the seed crystal has a smaller particle size, and it may be used after pulverization if necessary.
- the particle diameter of the seed crystal is usually 5 nm or more, preferably 10 nm or more, more preferably 20 nm or more, and is usually 5 ⁇ m or less, preferably 3 ⁇ m or less, more preferably 2 ⁇ m or less.
- the method for attaching the seed crystal on the support is not particularly limited.
- a dip method in which the seed crystal is dispersed in a solvent such as water and the support is immersed in the dispersion to attach the seed crystal to the surface
- a suction method in which the seed crystal is firmly attached to the surface of the support by immersing the support in which the crystal is dispersed in a solvent such as water and sealing one end in the dispersion and then sucking the support from the other end.
- a method in which a seed crystal mixed with a solvent such as water to form a slurry is coated on a support.
- the dip method and suction method are desirable for controlling the amount of seed crystal attached and producing a zeolite membrane with good reproducibility.
- the method of applying the seed crystal on the slurry and the suction method are desirable. Also, for the purpose of closely attaching the seed crystal to the support and / or removing the excess seed crystal, rubbing and pressing the support with the seed crystal attached with a finger wearing latex gloves following the dipping method or suction method. Is also preferably performed.
- the solvent for dispersing the seed crystal is not particularly limited, but water and an alkaline aqueous solution are particularly preferable. Although the kind of alkaline aqueous solution is not specifically limited, A sodium hydroxide aqueous solution and potassium hydroxide aqueous solution are preferable. These alkali species may be mixed.
- the alkali concentration of the alkaline aqueous solution is not particularly limited, and is usually 0.0001 mol% or more, preferably 0.0002 mol% or more, more preferably 0.001 mol% or more, and further preferably 0.002 mol% or more. Moreover, it is 1 mol% or less normally, Preferably it is 0.8 mol% or less, More preferably, it is 0.5 mol% or less, More preferably, it is 0.2 mol% or less.
- the solvent for dispersing the seed crystal is not particularly limited, but water is particularly preferable.
- the amount of the seed crystal to be dispersed is not particularly limited, and is usually 0.05% by mass or more, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and further preferably based on the total weight of the dispersion. Is 1% by mass or more, particularly preferably 2% by mass or more, and most preferably 3.0% by mass or more. Moreover, it is 20 mass% or less normally, Preferably it is 10 mass% or less, More preferably, it is 5 mass% or less, More preferably, it is 4 mass% or less.
- the amount of seed crystals to be dispersed is too small, the amount of seed crystals adhering to the support is small, so that a portion where no zeolite is generated on the support during hydrothermal synthesis is created, resulting in a defective film.
- the amount of seed crystals attached to the porous support by the dip method is almost constant when the amount of seed crystals in the dispersion is higher than a certain level, so the amount of seed crystals in the dispersion is too large. This is disadvantageous in terms of cost due to the waste of seed crystals.
- the drying temperature is usually 50 ° C. or higher, preferably 80 ° C. or higher, more preferably 100 ° C. or higher, and is usually 200 ° C. or lower, preferably 180 ° C. or lower, more preferably 150 ° C. or lower.
- the drying time is usually 10 minutes or longer, preferably 30 minutes or longer, and an upper limit is not specified, but it is usually 5 hours or shorter from an economical viewpoint.
- the support with the seed crystals attached is rubbed with a finger wearing latex gloves. Pushing is also preferably performed.
- the amount of the seed crystal to be deposited in advance on the porous support is not particularly limited, and is usually 0.1 g or more, preferably 0.3 g or more, by mass per 1 m 2 of the film-forming surface of the porous support. Preferably it is 0.5 g or more, more preferably 0.80 g or more, most preferably 1.0 g or more, usually 100 g or less, preferably 50 g or less, more preferably 10 g or less, still more preferably 8 g or less, most preferably 5 g. It is as follows.
- the amount of seed crystal attached is less than the above lower limit, crystals are hardly formed, and film growth tends to be insufficient or film growth tends to be uneven.
- the amount of the seed crystal exceeds the above upper limit, surface irregularities are increased by the seed crystal, or spontaneous nuclei are likely to grow due to the seed crystal falling from the support, thereby inhibiting film growth on the support. May be. In either case, it tends to be difficult to form a dense zeolite membrane.
- the zeolite membrane When forming a zeolite membrane on a porous support by hydrothermal synthesis, there are no particular limitations on the method for immobilizing the support, and it can take any form such as vertically or horizontally.
- the zeolite membrane may be formed by a stationary method, or the zeolite membrane may be formed under stirring of the aqueous reaction mixture.
- Hydrothermal synthesis is carried out by placing a support carrying a seed crystal as described above and a hydrothermal synthesis mixture prepared or an aqueous gel obtained by aging this into a pressure vessel, under self-generated pressure or crystallization. This is carried out by maintaining a predetermined temperature under a gas pressure that does not inhibit the above, with stirring, while rotating or swinging the container, or in a stationary state. Hydrothermal synthesis in a stationary state is desirable in that it does not inhibit crystal growth from the seed crystal on the support.
- the reaction temperature at the time of forming the zeolite membrane by hydrothermal synthesis is not particularly limited as long as it is a temperature suitable for obtaining a membrane having the target zeolite structure, but is usually 100 ° C. or higher, preferably 110 ° C. or higher. Preferably it is 120 ° C or higher, particularly preferably 130 ° C or higher, particularly preferably 140 ° C or higher, most preferably 150 ° C or higher, usually 200 ° C or lower, preferably 190 ° C or lower, more preferably 180 ° C or lower. More preferably, it is 170 ° C. or lower. If the reaction temperature is too low, the zeolite may be difficult to crystallize. In addition, if the reaction temperature is too high, a zeolite of a type different from the target zeolite may be easily generated.
- the heating (reaction) time for forming the zeolite membrane by hydrothermal synthesis is not particularly limited as long as it is a time suitable for obtaining a membrane having the target zeolite structure, but usually 3 hours or more, preferably 8 hours. More preferably, it is 12 hours or more, particularly preferably 15 hours or more, usually 10 days or less, preferably 5 days or less, more preferably 3 days or less, still more preferably 2 days or less, particularly preferably 1. 5 days or less. If the reaction time is too short, the zeolite may be difficult to crystallize. If the reaction time is too long, a zeolite of a type different from the target zeolite may be easily formed.
- the pressure at the time of hydrothermal synthesis is not particularly limited, and the self-generated pressure generated when the aqueous reaction mixture placed in a sealed container is heated to the above temperature range is sufficient. If necessary, an inert gas such as nitrogen may be added.
- the zeolite membrane composite obtained in the first hydrothermal synthesis is washed with water, dried by heating, and then immersed again in a newly prepared aqueous reaction mixture for hydrothermal synthesis. Just do it.
- the zeolite membrane composite obtained after the first hydrothermal synthesis does not necessarily need to be washed with water or dried, but the aqueous reaction mixture can be kept at the intended composition by washing with water and drying.
- the number of synthesis is usually 2 times or more and usually 10 times or less, preferably 5 times or less, more preferably 3 times or less.
- the washing with water may be repeated once or multiple times.
- the zeolite membrane composite obtained by hydrothermal synthesis is washed with water, heat-treated and dried.
- the heat treatment means that the zeolite membrane composite is dried by applying heat, and when the organic template is used, the organic template is baked and removed.
- the temperature of the heat treatment is usually 50 ° C. or higher, preferably 80 ° C. or higher, more preferably 100 ° C. or higher, usually 200 ° C. or lower, preferably 150 ° C. or lower when drying is intended.
- the temperature of the heat treatment is usually 250 ° C. or higher, preferably 300 ° C. or higher, more preferably 350 ° C. or higher, still more preferably 400 ° C. or higher, and usually 800 ° C. or lower when the purpose is to remove the organic template by baking.
- it is 600 degrees C or less, More preferably, it is 550 degrees C or less, Most preferably, it is 500 degrees C or less.
- the time for the heat treatment is not particularly limited as long as the zeolite membrane is sufficiently dried and the organic template is baked and removed.
- the purpose of drying preferably 0.5 hours or more, more preferably If it is 1 hour or longer and the purpose is to remove the organic template by baking, it varies depending on the rate of temperature rise or the rate of temperature fall, but it is preferably 1 hour or longer, more preferably 5 hours or longer.
- the upper limit of the heating time is not particularly limited, and is usually 200 hours or less, preferably 150 hours or less, more preferably 100 hours or less.
- the heat treatment for the purpose of firing the template may be performed in an air atmosphere, but may be performed in an atmosphere to which an inert gas such as nitrogen or oxygen is added.
- the obtained zeolite membrane composite is washed with water, and then the organic template is removed by, for example, heat treatment or extraction, preferably by the above heat treatment, that is, baking. Is appropriate.
- the rate of temperature increase during the heat treatment for the purpose of firing and removing the organic template is as much as possible. It is desirable to slow down.
- the heating rate is usually 5 ° C./min or less, preferably 2 ° C./min or less, more preferably 1 ° C./min or less, further preferably 0.5 ° C./min or less, particularly preferably 0.3 ° C./min or less. It is.
- the lower limit of the heating rate is usually 0.1 ° C./min or more in consideration of workability.
- the cooling rate is usually 5 ° C./min or less, preferably 2 ° C./min or less, more preferably 1 ° C./min or less, further preferably 0.5 ° C./min or less, particularly preferably 0.3 ° C./min or less. is there.
- the lower limit of the cooling rate is usually 0.1 ° C./min or more in consideration of workability.
- silicon (Si) atom sources used in the aqueous reaction mixture include aluminosilicate zeolite, fumed silica, colloidal silica, amorphous silica, sodium silicate, silicon alkoxide such as methyl silicate, ethyl silicate, and trimethylethoxysilane, and tetraethyl ortho.
- Silicate, aluminosilicate gel, etc. can be used.
- fumed silica, colloidal silica, amorphous silica, sodium silicate, methyl silicate, ethyl silicate, silicon alkoxide, and aluminosilicate gel are used. These may be used alone or in combination of two or more.
- the Si atom source is used so that the amount of other raw materials used with respect to the Si atom source is within the above-mentioned or later preferred range.
- the aluminum (Al) atom source used for the production of the porous support-MFI type zeolite membrane composite is not particularly limited, but aluminosilicate zeolite, amorphous aluminum hydroxide, aluminum hydroxide having a gibbsite structure, Bayerlite structure Aluminum hydroxide, aluminum nitrate, aluminum sulfate, aluminum oxide, sodium aluminate, boehmite, pseudoboehmite, aluminum alkoxide, aluminosilicate gel, etc., amorphous aluminum hydroxide, sodium aluminate, boehmite, pseudoboehmite, Aluminum alkoxide and aluminosilicate gel are preferable, and amorphous aluminum hydroxide, sodium aluminate, and aluminosilicate gel are particularly preferable. These may be used alone or in combination of two or more.
- the preferred range of the usage amount (Al atom / Si atomic ratio) of the aluminum atom source (including the aforementioned aluminosilicate zeolite and other aluminum atom sources) relative to silicon (Si atom) contained in the raw material mixture other than the seed crystal is
- the molar ratio is usually 0.001 or more, preferably 0.002 or more, more preferably 0.003 or more, further preferably 0.004 or more, usually 1.0 or less, preferably 0.5 or less. More preferably, it is 0.2 or less, and further preferably 0.1 or less.
- the amount of silicon atom source used relative to the aluminum atom source may be reduced.
- the amount of silicon atom source used relative to the aluminum atom source You can increase it.
- the aqueous reaction mixture may contain an atomic source other than the Si atom source and the Al atom source, such as Ga, Fe, B, Ti, Zr, Sn, and Zn.
- the type of alkali used as the alkali source is not particularly limited, and alkali metal hydroxides and alkaline earth metal hydroxides can be used.
- metal hydroxides include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, cesium hydroxide; calcium hydroxide, magnesium hydroxide, water Alkaline earth metal hydroxides such as strontium oxide and barium hydroxide can be used.
- an alkali source used in the aqueous reaction mixture a hydroxide ion of a counter anion of an organic template described below can be used.
- an organic template is not necessarily required, but by using an organic template (structure directing agent) of a type corresponding to each structure, It is preferable to use an organic template because the ratio of silicon atoms to aluminum atoms increases and crystallinity improves.
- the organic template may be of any type as long as it can form a desired zeolite membrane. Further, one type of template or a combination of two or more types may be used.
- organic template suitable for the reaction varies depending on the zeolite structure to be synthesized, and an organic template that provides a desired zeolite structure may be used. Specifically, for example, tetrapropylammonium hydroxide may be used for the MFI structure.
- the organic template When the organic template is a cation, it is accompanied by an anion that does not harm the formation of the zeolite.
- anions include halogen ions such as Cl ⁇ , Br ⁇ and I ⁇ , hydroxide ions, acetates, sulfates, and carboxylates.
- hydroxide ions are particularly preferably used. In the case of hydroxide ions, they function as an alkali source as described above.
- the ratio of the Si atom source and an organic template in the aqueous reaction mixture is usually 0.005 or higher, preferably at least 0.01, more preferably 0 0.02 or more, particularly preferably 0.05 or more, particularly preferably 0.1 or more, usually 1 or less, preferably 0.5 or less, more preferably 0.3 or less, particularly preferably 0.25 or less, particularly Preferably it is 0.2 or less.
- organic template / SiO 2 ratio of the aqueous reaction mixture is in this range, in addition to being able to form a dense zeolite membrane, a zeolite having excellent acid resistance and being less likely to desorb Al is obtained.
- the molar ratio R / Si between the alkali metal atom source (R) and silicon (Si) contained in the hydrothermal synthesis raw material mixture other than the seed crystal is usually 0.01 or more, preferably 0.02 or more, more preferably. Is 0.03 or more, more preferably 0.04 or more, particularly preferably 0.05 or more, and is usually 1.0 or less, preferably 0.6 or less, more preferably 0.4 or less, still more preferably 0.00. 2 or less, particularly preferably 0.1 or less.
- the molar ratio (R / Si) of the alkali metal atom source to silicon is larger than the above upper limit value, the produced zeolite may be easily dissolved, and the zeolite may not be obtained or the yield may be significantly reduced.
- R / Si is smaller than the lower limit, the raw material Al atom source and Si atom source are not sufficiently dissolved, and a uniform raw material mixture for hydrothermal synthesis cannot be obtained, making it difficult to produce MFI-type zeolite. There is.
- the amount of water in the hydrothermal synthesis raw material mixture is usually 10 or more, preferably 15 or more, more preferably 20 or more, and even more preferably 25 or more in terms of a molar ratio to silicon (Si) contained in the raw material mixture other than seed crystals. In particular, it is 30 or more, usually 500 mol or less, preferably 300 or less, more preferably 200 or less, still more preferably 150 or less, and particularly preferably 100 or less. If it is larger than the above upper limit, the reaction mixture may be too dilute to make it difficult to form a dense film without defects. If it is less than 10, since the reaction mixture is thick, spontaneous nuclei are likely to be generated, and the growth of MFI-type zeolite from the support may be inhibited, making it difficult to form a dense membrane.
- a seed crystal may be used as one component of the “zeolite” production raw material (raw material compound).
- raw material compound raw material compound
- hydrothermal synthesis it is not always necessary to have a seed crystal in the reaction system.
- the presence of the seed crystal can promote crystallization of the zeolite on the porous support.
- the method of making the seed crystal exist in the reaction system, and a method of adding the seed crystal to the aqueous reaction mixture as in the synthesis of the powdered zeolite, or attaching the seed crystal on the support.
- a method etc. can be used, in this invention, it is preferable to make a seed crystal adhere on a support body. By attaching a seed crystal in advance to the support, a dense zeolite membrane with high separation performance can be easily formed.
- the seed crystal to be used is not particularly limited as long as it is a zeolite that promotes crystallization, but in order to efficiently crystallize, it is preferably the same crystal type as the zeolite membrane to be formed.
- the particle diameter of the seed crystal is preferably close to the pore diameter of the support, and may be used after being pulverized if necessary.
- the particle size is usually 1 nm or more, preferably 10 nm or more, more preferably 50 nm or more, further preferably 0.1 ⁇ m or more, particularly preferably 0.5 ⁇ m or more, particularly preferably 0.7 ⁇ m or more, and most preferably 1 ⁇ m or more. It is usually 5 ⁇ m or less, preferably 3 ⁇ m or less, more preferably 2 ⁇ m or less, most preferably 1.5 ⁇ m or less, and particularly preferably 1.2 ⁇ m or less.
- the seed crystal has a smaller particle size, and it may be used after pulverization if necessary.
- the particle size of the seed crystal is usually 0.5 nm or more, preferably 1 nm or more, more preferably 2 nm or more, and is usually 5 ⁇ m or less, preferably 3 ⁇ m or less, more preferably 2 ⁇ m or less.
- the method for attaching the seed crystal on the support is not particularly limited.
- a dip method in which the seed crystal is dispersed in a solvent such as water and the support is immersed in the dispersion to attach the seed crystal to the surface
- a suction method in which the seed crystal is firmly attached to the surface of the support by immersing the support in which the crystal is dispersed in a solvent such as water and sealing one end in the dispersion and then sucking the support from the other end.
- a method in which a seed crystal mixed with a solvent such as water to form a slurry is coated on a support.
- the dip method and suction method are desirable for controlling the amount of seed crystal attached and producing a zeolite membrane with good reproducibility.
- the method of applying the seed crystal on the slurry and the suction method are desirable. Also, for the purpose of closely attaching the seed crystal to the support and / or removing the excess seed crystal, rubbing and pressing the support with the seed crystal attached with a finger wearing latex gloves following the dipping method or suction method. Is also preferably performed.
- the solvent for dispersing the seed crystal is not particularly limited, but water and an alkaline aqueous solution are particularly preferable. Although the kind of alkaline aqueous solution is not specifically limited, A sodium hydroxide aqueous solution and potassium hydroxide aqueous solution are preferable. These alkali species may be mixed.
- the alkali concentration of the alkaline aqueous solution is not particularly limited, and is usually 0.0001 mol% or more, preferably 0.0002 mol% or more, more preferably 0.001 mol% or more, and further preferably 0.002 mol% or more. Moreover, it is 1 mol% or less normally, Preferably it is 0.8 mol% or less, More preferably, it is 0.5 mol% or less, More preferably, it is 0.2 mol% or less.
- the solvent for dispersing the seed crystal is not particularly limited, but water is particularly preferable.
- the amount of the seed crystal to be dispersed is not particularly limited, and is usually 0.05% by mass or more, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and further preferably based on the total weight of the dispersion. Is 1% by mass or more, particularly preferably 2% by mass or more, and most preferably 3% by mass or more. Moreover, it is 20 mass% or less normally, Preferably it is 10 mass% or less, More preferably, it is 5 mass% or less, More preferably, it is 4 mass% or less.
- the amount of seed crystals to be dispersed is too small, the amount of seed crystals adhering to the support is small, so that a portion where no zeolite is generated on the support during hydrothermal synthesis is created, resulting in a defective film.
- the amount of seed crystals attached to the porous support by the dip method is almost constant when the amount of seed crystals in the dispersion is higher than a certain level, so the amount of seed crystals in the dispersion is too large. This is disadvantageous in terms of cost due to the waste of seed crystals.
- the drying temperature is usually 50 ° C. or higher, preferably 80 ° C. or higher, more preferably 100 ° C. or higher, and is usually 200 ° C. or lower, preferably 180 ° C. or lower, more preferably 150 ° C. or lower.
- the drying time is usually 10 minutes or longer, preferably 30 minutes or longer, and an upper limit is not specified, but it is usually 5 hours or shorter from an economical viewpoint.
- the support with the seed crystals attached is rubbed with a finger wearing latex gloves. Pushing is also preferably performed.
- the amount of the seed crystal to be deposited in advance on the porous support is not particularly limited, and is usually 0.1 g or more, preferably 0.3 g or more, by mass per 1 m 2 of the film-forming surface of the porous support. Preferably it is 0.5 g or more, more preferably 0.80 g or more, most preferably 1.0 g or more, usually 100 g or less, preferably 50 g or less, more preferably 10 g or less, still more preferably 8 g or less, most preferably 5 g. It is as follows.
- the amount of seed crystal attached is less than the above lower limit, crystals are hardly formed, and film growth tends to be insufficient or film growth tends to be uneven.
- the amount of the seed crystal exceeds the above upper limit, surface irregularities are increased by the seed crystal, or spontaneous nuclei are likely to grow due to the seed crystal falling from the support, thereby inhibiting film growth on the support. May be. In either case, it tends to be difficult to form a dense zeolite membrane.
- the zeolite membrane When forming a zeolite membrane on a porous support by hydrothermal synthesis, there are no particular limitations on the method for immobilizing the support, and it can take any form such as vertically or horizontally.
- the zeolite membrane may be formed by a stationary method, or the zeolite membrane may be formed under stirring of the aqueous reaction mixture.
- Hydrothermal synthesis is carried out by placing a support carrying a seed crystal as described above and a hydrothermal synthesis mixture prepared or an aqueous gel obtained by aging this into a pressure vessel, under self-generated pressure or crystallization. This is carried out by maintaining a predetermined temperature under a gas pressure that does not inhibit the above, with stirring, while rotating or swinging the container, or in a stationary state. Hydrothermal synthesis in a stationary state is desirable in that it does not inhibit crystal growth from the seed crystal on the support.
- the reaction temperature at the time of forming the zeolite membrane by hydrothermal synthesis is not particularly limited as long as it is a temperature suitable for obtaining a membrane having the target zeolite structure, but is usually 100 ° C. or higher, preferably 120 ° C. or higher. Preferably it is 130 ° C. or higher, particularly preferably 140 ° C. or higher, particularly preferably 150 ° C. or higher, most preferably 160 ° C. or higher, usually 200 ° C. or lower, preferably 190 ° C. or lower, more preferably 180 ° C. or lower, particularly preferably It is 170 degrees C or less. If the reaction temperature is too low, the zeolite may be difficult to crystallize. In addition, if the reaction temperature is too high, a zeolite of a type different from the target zeolite may be easily generated.
- the heating (reaction) time for forming a zeolite membrane by hydrothermal synthesis is not particularly limited, and may be any time suitable for obtaining a target membrane having a zeolite structure, but is usually 1 hour or more, preferably 5 hours. More preferably, it is 10 hours or more, usually 10 days or less, preferably 5 days or less, more preferably 3 days or less, still more preferably 2 days or less, and particularly preferably 1 day or less. If the reaction time is too short, the zeolite may be difficult to crystallize. If the reaction time is too long, a zeolite of a type different from the target zeolite may be easily formed.
- the pressure at the time of hydrothermal synthesis is not particularly limited, and the self-generated pressure generated when the aqueous reaction mixture placed in a sealed container is heated to the above temperature range is sufficient. If necessary, an inert gas such as nitrogen may be added.
- the zeolite membrane composite obtained in the first hydrothermal synthesis is washed with water, dried by heating, and then immersed again in a newly prepared aqueous reaction mixture for hydrothermal synthesis. Just do it.
- the zeolite membrane composite obtained after the first hydrothermal synthesis does not necessarily need to be washed with water or dried, but the aqueous reaction mixture can be kept at the intended composition by washing with water and drying.
- the number of synthesis is usually 2 times or more and usually 10 times or less, preferably 5 times or less, more preferably 3 times or less. Washing with water may be performed once or multiple times.
- the zeolite membrane composite obtained by hydrothermal synthesis is washed with water, heat-treated and dried.
- the heat treatment means that the zeolite membrane composite is dried by applying heat, and when the organic template is used, the organic template is baked and removed.
- the temperature of the heat treatment is usually 50 ° C. or higher, preferably 80 ° C. or higher, more preferably 100 ° C. or higher, usually 200 ° C. or lower, preferably 150 ° C. or lower when drying is intended.
- the temperature of the heat treatment is usually 350 ° C. or higher, preferably 400 ° C. or higher, more preferably 450 ° C. or higher, still more preferably 500 ° C. or higher, and usually 900 ° C. or lower, for the purpose of firing and removing the organic template.
- it is 800 degrees C or less, More preferably, it is 700 degrees C or less, Most preferably, it is 600 degrees C or less.
- the temperature of the heat treatment is too low, the residual ratio of the organic template tends to increase, and the pores of the zeolite decrease, which is used for the separation of ammonia. There is a possibility that the amount of permeation will decrease. If the heat treatment temperature is too high, the difference in coefficient of thermal expansion between the support and the zeolite will increase, and the zeolite membrane may be prone to cracking, and the denseness of the zeolite membrane will be lost, resulting in poor separation performance. There is. When tetrapropylammonium hydroxide is used as the organic template, the nitrogen atom content in the zeolite can be controlled by adjusting the heat treatment temperature.
- the time for the heat treatment is not particularly limited as long as the zeolite membrane is sufficiently dried and the organic template is baked and removed.
- the purpose of drying preferably 0.5 hours or more, more preferably If it is 1 hour or longer and the purpose is to remove the organic template by baking, it varies depending on the rate of temperature rise or the rate of temperature fall, but it is preferably 1 hour or longer, more preferably 5 hours or longer.
- the upper limit of the heating time is not particularly limited, and is usually 200 hours or less, preferably 150 hours or less, more preferably 100 hours or less.
- the heat treatment for the purpose of firing the template may be performed in an air atmosphere, but may be performed in an atmosphere to which an inert gas such as nitrogen or oxygen is added.
- the obtained zeolite membrane composite is washed with water, and then the organic template is removed by, for example, heat treatment or extraction, preferably by the above heat treatment, that is, baking. Is appropriate.
- the rate of temperature increase during the heat treatment for the purpose of firing and removing the organic template is as much as possible. It is desirable to slow down.
- the heating rate is usually 5 ° C./min or less, preferably 2 ° C./min or less, more preferably 1 ° C./min or less, particularly preferably 0.5 ° C./min or less, most preferably 0.3 ° C./min or less. It is.
- the lower limit of the heating rate is usually 0.1 ° C./min or more in consideration of workability.
- the cooling rate is usually 5 ° C./min or less, preferably 2 ° C./min or less, more preferably 1 ° C./min or less, particularly preferably 0.5 ° C./min or less, and most preferably 0.3 ° C./min or less. is there.
- the lower limit of the cooling rate is usually 0.1 ° C./min or more in consideration of workability.
- the synthesized zeolite membrane may be ion exchanged as necessary.
- the synthesized zeolite membrane undergoes ion exchange treatment.
- the ion exchange is an important control method because the thermal expansion characteristics of zeolite and the thermal stability of separation of ammonia, which are one of the features of the present invention, are greatly affected by the cation species in the zeolite.
- the ammonia permeation performance and / or separation performance of the zeolite membrane may be improved depending on the cation species used. That is, the cation species used in the present invention is appropriately selected in consideration of the permeation performance and separation performance of ammonia while ensuring the thermal expansion characteristics of the zeolite and the separation heat stability of ammonia.
- the ion exchange is usually performed after removing the organic template.
- the ions to be ion-exchanged are NH 4 + , methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, dimethylethylenediamine, tetramethylethylenediamine in order to increase the nitrogen content of the zeolite membrane surface.
- protons, NH 4 + , Na + , Li + , Cs + , Fe ions, Ga ions, and La ions are preferable.
- Plural kinds of these ions may be mixed in the zeolite, and the method of mixing the ions is preferably adopted in order to balance the thermal expansion characteristics and the ammonia permeation performance of the zeolite.
- NH 4 + methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, dimethylethylenediamine, tetramethylethylenediamine, diethylenetriamine, triethylenetetraamine
- Organic amines having 1 to 20 carbon atoms such as aniline, methylaniline, benzylamine, methylbenzylamine, hexamethylenediamine, N, N-diisopropylethylamine, N, N, N-trimethyl-1-adamantanamine, pyridine, and piperidine
- a cationic species in which an amine having a small molecular size such as NH 4 + or an organic amine having 1 to 6 carbon atoms is protonated is used.
- NH 4 + is particularly preferable among them.
- ion species for improving the permeation rate of ammonia protons, Na + , Li + , Cs + , Fe ions, Ga ions, and La ions are preferable, and Na + , Li + , and Cs + ions are particularly preferable. Most preferably, + ions coexist.
- the molar ratio of nitrogen atoms to Al atoms in the zeolite membrane can be controlled by adjusting the exchange amount of ions that essentially require ionic species containing nitrogen atoms.
- the content thereof is usually 0.01 or more, preferably 0.02 or more, in molar ratio with respect to Al atoms in the zeolite.
- it is 0.03 or more, more preferably 0.04 or more, particularly preferably 0.05 or more
- the upper limit is not particularly limited, but is usually 0.10 molar equivalent or less, preferably 0. 0.070 molar equivalents or less, more preferably 0.065 molar equivalents or less, still more preferably 0.060 molar equivalents or less, and particularly preferably 055 molar equivalents or less.
- the zeolite membrane after calcination (for example, when an organic template is used) is subjected to ion exchange, such as nitrate, sulfate, phosphate, organic acid salt, hydroxide, and halogen salt of Cl and Br,
- ion exchange such as nitrate, sulfate, phosphate, organic acid salt, hydroxide, and halogen salt of Cl and Br
- an acid such as hydrochloric acid may be used, usually after treatment at a temperature of room temperature to 100 ° C., followed by washing with water or washing with hot water of 40 ° C. to 100 ° C.
- the solvent used in the ion exchange treatment may be water or an organic solvent as long as the salt to be ion-exchanged is dissolved.
- the concentration of the salt to be treated is usually 10 mol / L or less, and the lower limit is 0.1 mol / L. As mentioned above, Preferably, it is 0.5 mol / L or more, More preferably, it is 1 mol / L or more. What is necessary is just to set these process conditions suitably according to the salt and solvent kind to be used. When an acid such as hydrochloric acid is used, the acid destroys the crystal structure of the zeolite. Therefore, the concentration of the acid to be treated is usually 5 mol / L or less, and the temperature and time may be set appropriately.
- the number of ion exchange treatments is not particularly limited, and the treatment may be repeated until a desired effect is obtained.
- the ion-exchanged zeolite membrane is fired at 200 to 500 ° C. as necessary, because if the residue derived from the ion-exchange treatment raw material is present in the pores of the zeolite after the ion-exchange treatment, gas permeability is hindered. Thus, the residue after the ion exchange treatment may be removed.
- nitrate treatment In certain embodiments of the present invention (for example, the zeolite membranes of Inventions B, C, D, and E), it is preferable to use nitrate treatment as a method for adjusting the content of nitrogen atoms in the zeolite membrane, Hereinafter, the nitrate treatment will be described.
- the synthesized zeolite membrane may be subjected to nitrate treatment as necessary.
- the nitrate treatment may be performed after the organic template is removed by baking even in a state containing the organic template.
- the nitrate treatment is performed by immersing the zeolite membrane composite in a solution containing nitrate, for example. This may be preferable because the effect of the nitrate blocking the fine defects present on the film surface may be obtained.
- nitrate when nitrate is present in the zeolite pores, it has the effect of improving the affinity of the zeolite membrane with ammonia, and is suitably employed as a technique for improving the permeability of ammonia.
- the solvent used for the nitrate treatment may be water or an organic solvent as long as the salt dissolves, and the nitrate used is not limited, but for example, magnesium nitrate, calcium nitrate, barium nitrate, aluminum nitrate, gallium nitrate, Examples thereof include indium nitrate, iron nitrate, cobalt nitrate, nickel nitrate, copper nitrate, and zinc nitrate. These may be used alone or in combination of two or more.
- the concentration of nitrate is usually 10 mol / L or less, and the lower limit is 0.1 mol / L or more, preferably 0.5 mol / L or more, more preferably 1 mol / L or more.
- the treatment temperature is usually from room temperature to 150 ° C., and the treatment may be performed for about 10 minutes to 48 hours, and these treatment conditions may be appropriately set according to the nitrate and solvent type to be used.
- the zeolite membrane after the nitrate treatment may be washed with water, and the nitrogen atom content of the zeolite membrane can be adjusted to a preferred range by repeating the washing with water.
- the synthesized zeolite membrane may be subjected to an aluminum salt treatment as necessary.
- the aluminum salt treatment may be performed after the organic template is removed by baking even in a state including the organic template.
- the aluminum salt treatment is performed by immersing the zeolite membrane composite in a solution containing, for example, an aluminum salt. Thereby, the effect that an aluminum salt closes the fine defect which exists in the film
- membrane surface may be acquired. Further, when the aluminum salt is present in the zeolite pores, it has an effect of attracting ammonia, and is suitably employed as a method for improving the ammonia permeability.
- the solvent used for the aluminum salt treatment may be water or an organic solvent as long as the salt dissolves, and the aluminum salt to be used is not limited.
- aluminum nitrate, aluminum sulfate, aluminum chloride, aluminum phosphate examples thereof include aluminum acetate, aluminum carbonate, and aluminum hydroxide. These may be used alone or in combination of two or more.
- the concentration of the aluminum salt is usually 10 mol / L or less, and the lower limit is 0.1 mol / L or more, preferably 0.5 mol / L or more, more preferably 1 mol / L or more.
- the treatment temperature is usually from room temperature to 150 ° C., and the treatment may be performed for about 10 minutes to 48 hours, and these treatment conditions may be appropriately set according to the aluminum salt and solvent type to be used.
- the zeolite membrane after the aluminum salt treatment may be washed with water, and the Al atom content of the zeolite membrane can be adjusted by repeating the washing with water.
- the synthesized zeolite membrane may be subjected to silylation treatment as necessary.
- the silylation treatment is performed by immersing the zeolite membrane composite in a solution containing, for example, a Si compound.
- the zeolite membrane surface can be modified with the Si compound to have specific physicochemical properties. For example, by reliably forming a layer containing a large amount of Si—OH on the zeolite membrane surface, the polarity of the membrane surface can be improved and the separation performance of polar molecules can be improved.
- the pore diameter of the zeolite can be controlled by silylation treatment, and a technique for improving the permeation selectivity of ammonia by performing this treatment is also preferably employed.
- the solvent used for the silylation treatment may be water or an organic solvent.
- the solution may be acidic or basic. In this case, the silylation reaction is catalyzed by the acid or base.
- An alkoxysilane is preferable.
- the treatment temperature is usually from room temperature to 150 ° C., and the treatment may be performed for about 10 minutes to 30 hours, and these treatment conditions may be appropriately set according to the silylating agent and solvent type to be used.
- the content of nitrogen atoms contained on the surface of the zeolite membrane of the present invention is determined by selecting the cation species containing nitrogen atoms in the zeolite contained in the zeolite membrane as described above, and adding the Al atoms / Si of the zeolite.
- a method of adjusting the atomic ratio a method of adjusting the content of nitrogen atoms by adjusting the amount of ion exchange by the ion exchange method, an organic template containing a nitrogen atom when producing a zeolite membrane as necessary (structure directing agent) )
- the method of treating the zeolite membrane with nitrate, the number of times of water washing the zeolite membrane treated with nitric acid It is possible to control by adjusting the method and appropriately combining these methods.
- the content of Al atoms contained in the surface of the zeolite membrane of the present invention is determined by adjusting the Al atom / Si atomic ratio in the zeolite contained in the zeolite membrane as described above, It can be controlled by a method of treating with an aluminum salt, a method of adjusting the number of times of rinsing with an aluminum salt-treated zeolite membrane, and a combination of these methods as appropriate.
- the content of the alkali metal element contained on the surface of the zeolite membrane of the present invention is the method for adjusting the Al atom / Si atomic ratio in the zeolite contained in the zeolite membrane as described above, ion exchange It can be controlled by adjusting the ion exchange amount by the method to adjust the content of the alkali metal element, adjusting the number of times of washing the zeolite membrane with water, and appropriately combining these methods.
- the zeolite membrane composite produced in this manner has excellent characteristics and can be suitably used as a means for membrane separation of ammonia from a mixed gas in the present invention.
- ammonia separation test In the apparatus schematically shown in Fig. 1, an ammonia separation test was performed as follows. In the apparatus of FIG. 1, a mixed gas containing ammonia gas (NH 3 ), nitrogen gas (N 2 ), and hydrogen (H 2 ) as a supply gas is mixed between the pressure vessel and the zeolite membrane composite at a flow rate of 100 SCCM. The pressure difference between the gas on the supply side and the gas permeated through the membrane is adjusted to be constant at 0.3 MPa by the back pressure valve, and the exhaust gas discharged from the pipe 10 is analyzed with a micro gas chromatograph. The permeate gas concentration and flow rate were calculated.
- NH 3 ammonia gas
- N 2 nitrogen gas
- H 2 hydrogen
- the sample gas temperature and The pressure difference between the supply gas side and the permeate gas side of the zeolite membrane composite was kept constant, and after the permeate gas flow rate was stabilized, the flow rate of the sample gas (permeate gas) permeated through the zeolite membrane composite was measured, and the gas permeance [ mol / (m 2 ⁇ s ⁇ Pa)] was calculated.
- the pressure difference (differential pressure) between the supply side and the permeation side of the supply gas was used.
- ⁇ ′ (Q1 / Q2) / (P1 / P2) (1)
- Q1 and Q2 respectively represent the permeation amount [mol ⁇ (m 2 ⁇ s) ⁇ 1 ] of a highly permeable gas and a less permeable gas
- P1 and P2 are respectively
- the pressure difference [Pa] between the supply side and the permeation side of the gas with high permeability and the gas with low permeability is shown.
- a raw material mixture for hydrothermal synthesis was prepared as follows. 1 mol / L-NaOH aqueous solution 1.45 g, 1 mol / L-KOH aqueous solution 5.78 g, and water 114.6 g were mixed with aluminum hydroxide (containing Al 2 O 3 -53.5% by mass, manufactured by Aldrich) 0 .19 g was added and stirred to dissolve to obtain a transparent solution.
- an alumina tube BN1 (outer diameter 6 mm, inner diameter 4 mm) manufactured by Noritake Company Limited was cut into a length of 80 mm, washed with an ultrasonic cleaner, and then dried. .
- the gel composition (molar ratio) of SiO 2 / Al 2 O 3 / NaOH / KOH / H 2 O / TMADAOH 1 / 0.033 / 0.1 / 0.06 / 20 / 0.07, What was crystallized by hydrothermal synthesis at 160 ° C. for 2 days was filtered, washed with water, and dried to produce CHA-type zeolite as a seed crystal.
- the seed crystal grain size was about 0.3 to 3 ⁇ m.
- the seed crystal was dispersed in water so as to be about 1% by mass to produce a seed crystal dispersion (CHA type seed crystal dispersion).
- the above porous support was prepared, and the support was immersed in the seed crystal dispersion for 1 minute, and then dried at 100 ° C. for 1 hour to attach the seed crystal to the support.
- the mass of the attached seed crystal was about 0.001 g.
- the support to which the seed crystal was attached was immersed in a Teflon (registered trademark) inner cylinder (200 ml) containing the above raw material mixture for hydrothermal synthesis in the vertical direction, and the autoclave was sealed. Heated under static pressure in a stationary state. After the elapse of a predetermined time, the support-zeolite membrane composite was taken out from the raw material mixture for hydrothermal synthesis after being allowed to cool, washed, and dried at 100 ° C. for 3 hours. Next, the dried membrane composite was calcined in air in an electric furnace at 450 ° C. for 10 hours and at 500 ° C. for 5 hours to remove the CHA-type zeolite membrane composite 1 from which the template contained in the zeolite was removed.
- Teflon registered trademark
- the temperature increase rate and the temperature decrease rate from room temperature to 450 ° C. were both 0.5 ° C./min, and the temperature increase rate and the temperature decrease rate from 450 ° C. to 500 ° C. were both 0.1 ° C./min.
- the mass of the CHA-type zeolite crystallized on the support which was determined from the difference between the mass of the membrane composite after calcination and the mass of the support, was about 0.279 to 0.289 g.
- the air permeation rate of the membrane composite after firing was 2.4 to 2.9 cm 3 / min.
- Example A1 ⁇ Evaluation of membrane separation performance> As pretreatment, at 200 ° C., a 50 vol% H 2/50 mixed gas vol% N 2 as a feed gas, is introduced between the CHA-type zeolite membrane composite 1 according to pressure vessel as in Production Example A1 The pressure was maintained at about 0.4 MPa, and the inside of the cylinder of the CHA-type zeolite membrane composite 1 was set at 0.098 MPa (atmospheric pressure) and dried for about 120 minutes.
- Example A2 Using the CHA-type zeolite membrane composite 1 described in Production Example A1, the temperature was set to 100 ° C., and the mixed gas was 3.0 vol% NH 3 /24.0 vol% N 2 /73.0 vol% H 2 . As a result of evaluating ammonia separation by the same method as in Example A1 except that the mixed gas was used, the ammonia gas concentration in the permeated gas was 4.1% by volume. From the obtained results, it can be seen that ammonia can be separated from the mixed gas.
- Example A3 Using the CHA-type zeolite membrane composite 1 described in Production Example A1, the temperature was 100 ° C., and the mixed gas was 2.0 vol% NH 3 /19.0 vol% N 2 /79.0 vol% H 2 . As a result of evaluating ammonia separation by the same method as in Example A1 except that the mixed gas was used, the ammonia gas concentration in the permeated gas was 2.3% by volume. From the obtained results, it can be seen that ammonia can be separated from the mixed gas.
- Example A1 With CHA-type zeolite membrane composite 1 prepared in Example A1, the temperature of the CHA-type zeolite membrane composite 1 as 100 ° C., mixing 12 vol% NH 3/50 vol% N 2/38 vol% H 2 As a result of evaluating ammonia separation by the same method as in Example A2 except that the gas was circulated at a flow rate of 100 SCCM, the hydrogen permeance was 7.0 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa).
- the nitrogen permeance is 2.1 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)], and the ammonia permeance is 2.4 ⁇ 10 ⁇ 7 [mol / (m 2 ⁇ s ⁇ Pa)]. there were.
- the permeance of hydrogen when hydrogen gas is circulated is 1.6 ⁇ 10 ⁇ 6 [mol / (m 2 ⁇ s ⁇ Pa)], and when nitrogen gas is circulated.
- the nitrogen permeance is 3.0 ⁇ 10 ⁇ 7 [mol / (m 2 ⁇ s ⁇ Pa)]. From these results, when ammonia gas is contained in the supply gas, both hydrogen and nitrogen are remarkably increased. It was found that permeance decreased. From this result, it is considered that when the ammonia gas concentration in the mixed gas is a specific amount or more, the ammonia in the supply gas is adsorbed on the zeolite and exhibits the effect of inhibiting the permeation of hydrogen and nitrogen.
- Production Example A2 Production of CHA-type zeolite membrane composite 2
- the CHA-type zeolite membrane composite 1 after removing the template obtained in Production Example A1 was placed in a Teflon (registered trademark) inner cylinder (65 ml) containing 45 g of a 1M aqueous ammonium nitrate solution.
- the autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under autogenous pressure.
- the CHA-type zeolite membrane is taken out of the aqueous solution after being allowed to cool, and after washing with hot water for 1 hour with ion-exchanged water at 100 ° C. three times, the CHA type membrane is dried at 100 ° C. for 4 hours or more An NH 4 + type CHA type zeolite membrane composite as the zeolite membrane composite 2 was obtained.
- Example A4 ⁇ Evaluation of membrane separation performance> Ammonia separation evaluation was performed in the same manner as in Example A1, except that the CHA-type zeolite membrane composite 2 described in Production Example A2 was used instead of the CHA-type zeolite membrane 1 described in Production Example A1.
- Table 4 shows the concentration of ammonia in the permeated gas and the permeance ratio of ammonia / hydrogen and ammonia / nitrogen.
- the ammonia concentration of the permeating gas is a value obtained by rounding off the first decimal place. From the results of Table 4, it can be seen that when the ammonia gas concentration in the mixed gas is a specific amount or more, ammonia can be efficiently separated. It can also be seen that ammonia separation can be performed efficiently even under high temperature conditions.
- an alumina tube (outer diameter 6 mm, pore diameter 0.15 ⁇ m, manufactured by Noritake Company Limited) was cut to a length of 40 mm, washed with water and dried.
- the mixture was aged at room temperature for 24 hours, then placed in a pressure vessel, left in an oven at 150 ° C., and subjected to hydrothermal synthesis for 72 hours. After this hydrothermal synthesis reaction, the reaction solution was cooled and the crystals produced by filtration were collected. The recovered crystals were dried at 100 ° C. for 12 hours to obtain crystals that were RHO type zeolite.
- the obtained RHO type zeolite was pulverized with a ball mill to produce a seed crystal dispersion. Specifically, 10 g of the above-mentioned RHO type zeolite, 300 g of 3 ⁇ mm HD alumina balls (made by Nikkato Co., Ltd.) and 90 g of water were placed in 500 mL of polybin and ball milled for 6 hours to obtain a 10% by mass RHO type zeolite dispersion. . Water was added to the zeolite dispersion so that the RHO type zeolite was 3% by mass to obtain a seed crystal dispersion.
- the seed crystal dispersion was dropped onto the support, and the seed crystal was adhered to the support by a rubbing method.
- the support to which the seed crystal is attached is immersed in a Teflon (registered trademark) inner cylinder containing a raw material mixture for hydrothermal synthesis in the vertical direction to seal the autoclave, and the autoclave is sealed at 150 ° C. for 72 hours under an autogenous pressure. And heated.
- Teflon registered trademark
- the substrate-zeolite membrane composite was taken out of the autoclave after being allowed to cool, and after washing, dried at 100 ° C. for 5 hours or more. After drying, the air permeation amount in an as-made state was 1.5 / (m 2 ⁇ min).
- the obtained membrane composite was fired at 300 degrees to obtain an RHO type zeolite membrane composite. From the difference between the weight of the zeolite membrane composite after calcination and the weight of the support, the weight of the RHO type zeolite crystallized on the support was 78 g / m 2 .
- the RHO-type zeolite membrane composite after removing the template is put into a Teflon (registered trademark) inner cylinder (65 ml) containing 45 g of 3M ammonium nitrate aqueous solution, the autoclave is sealed, and left standing at 110 ° C. for 1 hour. And heated under autogenous pressure.
- Teflon registered trademark
- the RHO type zeolite membrane was taken out from the aqueous solution, washed with water, and then dried at 100 ° C. for 4 hours or more to obtain an NH 4 + type RHO type zeolite membrane composite.
- this RHO type zeolite membrane composite was calcined in an electric furnace at 400 ° C. for 2 hours. At this time, the heating rate and the cooling rate up to 150 ° C. were both 2.5 ° C./min, the heating rate and the cooling rate from 150 ° C. to 400 ° C. were set to 0.5 ° C./min, and the RHO type zeolite membrane composite 1 Thus, an H + type RHO type zeolite membrane composite was obtained.
- Example A5 ⁇ Evaluation of membrane separation performance> Using the RHO type zeolite membrane composite 1 described in Production Example A3, an ammonia separation test from a mixed gas of ammonia / hydrogen / nitrogen was performed using the apparatus shown in FIG. 1 as described above. As pretreatment, at 250 ° C., a 50 vol% H 2/50 mixed gas vol% N 2 as a feed gas, is introduced between the pressure vessel and the RHO zeolite membrane composite 1, about a zero pressure. While maintaining the pressure at 3 MPa, the inside of the cylinder of the RHO type zeolite membrane composite 1 was set to 0.098 MPa (atmospheric pressure) and dried for about 120 minutes.
- 0.098 MPa atmospheric pressure
- the NH 4 + type RHO type zeolite membrane composite was put into a Teflon (registered trademark) inner cylinder (65 ml) containing 45 g of 1M aluminum nitrate aqueous solution.
- the autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under autogenous pressure.
- RHO type zeolite membrane composite After a predetermined time, after cooling under the, removed from the aqueous solution RHO type zeolite membrane composite, washed with water, dried over 4 hours at 100 ° C., RHO type zeolite membrane composite of the NH 4 + type and Al treated was further put into a Teflon (registered trademark) inner cylinder (65 ml) containing 45 g of a 1M sodium nitrate aqueous solution. The autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under autogenous pressure.
- the RHO type membrane is taken out from the aqueous solution, washed with water, dried at 100 ° C. for 4 hours or more, and after treatment with Al as the RHO type zeolite membrane composite 2, ions are converted into Na + type. An exchanged RHO type zeolite membrane composite was obtained.
- Example A6 ⁇ Evaluation of membrane separation performance> Using the RHO type zeolite membrane composite 2 described in Production Example A4, an ammonia separation test from a mixed gas of ammonia / hydrogen / nitrogen was carried out using the apparatus shown in FIG. As pretreatment, at 250 ° C., a 50 vol% H 2/50 mixed gas vol% N 2 as the feed gas 7, is introduced between the pressure vessel 2 and the zeolite membrane composite 1, about a zero pressure. While maintaining the pressure at 3 MPa, the inside of the cylinder of the RHO type zeolite membrane composite 2 was set to 0.098 MPa (atmospheric pressure) and dried for about 120 minutes.
- 0.098 MPa atmospheric pressure
- the temperature of the RHO-type zeolite membrane composite 2 was changed to 100 ° C. and 250 ° C. and allowed to flow, and the ammonia concentration and the permeance ratio of ammonia / hydrogen and ammonia / nitrogen were calculated.
- Table 6 shows the obtained results.
- the ammonia concentration of the permeating gas is a value obtained by rounding off the first decimal place. From the results in Table 6, it can be seen that when the ammonia gas concentration in the mixed gas is a specific amount or more, ammonia can be separated efficiently. It was also confirmed that the RHO type zeolite membrane composite was able to separate ammonia with high selectivity even under high temperature conditions.
- the ammonia permeance at 250 ° C. was 2.0 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)].
- the support to which the seed crystal is attached is immersed in a Teflon (registered trademark) inner cylinder containing the raw material mixture for hydrothermal synthesis produced by the same method as in Production Example A4, and the autoclave is sealed. And heated at 160 ° C. for 24 hours under autogenous pressure.
- Teflon registered trademark
- the substrate-zeolite membrane composite was taken out of the autoclave after being allowed to cool, and after washing, dried at 100 ° C. for 5 hours or more. After drying, the air permeation amount in the as-made state was 0.0 / (m 2 ⁇ min).
- the obtained membrane composite was fired to obtain an RHO type zeolite membrane composite. From the difference between the weight of the zeolite membrane composite after calcination and the weight of the support, the weight of the RHO type zeolite crystallized on the support was 62 g / m 2 .
- the RHO type zeolite membrane composite after removing the template was put in a Teflon (registered trademark) inner cylinder (65 ml) containing 50 g of 1M ammonium nitrate aqueous solution.
- the autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under autogenous pressure.
- the RHO type membrane was taken out from the aqueous solution and rinsed with 100 ° C. ion exchange water for 1 hour.
- the obtained NH 4 + type RHO type zeolite membrane composite 3 was placed in a Teflon (registered trademark) inner cylinder (65 ml) containing 45 g of 1M aluminum nitrate aqueous solution, and the autoclave was sealed and sealed at 100 ° C. for 1 hour. Heated in a stationary state under autogenous pressure.
- the RHO type zeolite composite membrane 3 is taken out from the aqueous solution, washed with water, dried at 100 ° C. for 4 hours or more, and treated with Al that is the RHO type zeolite membrane composite 4. 4 + -type give the RHO zeolite membrane composite of.
- Example A7 ⁇ Evaluation of membrane separation performance> Using the RHO type zeolite membrane composite 4 described in Production Example A5, an ammonia separation test from a mixed gas of ammonia (NH 3 ) / hydrogen (H 2 ) / nitrogen (N 2 ) was carried out by the above-described method as shown in FIG. Performed using the apparatus.
- a 10 vol% NH 3/20 vol% H 2/60 mixed gas vol% N 2 as a feed gas is introduced between the pressure vessel and the RHO zeolite membrane composite 4,
- the pressure was maintained at about 0.3 MPa, and the inside of the cylinder of the RHO zeolite membrane composite 4 was set at 0.098 MPa (atmospheric pressure) and dried for about 120 minutes.
- a 12 vol% NH 3/51 vol% N 2/37 mixed gas vol% H 2 was passed through at 100 SCCM, and set back pressure to 0.4 MPa.
- the differential pressure between the supply gas side and the permeate gas side of the RHO zeolite membrane composite 4 was 0.3 MPa.
- 3.9 SCCM of argon was supplied from the supply gas 9 as a sweep gas.
- the temperature of the RHO type zeolite membrane composite 4 is changed to 250 ° C., 300 ° C., and 325 ° C., and the mixed gas is circulated.
- the concentration of ammonia in the permeated gas and the permeance ratio of ammonia / hydrogen and ammonia / nitrogen are It is shown in Table 7.
- the concentration of ammonia in the permeated gas is a value obtained by rounding off the first decimal place. From these results, it was confirmed that NH 4 + type RHO type zeolite membrane treated with Al under high temperature conditions was able to separate ammonia with high selectivity.
- the RHO type membrane is taken out from the aqueous solution, rinsed with 100 ° C. ion exchange water for 1 hour, dried at 100 ° C. for 4 hours or more, and ion exchanged into Na + type.
- Type zeolite membrane composite was obtained.
- the obtained Na + type RHO type zeolite membrane was placed in a Teflon (registered trademark) inner cylinder (65 ml) containing 50 g of 1M aqueous aluminum nitrate solution, and the autoclave was sealed, and the mixture was sealed at 100 ° C. for 1 hour. Heated in a stationary state under autogenous pressure.
- the RHO type membrane is taken out of the aqueous solution, washed with 100 ° C. ion exchange water for 1 hour three times, and then dried at 100 ° C. for 4 hours or more to obtain an RHO type zeolite membrane.
- An Al-treated Na + type RHO type zeolite membrane composite as composite 5 was obtained.
- Example A8 ⁇ Evaluation of membrane separation performance> Example A7, except that instead of the RHO type zeolite membrane composite 4 described in Production Example A5, the RHO type zeolite membrane composite 5 described in Production Example A6 was used and argon was supplied in an amount of 8.3 SCCM as the sweep gas.
- a separation test of a mixed gas of 12.0 vol% NH 3 /51.0 vol% N 2 /37.0 vol% H 2 was performed in the same manner as described above.
- Table 8 shows the concentration of ammonia in the permeated gas and the permeance ratio of ammonia / hydrogen and ammonia / nitrogen. In Table 8, the ammonia concentration of the permeate gas is a value obtained by rounding off the first decimal place.
- the permeance of ammonia at 250 ° C. is 4.4 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)], and the permeance of ammonia at 325 ° C. is 1.1 ⁇ 10 ⁇ 7 [mol / (m 2 ⁇ s ⁇ Pa)].
- Example A9 Using the RHO-type zeolite membrane composite 5 described in Production Example A6, the temperature was 250 ° C., and the mixed gas was 2.0 vol% NH 3 /20.0 vol% N 2 /78.0 vol% H 2 . As a result of evaluating ammonia separation by the same method as in Example A8 except that the mixed gas was used, the ammonia gas concentration in the permeated gas was 19.9% by volume. From the obtained results, it can be seen that ammonia can be separated from the mixed gas.
- Example A10 Using the RHO type zeolite membrane composite 5 described in Production Example A6, the temperature was 250 ° C., and the mixed gas was 3.0 vol% NH 3 /20.0 vol% N 2 /77.0 vol% H 2 . As a result of evaluating ammonia separation by the same method as in Example A8 except that the mixed gas was used, the ammonia gas concentration in the permeated gas was 27.6% by volume. From the obtained results, it can be seen that ammonia can be separated from the mixed gas.
- aluminum hydroxide 53.5 mass% of Al 2 O 3 , manufactured by Aldrich
- Water is added so that the RHO type zeolite is 1% by mass to obtain a seed crystal dispersion, and the inside is evacuated.
- the seed crystal was adhered to the support by a rubbing method while the inside of the support was evacuated.
- the support on which the seed crystal is attached is immersed in a Teflon (registered trademark) inner cylinder containing the raw material mixture for hydrothermal synthesis in the vertical direction to seal the autoclave, and the autoclave is sealed at 160 ° C. for 24 hours under an autogenous pressure. And heated.
- Teflon registered trademark
- the substrate-zeolite membrane composite was taken out of the autoclave after being allowed to cool, and after washing, dried at 100 ° C. for 5 hours or more. After drying, the air permeation amount in the as-made state was 0.0 / (m 2 ⁇ min).
- the obtained membrane composite was fired to obtain an RHO type zeolite membrane composite. From the difference between the weight of the zeolite membrane composite after calcination and the weight of the support, the weight of the RHO type zeolite crystallized on the support was 56 g / m 2 .
- the RHO type zeolite membrane composite after removing the template was put in a Teflon (registered trademark) inner cylinder (65 ml) containing 50 g of 1M ammonium nitrate aqueous solution.
- the autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under autogenous pressure.
- the RHO type membrane was taken out from the aqueous solution and rinsed with 100 ° C. ion exchange water for 1 hour.
- the NH 4 + type RHO type zeolite membrane composite was put in a Teflon (registered trademark) inner cylinder (65 ml) containing 50 g of a 1M aqueous solution of aluminum nitrate.
- the autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under autogenous pressure.
- the RHO type membrane is taken out from the aqueous solution, washed with water, dried at 100 ° C. for 4 hours or more, and is an RHO type zeolite membrane composite 6 that has been treated with Al 4 + type. RHO type zeolite membrane composite was obtained.
- Example A11 ⁇ Evaluation of membrane separation performance> An RHO type zeolite membrane composite was prepared in the same manner as in Example A7, except that the RHO type zeolite membrane composite 6 described in Production Example A7 was used instead of the RHO type zeolite membrane composite 4 described in Production Example A5. and temperature 250 ° C. of the body 6, under the conditions of 325 ° C., were isolated test of 12 vol% NH 3/51 vol% N 2/37 mixed gas vol% H 2.
- Table 9 shows the concentration of ammonia in the permeated gas and the permeance ratio of ammonia / hydrogen and ammonia / nitrogen.
- the ammonia concentration of the permeating gas is a value obtained by rounding off the first decimal place. From these results, it can be seen that when the ammonia gas concentration in the mixed gas is a specific amount or more, ammonia can be efficiently separated. In addition, it was confirmed that the RHO film produced with the gel composition having an increased Al content was able to separate ammonia more selectively under high temperature conditions.
- the ammonia permeance at 250 ° C. is 1.3 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)], and the ammonia permeance at 325 ° C. is 2.8 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)].
- the three supports to which the seed crystals were attached were immersed vertically in a Teflon (registered trademark) inner cylinder (200 ml) containing the above-mentioned raw material mixture for hydrothermal synthesis, and the autoclave was sealed at 180 ° C. And heated for 30 hours in a stationary state under autogenous pressure. After the elapse of a predetermined time, the support-zeolite membrane composite was taken out of the reaction mixture after being allowed to cool, washed, and dried at 100 ° C. for 3 hours to obtain MFI type zeolite membrane composite 1. The mass of the MFI type zeolite crystallized on the support was 0.26 to 0.28 g. The air permeation amount of the fired membrane composite was 0.0 to 0.1 cm 3 / min.
- Example A12 ⁇ Evaluation of membrane separation performance> Ammonia separation evaluation was performed in the same manner as in Example A1, except that the MFI-type zeolite membrane composite 1 described in Production Example A8 was used instead of the CHA-type zeolite membrane composite 1 described in Production Example A1. .
- Table 10 shows the ammonia concentration and the permeance ratio of ammonia / hydrogen and ammonia / nitrogen in the permeate gas obtained.
- the ammonia concentration of the permeating gas is a value obtained by rounding off the first decimal place. Further, the permeance of ammonia at 250 ° C. was 7.5 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)].
- Example A13 Ammonia separation was carried out in the same manner as in Example A12 except that the temperature was 250 ° C. and the mixed gas was a mixed gas of 2.0 vol% NH 3 /20.0 vol% N 2 /78.0 vol% H 2 . As a result of the evaluation, the ammonia gas concentration in the permeated gas was 7.0% by volume. From the obtained results, it can be seen that ammonia can be separated from the mixed gas.
- Example A14 Ammonia separation was carried out in the same manner as in Example A12 except that the temperature was 250 ° C. and the mixed gas was a mixed gas of 3.0% by volume NH 3 /20.0% by volume N 2 /77.0% by volume H 2 . As a result of the evaluation, the ammonia gas concentration in the permeated gas was 10.7% by volume. From the obtained results, it can be seen that ammonia can be separated from the mixed gas.
- the nitrogen permeance is 3.3 ⁇ 10 ⁇ 9 [mol / (m 2 ⁇ s ⁇ Pa)], and the ammonia permeance is 7.5 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)]. there were.
- the permeance of hydrogen when hydrogen gas is circulated is 4.7 ⁇ 10 ⁇ 7 [mol / (m 2 ⁇ s ⁇ Pa)], and when nitrogen gas is circulated.
- the nitrogen permeance is 3.0 ⁇ 10 ⁇ 7 [mol / (m 2 ⁇ s ⁇ Pa)]. From these results, when ammonia gas is contained in the supply gas, both hydrogen and nitrogen are remarkably increased. It was found that permeance decreased. From this result, it is considered that when the ammonia gas concentration in the mixed gas is a specific amount or more, the ammonia in the supply gas is adsorbed on the zeolite and exhibits the effect of inhibiting the permeation of hydrogen and nitrogen.
- Table 11 shows data of Examples A1 to A3, A8 to 10, A12 to 14, and Comparative Examples A1 to A2. The evaluation results at 100 ° C. for Examples A1 to A3 and Comparative Examples A1 and A2 and at 250 ° C. for Examples A8 to 10 and A12 to 14 are shown. From these results, it was found that the concentration of ammonia with respect to hydrogen and nitrogen increases when the ammonia gas concentration in the mixed gas is a specific amount or more.
- Example B [Measurement of physical properties and separation performance]
- the physical properties and separation performance of zeolite or zeolite membrane composite were measured as follows.
- X-ray diffraction (XRD) measurement was performed based on the following conditions.
- Device name New D8 ADVANCE manufactured by Bruker Optical system: Concentrated optical system Optical system specifications
- Incident side Enclosed X-ray tube (CuK ⁇ ) Soller Slit (2.5 °) Divergence Slit (Variable Slit)
- Sample stage XYZ stage
- Light receiving side Semiconductor array detector (Lynx Eye 1D mode) Ni-filter Soller Slit (2.5 °) Goniometer radius: 280mm
- Measurement conditions X-ray output (CuK ⁇ ): 40 kV, 40 mA Scanning axis: ⁇ / 2 ⁇ Scanning range (2 ⁇ ): 5.0-70.0 °
- Measurement mode Continuous Reading width: 0.01 °
- Counting time 57.0 sec (0.3 sec x 190 ch)
- Automatic variable slit Automatic-DS: 1 mm (irradiation width)
- the measurement data was subject
- X-rays were irradiated in a direction perpendicular to the axial direction of the cylindrical tube. Also, the X-ray is not a line in contact with the surface of the sample table out of two lines where the cylindrical tubular membrane composite placed on the sample table and a surface parallel to the surface of the sample table are in contact with each other so that noise is not required as much as possible. The main line was placed on the other line above the surface of the sample table.
- the irradiation width was fixed to 1 mm by an automatic variable slit and measured, and Materials Data, Inc.
- XRD analysis software JADE + 9.4 (English version) was used to perform variable slit ⁇ fixed slit conversion to obtain an XRD pattern.
- Quantification was performed using the sensitivity correction coefficient provided by ULVAC-PHI Co., Ltd., and the background during quantitative calculation was determined by the Shirley method.
- Air permeation amount One end of the zeolite membrane composite was sealed, the other end was sealed and connected to a 5 kPa vacuum line, and the air flow was measured with a mass flow meter installed between the vacuum line and the zeolite membrane composite. The flow rate was measured and the air permeation amount [L / (m 2 ⁇ h)] was obtained.
- a mass flow meter 8300 manufactured by KOFLOC, for N 2 gas, and a maximum flow rate of 500 ml / min (20 ° C., converted to 1 atm) were used.
- a cylindrical zeolite membrane composite 1 is installed in a thermostat (not shown) in a state of being stored in a pressure vessel 2 made of stainless steel.
- the thermostat is provided with a temperature control device so that the temperature of the supply gas can be adjusted.
- One end of the cylindrical zeolite membrane composite 1 is sealed with an end pin 3 having a T-shaped cross section.
- the other end of the zeolite membrane complex 1 is connected to the discharge pipe 10 for the permeated gas 8 through the connection portion 4, and the pipe 10 extends to the outside of the pressure vessel 2.
- a pressure gauge 5 for measuring the supply pressure of the supply gas 7 from the supply pipe 12 and a back pressure valve 6 for adjusting the supply pressure are connected to the gas discharge pipe 13 from the pressure vessel 2.
- Each connection part is connected with good airtightness.
- a supply gas (sample gas) 7 is supplied between the pressure vessel 2 and the zeolite membrane composite 1 at a constant flow rate, and a back pressure valve 6 is used to supply the supply gas (sample gas) 7.
- the permeate gas 8 permeated through the zeolite membrane composite 1 with a constant pressure was measured with a flow meter connected to the pipe 10.
- One end of the cylindrical zeolite membrane composite 1 is sealed with an end pin 3 having a T-shaped cross section.
- the other end of the zeolite membrane composite 1 is connected to the discharge pipe 11 for the permeated gas 8 through the connection portion 4, and the pipe 11 extends to the outside of the pressure vessel 2.
- a pressure gauge 5 for measuring the pressure on the supply side of the supply gas 7 is connected to the supply pipe 12 for the supply gas (sample gas) 7 to the pressure vessel 2.
- Each connection part is connected with good airtightness.
- an ammonia separation test was performed as follows.
- a mixed gas containing ammonia, nitrogen, and hydrogen is supplied as a supply gas at a flow rate of 100 SCCM between the pressure vessel and the zeolite membrane composite, and the gas and membrane on the supply side are supplied by a back pressure valve.
- Adjust the pressure difference of the gas that has passed through the inside to be constant at 0.3 MPa, mix the exhaust gas discharged from the pipe 10 with helium, whose flow rate is controlled by the mass flow controller, as a standard substance, and analyze it with a micro gas chromatograph Then, the concentration and flow rate of the permeating gas were calculated.
- the sample gas temperature and The pressure difference between the supply gas side and the permeate gas side of the zeolite membrane composite was kept constant, and after the permeate gas flow rate was stabilized, the flow rate of the sample gas (permeate gas) permeated through the zeolite membrane composite was measured, and the gas permeance [ mol / (m 2 ⁇ s ⁇ Pa)] was calculated.
- the pressure difference (differential pressure) between the supply side and the permeation side of the supply gas was used.
- ⁇ ′ (Q1 / Q2) / (P1 / P2) (1)
- Q1 and Q2 respectively represent the permeation amount [mol ⁇ (m 2 ⁇ s) ⁇ 1 ] of a highly permeable gas and a low permeable gas
- P1 and P2 are respectively
- the pressure difference [Pa] between the supply side and the permeation side of the gas with high permeability and the gas with low permeability is shown.
- RHO type zeolite membrane composites 1 and 2 were produced by the following method. Prior to the production of the RHO type zeolite membrane composites 1 and 2, a hydrothermal synthesis raw material mixture 1, a support and a seed crystal dispersion 1 were prepared as follows.
- an alumina tube (outer diameter 6 mm, inner diameter 4 mm, pore diameter 0.15 ⁇ m, manufactured by Noritake Company Limited) was cut to a length of 80 mm, washed with water and dried. .
- the mixture was aged at room temperature for 24 hours, then placed in a pressure vessel, left in an oven at 150 ° C., and subjected to hydrothermal synthesis for 72 hours. After this hydrothermal synthesis reaction, the reaction solution was cooled and the crystals produced by filtration were collected. The recovered crystals were dried at 100 ° C. for 12 hours to obtain crystals that were RHO type zeolite.
- the obtained RHO type zeolite was pulverized with a ball mill to produce a seed crystal dispersion. Specifically, 10 g of the above-mentioned RHO type zeolite, 300 g of 3 ⁇ mm HD alumina balls (made by Nikkato Co., Ltd.) and 90 g of water were placed in 500 mL of polybin and ball milled for 6 hours to obtain a 10% by mass RHO type zeolite dispersion. . Water was added to the zeolite dispersion so that the RHO type zeolite was 1% by mass to obtain a seed crystal dispersion 1.
- the support to which the seed crystal was attached was immersed vertically in a Teflon (registered trademark) inner cylinder containing a raw material mixture for hydrothermal synthesis to seal the autoclave and heated at 160 ° C. for 24 hours under autogenous pressure. .
- the support-zeolite membrane complex was taken out of the autoclave after being allowed to cool, washed with ion-exchanged water, and dried at 100 ° C. for 5 hours or more. After drying, the air permeation amount in an as-made state was 0.0 L / (m 2 ⁇ min).
- the obtained membrane composite was fired to obtain an RHO type zeolite membrane composite. This RHO type zeolite membrane composite was heated from room temperature to 100 ° C. in 2 hours, heated from 100 ° C. to 300 ° C. in 20 hours, calcined at 300 ° C. for 5 hours, and then cooled to 100 ° C. in 20 hours.
- the temperature was lowered from 100 ° C. to room temperature in 2 hours. From the difference between the weight of the zeolite membrane composite after calcination and the weight of the support, the weight of the RHO type zeolite crystallized on the support was 62 g / m 2 .
- the RHO type zeolite membrane composite after removing the template was put in a Teflon container (registered trademark) inner cylinder (65 ml) containing 50 g of 1M ammonium nitrate aqueous solution.
- the autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under autogenous pressure.
- the RHO type membrane was taken out from the aqueous solution and rinsed with 100 ° C. ion exchange water for 1 hour.
- the obtained NH 4 + type RHO type zeolite membrane composite 1 was put into a Teflon container (registered trademark) inner cylinder (65 ml) containing 45 g of 1M aqueous aluminum nitrate solution, and the autoclave was sealed, and 1 ° C. at 100 ° C. Heated under time, standing, and autogenous pressure.
- Teflon container registered trademark
- inner cylinder 65 ml
- the NH 4 + type RHO type zeolite membrane composite 1 subjected to the above treatment is taken out from the aqueous solution, washed with ion-exchanged water, dried at 100 ° C. for 4 hours or more, and RHO.
- An Al-treated NH 4 + type RHO type zeolite membrane composite as a type 2 zeolite membrane composite 2 was obtained.
- the nitrogen atom / Al atom molar ratio of the zeolite membrane was 0.42, and the Si atom / Al atom molar ratio was 3.01.
- Example B1 ⁇ Evaluation of membrane separation performance> Using the RHO-type zeolite membrane composite 2 described in Production Example B1, an ammonia separation test from a mixed gas of ammonia gas (NH 3 ) / hydrogen gas (H 2 ) / nitrogen gas (N 2 ) was carried out by the above method. Specifically, using the apparatus shown in FIG.
- a 10 vol% NH 3/20 vol% H 2/60 mixed gas vol% N 2 as a feed gas is introduced between the pressure vessel and the RHO zeolite membrane composite 2,
- the pressure was maintained at about 0.3 MPa, and the inside of the cylinder of the RHO zeolite membrane composite 2 was set to 0.098 MPa (atmospheric pressure), and dried for about 120 minutes.
- the 12 vol% NH 3/51 vol% N 2/37 mixed gas vol% H 2 was passed through at 100 SCCM, and set back pressure to 0.4 MPa.
- the differential pressure between the supply gas side and the permeate gas side of the RHO zeolite membrane composite 2 was 0.3 MPa.
- 3.9 SCCM of argon was supplied from the supply gas 9 as a sweep gas.
- the permeance ratio is shown in Table 12. From the results of Table 12, it can be seen that ammonia can be efficiently separated by using an NH 4 + type RHO type zeolite membrane having a nitrogen atom / Al atom molar ratio of 0.42 by XPS measurement.
- the NH 4 + type RHO type zeolite membrane having a nitrogen atom / Al atom molar ratio of 0.42 by XPS measurement under high temperature conditions can separate ammonia with high selectivity.
- the ammonia permeance at 250 ° C. is 1.0 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)]
- the ammonia permeance at 325 ° C. is 2.0 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)].
- RHO type zeolite membrane composite 3 was manufactured by the following method.
- the support used was the same support as in Production Example B1, and the seed crystal dispersion was the same as the seed crystal dispersion 1 in Production Example B1.
- aluminum hydroxide 53.5 mass% of Al 2 O 3 , manufactured by Aldrich
- the support on which the seed crystal is attached is immersed in a Teflon (registered trademark) inner cylinder containing the hydrothermal synthesis raw material mixture 2 in the vertical direction to seal the autoclave, and the autogenous pressure is maintained at 160 ° C. for 24 hours. Heated under.
- Teflon registered trademark
- the support-zeolite membrane complex was taken out of the autoclave after being allowed to cool, washed with ion-exchanged water, and dried at 100 ° C. for 5 hours or more. After drying, the air permeation amount in an as-made state was 0.0 L / (m 2 ⁇ min).
- the obtained membrane composite was fired to obtain an RHO type zeolite membrane composite. This RHO type zeolite membrane composite was heated from room temperature to 100 ° C. in 2 hours, heated from 100 ° C. to 300 ° C. in 20 hours, calcined at 300 ° C. for 5 hours, and then cooled to 100 ° C. in 20 hours.
- the temperature was lowered from 100 ° C. to room temperature in 2 hours. From the difference between the weight of the zeolite membrane composite after calcination and the weight of the support, the weight of the RHO type zeolite crystallized on the support was 56 g / m 2 .
- the RHO type zeolite membrane composite after removing the template was put in a Teflon container (registered trademark) inner cylinder (65 ml) containing 50 g of 1M ammonium nitrate aqueous solution.
- the autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under autogenous pressure.
- the RHO type membrane was taken out from the aqueous solution and rinsed with 100 ° C. ion exchange water for 1 hour.
- the NH 4 + type RHO type zeolite membrane composite was put in a Teflon container (registered trademark) inner cylinder (65 ml) containing 50 g of 1M aqueous aluminum nitrate solution.
- the autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under autogenous pressure.
- the NH 4 + type RHO type zeolite membrane composite subjected to the above treatment is taken out from the aqueous solution, washed with ion-exchanged water, dried at 100 ° C. for 4 hours or more, and RHO type An Al-treated NH 4 + type RHO type zeolite membrane composite as the zeolite membrane composite 3 was obtained. Further, the nitrogen atom / Al atom molar ratio of the zeolite membrane measured by XPS was 0.76, and the Si atom / Al atomic molar ratio was 6.65.
- Example B2 ⁇ Evaluation of membrane separation performance> Aside from using the RHO type zeolite membrane composite 3 described in Production Example B2 instead of the RHO type zeolite membrane composite 2 described in Production Example B1, the supply amount of argon as a sweep gas was changed to 8.3 SCCM. in a similar manner as in example B1, under the conditions of 250 ° C. and 325 ° C., were isolated test of 12 vol% NH 3/51 vol% N 2/37 mixed gas vol% H 2.
- Table 13 shows the ammonia concentration and the permeance ratio of ammonia / hydrogen and ammonia / nitrogen in the permeate gas obtained. From the results shown in Table 13, it is understood that ammonia can be efficiently separated by using the NH 4 + type RHO type zeolite membrane having a nitrogen atom / Al atom molar ratio of 0.76 in XPS measurement. . In addition, it was confirmed that the RHO film produced with the gel composition having an increased Al atom content can separate ammonia more selectively under high temperature conditions.
- the permeance of ammonia at 250 ° C. is 1.3 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)], and the permeance of ammonia at 325 ° C. is 2.8 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)].
- Seed crystal dispersion 2 A seed crystal dispersion liquid was prepared in the same manner as seed crystal dispersion liquid 1 in Production Example B1, except that 10 mass% RHO zeolite dispersion liquid was prepared and water was added so that the RHO zeolite content was 3 mass%. 2 was produced.
- the seed crystal dispersion 2 was dropped on the support, and the seed crystal was adhered to the support by a rubbing method.
- the support to which the seed crystal is attached is immersed in a Teflon (registered trademark) inner cylinder containing the hydrothermal synthesis raw material mixture 1 in the vertical direction to seal the autoclave, and autogenous pressure is maintained at 150 ° C. for 72 hours. Heated under.
- Teflon registered trademark
- the support-zeolite membrane complex was taken out of the autoclave after being allowed to cool, washed with ion-exchanged water, and dried at 100 ° C. for 5 hours or more. After drying, the air permeation amount in an as-made state was 1.5 L / (m 2 ⁇ min).
- the obtained membrane composite was fired to obtain an RHO type zeolite membrane composite. This RHO type zeolite membrane composite was heated from room temperature to 150 ° C. in 2 hours, heated from 150 ° C. to 400 ° C. in 20 hours, calcined at 400 ° C. for 5 hours, and then cooled to 150 ° C. in 20 hours.
- the temperature was lowered from 150 ° C. to room temperature in 2 hours. From the difference between the weight of the zeolite membrane composite after calcination and the weight of the support, the weight of the RHO type zeolite crystallized on the support was 78 g / m 2 .
- the RHO type zeolite membrane composite after removing the template is put into a Teflon container (registered trademark) inner cylinder (65 ml) containing 45 g of 3M ammonium nitrate aqueous solution, and the autoclave is tightly sealed and left at 110 ° C. for 1 hour. The state was heated under autogenous pressure.
- the RHO type membrane was taken out from the aqueous solution, washed with ion-exchanged water, and then dried at 100 ° C. for 4 hours or more to obtain an NH 4 + type RHO type zeolite membrane composite.
- this RHO type zeolite membrane composite was calcined in an electric furnace at 400 ° C. for 2 hours. At this time, the temperature rising rate and the temperature decreasing rate up to 150 ° C. are both 2.5 ° C./min, the temperature increasing rate from 150 ° C. to 400 ° C. and the temperature decreasing rate are 0.5 ° C./min. Thus, an H + type RHO type zeolite membrane composite was obtained. Further, the nitrogen atom / Al atom molar ratio of the zeolite membrane measured by XPS was 0.23, and the Si atom / Al atomic molar ratio was 2.92.
- Example B3 ⁇ Evaluation of membrane separation performance> Using the RHO type zeolite membrane composite 4 described in Production Example B3, an ammonia separation test from a mixed gas of ammonia / hydrogen / nitrogen was performed using the apparatus shown in FIG. As a pretreatment, a mixed gas of 50% by volume H 2 /50% by volume N 2 is introduced as a supply gas at 250 ° C. between the pressure vessel and the RHO type zeolite membrane composite 4, and the pressure is about 0. While maintaining at 3 MPa, the inside of the cylinder of the RHO type zeolite membrane composite 4 was set to 0.098 MPa (atmospheric pressure) and dried for about 120 minutes.
- 0.098 MPa atmospheric pressure
- the ratio was calculated and the results obtained are shown in Table 14. From this result, compared with the separation results of the NH 4 + type RHO type zeolite membrane composites of Examples B1 and 2, the present H + type has a nitrogen atom / Al atom molar ratio of 0.23 by XPS measurement. It was confirmed that the RHO type zeolite membrane composite had a slightly reduced ammonia separation performance, but the separation performance was still high.
- the permeance of ammonia at 250 ° C. was 1.0 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)].
- RHO-type zeolite membrane composite 5 The RHO type zeolite membrane composite 5 was manufactured by the following method. In addition, as a raw material mixture for hydrothermal synthesis, the same thing as the hydrothermal synthesis raw material mixture 2 of manufacture example B2 is used, and a support body and seed crystal dispersion liquid are the support body and seed crystal dispersion liquid 1 of manufacture example B1, respectively. The same one was used.
- the support on which the seed crystal is attached is immersed in a Teflon (registered trademark) inner cylinder containing the hydrothermal synthesis raw material mixture 2 in the vertical direction to seal the autoclave, and the autogenous pressure is maintained at 160 ° C. for 24 hours. Heated under.
- Teflon registered trademark
- the support-zeolite membrane complex was taken out of the autoclave after being allowed to cool, washed with ion-exchanged water, and dried at 100 ° C. for 5 hours or more. After drying, the air permeation amount in an as-made state was 0.0 L / (m 2 ⁇ min).
- the obtained membrane composite was heated from room temperature to 100 ° C. in 2 hours, heated from 100 ° C. to 300 ° C. in 20 hours, and fired at 300 ° C. for 5 hours. The temperature was lowered to 100 ° C. in 20 hours, and the temperature was lowered from 100 ° C.
- RHO type zeolite membrane composite 5 does not use any raw material containing nitrogen atoms in its preparation process, and its content is less than 0.01 as the molar ratio of nitrogen atoms to Al atoms. From the difference between the weight of the zeolite membrane composite after calcination and the weight of the support, the weight of the RHO type zeolite crystallized on the support was 58 g / m 2 .
- the permeance of ammonia at 250 ° C. is 1.9 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)]
- the permeance of ammonia at 300 ° C. is 2.0 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)].
- the present Cs + type RHO type zeolite membrane essentially free of nitrogen atoms contains specific amounts of nitrogen atoms relative to Al atoms as determined by X-ray photoelectron spectroscopy. It was revealed that the ammonia separation ability was lower than any of the RHO type zeolite membranes of No. 3, and that the separation performance had a tendency to be greatly lowered when the temperature was further raised.
- Example C [Measurement of physical properties and separation performance]
- the physical properties and separation performance of zeolite or zeolite membrane composite were measured in the same manner as in Example B.
- RHO type zeolite membrane composites 1 and 2 were produced by the following method. Prior to the production of the RHO type zeolite membrane composites 1 and 2, a hydrothermal synthesis raw material mixture 1, a support and a seed crystal dispersion 1 were prepared as follows.
- an alumina tube (outer diameter 6 mm, inner diameter 4 mm, pore diameter 0.15 ⁇ m, manufactured by Noritake Company Limited) was cut to a length of 80 mm, washed with water and dried. .
- the mixture was aged at room temperature for 24 hours, then placed in a pressure vessel, left in an oven at 150 ° C., and subjected to hydrothermal synthesis for 72 hours. After this hydrothermal synthesis reaction, the reaction solution was cooled and the crystals produced by filtration were collected. The recovered crystals were dried at 100 ° C. for 12 hours to obtain crystals that were RHO type zeolite.
- the obtained RHO type zeolite was pulverized with a ball mill to produce a seed crystal dispersion. Specifically, 10 g of the above-mentioned RHO type zeolite, 300 g of 3 ⁇ mm HD alumina balls (made by Nikkato Co., Ltd.) and 90 g of water were placed in 500 mL of polybin and ball milled for 6 hours to obtain a 10% by mass RHO type zeolite dispersion. . Water was added to the zeolite dispersion so that the RHO type zeolite was 1% by mass to obtain a seed crystal dispersion 1.
- the support to which the seed crystal was attached was immersed vertically in a Teflon (registered trademark) inner cylinder containing a raw material mixture for hydrothermal synthesis to seal the autoclave and heated at 160 ° C. for 24 hours under autogenous pressure. .
- the substrate-zeolite membrane composite was taken out of the autoclave after being allowed to cool, washed with ion-exchanged water, and dried at 100 ° C. for 5 hours or more. After drying, the air permeation amount in an as-made state was 0.0 L / (m 2 ⁇ min).
- the obtained membrane composite was fired to obtain an RHO type zeolite membrane composite. This RHO type zeolite membrane composite was heated from room temperature to 100 ° C. in 2 hours, heated from 100 ° C. to 300 ° C. in 20 hours, calcined at 300 ° C. for 5 hours, and then cooled to 100 ° C. in 20 hours.
- the temperature was lowered from 100 ° C. to room temperature in 2 hours. From the difference between the weight of the zeolite membrane composite after calcination and the weight of the support, the weight of the RHO type zeolite crystallized on the support was 62 g / m 2 .
- the RHO type zeolite membrane composite after removing the template was put in a Teflon container (registered trademark) inner cylinder (65 ml) containing 50 g of 1M ammonium nitrate aqueous solution.
- the autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under autogenous pressure.
- the RHO type membrane was taken out from the aqueous solution and rinsed with 100 ° C. ion exchange water for 1 hour.
- the obtained NH 4 + type RHO type zeolite membrane composite 1 was put into a Teflon container (registered trademark) inner cylinder (65 ml) containing 45 g of 1M aqueous aluminum nitrate solution, and the autoclave was sealed, and 1 ° C. at 100 ° C. Heated under time, standing, and autogenous pressure.
- Teflon container registered trademark
- inner cylinder 65 ml
- the NH 4 + type RHO type zeolite membrane composite 1 subjected to the above treatment is taken out from the aqueous solution, washed with ion-exchanged water, dried at 100 ° C. for 4 hours or more, and RHO.
- An Al-treated NH 4 + type RHO type zeolite membrane composite as a type 2 zeolite membrane composite 2 was obtained. Further, the nitrogen atom / Al atom molar ratio of the zeolite membrane measured by XPS was 0.42, and the Si atom / Al atomic molar ratio was 3.01.
- Example C1 ⁇ Evaluation of membrane separation performance> Using the RHO type zeolite membrane composite 2 described in Production Example C1 and performing an ammonia separation test from a mixed gas of ammonia / hydrogen / nitrogen using the apparatus shown in FIG. It went by. As pretreatment, at 250 ° C., a 10 vol% NH 3/20 vol% H 2/60 mixed gas vol% N 2 as a feed gas, is introduced between the pressure vessel and the RHO zeolite membrane composite 2, The pressure was maintained at about 0.3 MPa, and the inside of the cylinder of the RHO zeolite membrane composite 2 was set to 0.098 MPa (atmospheric pressure), and dried for about 120 minutes.
- the 12 vol% NH 3/51 vol% N 2/37 mixed gas vol% H 2 was passed through at 100 SCCM, and set back pressure to 0.4 MPa. At this time, the differential pressure between the supply gas side and the permeate gas side of the RHO zeolite membrane composite 2 was 0.3 MPa. Further, 3.9 SCCM of argon was supplied from the supply gas 9 as a sweep gas.
- the permeance ratio is shown in Table 16.
- the ammonia permeance at 250 ° C. is 1.0 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)]
- the ammonia permeance at 325 ° C. is 2.0 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)].
- RHO type zeolite membrane composite 3 was manufactured by the following method.
- the support used was the same support as in Production Example C1, and the seed crystal dispersion was the same as the seed crystal dispersion 1 in Production Example C1.
- aluminum hydroxide 53.5 mass% of Al 2 O 3 , manufactured by Aldrich
- a seed crystal dispersion 1 and a support were prepared in the same manner as in Production Example C1, and the support whose inside was evacuated was immersed in this seed crystal dispersion 1 for 1 minute, and then the inside of the support was evacuated. In the state, the seed crystal was adhered to the support by a rubbing method.
- the support on which the seed crystal is attached is immersed in a Teflon (registered trademark) inner cylinder containing the raw material mixture for hydrothermal synthesis in the vertical direction to seal the autoclave, and the autoclave is sealed at 160 ° C. for 24 hours under an autogenous pressure. And heated.
- Teflon registered trademark
- the support-zeolite membrane complex was taken out of the autoclave after being allowed to cool, washed with ion-exchanged water, and dried at 100 ° C. for 5 hours or more. After drying, the air permeation amount in an as-made state was 0.0 L / (m 2 ⁇ min).
- the obtained membrane composite was fired to obtain an RHO type zeolite membrane composite. This RHO type zeolite membrane composite was heated from room temperature to 100 ° C. in 2 hours, heated from 100 ° C. to 300 ° C. in 20 hours, calcined at 300 ° C. for 5 hours, and then cooled to 100 ° C. in 20 hours.
- the temperature was lowered from 100 ° C. to room temperature in 2 hours. From the difference between the weight of the zeolite membrane composite after calcination and the weight of the support, the weight of the RHO type zeolite crystallized on the support was 56 g / m 2 .
- the RHO type zeolite membrane composite after removing the template was put in a Teflon container (registered trademark) inner cylinder (65 ml) containing 50 g of 1M ammonium nitrate aqueous solution.
- the autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under autogenous pressure.
- the RHO type membrane was taken out from the aqueous solution and rinsed with 100 ° C. ion exchange water for 1 hour.
- the NH 4 + type RHO type zeolite membrane composite was put in a Teflon container (registered trademark) inner cylinder (65 ml) containing 50 g of 1M aqueous aluminum nitrate solution.
- the autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under autogenous pressure.
- the RHO type membrane is taken out from the aqueous solution, washed with ion-exchanged water, dried at 100 ° C. for 4 hours or longer, and the RHO type zeolite membrane composite 3 treated with Al 4 NH 4.
- a + type RHO type zeolite membrane composite was obtained. Further, the nitrogen atom / Al atom molar ratio of the zeolite membrane measured by XPS was 0.76, and the Si atom / Al atomic molar ratio was 6.65.
- Example C2 ⁇ Evaluation of membrane separation performance> Example C1 except that RHO type zeolite membrane composite 3 described in Production Example C2 was used instead of RHO type zeolite membrane composite 2 described in Production Example C1 and argon was supplied in an amount of 8.3 SCCM as a sweep gas. in the same manner as was done with 250 ° C., under the conditions of 325 ° C., a separation test of 12 vol% NH 3/51 vol% N 2/37 mixed gas vol% H 2.
- Table 17 shows the concentration of ammonia in the permeated gas and the permeance ratio of ammonia / hydrogen and ammonia / nitrogen.
- the permeance of ammonia at 250 ° C. is 1.3 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)], and the permeance of ammonia at 325 ° C. is 2.8 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)]. From the results in Table 17, it can be seen that ammonia can be efficiently separated by using this NH 4 + type RHO type zeolite membrane having a Si atom / Al atom molar ratio of 6.65. Further, comparing the concentration of ammonia in the obtained permeated gas at 250 ° C.
- the present NH 4 + type RHO type zeolite membrane having a Si atom / Al atom molar ratio of 6.65 by XPS measurement.
- the rate of change was about 5%, and it was found that the zeolite membrane was a separation membrane having excellent separation heat stability.
- An NH 4 + type RHO type zeolite membrane composite obtained by the same method as the RHO type zeolite membrane composite 1 of Production Example C1 was made from a Teflon container (registered trademark) inner cylinder containing 50 g of 1M sodium nitrate aqueous solution. (65 ml). The autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under autogenous pressure.
- the RHO type membrane is taken out from the aqueous solution, rinsed with 100 ° C. ion exchange water for 1 hour, dried at 100 ° C. for 4 hours or more, and ion exchanged into Na + type.
- Type zeolite membrane composite was obtained.
- the obtained Na + type RHO type zeolite membrane is put into a Teflon container (registered trademark) inner cylinder (65 ml) containing 50 g of 1M aluminum nitrate aqueous solution, and the autoclave is tightly sealed, and at 100 ° C. for 1 hour. Heated in a stationary state under autogenous pressure.
- the RHO type membrane is taken out from the aqueous solution, washed with ion-exchanged water, dried at 100 ° C. for 4 hours or more, and Al-treated Na + type as RHO type zeolite membrane composite 4 RHO type zeolite membrane composite was obtained.
- the Na / Al atomic molar ratio of the zeolite membrane measured by XPS was 0.05
- the N atomic / Al atomic molar ratio was 1.21
- the Si atomic / Al atomic molar ratio was 7.46.
- Example C3 ⁇ Evaluation of membrane separation performance> Using the RHO type zeolite membrane composite 4 described in Production Example C3, an ammonia separation test from a mixed gas of ammonia / hydrogen / nitrogen was carried out using the apparatus shown in FIG. As pretreatment, under the conditions of 250 ° C., introduced between 10 vol% NH 3/20 vol% H 2/60 mixed gas vol% N 2 as a feed gas, the pressure vessel and the RHO zeolite membrane composite 4 Then, the pressure was kept at about 0.3 MPa, and the inside of the cylinder of the RHO zeolite membrane composite 4 was set at 0.098 MPa (atmospheric pressure), and dried for about 120 minutes.
- an alumina tube (outer diameter 6 mm, inner diameter 4 mm, pore diameter 0.15 ⁇ m, manufactured by Noritake Company Limited) was cut into a length of 40 mm, washed with water, and dried.
- the support whose inside was evacuated was immersed in this seed crystal dispersion 1 for 1 minute, and then the seed crystal was attached to the support by rubbing in a state where the inside of the support was evacuated.
- the support on which the seed crystal is attached is immersed in a Teflon (registered trademark) inner cylinder containing the hydrothermal synthesis raw material mixture 1 in the vertical direction to seal the autoclave, and the autogenous pressure is maintained at 160 ° C. for 24 hours. Heated under.
- Teflon registered trademark
- the substrate-zeolite membrane composite was taken out of the autoclave after being allowed to cool, washed with ion-exchanged water, and dried at 100 ° C. for 5 hours or more. After drying, the air permeation amount in an as-made state was 0.0 L / (m 2 ⁇ min).
- the obtained membrane composite was fired to obtain an RHO type zeolite membrane composite. This RHO type zeolite membrane composite was heated from room temperature to 100 ° C. in 2 hours, heated from 100 ° C. to 300 ° C. in 20 hours, calcined at 300 ° C. for 5 hours, and then cooled to 100 ° C. in 20 hours.
- the temperature was lowered from 100 ° C. to room temperature in 2 hours. From the difference between the weight of the zeolite membrane composite after calcination and the weight of the support, the weight of the RHO type zeolite crystallized on the support was 52 g / m 2 .
- the RHO type zeolite membrane composite after removing the template was put in a Teflon container (registered trademark) inner cylinder (65 ml) containing 50 g of 1M ammonium nitrate aqueous solution.
- the autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under autogenous pressure.
- the RHO type membrane was taken out from the aqueous solution and rinsed with 100 ° C. ion exchange water for 1 hour.
- a zeolite membrane can be designed for highly selective separation of ammonia from the mixed gas.
- the permeance of ammonia at 250 ° C. is 3.0 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)], and the permeance of ammonia at 300 ° C. is 2.9 ⁇ 10 ⁇ 8 [mol / (M 2 ⁇ s ⁇ Pa)].
- Example D [Measurement of physical properties and separation performance]
- the physical properties and separation performance of zeolite or zeolite membrane composite were measured in the same manner as in Example B.
- RHO type zeolite membrane composites 1 and 2 were produced by the following method. Prior to the production of the RHO type zeolite membrane composites 1 and 2, a hydrothermal synthesis raw material mixture 1, a support and a seed crystal dispersion 1 were prepared as follows.
- an alumina tube (outer diameter 6 mm, inner diameter 4 mm, pore diameter 0.15 ⁇ m, manufactured by Noritake Company Limited) was cut to a length of 80 mm, washed with water and dried. .
- the mixture was aged at room temperature for 24 hours, then placed in a pressure vessel, left in an oven at 150 ° C., and subjected to hydrothermal synthesis for 72 hours. After this hydrothermal synthesis reaction, the reaction solution was cooled and the crystals produced by filtration were collected. The recovered crystals were dried at 100 ° C. for 12 hours to obtain crystals that were RHO type zeolite.
- the obtained RHO type zeolite was pulverized with a ball mill to produce a seed crystal dispersion. Specifically, 10 g of the above-mentioned RHO type zeolite, 300 g of 3 ⁇ mm HD alumina balls (made by Nikkato Co., Ltd.) and 90 g of water were placed in 500 mL of polybin and ball milled for 6 hours to obtain a 10% by mass RHO type zeolite dispersion. . Water was added to the zeolite dispersion so that the RHO type zeolite was 1% by mass to obtain a seed crystal dispersion 1.
- the support to which the seed crystal was attached was immersed vertically in a Teflon (registered trademark) inner cylinder containing a raw material mixture for hydrothermal synthesis to seal the autoclave and heated at 160 ° C. for 24 hours under autogenous pressure. .
- the substrate-zeolite membrane composite was taken out of the autoclave after being allowed to cool, washed with ion-exchanged water, and dried at 100 ° C. for 5 hours or more. After drying, the air permeation amount in an as-made state was 0.0 L / (m 2 ⁇ min).
- the obtained membrane composite was fired to obtain an RHO type zeolite membrane composite. This RHO type zeolite membrane composite was heated from room temperature to 100 ° C. in 2 hours, heated from 100 ° C. to 300 ° C. in 20 hours, calcined at 300 ° C. for 5 hours, and then cooled to 100 ° C. in 20 hours.
- the temperature was lowered from 100 ° C. to room temperature in 2 hours. From the difference between the weight of the zeolite membrane composite after calcination and the weight of the support, the weight of the RHO type zeolite crystallized on the support was 62 g / m 2 .
- the RHO type zeolite membrane composite after removing the template was put in a Teflon container (registered trademark) inner cylinder (65 ml) containing 50 g of 1M ammonium nitrate aqueous solution.
- the autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under autogenous pressure.
- the obtained NH 4 + type RHO type zeolite membrane composite 1 was put in a Teflon container (registered trademark) inner cylinder (65 ml) containing 50 g of a 1M sodium nitrate aqueous solution.
- the autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under autogenous pressure.
- the RHO type membrane is taken out from the aqueous solution, rinsed with 100 ° C. ion exchange water for 1 hour, dried at 100 ° C. for 4 hours or more, and ion exchanged into Na + type.
- Type zeolite membrane composite was obtained.
- the obtained Na + type RHO type zeolite membrane is put into a Teflon container (registered trademark) inner cylinder (65 ml) containing 50 g of 1M aluminum nitrate aqueous solution, and the autoclave is tightly sealed, and at 100 ° C. for 1 hour. Heated in a stationary state under autogenous pressure.
- the RHO type membrane is taken out from the aqueous solution, washed with ion-exchanged water, dried at 100 ° C. for 4 hours or longer, and treated with Al + Na + type RHO type zeolite membrane composite 2 RHO type zeolite membrane composite was obtained. Further, the alkali metal / Al atomic molar ratio of the zeolite membrane of the zeolite composite membrane measured by XPS was 0.05, the N atomic / Al atomic molar ratio was 1.21, and the Si atomic / Al atomic molar ratio was 7.46. there were.
- Example D1 ⁇ Evaluation of membrane separation performance> Using the RHO-type zeolite membrane composite 2 described in Production Example D1 and performing an ammonia separation test from a mixed gas of ammonia / hydrogen / nitrogen using the apparatus shown in FIG. It went by. As pretreatment, under the conditions of 250 ° C., introduced between 10 vol% NH 3/20 vol% H 2/60 mixed gas vol% N 2 as a feed gas, the pressure vessel and the RHO zeolite membrane composite 2 Then, the pressure was maintained at about 0.3 MPa, and the inside of the cylinder of the RHO zeolite membrane composite 2 was set to 0.098 MPa (atmospheric pressure) and dried for about 120 minutes.
- 0.098 MPa atmospheric pressure
- the 12 vol% NH 3/51 vol% N 2/37 mixed gas vol% H 2 was passed through at 100 SCCM, and set back pressure to 0.4 MPa.
- the differential pressure between the supply gas side and the permeate gas side of the RHO zeolite membrane composite was 0.3 MPa.
- 8.3 SCCM of argon was supplied from the supply gas 9 as a sweep gas.
- Table 20 shows the concentration of ammonia in the permeated gas and the permeance ratio of ammonia / hydrogen and ammonia / nitrogen. From the results of Table 20, it can be seen that ammonia can be efficiently separated by using a Na + type RHO type zeolite membrane.
- RHO type zeolite membrane composite 3 was manufactured by the following method.
- the support used was the same support as in Production Example D1, and the seed crystal dispersion was the same as the seed crystal dispersion 1 in Production Example D1.
- aluminum hydroxide 53.5 mass% of Al 2 O 3 , manufactured by Aldrich
- a seed crystal and a support are prepared in the same manner as in Production Example D1, and the support whose inside is evacuated is immersed in this seed crystal dispersion 1 for 1 minute, and then rubbed in a state where the inside of the support is evacuated.
- the seed crystal was attached to the support by the method.
- the support on which the seed crystal is attached is immersed in a Teflon (registered trademark) inner cylinder containing the hydrothermal synthesis raw material mixture 2 in the vertical direction to seal the autoclave, and the autogenous pressure is maintained at 160 ° C. for 24 hours. Heated under.
- Teflon registered trademark
- the support-zeolite membrane complex was taken out of the autoclave after being allowed to cool, washed with ion-exchanged water, and dried at 100 ° C. for 5 hours or more. After drying, the air permeation amount in an as-made state was 0.0 L / (m 2 ⁇ min).
- the obtained membrane composite was fired to obtain an RHO type zeolite membrane composite. This RHO type zeolite membrane composite was heated from room temperature to 100 ° C. in 2 hours, heated from 100 ° C. to 300 ° C. in 20 hours, calcined at 300 ° C. for 5 hours, and then cooled to 100 ° C. in 20 hours.
- the temperature was lowered from 100 ° C. to room temperature in 2 hours. From the difference between the weight of the zeolite membrane composite after calcination and the weight of the support, the weight of the RHO type zeolite crystallized on the support was 56 g / m 2 .
- the RHO type zeolite membrane composite after removing the template was put in a Teflon container (registered trademark) inner cylinder (65 ml) containing 50 g of 1M ammonium nitrate aqueous solution.
- the autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under autogenous pressure.
- the RHO type membrane was taken out from the aqueous solution and rinsed with 100 ° C. ion exchange water for 1 hour.
- the NH 4 + type RHO type zeolite membrane composite was put in a Teflon container (registered trademark) inner cylinder (65 ml) containing 50 g of 1M aqueous aluminum nitrate solution.
- the autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under autogenous pressure.
- the NH 4 + type RHO type zeolite membrane composite subjected to the above treatment is taken out from the aqueous solution, washed with ion-exchanged water, dried at 100 ° C. for 4 hours or more, and RHO type An Al-treated NH 4 + type RHO type zeolite membrane composite as the zeolite membrane composite 3 was obtained. Further, the N atom / Al atom molar ratio of the zeolite membrane measured by XPS was 0.76, and the Si atom / Al atom molar ratio was 6.65. Alkali metal was not detected.
- Table 21 shows the ammonia concentration and the permeance ratio of ammonia / hydrogen and ammonia / nitrogen in the permeate gas obtained. From the results in Table 21, it can be seen that ammonia can be efficiently separated by using an NH 4 + type RHO type zeolite membrane. In addition, it was confirmed that the RHO film produced with the gel composition having an increased Al content was able to separate ammonia more selectively under high temperature conditions. However, the ammonia permeance at 250 ° C. is 1.3 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)], which is lower in permeability than the RHO type zeolite membrane composite 2 containing an alkali metal. It became clear.
- aluminum hydroxide 53.5 mass% of Al 2 O 3 , manufactured by Aldrich
- a seed crystal dispersion 1 and a support were prepared in the same manner as in Production Example D1, and the support whose inside was evacuated was immersed in this seed crystal dispersion 1 for 1 minute, and then the inside of the support was evacuated. In the state, the seed crystal was adhered to the support by a rubbing method.
- the support on which the seed crystal is attached is immersed in a Teflon (registered trademark) inner cylinder containing the hydrothermal synthesis raw material mixture 2 in the vertical direction to seal the autoclave, and the autogenous pressure is maintained at 160 ° C. for 24 hours. Heated under.
- Teflon registered trademark
- the support-zeolite membrane complex was taken out of the autoclave after being allowed to cool, washed with ion-exchanged water, and dried at 100 ° C. for 5 hours or more. After drying, the air permeation amount in an as-made state was 0.0 L / (m 2 ⁇ min).
- the obtained membrane composite was heated from room temperature to 100 ° C. in 2 hours, heated from 100 ° C. to 300 ° C. in 20 hours, and fired at 300 ° C. for 5 hours. The temperature was lowered to 100 ° C. in 20 hours, and the temperature was lowered from 100 ° C.
- the ion pair at the Al site of the zeolite is essentially an alkali metal (Cs and Na ) Become a cation.
- the weight of the RHO type zeolite crystallized on the support was 58 g / m 2 .
- the alkali metal / Al atomic molar ratio of the zeolite membrane of the zeolite composite membrane measured by XPS was 0.073.
- Table 22 shows the ammonia concentration and the permeance ratio of ammonia / hydrogen and ammonia / nitrogen in the permeated gas obtained by setting the temperature of the RHO type zeolite membrane composite 4 to 250 ° C. and circulating the mixed gas. Further, the permeance of ammonia at 250 ° C. was 1.9 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)].
- Example E Measurement of physical properties and separation performance
- XRD measurement was performed under the same conditions as in Example B, and separation performance and the like were measured as in Example B.
- Measurement atmosphere Air temperature rising condition: 20 °C / min
- Example E1 (Production of RHO type zeolite) RHO type zeolite was synthesized as follows.
- This hydrothermal synthesis raw material mixture was aged at room temperature for 24 hours, then placed in a pressure vessel and left in an oven at 150 ° C., and hydrothermal synthesis was performed for 72 hours. After this hydrothermal synthesis reaction, the reaction solution was cooled and the crystals produced by filtration were collected. The collected crystals were dried at 100 ° C. for 12 hours.
- the rate of change of the coefficient of thermal expansion at 200 ° C. with respect to 30 ° C. was ⁇ 1.55%
- the rate of change of the coefficient of thermal expansion at 300 ° C. with respect to 30 ° C. was 0.02 %
- the change rate of the thermal expansion coefficient at 400 ° C. with respect to 30 ° C. was ⁇ 0.01%, and it was confirmed that there was almost no thermal expansion or contraction compared with the thermal expansion coefficient at 30 ° C.
- Example E2 ⁇ Preparation of RHO type zeolite membrane composite 1> A porous support-RHO type zeolite membrane composite was prepared by hydrothermal synthesis of RHO type zeolite directly on the porous support. As the porous support, an alumina tube (outer diameter 6 mm, pore diameter 0.15 ⁇ m, manufactured by Noritake Co., Ltd.) was cut to a length of 40 mm, washed with water and dried.
- an alumina tube outer diameter 6 mm, pore diameter 0.15 ⁇ m, manufactured by Noritake Co., Ltd.
- RHO zeolite synthesized by the method described in Example E1 and ground by a ball mill was used as a seed crystal on the porous support. Ball milling was carried out as follows. In 500 mL of polybin, 10 g of the above-mentioned RHO type zeolite for seed crystal, 300 g of 3 ⁇ mm HD alumina balls (made by Nikkato Co., Ltd.), and 90 g of water were ball milled for 6 hours to obtain a 10 mass% RHO type zeolite dispersion. Water was added to the zeolite dispersion so that the RHO type zeolite was 3% by mass to obtain a seed crystal dispersion. This seed crystal dispersion was dropped onto the support, and the seed crystal was adhered to the support by a rubbing method.
- the support to which the seed crystal was attached was immersed vertically in a Teflon (registered trademark) inner cylinder containing a raw material mixture for hydrothermal synthesis to seal the autoclave, and heated at 150 ° C. for 72 hours under autogenous pressure. .
- the substrate-zeolite membrane composite was taken out of the autoclave after being allowed to cool, and after washing, dried at 100 ° C. for 5 hours or more. After drying, the air permeation amount in an as-made state was 1.5 / (m 2 ⁇ min).
- the obtained membrane composite was fired to obtain an RHO type zeolite membrane composite. From the difference between the weight of the zeolite membrane composite after calcination and the weight of the support, the weight of the RHO type zeolite crystallized on the support was 78 g / m 2 .
- the RHO type zeolite membrane composite after removing the template was placed in an inner tube (65 ml) made of Teflon (registered trademark) containing 45 g of 3M aqueous ammonium nitrate solution.
- the autoclave was sealed and heated at 110 ° C. for 1 hour in a stationary state under autogenous pressure.
- the RHO type membrane was taken out from the aqueous solution, washed with water, and then dried at 100 ° C. for 4 hours or more to obtain an NH 4 + type RHO type zeolite membrane composite.
- this RHO type zeolite membrane composite was calcined in an electric furnace at 400 ° C. for 2 hours. At this time, the heating rate and the cooling rate to 150 ° C are both 2.5 ° C / min, the heating rate and the cooling rate from 150 ° C to 400 ° C are 0.5 ° C / min, and an H + type RHO zeolite A membrane complex was obtained.
- the produced RHO type zeolite membrane composite is referred to as “RHO type zeolite membrane composite 1”.
- Example E3 (Evaluation of membrane separation performance) Using the RHO type zeolite membrane composite 1 described in Example E2, an ammonia separation test from a mixed gas of ammonia / hydrogen / nitrogen was performed using the apparatus shown in FIG. As pretreatment, a mixed gas of 50% H 2 /50% N 2 is introduced between the pressure vessel 2 and the zeolite membrane composite 1 as a supply gas 7 at 250 ° C., and the pressure is set to about 0.3 MPa. Then, the inside of the cylinder of the zeolite membrane composite 1 was set to 0.098 MPa (atmospheric pressure) and dried for about 120 minutes.
- a mixed gas of 50% H 2 /50% N 2 is introduced between the pressure vessel 2 and the zeolite membrane composite 1 as a supply gas 7 at 250 ° C.
- the pressure is set to about 0.3 MPa.
- the inside of the cylinder of the zeolite membrane composite 1 was set to 0.098 MPa (atmospheric pressure) and dried for about 120 minutes
- Table 25 shows the concentration of ammonia in the permeated gas and the permeance ratio of ammonia / hydrogen and ammonia / nitrogen obtained by changing the temperature of the RHO type zeolite membrane composite 1 from 150 ° C. to 300 ° C. From these results, it was confirmed that the ammonia could be separated with high selectivity without causing any gaps or defects between the zeolite particles due to the small thermal expansion or contraction of the RHO zeolite under high temperature conditions. .
- the ammonia permeance at 250 ° C. was 1.0 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)].
- the zeolite membrane composite of the present invention is synthesized using zeolite with a change rate of thermal expansion coefficient within a specific range as a seed crystal, so that ammonia can be stably and highly selectively even under high temperature conditions. It shows that it can be separated.
- Example E4 ⁇ Synthesis of Na + type RHO>
- hydrothermal synthesis was performed by the method described in “Microporous and Mesoporous Materials 132 (2010) 352-356)”. After the hydrothermal synthesis reaction, the reaction solution was cooled and the crystals produced by filtration were collected. The collected crystals were dried at 100 ° C. for 12 hours.
- the results of measuring the coefficient of thermal expansion of the obtained RHO type zeolite are shown in FIG. It was confirmed that the thermal expansion coefficient of Na + type RHO can be approximated to a linear line with respect to temperature. From this approximate expression, the change rate of the thermal expansion coefficient at 300 ° C. with respect to 30 ° C. was estimated to be 0.23%, and the change rate of the thermal expansion coefficient at 400 ° C. with respect to 30 ° C. was estimated to be 0.33%.
- Example E5 ⁇ Synthesis of RHO zeolite membrane composite 2>
- the support on which the seed crystal is attached is immersed vertically in a Teflon (registered trademark) inner cylinder containing a raw material mixture for hydrothermal synthesis to seal the autoclave and heated at 150 ° C. for 72 hours under an autogenous pressure.
- an NH 4 + type RHO type zeolite membrane composite was obtained by the method described in Example E2.
- the NH 4 + type RHO type zeolite membrane composite was put in a Teflon (registered trademark) container inner cylinder (65 ml) containing 45 g of 1M aluminum nitrate aqueous solution.
- the autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under autogenous pressure.
- the RHO type membrane was taken out from the aqueous solution, washed with water, dried at 100 ° C. for 4 hours or longer, and an Al-treated NH 4 + type RHO type zeolite membrane composite was obtained. .
- the RHO type membrane is taken out from the aqueous solution, washed with water, dried at 100 ° C. for 4 hours or more, and subjected to Al treatment to obtain an RHO type zeolite membrane composite ion-exchanged to Na + type. It was.
- RHO type zeolite membrane composite 2 the manufactured RHO type zeolite membrane composite ion-exchanged to Na + type after the Al treatment.
- Example E6 ⁇ Evaluation of membrane separation performance> Using the RHO type zeolite membrane composite 2 described in Example E5, an ammonia separation test from a mixed gas of ammonia / hydrogen / nitrogen was performed using the apparatus shown in FIG. As pretreatment, a mixed gas of 50% H 2 /50% N 2 is introduced between the pressure vessel 2 and the zeolite membrane composite 1 as a supply gas 7 at 250 ° C., and the pressure is set to about 0.3 MPa. Then, the inside of the cylinder of the zeolite membrane composite was set to 0.098 MPa (atmospheric pressure) and dried for about 120 minutes.
- a mixed gas of 50% H 2 /50% N 2 is introduced between the pressure vessel 2 and the zeolite membrane composite 1 as a supply gas 7 at 250 ° C.
- the pressure is set to about 0.3 MPa.
- the inside of the cylinder of the zeolite membrane composite was set to 0.098 MPa (atmospheric pressure) and dried for about 120 minutes.
- Table 26 shows the ammonia concentration and the permeance ratio of ammonia / hydrogen and ammonia / nitrogen in the permeated gas obtained by changing the temperature of the RHO type zeolite membrane composite 2 to 50 ° C. and 250 ° C. From these results, it was confirmed that the ammonia could be separated with high selectivity without causing any gaps or defects between the zeolite particles due to the small thermal expansion or contraction of the RHO zeolite under high temperature conditions. .
- the ammonia permeance at 250 ° C. was 2.0 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)]. Therefore, it was confirmed that the RHO type membrane composite stably separated ammonia under high temperature conditions when the change rate of the thermal expansion coefficient of the zeolite constituting the zeolite membrane composite was in a specific range.
- MFI type zeolite was synthesized as follows. To a mixture of 13.65 g of 50 wt% NaOH aqueous solution and 101 g of water, 0.15 g of sodium aluminate (containing Al 2 O 3 -62.2% by mass) was added and stirred for 10 minutes at room temperature. To this was added 32.3 g of colloidal silica (Snowtech-40, Nissan Chemical Co., Ltd.), and the mixture was stirred at 50 degrees for 5 hours to obtain a raw material mixture for hydrothermal reaction.
- colloidal silica Snowtech-40, Nissan Chemical Co., Ltd.
- the hydrothermal synthesis raw material mixture was placed in a pressure vessel, and hydrothermal synthesis was performed in an oven at 180 ° C. for 30 hours while stirring at 15 rpm. After this hydrothermal synthesis reaction, the reaction solution was cooled and the crystals produced by filtration were collected. The collected crystals were dried at 100 ° C. for 12 hours.
- the rate of change of the coefficient of thermal expansion at 200 ° C. relative to 30 ° C. is 0.13%
- the rate of change of the coefficient of thermal expansion at 300 ° C. relative to 30 ° C. is The rate of change of the thermal expansion coefficient at 400 ° C. with respect to 0.15% and 30 ° C. was 0.13% (both in the c-axis direction), and it was confirmed that the zeolite was expanded as compared with 30 ° C.
- a raw material mixture for hydrothermal synthesis was prepared by the following method. To a mixture of 13.65 g of 50 wt% NaOH aqueous solution and 101 g of water, 0.15 g of sodium aluminate (containing Al 2 O 3 -62.2% by mass) was added and stirred for 10 minutes at room temperature. To this was added 32.3 g of colloidal silica (Snowtech-40, Nissan Chemical Co., Ltd.), and the mixture was stirred at 50 degrees for 5 hours to obtain a raw material mixture for hydrothermal reaction.
- colloidal silica Snowtech-40, Nissan Chemical Co., Ltd.
- ZSM5 zeolite Tosoh HSZ-800 series 822H0A
- ZSM5 seed crystal aqueous solution aqueous solution in which the concentration of this seed crystal is about 0.4% by mass
- the substrate was immersed for 1 minute, dried at 70 ° C. for 1 hour, again immersed in a ZSM5 seed crystal solution for 1 minute, and then dried at 70 ° C. for 1 hour to attach seed crystals.
- the mass of the attached seed crystal was about 0.0016 g.
- an alumina tube BN1 (outer diameter 6 mm, inner diameter 4 mm) manufactured by Noritake Company Limited was cut to a length of 80 mm, washed with an ultrasonic cleaner, and then dried. It was. Three porous supports with seed crystals attached were prepared by the above method.
- the three supports to which the seed crystals were attached were each immersed in a Teflon (registered trademark) inner cylinder (200 ml) containing the aqueous reaction mixture in the vertical direction, and the autoclave was sealed. At 180 ° C. for 30 hours, Heated under static pressure in a stationary state. After the elapse of a predetermined time, the support-zeolite membrane composite was taken out of the reaction mixture after being cooled, washed, and dried at 100 ° C. for 3 hours to obtain an MFI type zeolite membrane composite 2. The mass of the MFI zeolite crystallized on the support was 0.26 to 0.28 g. The air permeation amount of the fired membrane composite was 0.0 to 0.1 cm 3 / min.
- Example E9 ⁇ Evaluation of membrane separation performance> It was obtained by changing the temperature of the MFI-type zeolite membrane composite 2 described in Example E8 to 100 ° C. to 250 ° C. and flowing a mixed gas of 12% ammonia / 51% nitrogen / 37% nitrogen at a flow rate of 100 SCCM.
- Table 27 shows the concentration of ammonia in the permeated gas and the permeance ratio of ammonia / hydrogen and ammonia / nitrogen. Even when the temperature was changed from 150 ° C. to 250 ° C., it was confirmed that ammonia permeated through the membrane with high selectivity.
- the thermal expansion coefficient of the zeolite was the same as that of the RHO type zeolite membrane composite. It is thought that it is comparable. Further, the permeance of ammonia at 250 ° C. was 7.5 ⁇ 10 ⁇ 8 [mol / (m 2 ⁇ s ⁇ Pa)].
- a CHA-type zeolite was synthesized as follows. A mixture of 0.6 g NaOH (manufactured by Kishida Chemical Co., Ltd.), 1.1 g KOH (manufactured by Kishida Chemical Co., Ltd.) and 10 g of water contains aluminum hydroxide (Al 2 O 3 -53.5% by mass, manufactured by Aldrich Co., Ltd.) ) 0.5 g was added, stirred and dissolved to obtain a transparent solution.
- TMADAOH N, N, N-trimethyl-1-adamantanammonium hydroxide
- colloidal silica manufactured by Nissan Chemical Co., Ltd.
- 12 g of Snowtech-40 was added and stirred for 2 hours to obtain a raw material mixture for hydrothermal synthesis.
- This hydrothermal synthesis raw material mixture was put in a pressure vessel, and hydrothermal synthesis was carried out in an oven at 190 ° C. for 15 hours while stirring at 15 rpm. After this hydrothermal synthesis reaction, the reaction solution was cooled and the crystals produced by filtration were collected. The collected crystals were dried at 100 ° C. for 12 hours.
- the rate of change of the coefficient of thermal expansion at 200 ° C. with respect to 30 ° C. was ⁇ 0.13%
- the rate of change of the coefficient of thermal expansion at 300 ° C. with respect to 30 ° C. was ⁇ 0.
- the rate of change of the coefficient of thermal expansion at 400 ° C. with respect to 30% and 30 ° C. was ⁇ 0.40% (both in the c-axis direction), confirming that the zeolite contracted compared to 30 ° C.
- an alumina tube BN1 (outer diameter 6 mm, inner diameter 4 mm) manufactured by Noritake Company Limited was cut into a length of 80 mm, washed with an ultrasonic cleaner, and then dried. .
- the gel composition (molar ratio) of SiO 2 / Al 2 O 3 / NaOH / KOH / H 2 O / TMADAOH 1 / 0.033 / 0.1 / 0.06 / 20 / 0.07,
- a CHA-type zeolite obtained by hydrothermal synthesis at 160 ° C. for 2 days for crystallization was filtered, washed with water and dried.
- the seed crystal grain size was about 0.3 to 3 ⁇ m.
- the support was immersed for 1 minute in a dispersion of this seed crystal in water at a concentration of about 1% by mass (CHA seed crystal aqueous solution), and then dried at 100 ° C. for 1 hour to attach the seed crystal.
- the mass of the attached seed crystal was about 0.001 g.
- the mass of the CHA-type zeolite crystallized on the support which was determined from the difference between the mass of the membrane composite after calcination and the mass of the support, was about 0.279 to 0.289 g.
- the air permeation amount of the membrane composite after firing was 2.4 to 2.9 cm 3 / min.
- CHA-type zeolite membrane composite 3 the produced CHA-type zeolite membrane composite is referred to as “CHA-type zeolite membrane composite 3”.
- the zeolite membrane composite of the present invention obtained in Examples E2 and E5 is a plurality of components stably containing ammonia and hydrogen and / or nitrogen even under high temperature conditions exceeding 200 ° C. It was found that ammonia can be efficiently separated from the gas mixture consisting of the above into the permeate side with high permeability.
- the zeolite membrane composite obtained in Reference Example E2 it is considered that the zeolite permeation or defects occurred due to the thermal contraction of the zeolite at a temperature exceeding 200 ° C., and the ammonia permeation selectivity was lowered. . That is, the change rate of the thermal expansion coefficient at 300 ° C.
- the thermal contraction rate at 30 ° C. of the CHA-type zeolite obtained in Reference Example E2 is as large as ⁇ 0.30%, so that it exceeds 200 ° C. It is considered that cracking occurred in the zeolite grain boundary due to thermal contraction of the zeolite in a high temperature range, and gas permeated through the crack, so that the ammonia separation performance was lowered. That is, the zeolite membrane composite maintains high density in a temperature range exceeding 200 ° C., and ammonia is selectively and highly permeable from a gas mixture composed of a plurality of components including ammonia and hydrogen and / or nitrogen. In order to achieve this, it has been clarified that the change in the coefficient of thermal expansion at 300 ° C.
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Abstract
Description
高分子膜は、例えば平膜や中空糸膜などへの加工性に優れる特徴を持つ一方で、膨潤しやすく、耐熱性が低いという技術的課題が残されている。また、高分子膜は、反応性薬品に対する耐性も低く、硫化物などの吸着性の成分によっても劣化が起こりやすい技術的課題が残されている。更に、高分子膜は、圧力により変形しやすく、それにより分離性能が低下するため、特に本発明の課題の一つとなる高温条件下でのアンモニアの分離においては、実用的ではない。
水素ガス、窒素ガスおよびアンモニアガスの混合ガスから高濃度のアンモニアガスを含有する混合ガスを分離する方法としては、1)分離膜を用いて、該混合ガスから水素ガスおよび/または窒素ガスを選択的に透過させる方法、2)分離膜を用いて、該混合ガスからアンモニアガスを選択的に透過させる方法が挙げられる。
前者の水素ガスおよび/または窒素ガスを選択的に透過させる方法としては、種々のゼオライトの多結晶性層を用いる方法(特許文献5)やモレキュラーシーブフィルムを用いる方法(特許文献6)が提案されている。また、特許文献7では、水素ガスおよび/または窒素ガスを選択的に透過させる方法ならびにアンモニアガスを選択的に透過させる方法が記載され、セラミックス基材にシリカ含有層が積層された分離膜を用いて、水素ガス、窒素ガスおよびアンモニアガスの混合物である生成ガスから水素ガス、窒素ガス及びアンモニアガスの少なくとも1成分を分離する分離方法が提案されている。具体的には、特許文献7では、分離膜をアンモニアの製造に適用した概略フローチャートとして、高温条件下では水素ガスが選択的にシリカ膜を透過する為、分離膜を2段に設置し、1段目の分離膜で水素ガスを透過側に分離し、1段目の分離膜で透過しなかった窒素ガスとアンモニアガスから、2段目の分離膜でアンモニアガスを透過側に分離することが示されている。一方、水素ガスとアンモニアガスの混合ガスからアンモニアガスを分離する条件としては、50℃といった低温条件下にする必要があり、しかも該混合ガス中のアンモニアガス濃度は、60モル%を超えることが必要であることが示されている。
更に、特許文献7で提案されている高温条件下で1段目の膜で透過側に分離した水素ガスをリサイクルするプロセスでは、水素ガスを昇圧するエネルギーを要する課題があり、また2段目の膜の窒素ガスとアンモニアガスの分離ではアンモニアガスの透過度は十分でなく、膜面積が大きくなる恐れもある。さらに、高温条件下で水素ガスと、窒素ガスと、アンモニアガスとの混合ガスから原料ガスとなる水素ガスを分離する特許文献7の手法では、例えば、本発明の一実施形態である分離膜をアンモニア合成反応器に直接取り付けてアンモニアを合成する際には、原料ガスが透過してしまうため上記の反応平衡の制約から反応が不利となり、高濃度のアンモニアガスを生成させることはできない。以上の観点からすると、このような分離膜を用いて、水素ガスと、窒素ガスと、アンモニアガスとの混合ガスから水素ガスおよび/または窒素ガスを選択的に透過させる手法は、製造時のエネルギーコストが高騰し、且つプロセスも煩雑になるばかりで、わざわざアンモニア製造プロセスに分離膜を導入する優位性を見出すことは難しい。
これに対して、分離膜を用いて、水素ガスと、窒素ガスと、アンモニアガスとの混合ガスからアンモニアガスを選択的に透過させる手法は、上記の種々の課題を解決する手法として有効である。しかしながら、公知文献7で提案されているシリカ含有層を積層した分離膜を用いたアンモニアガス分離方法では、60モル%を超えるアンモニアガス濃度の混合ガスを用いて、且つアンモニアによるブロッキング効果を発現させるために該混合ガスを50℃まで冷却する必要があることが示され、しかもアンモニアガス分離能もアンモニアガスが水素ガスより多少透過しやすい程度である。このようなプロセスでは、そもそも60モル%を超えるアンモニアガス濃度の混合ガスをどのように調達するのかといった課題があり、そのような混合ガスが調達できたとしても冷却に多大なエネルギーを有する為、経済性のあるプロセスを完成させることは難しい。
一方、特許文献8で提案されている酸素8員環を有する特定のゼオライトを用いてアンモニアガスと水素ガスおよび/または窒素ガスの混合ガスからアンモニアガスを分離する手法は、アンモニアガスを透過させる為に上記のような制約はなく、工業プロセスに適用できる有効な手法と成り得る。しかしながら、特許文献8で提案されているゼオライトの細孔径を利用した分子篩作用によるアンモニアの分離方法ではアンモニアガスと窒素ガスのパーミエンス比(理想分離係数)は、高々、14程度が達成されているに過ぎず、その透過性能は十分なものではない。また、特許文献8では、窒素ガスに対する水素ガスならびにアンモニアガスのパーミエンス比を個別に求め、それらの比の値の比較から、水素ガスと、窒素ガスと、アンモニアガスとの混合ガスからは基本的にアンモニアガスが選択的に透過すると提案されているが、特に水素ガスに対するアンモニアガスのパーミエンス比からするとその透過性能は十分なものではなく、上記のゼオライト細孔径を活用した分子篩作用によるアンモニアガス分離の有効性は限定的である。更に、特許文献8では、140℃での窒素とアンモニアガスの混合ガスからのアンモニアガスの分離を行っているが、アンモニアガス透過前後の各種ガスのパーミエンスを比較すると、透過後にはいずれのガスのパーミエンス値が上昇しており、140℃といった比較的低温条件下においてもゼオライト膜の耐久性が損なわれるといった課題が残されている。これらの課題に対して、ゼオライト膜を用いてアンモニアガスを効率的に透過させる為には、アンモニアが本質的にはゼオライトへの吸着能を有するため、供給混合ガスの組成や分離させる際の温度もまた適切に組み合わせる必要がある。しかしながら、特許文献8では、その適正な分離条件についての記載はなく、提案もなされていないばかりか、水素ガスと、窒素ガスと、アンモニアガスとの混合ガスや、水素ガスと、アンモニアガスとの混合ガスからアンモニアを分離する手法は実証されていない。
一方、アンモニア製造プロセスにおいては、特許文献9のように、近年、低温、低圧条件下でも高活性なアンモニア製造触媒プロセスが報告され、製造時の消費エネルギーを低減させるプロセスとして期待されている。しかしながら、この革新的な製造プロセスのみでは、上記のようにアンモニアの生成反応が平衡反応である理由から、反応平衡の制約により平衡組成を超える高濃度のアンモニアガスを含む混合ガスを生成させることはできず、本質的に、上記の生成アンモニアの回収や原料ガスのリサイクル工程を含めた製造時のエネルギー消費量の低減といった課題を解決することはできない。
[A2] 前記混合ガス中の水素ガス/窒素ガスの体積比が0.2以上、3以下である、[A1]に記載のアンモニアの分離方法。
[A3] アンモニアを分離する際の温度が、50℃より高く、500℃以下である、[A1]または[A2]に記載のアンモニアの分離方法。
[A4]前記ゼオライト膜を構成するゼオライトが、RHO型ゼオライトまたはMFI型ゼオライトである、[A1]~[A3]のいずれかに記載のアンモニアの分離方法。
[A5]水素ガスと窒素ガスからアンモニアを製造する工程を含み、該製造工程で得られるアンモニアガスを含む混合ガスからアンモニアを[A1]~[A4]のいずれかに記載の分離方法により分離するアンモニアの分離方法。
[B1]X線光電子分光法により下記測定条件により求められるAl原子に対する窒素原子のモル比が0.01以上、4以下であることを特徴とするゼオライト膜。
(測定条件)
測定の際のX線源:単色化Al-Kα線、出力16kV-34W
定量計算の際のバックグラウンドの決定法:Shirley法
[B2]前記ゼオライト膜がアンモニウム塩で処理されたゼオライト膜であることを特徴とする、[B1]に記載のゼオライト膜。
[B3]前記ゼオライト膜が更に硝酸アルミニウムで処理されたゼオライト膜であることを特徴とする、[B2]に記載のゼオライト膜。
[B4]前記ゼオライトが、RHO型ゼオライトである、[B1]~[B3]のいずれかに記載のゼオライト膜。
[B5]前記ゼオライト膜が、アンモニアガス分離用であることを特徴する[B1]~[B4]のいずれかに記載のゼオライト膜。
[B6]少なくともアンモニアガスと、水素ガスおよび/または窒素ガスを含む混合ガスから、[B1]~[B5]のいずれかに記載のゼオライト膜を用いてアンモニアガスを透過させて分離する、アンモニアの分離方法。
[B7] 水素ガスと窒素ガスからアンモニアを製造する工程で得られるアンモニアを[B6]に記載の分離方法により分離するアンモニアの分離方法。
[C1]X線光電子分光法を用いて下記測定条件により決定されるAl原子に対するSi原子のモル比が2.0以上、10以下であることを特徴とするゼオライト膜。
(測定条件)
測定の際のX線源:単色化Al-Kα線、出力16kV-34W
定量計算の際のバックグラウンドの決定法:Shirley法
[C2]前記ゼオライト膜が、X線光電子分光法を用いて下記測定条件により求められる決定されるAl原子に対する窒素原子のモル比が0.01以上、4以下であることを特徴とする、[C1]に記載のゼオライト膜。
(測定条件)
測定の際のX線源:単色化Al-Kα線、出力16kV-34W
定量計算の際のバックグラウンドの決定法:Shirley法
[C3]前記ゼオライト膜がアルミニウム塩で処理されたゼオライト膜であることを特徴とする、[C1]または[C2]に記載のゼオライト膜。
[C4]前記ゼオライト膜がアンモニウム塩で処理されたゼオライト膜であることを特徴とする、[C1]~[C3]のいずれかに記載のゼオライト膜。
[C5]前記ゼオライト膜がアンモニウム塩で処理後、アルミニウム塩で処理されたゼオライト膜であることを特徴とする、[C1]~[C4]のいずれかに記載のゼオライト膜。
[C6]前記ゼオライトが、RHO型ゼオライトである、[C1]~[C5]のいずれかに記載のゼオライト膜。
[C7]前記ゼオライト膜が、アンモニア分離用であることを特徴する[C1]~[C6]のいずれかに記載のゼオライト膜。
[C8]少なくともアンモニアガスと、水素ガスおよび/または窒素ガスを含む混合ガスから、[C1]~[C7]のいずれかに記載のゼオライト膜を用いてアンモニアガスを透過させて分離する、アンモニアの分離方法。
[C9]水素ガスと窒素ガスからアンモニアを製造する工程で得られるアンモニアを[C8]に記載の分離方法により分離するアンモニアの分離方法。
[D1]X線光電子分光法により下記測定条件により決定されるAl原子に対するアルカリ金属原子のモル比が0.01以上、0.070以下であることを特徴とするゼオライト膜。
(測定条件)
測定の際のX線源:単色化Al-Kα線、出力16kV-34W
定量計算の際のバックグラウンドの決定法:Shirley法
[D2]前記ゼオライト膜が、X線光電子分光法により下記測定条件で決定されるAl原子に対する窒素原子のモル比が0.01以上、4以下であることを特徴とする、[D1]に記載のゼオライト膜。
(測定条件)
測定の際のX線源:単色化Al-Kα線、出力16kV-34W
定量計算の際のバックグラウンドの決定法:Shirley法
[D3]前記ゼオライト膜がアルカリ金属塩で処理されたゼオライト膜であることを特徴とする、[D1]または[D2]に記載のゼオライト膜。
[D4]前記ゼオライト膜がアンモニウム塩で処理されたゼオライト膜であることを特徴とする、[D1]~[D3]のいずれかに記載のゼオライト膜。
[D5]前記ゼオライト膜がアンモニウム塩で処理後、アルカリ金属塩で処理されたゼオライト膜であることを特徴とする、[D1]~[D4]のいずれかに記載のゼオライト膜。
[D6]前記ゼオライトが、RHO型ゼオライトである、[D1]~[D5]のいずれかに記載のゼオライト膜。
[D7]前記ゼオライト膜が、アンモニアガス分離用であることを特徴する[D1]~[D6]のいずれかに記載のゼオライト膜。
[D8]少なくともアンモニアガスと、水素ガスおよび/または窒素ガスを含む混合ガスから、[D1]~[D7]のいずれかに記載のゼオライト膜を用いてアンモニアガスを透過させて分離する、アンモニアの分離方法。
[D9]水素ガスと窒素ガスからアンモニアを製造する工程で得られるアンモニアを[D8]に記載の分離方法により分離するアンモニアの分離方法。
すなわち、本発明の課題の一つである高温条件下で、アンモニアガスと水素ガスおよび/または窒素ガスを含む複数の成分からなる気体混合物からアンモニアガスを高選択的に且つ高透過性で分離する為には、種々のゼオライト膜複合体の中でも、特定の温度領域での熱膨張変化率を示すゼオライトを成膜化したゼオライト膜複合体を適用する必要があることを見出し、本発明を完成するに至った。なお、本明細書において、熱膨張率の変化率とは、熱膨張率の変化率が最大となる軸方向についての熱膨張率の変化率である。例えば、CHA型ゼオライトはa軸とc軸方向で異なる熱膨張/収縮率を有するが、その変化率はc軸の方が大きい。従って、CHAの熱膨張率の変化率はc軸方向の熱膨張率の変化率である。同様に、MFI型ゼオライトはa軸、b軸、c軸方向で異なる熱膨張/収縮率を有するが、その変化率はc軸の方が大きい。従って、本明細書でのMFIの熱膨張率の変化率はc軸方向の熱膨張率の変化率となる。一方、RHO型ゼオライトは立方晶系であり、結晶軸は全て等価のため、軸方向に寄らず熱膨張率の変化率は一定である。本発明の第五実施形態(発明E)はこのような知見に基づいて達成されたものであり、下記を提供する。
[E1]ゼオライトを含むアンモニア分離用ゼオライト膜複合体であって、前記ゼオライトの30℃における熱膨張率に対する300℃における熱膨張率の変化率が±0.25%以内であり、30℃における熱膨張率に対する400℃における熱膨張率の変化率が±0.35%以内である、アンモニア分離用ゼオライト膜複合体。
[E2]前記ゼオライトの30℃における熱膨張率に対する300℃における該熱膨張率の変化率に対する、30℃における熱膨張率に対する400℃における該熱膨張率の変化率が、±120%以内である、[E1]に記載のアンモニア分離用ゼオライト膜複合体。
[E3]前記ゼオライトが、RHO型ゼオライトまたはMFI型ゼオライトである、[E1]または[E2]に記載のアンモニア分離用ゼオライト膜複合体。
[E4]前記ゼオライトのSiO2/Al2O3モル比が6以上500以下である、[E1]~[E3]のいずれかに記載のアンモニア分離用ゼオライト膜複合体。
[E5]少なくともアンモニアガスと、水素ガスおよび/または窒素ガスを含む気体混合物から、[E1]~[E4]のいずれかに記載のアンモニアガス分離用ゼオライト膜複合体を用いてアンモニアを分離する、アンモニアの分離方法。
[E6]水素ガスと窒素ガスからアンモニアを製造する工程で得られるアンモニアを[E5]に記載の分離方法により分離するアンモニアの分離方法。
第二乃至第五の実施形態は、特に、アンモニアの省エネルギー型製造プロセスの完成に貢献するアンモニアガス分離膜に関する技術であり、また、本発明の態様の一つである反応分離型アンモニア製造プロセスへの適用が期待できる技術となる。
本発明のゼオライト膜の具体的な適用例としては、ハーバー・ボッシュプロセスに代表されるアンモニア製造プロセス等において、反応器から回収されるアンモニアガスと水素ガスおよび窒素ガスを含む複数の成分からなる混合ガスからアンモニアを回収する際に、従来の冷却凝縮分離法よりも効率的にアンモニア分離ができるため、アンモニア凝縮のための冷却エネルギーを低減させることができる。
また、別の態様としては、本発明のゼオライト膜は高温条件下でも安定してアンモニアガスと水素ガスおよび窒素ガスを含む複数の成分からなる混合ガスからアンモニアガスを高い透過度で効率的に透過側に分離することができるため、本発明のゼオライト膜を反応器内に設置し、アンモニアガスを生成させながら同時に生成するアンモニアガスを回収する、反応分離型アンモニア製造プロセスが設計できる。
本発明の第二乃至第五の実施形態によれば、高温条件下でも安定して、アンモニアガスと水素ガスおよび/または窒素ガスを含む複数の成分からなる混合ガスから連続してアンモニアガスを高い選択性で効率的に透過側に分離することができる。また、本発明のゼオライト膜は、より高温条件下でも安定して使用できるために、アンモニアガスの透過度が高く、その結果、分離に必要な膜面積を小さくすることができ、小規模な設備で、低コストでのアンモニアガス分離が可能となる。
本発明のゼオライト膜の具体的な適用例としては、ハーバー・ボッシュプロセスに代表されるアンモニア製造プロセス等において、反応器から回収されるアンモニアガスと水素ガスおよび/または窒素ガスを含む複数の成分からなる混合ガスからアンモニアを回収する際に、従来の冷却凝縮分離法よりも効率的にアンモニア分離ができるため、アンモニア凝縮のための冷却エネルギーを低減することができる。
また、別の態様としては、本発明のゼオライト膜は高温条件下でも安定してアンモニアガスと水素ガスおよび/または窒素ガスを含む複数の成分からなる混合ガスからアンモニアガスを高い透過度で効率的に透過側に分離することができるため、本発明のゼオライト膜を反応器内に設置し、アンモニアガスを生成させながら同時に生成するアンモニアガスを回収する、反応分離型アンモニア製造プロセスが設計できる。
特に、第一乃至第五の実施形態の反応分離型アンモニア製造プロセスへの適用は、アンモニア製造時の反応圧の低圧化が期待されるだけではなく、原料ガスのアンモニアガスへの転化率が著しく向上し、製造時の回収ガスの反応器へのリサイクル量を低減させることが期待できる。すなわち、本発明のゼオライト膜を採用した反応分離型アンモニア製造プロセスにより、製造時のエネルギー消費量を抑えることが可能となり、経済性にも優れた省エネルギー型のアンモニア製造が可能になる。
また、本発明のアンモニアの分離方法の他の実施形態は、特定のゼオライト膜に、アンモニアと水素および/または窒素を含む複数の成分からなる混合ガスを接触させ、該混合ガスから、アンモニアを選択的に透過させて分離することを特徴とするものである。
以下、詳細について説明する。
本実施形態に係るアンモニアの分離方法は、少なくとも、アンモニアと、水素と、窒素と、を含む混合ガスからアンモニアを効率的に分離する際に効果的に用いることができるために、このような混合ガスが得られるアンモニアの製造方法と組み合わせて使用することが効果的である。すなわち、水素と窒素からアンモニアを製造する第一工程、および第一工程で得られるアンモニアを後述するアンモニアの分離方法により分離する第二工程、を含み、第一工程で得られたアンモニアを第二工程でアンモニアを分離するアンモニア製造方法以外にも、上記第一工程および上記第二工程が一つの反応器内で進行する、アンモニアの製造方法も本発明の好ましい態様の一つである。第一工程および第二工程が一つの反応器内で進行するとは、第一工程および第二工程が同時に進行するということである。つまり、本発明の一実施形態では、容器内で水素ガスと窒素ガスからアンモニアガスを製造し、該容器内において、製造されたアンモニアガスを含む混合ガスからアンモニアを分離しながらアンモニアを効率良く製造することができる。
アンモニアの工業製造方法としては、特段の制限はないが、ハーバー・ボッシュ法が挙げられる。この方法においては、基本的には酸化鉄を触媒とし、300℃~500℃、10~40MPaという高温高圧下で、窒素及び水素ガスを触媒上で反応させてアンモニアを生成させ、反応器出口ガス中に含まれる生成アンモニアを冷却して凝縮分離して製品として回収する一方、未反応の窒素及び水素ガスは分離され原料ガスとしてリサイクルされるプロセスが採用されている。また、ハーバー・ボッシュ法の改良方法として、より低圧条件下でアンモニアが製造可能なRu系担持触媒が1980年代に開発され、上記ハーバー・ボッシュプロセスと組み合わせたプロセスも工業化されているが、その基本製造プロセスは100年に亘り変わっていない。このように、一般にアンモニア製造工業触媒は鉄系触媒とRu系触媒に大別される。アンモニア製造時に用いる原料ガスのモル比は、理論比となる水素/窒素=3が好ましいが、Ru系触媒では水素による触媒被毒が起こりやすい為に、このモル比を下げた製造条件が好ましく用いられる。この点を考慮すると、特に制限はされないが、本発明のアンモニア分離技術と組み合わせるアンモニア製造触媒プロセスとしては、後述するアンモニア分離における供給ガス中に含有される水素ガス/窒素ガスの好ましい体積比に近づくため、Ru系触媒を用いるプロセスが好ましく、この組み合わせにより、生成するアンモニア分離において水素の透過量を低減することができる。
本発明のアンモニアの分離方法の第一実施形態は、ゼオライト膜を用いて、アンモニアと水素および窒素を含む複数の成分からなる混合ガスを該ゼオライト膜に接触させ、該混合ガスからアンモニアを選択的に透過させて分離することを特徴とするものである。
また、本発明のアンモニアの分離方法は、特定のゼオライト膜を用いて、アンモニアと水素および/または窒素を含む複数の成分からなる混合ガスを該ゼオライト膜に接触させ、該混合ガスから、アンモニアを選択的に透過させて分離することを特徴とするものである。
なお、上述の通り、本発明によれば、反応器内で水素ガスと窒素ガスからアンモニアガスを製造し、上記反応器内において、ゼオライト膜を用いて製造されたアンモニアガスを透過させながら効率よくアンモニアを製造・回収することができる。
すなわち、本発明は、先ずゼオライトへのアンモニアの吸着を積極的に行って、ゼオライト膜の細孔径を制御して、アンモニアの分離選択性を高めながら、一方、細孔内ではアンモニアの吸着/脱離によるホッピング移動を用いてアンモニアを選択的に透過させる技術となる。これに対して、特許文献8では、このようなアンモニア吸着ゼオライト膜はアンモニア透過において閉塞の原因となる為、このような吸着を起こらないゼオライトを設計し、ゼオライトの細孔径を利用した分子篩によりアンモニアを分離する技術を提案している点で大きく異なる。一方、特許文献7で提案されているようなシリカ膜では、アンモニアの吸着が起こりにくく、また、アンモニアが吸着されても熱安定性が低い為に、本発明のような効果は発現しない。
一方、ゼオライトへのアンモニアの吸着/脱離が伴う細孔内ホッピング機構を主に活用してアンモニアの分離を行う本発明においては、アンモニア分離の際の温度は、使用するゼオライト膜の長期耐久性、ゼオライト膜のアンモニアの分離性能、ならびに、アンモニア製造設備と組み合わせる際のプロセス全体の製造エネルギー収支に大きく影響を与える為、重要な設計因子の一つとなる。これらの視点からすると、本発明においては、アンモニア合成における生成ガスを分離する場合には、アンモニア分離の際の温度は、通常、アンモニアの合成温度と同じかそれ以下の温度であり、アンモニア分離の際の温度は、アンモニア分離を行う分離器内の温度、すなわち、分離に供する混合ガスの温度、分離されたアンモニアガスの温度である。また、分離膜の温度は分離器内の温度と略同じであるとみなすことができる。アンモニアの製造プロセス設計からは合成温度と同じ温度で分離を行うと反応器にリサイクルする水素、窒素の昇温が不要となるため好ましい。このため、アンモニア分離の際の好ましい温度はアンモニア合成反応における反応温度にもよるが、通常500℃以下、好ましくは450℃以下、さらに好ましくは400℃以下である。本発明のゼオライト膜を用いてこれらの温度条件下でアンモニアの分離を行うと、該ゼオライト膜は安定性が高いため、長期に亘り連続的な操業が可能となるばかりでなく、高いアンモニアの透過選択性が発現する。一方、その下限は通常50℃を超える温度、好ましくは100℃以上、より好ましくは150℃以上、特に好ましくは200℃以上、その中でも、好ましくは250℃以上、とりわけ好ましくは300℃以上である。これらの温度条件下でアンモニアの分離をおこなうと、ゼオライト細孔内に吸着されたアンモニアの脱離速度が向上し、その結果ゼオライト膜のアンモニア透過速度が向上する。また、アンモニア製造プロセスとして、原料ガスのリサイクルを行う際には、水素、窒素の昇温にかかるエネルギーが低減されるために、より高温条件下でのアンモニア分離が好ましく、その観点からは、その下限は、好ましくは250℃以上、より好ましくは300℃以上である。
本発明のような細孔内ホッピング移動によるアンモニアの分離方法おいては、ゼオライト細孔内のAl原子に対するアルカリ金属原子のモル比を飽和量比未満に制御することによりその速度を制御できる為、該モル比の制御は重要であり、本発明の第四実施形態のような該モル比を0.01以上、0.070以下に制御する手法と組み合わせると好ましい場合がある。
供給ガス(混合ガス)中のその他のガス組成は特段の制限はないが、供給ガス中に含有される水素ガス/窒素ガスの体積比は、通常3以下、より好ましくは、2以下である。この体積比に調整することにより、アンモニア分離時の水素の透過量が低減され、アンモニアの分離選択性が向上する。このような理由から、本発明のアンモニア分離プロセスの供給ガスをアンモニア製造プロセスから得る場合には、特に限定はされないが、原料ガス中の水素ガス/窒素ガスの体積比を低くしたRu系アンモニア製造触媒プロセスと組み合わせるのが好ましい。一方、その下限は、少なければ少ないほどアンモニア分離選択性が向上する為、特に限定されないが、通常0.2以上、好ましくは0.3以上、より好ましくは0.5以上である。ここで、上限ならびに下限の記載値は有効数字の範囲内で有効とするもので、すなわち、上限3以下とは2.5以上3.5未満を、一方0.2以上とは0.15以上0.25未満を、1.0以上とは0.95以上1.05未満を意味する。
図1の装置における混合ガスの分離操作については、実施例の項において説明する。
多段に設けた膜モジュールで分離する場合には、後段の膜モジュールにガスを供給する際に、必要に応じて供給ガスの圧力を昇圧器などで調整してもよい。
α=(Q’1/Q’2)/(P’1/P’2)
〔上記式中、Q’1およびQ’2は、それぞれ、透過性の高いガスおよび透過性の低いガスの透過量[mol/(m2・s・Pa)]を示し、P’1およびP’2は、それぞれ、供給ガス中の透過性の高いガスおよび透過性の低いガスの分圧[Pa]を示す。〕
分離係数αは次のように求めることもできる。
α=(C’1/C’2)/(C1/C2)
〔上記式中、C’1およびC’2は、それぞれ、透過ガス中の透過性の高いガスおよび透過性の低いガスの濃度[体積%]を示し、C1およびC2は、それぞれ、供給ガス中の透過性の高いガスおよび透過性の低いガスの濃度[体積%]を示す。〕
本発明において、ゼオライト膜を構成するゼオライトはアルミノ珪酸塩である。アルミノ珪酸塩は、SiとAlの酸化物を主成分とするものであり、本発明の効果を損なわない限り、それ以外の元素が含まれていてもよい。本発明のゼオライト中に含まれるカチオン種としては、ゼオライトのイオン交換サイトに配位しやすいカチオン種が望ましく、例えば、周期律表の第1族、第2族、第8族、第9族、第10族、第11族、及び、第12族の元素群から選ばれるカチオン種、NH4 +、ならびにこれらの二種以上のカチオン種であり、より好ましくは、周期律表の第1族、第2族の元素群から選ばれるカチオン種、NH4 +、ならびにこれらの二種以上のカチオン種である。
ゼオライトのSiO2/Al2O3モル比は、後に述べる水熱合成の反応条件により調整することができる。
また、本発明の第五の実施形態(ゼオライト膜複合体E)では、フレームワーク密度が18.0T/nm3以下であるゼオライトが好ましく、より好ましくはAFX、DDR、ERI、LEV、RHO、MOR、MFI、FAUであり、さらに好ましくはDDR、RHO、MOR、MFI、FAUであり、最も好ましくはRHO、MFIである。
本発明におけるゼオライト膜とは、ゼオライトにより構成される膜状物のことであり、好ましくは、多孔質支持体の表面にゼオライトを結晶化させて形成されたものである。膜を構成する成分として、ゼオライト以外にシリカ、アルミナなどの無機バインダー、ポリマーなどの有機物、あるいはゼオライト表面を修飾するシリル化剤などを必要に応じて含んでいてもよい。
本発明で用いられるゼオライト膜に含まれる好ましいゼオライトは上述の通りであるが、ゼオライト膜に含まれるゼオライトは1種でもよいし、複数種含まれていてもよい。また、ANA、GIS、MERのような混相で生成しやすいゼオライトや、結晶以外にもアモルファス成分などが含有されていてもよい。
ゼオライト膜Bは、X線光電子分光法(XPS)により決定されるAl原子に対する窒素原子のモル比が特定の範囲となる表面を有する、ゼオライト膜であることが好ましい。ここで、本明細書におけるゼオライト膜の表面とは、アンモニアを分離する為にアンモニアと水素および/または窒素とを含む複数の成分からなる混合ガスを供給する側のゼオライト膜の表面を意味し、多孔質支持体上に成膜化された形態でゼオライト膜複合体を使用する場合には、多孔質支持体が接触していない面を意味する。尚、本明細書において、ゼオライト膜中に含まれるAl原子に対する窒素原子のモル比とは、以下の測定条件下でのX線光電子分光法(XPS)により決定される数値である。
測定の際のX線源:単色化Al-Kα線、出力16kV-34W
定量計算の際のバックグラウンドの決定法:Shirley法
本発明で用いられるゼオライト膜Cは、X線光電子分光法(XPS)により決定されるAl原子に対するSi原子のモル比が特定の範囲となる表面を有する、ゼオライト膜であることを特徴とする。尚、本明細書において、ゼオライト膜中に含まれるAl原子に対するSi原子のモル比とは、以下の測定条件下でのX線光電子分光法(XPS)により決定される数値である。
測定の際のX線源:単色化Al-Kα線、出力16kV-34W
定量計算の際のバックグラウンドの決定法:Shirley法
本実施形態においては、上記のXPS測定により決定されるゼオライト膜表面に含まれるSi原子含有量は、ゼオライト膜表面のAl原子に対して、モル比で、2.0以上、好ましくは、2.5以上、より好ましくは、3.0以上であり、その上限は、通常10以下、好ましくは8.0以下、より好ましくは7.0以下、特に好ましくは6.7以下である。本発明においては、ゼオライト膜中のAl原子に対するSi原子のモル比は、後述するように、ゼオライト膜中のゼオライトのSiO2/Al2O3比を制御する方法、ゼオライト膜をアルミニウム塩で処理する方法等により制御することができる。このような特定のSi原子/Al原子モル比のゼオライト膜を使用することにより、アンモニアと水素および/または窒素を含む複数の成分からなる混合ガスからアンモニアを分離する際に、本実施例から明らかなように、ゼオライト膜の緻密性ならびに耐化学反応性や耐熱性等の耐久性を向上させることができると共に、高い透過選択性ならびに高い透過度を示すと共に高温時の分離熱安定性を向上させることができる。
本実施形態においては、未だ詳らかではなく特に限定はされないが、後述するようにアンモニアのゼオライトへの吸着を利用して膜分離に用いるゼオライトの有効細孔径を制御するとともに、ゼオライト細孔内でのアンモニアのホッピング機構に基づいてアンモニアを分離することを特徴とする。このようにゼオライトへのアンモニアの吸着/脱離が伴う細孔内ホッピング機構を主に活用してアンモニアの分離を行う本発明においては、先ずはアンモニアを含む供給混合ガス中のアンモニアとゼオライト膜表面との吸着親和性を、該混合ガス中に含まれるその他の水素や窒素等のガスよりも如何に高めるかが重要な設計因子となる。この視点から、Al原子をゼオライト膜表面により多く存在させるとゼオライト膜表面の極性が変化し、供給ガス中のアンモニアとの吸着親和性が高まる為にアンモニア分離性能が向上する。また、本実施形態においては、ゼオライト膜表面のAl原子の含有量は、ゼオライト膜を構成するゼオライトのSiO2/Al2O3比やゼオライト膜形成後のアルミニウム塩処理等により制御されるが、特に後者のアルミニウム塩処理は、ゼオライト膜表面に存在する微細な欠陥を封止する効果もあり、ゼオライト膜の緻密性ならびに耐化学反応性や耐熱性等の耐久性を向上させることができると共に、本発明の課題の一つであるゼオライト膜の高温時の分離熱安定性の向上に大きく貢献する。
本発明の第四実施形態で用いられるゼオライト膜Dは、X線光電子分光法(XPS)により決定されるAl原子に対するアルカリ金属原子のモル比が特定の範囲となる表面を有する、ゼオライト膜であることが好ましい。尚、本明細書において、ゼオライト膜中に含まれるAl原子に対するアルカリ金属原子のモル比とは、以下の測定条件下でのX線光電子分光法(XPS)により決定される数値である。
測定の際のX線源:単色化Al-Kα線、出力16kV-34W
定量計算の際のバックグラウンドの決定法:Shirley法
また、本実施形態においては、上記のゼオライト膜表面のアルカリ金属原子の含有量を制御するとともに、必要に応じて、XPS測定により決定されるゼオライト膜表面に含まれる窒素原子の含有量を特定の領域に制御すると、アンモニアと水素および/または窒素を含む複数の成分からなる混合ガスからアンモニア分離する際の分離選択性が著しく向上する傾向がある為、ゼオライト膜表面にアルカリ金属原子と窒素原子とを共存させ、それらの含有量を適切に制御するのが好ましい。このようにゼオライト膜表面に窒素原子を存在させる場合、その窒素原子の含有量は、ゼオライト膜表面のAl原子に対して、モル比で、通常、0.01以上、好ましくは、0.05以上、より好ましくは、0.10以上であり、更に好ましくは0.20以上、特に好ましくは0.30以上、とりわけ好ましくは0.50以上であり、その上限は、ゼオライト膜に含まれるゼオライト中の窒素原子を含むカチオン種の構造や必要に応じてゼオライト膜の硝酸塩処理を行う際に残留する硝酸イオン量に依存するために特に制限されないが、通常4以下、好ましくは、3以下、より好ましくは、1以下である。このような特定の窒素原子/Al原子比の表面組成を有するゼオライトを使用すると、ゼオライト膜の緻密性ならびに耐化学反応性や耐熱性等の耐久性を向上させることができると共に、アンモニアと水素および/または窒素を含む複数の成分からなる混合ガスからアンモニアを高選択的に分離することができる為、好ましい。尚、上記の上限ならびに下限の記載値は有効数字範囲内で有効とするものである。すなわち、上限4以下とは4.5未満を、一方0.01以上とは0.005以上を意味する。
具体的には、ゼオライトの30℃における熱膨張率に対する300℃における熱膨張率の変化率が±0.25%以内であり、30℃における熱膨張率に対する400℃における熱膨張率の変化率が±0.35%以内である。
本実施形態のゼオライトが定義される熱膨張率とは、以下の条件で算出される数値である。尚、本明細書では、熱膨張率の数値は、正数の場合は、ゼオライトが膨張したことを表し、負数の場合はゼオライトが収縮したことを表す。
本発明において、ゼオライトの30℃の熱膨張率に対する所定温度における熱膨張率の変化率は、以下の条件下での昇温XRD測定法により30℃及び所定温度で測定した結晶子定数を求め、下記式(1)により求めることができる。
一方、ゼオライトの30℃における熱膨張率に対する400℃の熱膨張率の変化率は、その絶対値として、0.35%以下、好ましくは0.30%以下、更に好ましくは、0.25%以下、とりわけ好ましくは0.20%以下、特に好ましくは0.15%以下、最も好ましくは0.10%以下である。すなわち、ゼオライトの30℃における熱膨張率に対する400℃における熱膨張率の変化率は、±0.35%以内であり、好ましくは±0.30%以内、更に好ましくは±0.25%以内、とりわけ好ましくは±0.20%以内、特に好ましくは±0.15%以内、最も好ましくは±0.10%以内である。このような、低い熱膨張率の変化率を示すゼオライトを多孔質支持体上に成膜したゼオライト膜複合体は、アンモニアと水素および/または窒素を含む複数の成分からなる気体混合物からアンモニアを透過させる際に、200℃を超える温度条件、特に250℃を超える温度条件、更には300℃を超える温度に該複合体を昇温した際に、ゼオライトの熱膨張(収縮)によるゼオライト粒界の亀裂が発生しにくい為、高温条件下でも安定してアンモニアを高い透過度で効率的に透過側に分離することができる。このような熱膨張率を示すゼオライトを用いたゼオライト膜複合体は、特に本実施例のRHO型ゼオライトに記載されるように、温度に対して非線形的な熱膨張/収縮の挙動を示しても、高温条件下においては、膜として、安定して高い分離性能を発現する。ここで、温度に対して非線形的な熱膨張/収縮の挙動とは、温度に対して単調に熱膨張または収縮しない挙動、つまり、例えば、ある温度領域では熱膨張或いは熱収縮挙動を示すが、それ以外の温度領域では逆の挙動、すなわち前者であれば熱収縮、後者であれば熱膨張する挙動をいう。
本実施形態のゼオライト中に含まれるカチオン種としては、ゼオライトのイオン交換サイトに配位しやすいカチオン種が望ましく、例えば、周期律表の第1族、第2族、第8族、第9族、第10族、第11族、及び、第12族の元素群から選ばれるカチオン種、NH4 +、ならびにこれらの二種以上のカチオン種であり、より好ましくは、周期律表の第1族、第2族の元素群から選ばれるカチオン種、NH4 +、ならびにこれらの二種以上のカチオン種である。
なお、本発明においては、平均一次粒子径は、本発明のゼオライト膜複合体の表面、あるいは破断面を走査型電子顕微鏡による観察において、任意に選択した30個以上の粒子について一次粒子径を測定し、平均値として求められる。
本発明において、ゼオライト膜は、好ましくは、多孔質支持体の表面などに形成される。好ましくは、ゼオライトは、多孔質支持体に対して膜状に結晶化される。
特に、アルミナ、シリカ、ムライトのうち少なくとも1種を含む無機多孔質支持体は、無機多孔質支持体の部分的なゼオライト化が容易であるため、無機多孔質支持体とゼオライトの結合が強固になり、緻密で分離性能の高いゼオライト膜が形成されやすくなるのでより好ましい。
本発明において用いられる多孔質支持体は、その表面(以下「多孔質支持体表面」ともいう。)において、多孔質支持体上に形成されるゼオライトを結晶化させる作用を有することが好ましい。
上記多孔質支持体表面は、細孔径が制御されていることが好ましい。多孔質支持体表面付近における多孔質支持体の平均細孔径は、通常0.02μm以上、好ましくは0.05μm以上、さらに好ましくは0.1μm以上、より好ましくは0.15μm以上、さらに好ましくは0.5μm以上であり、とりわけ好ましくは0.7μm以上、最も好ましくは1.0μm以上であり、通常20μm以下、好ましくは10μm以下、さらに好ましくは5μm以下特に好ましくは2μm以下である。このような範囲の細孔径を有する多孔質支持体を使用することにより、アンモニアの透過選択性を向上させる緻密なゼオライト膜を形成させることができる。
多孔質支持体の表面は滑らかであることが好ましく、必要に応じて表面をやすり等で研磨してもよい。
本発明において用いられる多孔質支持体の、多孔質支持体表面付近以外の部分の細孔径は制限されるものではなく、また特に制御される必要は無いが、その他の部分の気孔率は通常20%以上、より好ましくは30%以上、通常60%以下、好ましくは50%以下である。多孔質支持体表面付近以外の部分の気孔率は、気体や液体を分離する際の透過流量を左右し、上記下限以上であることにより透過物が拡散しやすくなる傾向があり、上記上限値以下では多孔質支持体の強度が低下するのを防ぎやすくなる傾向がある。また透過流量を制御する方法として、気孔率の異なる多孔質体を層状に組み合わせた多孔質支持体を用いてもよい。
本発明において用いられる多孔質支持体の形状は、混合ガスや液体混合物を有効に分離できるものであれば制限されるものではなく、具体的には平板状、管状、円筒状、多数の貫通孔を有するハニカム状のものやモノリスなどが挙げられる。また、多孔質支持体の大きさ等は任意であり、所望のゼオライト膜複合体が得られるように適宜選択して調整すればよい。これらの中でも、多孔質支持体の形状は管状であるものが好ましい場合がある。
管状の多孔質支持体の長さは、特段の制限はないが、通常2cm以上、好ましくは4cm以上、さらに好ましくは5cm以上、特に好ましくは10cm以上であり、とりわけ好ましくは40cm以上であり、最も好ましくは50cm以上であり、一方、通常200cm以下、好ましくは150cm以下、より好ましくは100cm以下である。多孔質支持体の長さが上記下限値以上の場合、1本あたりの混合ガスの分離処理量を多くすることができるために、設備コストを低減することができる。また、上記上限値以下の場合、ゼオライト膜複合体の製造を簡略化でき、さらには、使用時の振動等により折れやすい等の問題が生じるのを防ぐことができる。
管状の多孔質支持体の内径は通常0.1cm以上、好ましく0.2cm以上、より好ましくは0.3cm以上、特に好ましくは0.4cm以上であり、通常2cm以下、好ましくは1.5cm以下、より好ましくは1.2cm以下、特に好ましくは1.0cm以下である。外径は、通常0.2cm以上、好ましくは0.3cm以上、より好ましくは0.6cm以上、特に好ましくは1.0cm以上であり、通常2.5cm以下、好ましくは1.7cm以下、より好ましくは1.3cm以下である。管状の多孔質支持体の肉厚は、通常0.1mm以上、好ましくは0.3mm以上、より好ましくは0.5mm以上、さらに好ましくは0.7mm以上、さらに好ましくは1.0mm以上、特に好ましくは1.2mm以上であり、通常4mm以下、好ましくは3mm以下、より好ましくは2mm以下である。管状の多孔質支持体の内径、外径及び肉厚がそれぞれ、上記下限値以上であれば、支持体の強度を向上させて折れにくくすることができる。また、管状の支持体の内径及び外径がそれぞれ上記上限値以下であれば、アンモニアの分離に伴う設備のサイズを小さくすることができるために、経済的に有利になりうる。また、管状の支持体の肉厚が上記上限値以下であれば、透過性能が向上する傾向がある。
本発明においては、ゼオライト膜は、少なくとも、ゼオライトと、支持体と、を含んで構成されるゼオライト膜複合体として使用することが好ましい。
本発明において、ゼオライト膜複合体とは、上記の多孔質支持体の表面などに上記のゼオライトが膜状に、好ましくは結晶化して固着しているものであり、場合によっては、ゼオライトの一部が、支持体の内部にまで固着している状態のものが好ましい。
ゼオライト膜複合体としては、例えば、多孔質支持体の表面などにゼオライトを水熱合成により膜状に結晶化させたものが好ましい。
本発明のある一実施形態(ゼオライト膜B~E)においては、好ましくは、MFI型ゼオライト-多孔質アルミナ支持体、RHO型ゼオライト-多孔質アルミナ支持体、より好ましくは、RHO型ゼオライト-多孔質アルミナ支持体である。
本発明において、ゼオライト膜複合体の形成方法は、上記したゼオライト膜を多孔質支持体上に形成可能な方法であれば特に制限されず、公知の方法により製造することができる。例えば、(1)支持体上にゼオライトを膜状に結晶化させる方法、(2)支持体にゼオライトを無機バインダーあるいは有機バインダーなどで固着させる方法、(3)ゼオライトを分散させたポリマーを支持体に固着させる方法、(4)ゼオライトのスラリーを支持体に含浸させ、場合によっては吸引することによりゼオライトを支持体に固着させる方法、などの何れの方法も用いることができる。
この場合、ゼオライト膜複合体は、例えば、組成を調整して均一化した水性反応混合物を、内部に多孔質支持体を入れたオートクレーブなどの耐熱耐圧容器に入れて密閉し、一定時間加熱することにより製造することができる。
ゼオライト膜複合体の製造方法についてより理解が深まるように、下記に代表例として、RHO型ゼオライト膜複合体ならびにMFI型ゼオライト膜複合体の製造方法について詳細に説明するが、本発明のゼオライト膜及び該製造方法はこれに限定されるものではない。
本発明において用いられるRHO型ゼオライトとは、International Zeolite Association(IZA)が定めるゼオライトの構造を規定するコードでRHO構造のものを示す。RHO型ゼオライトは3.6×3.6Åの径を有する酸素8員環からなる3次元細孔を有することを特徴とする構造をとり、その構造はX線回折データにより特徴付けられる。
本発明において用いられるRHO型ゼオライトのフレームワーク密度は、14.1T/1000Åである。フレームワーク密度とは、ゼオライトの1000Å3あたりの酸素以外の骨格を構成する原子の数を意味し、この値はゼオライトの構造により決まるものである。なおフレームワーク密度とゼオライトとの構造の関係はATLAS OF ZEOLITE FRAMEWORK TYPES Fifth Revised Edition 2007 ELSEVIER に示されている。
本発明において用いられるMFI型ゼオライトとは、International Zeolite Association(IZA)が定めるゼオライトの構造を規定するコードでMFI構造のものを示す。MFI型ゼオライトは5.1×5.5Åあるいは5.3×5.6Åの径を有する酸素10員環からなる3次元細孔を有することを特徴とする構造をとり、その構造はX線回折データにより特徴付けられる。
本発明において用いられるMFI型ゼオライトのフレームワーク密度は、17.9T/1000Åである。フレームワーク密度とは、ゼオライトの1000Å3あたりの酸素以外の骨格を構成する原子の数を意味し、この値はゼオライトの構造により決まるものである。なおフレームワーク密度とゼオライトとの構造の関係はATLAS OF ZEOLITE FRAMEWORK TYPES Fifth Revised Edition 2007 ELSEVIER に示されている。
水性反応混合物に用いるケイ素(Si)原子源としては特に限定されないが、例えば、アルミノシリケートゼオライト、ヒュームドシリカ、コロイダルシリカ、無定型シリカ、珪酸ナトリウム、珪酸メチル、珪酸エチル、トリメチルエトキシシラン等のシリコンアルコキシド、テトラエチルオルトシリケート、アルミノシリケートゲルなどが挙げられ、好ましくは、アルミノシリケートゼオライト、ヒュームドシリカ、コロイダルシリカ、無定型シリカ、珪酸ナトリウム、珪酸メチル、珪酸エチル、シリコンアルコキシド、アルミノシリケートゲルが挙げられる。これらは、1種を単独で用いてもよく、2種以上を混合して用いてもよい。
多孔質支持体-RHO型ゼオライト膜複合体の製造に用いられるアルミニウム(Al)原子源は、特に限定されないが、アルミノシリケートゼオライト、アモルファスの水酸化アルミニウム、ギブサイト構造を持つ水酸化アルミニウム、バイヤーライト構造を持つ水酸化アルミニウム、硝酸アルミニウム、硫酸アルミニウム、酸化アルミニウム、アルミン酸ナトリウム、ベーマイト、擬ベーマイト、アルミニウムアルコキシド、アルミノシリケートゲルなどが挙げられ、アルミノシリケートゼオライト、アモルファスの水酸化アルミニウム、アルミン酸ナトリウム、ベーマイト、擬ベーマイト、アルミニウムアルコキシド、アルミノシリケートゲルが好ましく、アルミノシリケートゼオライト、アモルファスの水酸化アルミニウム、アルミン酸ナトリウム、アルミノシリケートゲルが特に好ましい。これらは、1種を単独で用いてもよく、2種以上を混合して用いてもよい。
金属水酸化物としては、具体的には、例えば、水酸化ナトリウム、水酸化カリウム、水酸化リチウム、水酸化ルビジウム、水酸化セシウム等のアルカリ金属水酸化物;水酸化カルシウム、水酸化マグネシウム、水酸化ストロンチウム、水酸化バリウム等のアルカリ土類金属水酸化物等を用いることができる。
水熱合成用原料混合物中の水の量は、種結晶以外の原料混合物に含まれるケイ素(Si原子)に対するモル比で通常10以上、好ましくは20以上、より好ましくは30以上、更に好ましくは40以上、特に好ましくは50以上であり、通常200モル以下、好ましく150以下、より好ましくは100以下、さらに好ましくは80以下、特に好ましくは60以下である。上記上限よりも大きいと、反応混合物が希薄すぎて、欠陥のない緻密な膜ができにくくなることがある。10未満であると、反応混合物が濃いために、自発核が生じやすくなり、支持体からのRHO型ゼオライトの成長を阻害し、緻密な膜ができにくくなることがある。
本発明において、「ゼオライト」製造原料(原料化合物)の一成分として種結晶を用いてもよい。
水熱合成に際して、必ずしも反応系内に種結晶を存在させる必要は無いが、種結晶を存在させることで、多孔質支持体上でのゼオライトの結晶化を促進できる。反応系内に種結晶を存在させる方法としては特に限定されず、粉末のゼオライトの合成時のように、水性反応混合物中に種結晶を加える方法や、支持体上に種結晶を付着させておく方法などを用いることができるが、本発明では、支持体上に種結晶を付着させておくことが好ましい。支持体上に予め種結晶を付着させておくことで緻密で分離性能の高いゼオライト膜が生成しやすくなる。
支持体の細孔径によっては種晶の粒子径が小さいほうが望ましい場合があり、必要に応じて粉砕して用いても良い。種晶の粒径は、通常5nm以上、好ましくは10nm以上、より好ましくは20nm以上であり、通常5μm以下、好ましくは3μm以下、より好ましくは2μm以下である。
<MFI型ゼオライト膜の製造方法>
水性反応混合物に用いるケイ素(Si)原子源としては、例えば、アルミノシリケートゼオライト、ヒュームドシリカ、コロイダルシリカ、無定型シリカ、珪酸ナトリウム、珪酸メチル、珪酸エチル、トリメチルエトキシシラン等のシリコンアルコキシド、テトラエチルオルトシリケート、アルミノシリケートゲルなどを用いることができる。好ましくは、ヒュームドシリカ、コロイダルシリカ、無定型シリカ、珪酸ナトリウム、ケイ酸メチル、ケイ酸エチル、シリコンアルコキシド、アルミノシリケートゲルが挙げられる。これらは、1種を単独で用いてもよく、2種以上を混合して用いてもよい。
多孔質支持体-MFI型ゼオライト膜複合体の製造に用いられるアルミニウム(Al)原子源は、特に限定されないが、アルミノシリケートゼオライト、アモルファスの水酸化アルミニウム、ギブサイト構造を持つ水酸化アルミニウム、バイヤーライト構造を持つ水酸化アルミニウム、硝酸アルミニウム、硫酸アルミニウム、酸化アルミニウム、アルミン酸ナトリウム、ベーマイト、擬ベーマイト、アルミニウムアルコキシド、アルミノシリケートゲルなどが挙げられ、アモルファスの水酸化アルミニウム、アルミン酸ナトリウム、ベーマイト、擬ベーマイト、アルミニウムアルコキシド、アルミノシリケートゲルが好ましく、アモルファスの水酸化アルミニウム、アルミン酸ナトリウム、アルミノシリケートゲルが特に好ましい。これらは、1種を単独で用いてもよく、2種以上を混合して用いてもよい。
アルカリ金属原子源は、その適当量を使用することにより、アルミニウムに後述の有機構造規定剤が好適な状態に配位しやすくなるため、結晶構造を作りやすくできる。アルカリ金属原子源(R)と、種結晶以外の水熱合成用原料混合物に含まれるケイ素(Si)とのモル比R/Siは、通常0.01以上、好ましくは0.02以上、より好ましくは0.03以上、さらに好ましくは0.04以上、特に好ましくは0.05以上であり、通常1.0以下、好ましくは0.6以下、より好ましくは0.4以下、さらに好ましくは0.2以下、特に好ましくは0.1以下である。
水熱合成用原料混合物中の水の量は、種結晶以外の原料混合物に含まれるケイ素(Si)に対するモル比で通常10以上、好ましくは15以上、より好ましくは20以上、更に好ましくは25以上、特に好ましくは30以上であり、通常500モル以下、好ましく300以下、より好ましくは200以下、さらに好ましくは150以下、特に好ましくは100以下である。上記上限よりも大きいと、反応混合物が希薄すぎて、欠陥のない緻密な膜ができにくくなることがある。10未満であると、反応混合物が濃いために、自発核が生じやすくなり、支持体からのMFI型ゼオライトの成長を阻害し、緻密な膜ができにくくなることがある。
本発明において、「ゼオライト」製造原料(原料化合物)の一成分として種結晶を用いてもよい。
水熱合成に際して、必ずしも反応系内に種結晶を存在させる必要は無いが、種結晶を存在させることで、多孔質支持体上でのゼオライトの結晶化を促進できる。反応系内に種結晶を存在させる方法としては特に限定されず、粉末のゼオライトの合成時のように、水性反応混合物中に種結晶を加える方法や、支持体上に種結晶を付着させておく方法などを用いることができるが、本発明では、支持体上に種結晶を付着させておくことが好ましい。支持体上に予め種結晶を付着させておくことで緻密で分離性能の高いゼオライト膜が生成しやすくなる。
支持体の細孔径によっては種結晶の粒子径が小さいほうが望ましい場合があり、必要に応じて粉砕して用いてもよい。種結晶の粒径は、通常0.5nm以上、好ましくは1nm以上、より好ましくは2nm以上であり、通常5μm以下、好ましくは3μm以下、より好ましくは2μm以下である。
合成されたゼオライト膜は、必要に応じてイオン交換してもよい。特に、本発明のある実施形態(例えば、発明B、C、D、Eのゼオライト膜)においては、合成されたゼオライト膜は、イオン交換処理を行う。本発明の特徴の一つであるゼオライトの熱膨張特性、アンモニアの分離熱安定性は、ゼオライト中のカチオン種により大きく影響を受ける為、本イオン交換が重要な制御法となる。また、後述するように、用いるカチオン種によりゼオライト膜のアンモニアの透過性能および/または分離性能が向上する場合がある。すなわち、本発明で用いるカチオン種は、上記のゼオライトの熱膨張特性、アンモニアの分離熱安定性を確保しながら、アンモニアの透過性能と分離性能を加味して適宜選定される。
イオン交換は、有機テンプレートを用いてゼオライト膜を合成した場合は、通常、有機テンプレートを除去した後に行う。イオン交換するイオンとしては、本発明においては、ゼオライト膜表面の窒素含有量を増やすために、NH4 +やメチルアミン、ジメチルアミン、トリメチルアミン、エチルアミン、ジエチルアミン、トリエチルアミン、エチレンジアミン、ジメチルエチレンジアミン、テトラメチルエチレンジアミン、ジエチレントリアミン、トリエチレンテトラアミン、アニリン、メチルアニリン、ベンジルアミン、メチルベンジルアミン、ヘキサメチレンジアミン、N,N-ジイソプロピルエチルアミン、N,N,N-トリメチル-1-アダマンタンアミン、ピリジン、ピペリジン等の炭素数1~20の有機アミンがプロトン化されたカチオン種のいずれかが好ましく、その他、プロトン、Na+、K+、Li+、Rb+、Cs+などのアルカリ金属イオン、Ca2+、Mg2+、Sr2+、Ba2+などのアルカリ土類金属イオン、ならびにFe、Cu、Zn、Ga、Laなどの遷移金属のイオンなどを共存させてもよい。これらの中では、プロトン、NH4 +、Na+、Li+、Cs+、Feイオン、Gaイオン、Laイオンが好ましい。これらのイオンは、ゼオライト中に複数種混在していてもよく、上記のゼオライトの熱膨張特性とアンモニア透過性能のバランスをとる上で、上記イオンを混在させる手法は好適に採用される。このようにイオン交換するカチオン種ならびにそれらの量を制御する事で、ゼオライトのアンモニア親和性ならびにゼオライト細孔内の有効細孔径を制御することが可能となり、アンモニアの透過選択性を上げ、かつアンモニアの透過速度も向上させることができる。これらの中でアンモニアの透過選択性を上げるイオン種としては、NH4 +やメチルアミン、ジメチルアミン、トリメチルアミン、エチルアミン、ジエチルアミン、トリエチルアミン、エチレンジアミン、ジメチルエチレンジアミン、テトラメチルエチレンジアミン、ジエチレントリアミン、トリエチレンテトラアミン、アニリン、メチルアニリン、ベンジルアミン、メチルベンジルアミン、ヘキサメチレンジアミン、N,N-ジイソプロピルエチルアミン、N,N,N-トリメチル-1-アダマンタンアミン、ピリジン、ならびにピペリジン等の炭素数1~20の有機アミンがプロトン化されたカチオン種が好ましく、その中では、NH4 +や炭素数1~6の有機アミンのような分子サイズの小さなアミンがプロトン化されたカチオン種が上記の理由からより好ましく、その中でも特にNH4 +が好ましい。一方、アンモニアの透過速度を向上させるイオン種としては、プロトン、Na+、Li+、Cs+、Feイオン、Gaイオン、Laイオンが好ましく、Na+、Li+、Cs+イオンが特に好ましく、Na+イオンを共存させるのが最も好ましい。本発明においては、このように窒素原子を含有するイオン種を必須とするイオンの交換量を調整することにより、ゼオライト膜中のAl原子に対する窒素原子のモル比を制御することができる。
本発明のある実施形態(例えば、発明B、C、D、Eのゼオライト膜)、においては、ゼオライト膜中の窒素原子の含有量を調整する方法として、硝酸塩処理を併用することが好ましいため、以下、硝酸塩処理について説明する。
硝酸塩の濃度は通常10mol/L以下であり、下限は、0.1mol/L以上、好ましくは、0.5mol/L以上、より好ましくは、1mol/L以上である。処理温度は通常、室温から150℃以下であり、処理は10分から48時間程度行えばよく、これらの処理条件は、用いる硝酸塩、溶媒種に応じて適宜設定すればよい。硝酸塩処理後のゼオライト膜は、水洗を行ってもよく、水洗を繰り返すことによってゼオライト膜の窒素原子含有量を好ましい範囲に調整することができる。
本発明においては、合成されたゼオライト膜は、必要に応じてアルミニウム塩処理を施してもよい。アルミニウム塩処理は、有機テンプレートを含む状態でも、焼成により有機テンプレートを除去した後に実施しても構わない。アルミニウム塩処理は、ゼオライト膜複合体を、例えばアルミ塩を含む溶液に浸漬して行う。これにより、膜表面に存在する微細な欠陥をアルミ塩がふさぐ効果が得られることがある。更に、アルミニウム塩がゼオライト細孔に存在する場合はアンモニアを引き寄せる効果があり、アンモニアの透過性を向上させる手法として好適に採用される。アルミニウム塩処理に用いる溶媒は、塩が溶解すれば水であっても有機溶媒であってもよく、用いるアルミ塩に制限はないが、例えば、硝酸アルミニウム、硫酸アルミニウム、塩化アルミニウム、リン酸アルミニウム、酢酸アルミニウム、炭酸アルミニウム、水酸化アルミニウムなどが挙げられる。これらは、1種を単独で用いてもよく、2種以上を混合して用いてもよい。
アルミニウム塩の濃度は通常10mol/L以下であり、下限は、0.1mol/L以上、好ましくは、0.5mol/L以上、より好ましくは、1mol/L以上である。処理温度は通常、室温から150℃以下であり、処理は10分から48時間程度行えばよく、これらの処理条件は、用いるアルミニウム塩、溶媒種に応じて適宜設定すればよい。アルミニウム塩処理後のゼオライト膜は、水洗を行ってもよく、水洗を繰り返すことによってゼオライト膜のAl原子含有量を調整することができる。本発明のSi原子/Al原子比率を大きくするためには、処理するアルミニウム塩の濃度や処理量を減らしたり、アルミニウム塩処理後の水洗の回数を増やすことが好ましく、一方、当該比率を小さくするためには、処理するアルミニウム塩の濃度や処理量を増やしたり、アルミニウム塩処理後の水洗の回数を減らすことが好ましい。
本発明においては、合成されたゼオライト膜は、必要に応じてシリル化処理を施してもよい。シリル化処理は、ゼオライト膜複合体を、例えばSi化合物を含む溶液に浸漬して行う。これにより、ゼオライト膜表面がSi化合物により修飾されて、特定の物理化学的性質を有するものとすることができる。例えば、ゼオライト膜表面にSi-OHを多く含む層を確実に形成することで膜表面の極性が向上し、極性分子の分離性能を向上させることができる。また、ゼオライト膜表面をSi化合物により修飾することで膜表面に存在する微細な欠陥をふさぐ効果が得られることがある。更に、シリル化処理によりゼオライトの細孔径の制御が可能であり、該処理を行うことでアンモニアの透過選択性を向上させる手法も好適に採用される。
本発明においては、また、本発明のゼオライト膜表面に含まれるAl原子の含有量は、上記のように、ゼオライト膜に含まれるゼオライト中のAl原子/Si原子比を調整する方法、ゼオライト膜をアルミニウム塩で処理する方法、アルミニウム塩処理をしたゼオライト膜を水洗する際の水洗回数を調整する方法、ならびにこれらの方法を適宜組み合わせることにより制御することができる。
本発明においては、また、本発明のゼオライト膜表面に含まれるアルカリ金属元素の含有量は、上記のように、ゼオライト膜に含まれるゼオライト中のAl原子/Si原子比を調整する方法、イオン交換法によるイオン交換量を調整してアルカリ金属元素の含有量を調整する方法、ゼオライト膜を水洗する際の水洗回数を調整する方法、ならびにこれらの方法を適宜組み合わせることにより制御することができる。
なお、以下において、「CHA型珪酸塩のゼオライト」を単に「CHA型ゼオライト」、「RHO型珪酸塩のゼオライト」を単に「RHO型ゼオライト」、「MFI型珪酸塩のゼオライト」を単に「MFI型ゼオライト」と称する。
[分離性能の測定]
以下において、ゼオライト膜複合体の分離性能の測定は次のとおり行った。
図1に模式的に示す装置において、以下のとおりアンモニア分離試験を行った。図1の装置において、供給ガスとしてアンモニアガス(NH3)と、窒素ガス(N2)と、水素(H2)と、を含む混合ガスを100SCCMの流量で耐圧容器とゼオライト膜複合体との間に供給し、背圧弁により供給側のガスと膜内を透過したガスの圧力差が0.3MPaで一定になるように調整し、配管10から排出される排出ガスをマイクロガスクロマトグラフで分析し、透過ガスの濃度、及び流量を算出した。
また、この測定結果に基づいて、下記式(1)により理想分離係数α’を算出した。
α’=(Q1/Q2)/(P1/P2) (1)
〔式(1)中、Q1およびQ2は、それぞれ、透過性の高いガスおよび透過性の低いガスの透過量[mol・(m2・s)-1]を示し、P1およびP2は、それぞれ、透過性の高いガスおよび透過性の低いガスの、供給側と透過側の圧力差[Pa]を示す。〕
これは、各ガスのパーミエンスの比率を示しており、従って、各ガスのパーミエンスを算出し、その比率から求めることができる。
以下の方法により、CHA型ゼオライト膜複合体1を製造した。
最初に、水熱合成用原料混合物を以下のとおり調製した。
1mol/L-NaOH水溶液1.45g、1mol/L-KOH水溶液5.78g、水114.6gを混合したものに水酸化アルミニウム(Al2O3-53.5質量%含有、アルドリッチ社製)0.19gを加えて撹拌し溶解させ、透明溶液とした。これに有機テンプレートとして、TMADAOH25質量%水溶液2.43gを加え、さらにコロイダルシリカ(日産化学社製スノーテック-40)10.85gを加えて2時間撹拌し、水熱合成用原料混合物とした。この混合物の組成(モル比)は、SiO2/Al2O3/NaOH/KOH/H2O/TMADAOH=1/0.018/0.02/0.08/100/0.04、SiO2/Al2O3=58であった。
多孔質支持体としては、ノリタケカンパニーリミテド社製のアルミナチューブBN1(外径6mm、内径4mm)を80mmの長さに切断した後、超音波洗浄機で洗浄し、その後乾燥させたものを用いた。
種結晶として、SiO2/Al2O3/NaOH/KOH/H2O/TMADAOH=1/0.033/0.1/0.06/20/0.07のゲル組成(モル比)で、160℃、2日間水熱合成して結晶化させたものを、濾過、水洗、乾燥して、種結晶であるCHA型ゼオライトを製造した。なお、種結晶の粒径は0.3~3μm程度であった。次に、該種結晶を約1質量%となるように水中に分散させて、種結晶分散液(CHA型種結晶分散液)を製造した。
上記の多孔質支持体を用意し、上記支持体を上記種結晶分散液に1分間浸した後、100℃で1時間乾燥させて、支持体に種結晶を付着させた。付着した種結晶の質量は約0.001gであった。
次に、乾燥後の膜複合体を、空気中、電気炉で、450℃にて10時間、500℃で5時間焼成し、ゼオライト中に含まれるテンプレートを除去したCHA型ゼオライト膜複合体1を得た。このときの室温から450度までの昇温速度と降温速度はともに0.5℃/分、450度から500度までの昇温速度と降温速度はともに0.1℃/分とした。焼成後の膜複合体の質量と支持体の質量の差から求めた、支持体上に結晶化したCHA型ゼオライトの質量は約0.279~0.289gであった。また、焼成後の膜複合体の空気透過量は2.4~2.9cm3/分であった。
<膜分離性能の評価>
前処理として、200℃で、供給ガスとして50体積%H2/50体積%N2の混合ガスを、耐圧容器と製造例A1に記載のCHA型ゼオライト膜複合体1との間に導入して、圧力を約0.4MPaに保ち、CHA型ゼオライト膜複合体1の円筒の内側を0.098MPa(大気圧)として、約120分間乾燥した。
CHA型ゼオライト膜複合体1を用いて、CHA型ゼオライト膜複合体1の温度を100℃、150℃、200℃及び250℃とした条件下において、上述の方法により、アンモニア分離試験を行った。なお、混合ガスとして、12.0体積%NH3/51.0体積%N2/37.0体積%H2の混合ガスを使用した。得られた透過ガスのアンモニアの濃度とアンモニア/水素(NH3/H2)、アンモニア/窒素(NH3/N2)のパーミエンス比を表3に示した。表3中、透過ガスのアンモニアの濃度は小数第一位を四捨五入した値である。
製造例A1に記載のCHA型ゼオライト膜複合体1を用いて、温度を100℃とし、混合ガスを3.0体積%NH3/24.0体積%N2/73.0体積%H2の混合ガスとした以外は実施例A1と同様の手法によりアンモニア分離の評価を行った結果、透過ガス中のアンモニアガス濃度は、4.1体積%であった。得られた結果から、混合ガスからアンモニアの分離が可能であることが分かる。
製造例A1に記載のCHA型ゼオライト膜複合体1を用いて、温度を100℃とし、混合ガスを2.0体積%NH3/19.0体積%N2/79.0体積%H2の混合ガスとした以外は実施例A1と同様の手法によりアンモニア分離の評価を行った結果、透過ガス中のアンモニアガス濃度は、2.3体積%であった。得られた結果から、混合ガスからアンモニアの分離が可能であることが分かる。
製造例A1に記載のCHA型ゼオライト膜複合体1の温度を100℃とし、0.7体積%NH3/80.0体積%N2/19.3体積%H2の混合ガスを用いた以外は実施例A1と同様の手法でアンモニア分離の評価を行った。その結果、透過ガスのアンモニアガス濃度は、0.8体積%であった。
製造例A1に記載のCHA型ゼオライト膜複合体1の温度を100℃とし、0.8体積%NH3/20.1体積%N2/79.1体積%H2の混合ガスを用いた以外は実施例A1と同様の手法でアンモニア分離の評価を行った。その結果、透過ガスのアンモニアガス濃度は、0.8体積%であった。
実施例A1において作製したCHA型ゼオライト膜複合体1を用いて、CHA型ゼオライト膜複合体1の温度を100℃とし、12体積%NH3/50体積%N2/38体積%H2の混合ガスを100SCCMの流量で流通させた以外は実施例A2と同様の手法でアンモニア分離の評価を行った結果、水素のパーミエンスは7.0×10-8[mol/(m2・s・Pa)]、窒素のパーミエンスは2.1×10-8[mol/(m2・s・Pa)]、アンモニアのパーミエンスは2.4×10-7[mol/(m2・s・Pa)]であった。これに対して、水素ガス単味を流通させた際の水素のパーミエンスは1.6×10-6[mol/(m2・s・Pa)]であり、窒素ガス単味を流通させた際の窒素のパーミエンスは3.0×10-7[mol/(m2・s・Pa)]であり、これらの結果から供給ガスにアンモニアガスが含有されると、水素ならびに窒素は、いずれも著しくパーミエンスが低下することが判った。本結果から、混合ガス中のアンモニアガス濃度が特定量以上であることにより、供給ガス中のアンモニアがゼオライトに吸着し、水素や窒素の透過を阻害する効果を発現したと考えられる。
製造例A1で得られたテンプレート除去後のCHA型ゼオライト膜複合体1を1Mの硝酸アンモニウム水溶液45gが入ったテフロン(登録商標)製内筒(65ml)に入れた。オートクレーブを密栓し、100℃で1時間、静置状態、自生圧力下で加熱した。
<膜分離性能の評価>
製造例A1に記載のCHA型ゼオライト膜1の代わりに製造例A2に記載のCHA型ゼオライト膜複合体2を用いた以外は、実施例A1と同様の方法により、アンモニアの分離評価を行った。得られた透過ガスのアンモニアの濃度とアンモニア/水素、アンモニア/窒素のパーミエンス比を表4に示す。表4中、透過ガスのアンモニアの濃度は小数第一位を四捨五入した値である。表4の結果から、混合ガス中のアンモニアガス濃度が特定量以上であることにより、効率良くアンモニアの分離が可能であることが分かる。また、高温条件下においても効率よくアンモニア分離が可能であることが分かる。
(水熱合成用原料混合物)
6.8gの18-クラウン-6-エーテル(東京化成社製)と2.1gのNaOH(キシダ化学社製)及び4.2gのCsOH・H2O(三津和化学社製)を125.9gの水に溶解し、80℃で3時間撹拌することにより、クラウンエーテル-アルカリ水溶液を得た。その後、8.9gのY型(FAU)ゼオライト(SAR=30、Zeolyst社製 CBV720)に上記クラウンエーテル-アルカリ水溶液を滴下し、水熱合成用原料混合物を調製した。得られた水熱合成用原料混合物のゲル組成(モル比)はSiO2/Al2O3/NaOH/CsOH/H2O/18-クラウン-6-エーテル=1/0.033/0.36/0.18/50/0.18であった。
多孔質支持体としてはアルミナチューブ(外径6mm、細孔径0.15μm、ノリタケカンパニーリミテド社製)を40mmの長さに切断した後、水で洗浄したのち乾燥させたものを用いた。
23gの18-クラウン-6-エーテル(東京化成社製)と6gのNaOH(キシダ化学社製)及び5gのCsOH・H2O(三津和化学社製)を84gの水に溶解させ、得られた溶液を80℃で3時間撹拌することにより、クラウンエーテル-アルカリ水溶液を得た。
上記の種結晶分散液を支持体に滴下し、ラビング法により種結晶を支持体に付着させた。
<膜分離性能の評価>
製造例A3に記載のRHO型ゼオライト膜複合体1を用いて、アンモニア/水素/窒素の混合ガスからのアンモニア分離試験を上述の通り、図1の装置を用いて行った。
前処理として、250℃で、供給ガスとして50体積%H2/50体積%N2の混合ガスを、耐圧容器とRHO型ゼオライト膜複合体1との間に導入して、圧力を約0.3MPaに保ち、RHO型ゼオライト膜複合体1の円筒の内側を0.098MPa(大気圧)として、約120分間乾燥した。
その後、12体積%NH3/51体積%N2/37体積%H2の混合ガスを100SCCMで流通させ、背圧を0.4MPaに設定した。この時、RHO型ゼオライト膜複合体1の供給ガス側と透過ガス側の差圧は、0.3MPaであった。
種結晶を付着させた支持体を、水熱合成用原料混合物2の入ったテフロン(登録商標)製内筒に垂直方向に浸漬してオートクレーブを密閉し、150℃で72時間、自生圧力下で加熱した以外は、製造例A3において、NH4 +型からH+型への変換を行わなかった以外は記載の方法でNH4 +型のRHO型ゼオライト膜複合体を得た。
その後、NH4 +型のRHO型ゼオライト膜複合体を、1Mの硝酸アルミニウム水溶液45gが入ったテフロン(登録商標)製内筒(65ml)に入れた。オートクレーブを密栓し、100℃で1時間、静置状態、自生圧力下で加熱した。
<膜分離性能の評価>
製造例A4に記載のRHO型ゼオライト膜複合体2を用いて、アンモニア/水素/窒素の混合ガスからのアンモニア分離試験を上述の方法により、図1の装置を用いて行った。
前処理として、250℃で、供給ガス7として50体積%H2/50体積%N2の混合ガスを、耐圧容器2とゼオライト膜複合体1との間に導入して、圧力を約0.3MPaに保ち、RHO型ゼオライト膜複合体2の円筒の内側を0.098MPa(大気圧)として、約120分間乾燥した。
その後、12体積%NH3/51体積%N2/37体積%H2の混合ガスを100SCCMで流通させ、背圧を0.4MPaに設定した。この時、ゼオライト膜複合体2の供給ガス7側と透過ガス8側の差圧は、0.3MPaであった。
RHO型ゼオライトが1質量%になるように水を添加して種結晶分散液を得る以外は、製造例A4と同様の方法により種結晶及び支持体を用意し、内側を真空に引いた支持体をこの種結晶分散液に1分間浸し、その後支持体の内側を真空に引いた状態でラビング法により種結晶を支持体に付着させた。
<膜分離性能の評価>
製造例A5に記載のRHO型ゼオライト膜複合体4を用いて、アンモニア(NH3)/水素(H2)/窒素(N2)の混合ガスからのアンモニア分離試験を上述の方法により図1の装置を用いて行った。
前処理として、250℃で、供給ガスとして10体積%NH3/20体積%H2/60体積%N2の混合ガスを、耐圧容器とRHOゼオライト膜複合体4との間に導入して、圧力を約0.3MPaに保ち、RHOゼオライト膜複合体4の円筒の内側を0.098MPa(大気圧)として、約120分間乾燥した。その後、12体積%NH3/51体積%N2/37体積%H2の混合ガスを100SCCMで流通させ、背圧を0.4MPaに設定した。この時、RHOゼオライト膜複合体4の供給ガス側と透過ガス側の差圧は、0.3MPaであった。また、供給ガス9からスイープガスとしてアルゴンを3.9SCCM供給した。
製造例A5のRHO型ゼオライト膜複合体3と同様の方法により得られたNH4 +型のRHO型ゼオライト膜複合体を、1Mの硝酸ナトリウム水溶液50gが入ったテフロン(登録商標)製内筒(65ml)に入れた。オートクレーブを密栓し、100℃で1時間、静置状態、自生圧力下で加熱した。
<膜分離性能の評価>
製造例A5に記載のRHO型ゼオライト膜複合体4の代わりに、製造例A6に記載のRHO型ゼオライト膜複合体5を用いて、スイープガスとしてアルゴンを8.3SCCM供給した以外は、実施例A7と同様の方法で12.0体積%NH3/51.0体積%N2/37.0体積%H2の混合ガスの分離試験を行った。
得られた透過ガスのアンモニアの濃度とアンモニア/水素、アンモニア/窒素のパーミエンス比を表8に示す。表8中、透過ガスのアンモニアの濃度は小数第一位を四捨五入した値である。また、250℃でのアンモニアのパーミエンスは4.4×10-8[mol/(m2・s・Pa)]、325℃でのアンモニアのパーミエンスは1.1×10-7[mol/(m2・s・Pa)]であった。これらの結果から、混合ガス中のアンモニアガス濃度が特定量以上であることにより、効率良くアンモニアの分離が可能であることが分かる。また、高温条件下においても、高選択的にアンモニアが分離出来ている事が確認できた。
製造例A6に記載のRHO型ゼオライト膜複合体5を用いて、温度を250℃とし、混合ガスを2.0体積%NH3/20.0体積%N2/78.0体積%H2の混合ガスとした以外は実施例A8と同様の手法によりアンモニア分離の評価を行った結果、透過ガス中のアンモニアガス濃度は、19.9体積%であった。得られた結果から、混合ガスからアンモニアの分離が可能であることが分かる。
製造例A6に記載のRHO型ゼオライト膜複合体5を用いて、温度を250℃とし、混合ガスを3.0体積%NH3/20.0体積%N2/77.0体積%H2の混合ガスとした以外は実施例A8と同様の手法によりアンモニア分離の評価を行った結果、透過ガス中のアンモニアガス濃度は、27.6体積%であった。得られた結果から、混合ガスからアンモニアの分離が可能であることが分かる。
(水熱合成用混用物)
水熱合成のための原料混合物として、以下のものを調製した。
6.8gの18-クラウン-6-エーテル(東京化成社製)と2.1gのNaOH(キシダ化学社製)及び4.2gのCsOH・H2O(三津和化学社製)を125.9gの水に溶解し、80℃で3時間撹拌することにより、クラウンエーテル-アルカリ水溶液を得た。その後、8.9gのY型(FAU)ゼオライト(SAR=30、Zeolyst社製 CBV720)と0.2gの水酸化アルミニウム(Al2O3 53.5質量%、Aldrich社製)に上記クラウンエーテル-アルカリ水溶液を滴下し、水熱合成用原料混合物を調製した。得られた水熱合成用原料混合物のゲル組成(モル比)はSiO2/Al2O3/NaOH/CsOH/H2O/18-クラウン-6-エーテル=1/0.040/0.36/0.18/50/0.18であった。
RHO型ゼオライトが1質量%になるように水を添加して種結晶分散液を得る以外は、製造例A4と同様の方法により種結晶及び支持体を用意し、内側を真空に引いた支持体をこの種結晶分散液に1分間浸し、その後支持体の内側を真空に引いた状態でラビング法により種結晶を支持体に付着させた。
<膜分離性能の評価>
製造例A5に記載のRHO型ゼオライト膜複合体4の代わりに、製造例A7に記載のRHO型ゼオライト膜複合体6を用いた以外は、実施例A7と同様の方法で、RHO型ゼオライト膜複合体6の温度が250℃と、325℃の条件下において、12体積%NH3/51体積%N2/37体積%H2の混合ガスの分離試験を行った。
(水熱合成用原料混合物)
水熱合成用原料混合物を下記の方法により調製した。
50wt%-NaOH水溶液13.65g、水101gを混合したものにアルミン酸ナトリウム(Al2O3-62.2質量%含有)0.15gを加えて10分間室温で撹拌した。これにコロイダルシリカ(日産化学社製 スノーテック-40)32.3gを加えて、50度で5時間撹拌し、水熱反応用原料混合物とした。この反応用原料混合物の組成(モル比)は、SiO2/Al2O3/NaOH/H2O=3.05/0.013/0.193/100、SiO2/Al2O3=239であった。
ZSM5ゼオライト(東ソー製 HSZ-800シリーズ 822H0A)を乳鉢ですりつぶしたものを用意し、この種結晶の濃度が約0.4質量%となるように種結晶を分散させて、種結晶分散液を作製した。
(膜複合体の製造)
上述の種結晶分散液中に製造例A1と同じ処理を行った多孔質支持体を1分間浸した後、70℃で1時間乾燥させ、再度種結晶分散液に1分間浸した後、70℃で1時間乾燥させ、支持体に種結晶を付着させた。付着した種結晶の質量は約0.0016gであった。また、上記方法により種結晶が付着した多孔質支持体を用意した。
<膜分離性能の評価>
製造例A1に記載のCHA型ゼオライト膜複合体1の代わりに、製造例A8に記載のMFI型ゼオライト膜複合体1を用いた以外は、実施例A1と同様の方法によりアンモニア分離評価を行った。得られた透過ガスのアンモニアの濃度とアンモニア/水素、アンモニア/窒素のパーミエンス比を表10に示す。表10中、透過ガスのアンモニアの濃度は小数第一位を四捨五入した値である。また、250℃でのアンモニアのパーミエンスは7.5×10-8[mol/(m2・s・Pa)]であった。これらの結果から、混合ガス中のアンモニアガス濃度が特定量以上であることにより、効率良くアンモニアの分離が可能であることが分かる。また、150℃から250℃に温度を変えても、アンモニアが高い選択性で膜内を透過している事が確認できた。従って、高温条件下においても高選択的にアンモニアが分離出来ている事が確認できた。
温度を250℃とし、混合ガスを2.0体積%NH3/20.0体積%N2/78.0体積%H2の混合ガスとした以外は実施例A12と同様の手法によりアンモニア分離の評価を行った結果、透過ガス中のアンモニアガス濃度は、7.0体積%であった。得られた結果から、混合ガスからアンモニアの分離が可能であることが分かる。
温度を250℃とし、混合ガスを3.0体積%NH3/20.0体積%N2/77.0体積%H2の混合ガスとした以外は実施例A12と同様の手法によりアンモニア分離の評価を行った結果、透過ガス中のアンモニアガス濃度は、10.7体積%であった。得られた結果から、混合ガスからアンモニアの分離が可能であることが分かる。
製造例A8において作製したMFI型ゼオライト膜複合体1を用いて、MFI型ゼオライト膜複合体1の温度を250℃とし、12体積%NH3/50体積%N2/38体積%H2の混合ガスを100SCCMの流量で流通させた以外は実施例A12と同様の手法でアンモニア分離の評価を行った結果、水素のパーミエンスは1.6×10-8[mol/(m2・s・Pa)]、窒素のパーミエンスは3.3×10-9[mol/(m2・s・Pa)]、アンモニアのパーミエンスは7.5×10-8[mol/(m2・s・Pa)]であった。これに対して、水素ガス単味を流通させた際の水素のパーミエンスは4.7×10-7[mol/(m2・s・Pa)]であり、窒素ガス単味を流通させた際の窒素のパーミエンスは3.0×10-7[mol/(m2・s・Pa)]であり、これらの結果から供給ガスにアンモニアガスが含有されると、水素ならびに窒素は、いずれも著しくパーミエンスが低下することが判った。本結果から、混合ガス中のアンモニアガス濃度が特定量以上であることにより、供給ガス中のアンモニアがゼオライトに吸着し、水素や窒素の透過を阻害する効果を発現したと考えられる。
[物性および分離性能の測定]
以下において、ゼオライトあるいはゼオライト膜複合体の物性や分離性能等の測定は次のとおり行った。
XRD測定は以下の条件に基づき行った。
装置名:Bruker社製New D8 ADVANCE
光学系:集中光学系
光学系仕様 入射側:封入式X線管球(CuKα)
Soller Slit (2.5°)
Divergence Slit (Valiable Slit)
試料台:XYZステージ
受光側:半導体アレイ検出器(Lynx Eye 1D mode)
Ni-filter
Soller Slit (2.5°)
ゴニオメーター半径:280mm
測定条件 X線出力(CuKα):40kV、40mA
走査軸:θ/2θ
走査範囲(2θ):5.0-70.0°
測定モード:Continuous
読込幅:0.01°
計数時間:57.0sec(0.3sec×190ch)
自動可変スリット(Automatic-DS):1mm(照射幅)
測定データには可変→固定スリット補正を行った。
また、照射幅を自動可変スリットによって1mmに固定して測定し、Materials Data, Inc.のXRD解析ソフトJADE+9.4(英語版)を用いて可変スリット→固定スリット変換を行ってXRDパターンを得た。
XPS測定は以下の条件に基づき行った。
機種名:アルバック・ファイ株式会社製Quantum2000
測定の際のX線源:単色化Al-Kα,出力16kV-34W
(X線発生面積170umφ)
帯電中和:電子銃5μA、イオン銃3V
分光系:パスエネルギー
ワイドスペクトル:187.70eV
ナロースペクトル(N1s,O1s,Na1s,Al2p,Si2p,Cs3d5)):58.70eV
※Csが検出される場合はCs3d5とAl2pのピーク位置が重なったため、Al2pの代わりにAl2sのピークを採用した。(Csを含有していないサンプルを用いてAl2pとAl2sのいずれを用いても表面組成の分析値に差がないこと確認した。)
測定領域:300μm角
取り出し角:45°(表面より)
エネルギー補正;Si2p=103.4eV
ゼオライト膜複合体の一端を封止し、他端を、密閉状態で5kPaの真空ラインに接続して、真空ラインとゼオライト膜複合体の間に設置したマスフローメーターで空気の流量を測定し、空気透過量[L/(m2・h)]とした。マスフローメーターとしてはKOFLOC社製8300、N2ガス用、最大流量500ml/min(20℃、1気圧換算)を用いた。KOFLOC社製8300においてマスフローメーターの表示が10ml/min(20℃、1気圧換算)以下であるときはLintec社製MM-2100M、Airガス用、最大流量20ml/min(0℃、1気圧換算)を用いて測定した。
図1に模式的に示す装置において、以下のとおりアンモニア分離試験を行った。図1の装置において、供給ガスとしてアンモニアと、窒素と、水素と、を含む混合ガスを100SCCMの流量で耐圧容器とゼオライト膜複合体との間に供給し、背圧弁により供給側のガスと膜内を透過したガスの圧力差が0.3MPaで一定になるように調整し、配管10から排出される排出ガスにマスフローコントローラーで流量を制御したヘリウムを標準物質として混合し、マイクロガスクロマトグラフで分析し、透過ガスの濃度、及び流量を算出した。
また、この測定結果に基づいて、下記式(1)により理想分離係数α’を算出した。
α’=(Q1/Q2)/(P1/P2) (1)
〔式(1)中、Q1およびQ2は、それぞれ、透過性の高いガスおよび透過性の低いガスの透過量[mol・(m2・s)-1]を示し、P1およびP2は、それぞれ、透過性の高いガスおよび透過性の低いガスの、供給側と透過側の圧力差[Pa]を示す。〕
これは、各ガスのパーミエンスの比率を示しており、従って、各ガスのパーミエンスを算出し、その比率から求めることができる。
以下の方法により、RHO型ゼオライト膜複合体1、2を製造した。RHO型ゼオライト膜複合体1、2の製造に先立ち、下記の通り、水熱合成用原料混合物1、支持体及び種結晶分散液1を用意した。
6.8gの18-クラウン-6-エーテル(東京化成社製)と2.1gのNaOH(キシダ化学社製)及び4.2gのCsOH・H2O(三津和化学社製)を125.9gの水に溶解し、80℃で3時間撹拌することにより、クラウンエーテル-アルカリ水溶液を得た。その後、8.9gのY型(FAU)ゼオライト(SAR=30、Zeolyst社製 CBV720)に上記クラウンエーテル-アルカリ水溶液を滴下し、水熱合成用原料混合物を調製した。得られた水熱合成用原料混合物1のゲル組成(モル比)はSiO2/Al2O3/NaOH/CsOH/H2O/18-クラウン-6-エーテル=1/0.033/0.36/0.18/50/0.18であった。
多孔質支持体としてはアルミナチューブ(外径6mm、内径4mm、細孔径0.15μm、ノリタケカンパニーリミテド社製)を80mmの長さに切断した後、水で洗浄したのち乾燥させたものを用いた。
23gの18-クラウン-6-エーテル(東京化成社製)と6gのNaOH(キシダ化学社製)及び5gのCsOH・H2O(三津和化学社製)を84gの水に溶解させ、得られた溶液を80℃で3時間撹拌することにより、クラウンエーテル-アルカリ水溶液を得た。
次に、内側を真空に引いた支持体をこの種結晶分散液1に1分間浸し、その後支持体の内側を真空に引いた状態でラビング法により種結晶を支持体に付着させた。
<膜分離性能の評価>
製造例B1に記載のRHO型ゼオライト膜複合体2を用いて、アンモニアガス(NH3)/水素ガス(H2)/窒素ガス(N2)の混合ガスからのアンモニア分離試験を上述の方法により図1の装置を用いて、具体的には下記の方法により行った。
前処理として、250℃で、供給ガスとして10体積%NH3/20体積%H2/60体積%N2の混合ガスを、耐圧容器とRHOゼオライト膜複合体2との間に導入して、圧力を約0.3MPaに保ち、RHOゼオライト膜複合体2の円筒の内側を0.098MPa(大気圧)として、約120分間乾燥した。
その後、供給ガスとして、12体積%NH3/51体積%N2/37体積%H2の混合ガスを100SCCMで流通させ、背圧を0.4MPaに設定した。この時、RHOゼオライト膜複合体2の供給ガス側と透過ガス側の差圧は、0.3MPaであった。また、供給ガス9からスイープガスとしてアルゴンを3.9SCCM供給した。
以下の方法により、RHO型ゼオライト膜複合体3を製造した。なお、支持体は製造例B1と同様の支持体を使用し、種結晶分散液は製造例B1の種結晶分散液1と同様のものを使用した。
水熱合成原料混合物2として、以下のものを調製した。
6.8gの18-クラウン-6-エーテル(東京化成社製)と2.1gのNaOH(キシダ化学社製)及び4.2gのCsOH・H2O(三津和化学社製)を125.9gの水に溶解し、80℃で3時間撹拌することにより、クラウンエーテル-アルカリ水溶液を得た。その後、8.9gのY型(FAU)ゼオライト(SAR=30、Zeolyst社製 CBV720)と0.2gの水酸化アルミニウム(Al2O3 53.5質量%、Aldrich社製)に上記クラウンエーテル-アルカリ水溶液を滴下し、水熱合成用原料混合物を調製した。得られた水熱合成用原料混合物2のゲル組成(モル比)はSiO2/Al2O3/NaOH/CsOH/H2O/18-クラウン-6-エーテル=1/0.040/0.36/0.18/50/0.18であった。
内側を真空に引いた支持体を種結晶分散液1に1分間浸し、その後支持体の内側を真空に引いた状態でラビング法により種結晶を支持体に付着させた。
<膜分離性能の評価>
製造例B1に記載のRHO型ゼオライト膜複合体2の代わりに、製造例B2に記載のRHO型ゼオライト膜複合体3を用いて、スイープガスであるアルゴンの供給量を8.3SCCMに変更した以外は、実施例B1と同様の方法で、250℃及び325℃の条件下において、12体積%NH3/51体積%N2/37体積%H2の混合ガスの分離試験を行った。
以下の方法により、RHO型ゼオライト膜複合体4を製造した。なお、水熱合成用原料混合物及び支持体は、それぞれ製造例B1の水熱合成用原料混合物1及び支持体と同じものを使用した。
10質量%のRHO型ゼオライト分散液を作製した後に、RHO型ゼオライトが3質量%となるように水を添加した以外は、製造例B1の種結晶分散液1と同様の方法により種結晶分散液2を製造した。
種結晶分散液2を支持体に滴下し、ラビング法により種結晶を支持体に付着させた。
<膜分離性能の評価>
製造例B3に記載のRHO型ゼオライト膜複合体4を用いて、アンモニア/水素/窒素の混合ガスからのアンモニア分離試験を、図1の装置を用いて行った。
前処理として、250℃で、供給ガスとして50体積%H2/50体積%N2の混合ガスを、耐圧容器とRHO型ゼオライト膜複合体4との間に導入して、圧力を約0.3MPaに保ち、RHO型ゼオライト膜複合体4の円筒の内側を0.098MPa(大気圧)として、約120分間乾燥した。
その後、12体積%NH3/51体積%N2/37体積%H2の混合ガスを100SCCMで流通させ、背圧を0.4MPaに設定した。この時、RHO型ゼオライト膜複合体4の供給ガス側と透過ガス側の差圧は、0.3MPaであった。また、供給ガス9からスイープガスとしてアルゴンを2.4SCCM供給した。
以下の方法により、RHO型ゼオライト膜複合体5を製造した。なお、水熱合成用原料混合物としては、製造例B2の水熱合成原料混合物2と同じものを使用し、支持体及び種結晶分散液は、それぞれ製造例B1の支持体及び種結晶分散液1と同じものを使用した。
内側を真空に引いた支持体を種結晶分散液1に1分間浸し、その後支持体の内側を真空に引いた状態でラビング法により種結晶を支持体に付着させた。
<膜分離性能の評価>
製造例B4に記載のRHO型ゼオライト膜複合体5を用いて、アンモニア/水素/窒素の混合ガスからのアンモニア分離試験を上述の方法により図1の装置を用いて行った。
前処理として、250℃で、供給ガスとして10体積%NH3/20体積%H2/60体積%N2の混合ガスを、耐圧容器とRHOゼオライト膜複合体5との間に導入して、圧力を約0.3MPaに保ち、RHOゼオライト膜複合体2の円筒の内側を0.098MPa(大気圧)として、約120分間乾燥した。
その後、12体積%NH3/51体積%N2/37体積%H2の混合ガスを100SCCMで流通させ、背圧を0.4MPaに設定した。この時、RHOゼオライト膜複合体5の供給ガス側と透過ガス側の差圧は、0.3MPaであった。また、供給ガス9からスイープガスとしてアルゴンを3.9SCCM供給した。
[物性および分離性能の測定]
以下において、ゼオライトあるいはゼオライト膜複合体の物性や分離性能等の測定は実施例Bと同様に行った。
以下の方法により、RHO型ゼオライト膜複合体1、2を製造した。RHO型ゼオライト膜複合体1、2の製造に先立ち、下記の通り、水熱合成用原料混合物1、支持体及び種結晶分散液1を用意した。
6.8gの18-クラウン-6-エーテル(東京化成社製)と2.1gのNaOH(キシダ化学社製)及び4.2gのCsOH・H2O(三津和化学社製)を125.9gの水に溶解し、80℃で3時間撹拌することにより、クラウンエーテル-アルカリ水溶液を得た。その後、8.9gのY型(FAU)ゼオライト(SAR=30、Zeolyst社製 CBV720)に上記クラウンエーテル-アルカリ水溶液を滴下し、水熱合成用原料混合物を調製した。得られた水熱合成用原料混合物1のゲル組成(モル比)はSiO2/Al2O3/NaOH/CsOH/H2O/18-クラウン-6-エーテル=1/0.033/0.36/0.18/50/0.18であった。
多孔質支持体としてはアルミナチューブ(外径6mm、内径4mm、細孔径0.15μm、ノリタケカンパニーリミテド社製)を80mmの長さに切断した後、水で洗浄したのち乾燥させたものを用いた。
23gの18-クラウン-6-エーテル(東京化成社製)と6gのNaOH(キシダ化学社製)及び5gのCsOH・H2O(三津和化学社製)を84gの水に溶解させ、得られた溶液を80℃で3時間撹拌することにより、クラウンエーテル-アルカリ水溶液を得た。
次に、内側を真空に引いた支持体をこの種結晶分散液1に1分間浸し、その後支持体の
内側を真空に引いた状態でラビング法により種結晶を支持体に付着させた。
<膜分離性能の評価>
製造例C1に記載のRHO型ゼオライト膜複合体2を用いて、アンモニア/水素/窒素の混合ガスからのアンモニア分離試験を上述の方法により図1の装置を用いて、具体的には下記の方法により行った。
前処理として、250℃で、供給ガスとして10体積%NH3/20体積%H2/60体積%N2の混合ガスを、耐圧容器とRHOゼオライト膜複合体2との間に導入して、圧力を約0.3MPaに保ち、RHOゼオライト膜複合体2の円筒の内側を0.098MPa(大気圧)として、約120分間乾燥した。
その後、供給ガスとして、12体積%NH3/51体積%N2/37体積%H2の混合ガスを100SCCMで流通させ、背圧を0.4MPaに設定した。この時、RHOゼオライト膜複合体2の供給ガス側と透過ガス側の差圧は、0.3MPaであった。また、供給ガス9からスイープガスとしてアルゴンを3.9SCCM供給した。
以下の方法により、RHO型ゼオライト膜複合体3を製造した。なお、支持体は製造例C1と同様の支持体を使用し、種結晶分散液は製造例C1の種結晶分散液1と同様のものを使用した。
水熱合成のための原料混合物2として、以下のものを調製した。
6.8gの18-クラウン-6-エーテル(東京化成社製)と2.1gのNaOH(キシダ化学社製)及び4.2gのCsOH・H2O(三津和化学社製)を125.9gの水に溶解し、80℃で3時間撹拌することにより、クラウンエーテル-アルカリ水溶液を得た。その後、8.9gのY型(FAU)ゼオライト(SAR=30、Zeolyst社製 CBV720)と0.2gの水酸化アルミニウム(Al2O3 53.5質量%、Aldrich社製)に上記クラウンエーテル-アルカリ水溶液を滴下し、水熱合成用原料混合物を調製した。得られた水熱合成用原料混合物2のゲル組成(モル比)はSiO2/Al2O3/NaOH/CsOH/H2O/18-クラウン-6-エーテル=1/0.040/0.36/0.18/50/0.18であった。
製造例C1と同様の方法により種結晶分散液1及び支持体を用意し、内側を真空に引いた支持体をこの種結晶分散液1に1分間浸し、その後支持体の内側を真空に引いた状態でラビング法により種結晶を支持体に付着させた。
<膜分離性能の評価>
製造例C1に記載のRHO型ゼオライト膜複合体2の代わりに、製造例C2に記載のRHO型ゼオライト膜複合体3を用いて、スイープガスとしてアルゴンを8.3SCCM供給した以外は、実施例C1と同様の方法で、250℃と、325℃の条件下において、12体積%NH3/51体積%N2/37体積%H2の混合ガスの分離試験を行った。
以下の方法により、RHO型ゼオライト膜複合体4を製造した。
<膜分離性能の評価>
製造例C3に記載のRHO型ゼオライト膜複合体4を用いて、アンモニア/水素/窒素の混合ガスからのアンモニア分離試験を上述の方法により図1の装置を用いて行った。
前処理として、250℃の条件下で、供給ガスとして10体積%NH3/20体積%H2/60体積%N2の混合ガスを、耐圧容器とRHOゼオライト膜複合体4との間に導入して、圧力を約0.3MPaに保ち、RHOゼオライト膜複合体4の円筒の内側を0.098MPa(大気圧)として、約120分間乾燥した。
その後、12体積%NH3/51体積%N2/37体積%H2の混合ガスを100SCCMで流通させ、背圧を0.4MPaに設定した。この時、RHOゼオライト膜複合体の供給ガス側と透過ガス側の差圧は、0.3MPaであった。また、供給ガス9からスイープガスとしてアルゴンを8.3SCCM供給した。
得られた透過ガスのアンモニアの濃度とアンモニア/水素、アンモニア/窒素のパーミエンス比を表18に示す。尚、また、250℃でのアンモニアのパーミエンスは4.4×10-8[mol/(m2・s・Pa)]であり、325℃でのアンモニアのパーミエンスは1.1×10-7[mol/(m2・s・Pa)]であった。表18の結果から、XPS測定でSi原子/Al原子モル比が7.46である、Na+型のRHO型ゼオライト膜を用いることにより、効率良くアンモニアの分離が可能であることが分かる。また、250℃と325℃との得られた透過ガスのアンモニアの濃度を比較すると、XPS測定でSi原子/Al原子モル比が7.46である、本Na+型のRHO型ゼオライト膜の場合は、その変化率は20%程度であり、本ゼオライト膜は分離熱安定性に若干劣る分離膜であるが、依然として高い分離熱安定性を示すことが判った。
以下の方法により、RHO型ゼオライト膜複合体5を製造した。なお、水熱合成用混合物は製造例C1の水熱合成用原料混合物1と同じものを使用し、種結晶分散液は種結晶分散液1と同じものを使用した。
多孔質支持体としてアルミナチューブ(外径6mm、内径4mm、細孔径0.15μm、ノリタケカンパニーリミテド社製)を40mmの長さに切断した後、水で洗浄したのち乾燥させたものを用いた。
(膜複合体の製造)
内側を真空に引いた支持体をこの種結晶分散液1に1分間浸し、その後支持体の内側を真空に引いた状態でラビング法により種結晶を支持体に付着させた。
<膜分離性能の評価>
製造例C4に記載のRHO型ゼオライト膜複合体5を用いて、アンモニア(NH3)/水素(H2)/窒素(N2)の混合ガスからのアンモニア分離試験を上述の方法により図1の装置を用いて行った。
前処理として、250℃の条件下で、供給ガスとして10体積%NH3/20体積%H2/60体積%N2の混合ガスを、耐圧容器とRHOゼオライト膜複合体5との間に導入して、圧力を約0.3MPaに保ち、RHOゼオライト膜複合体5の円筒の内側を0.098MPa(大気圧)として、約120分間乾燥した。
その後、12体積%NH3/51体積%N2/37体積%H2の混合ガスを100SCCMで流通させ、背圧を0.4MPaに設定した。この時、RHOゼオライト膜複合体の供給ガス側と透過ガス側の差圧は、0.3MPaであった。また、供給ガス9からスイープガスとしてアルゴンを3.9SCCM供給した。
得られた透過ガスのアンモニアの濃度とアンモニア/水素、アンモニア/窒素のパーミエンス比を表19に示す。本結果より、Al処理をしてない本NH4 +型のRHO型ゼオライト膜は、Al処理したNH4 +型のRHO型ゼオライト膜と比べて分離性能が低くなることが明らかとなった。すなわち、本結果によりNH4 +型のRHO型ゼオライト膜をAl処理することで、ゼオライト膜のSi原子に対するAl原子を適度に制御することにより、アンモニアと水素および/または窒素を含む複数の成分からなる混合ガスからアンモニアを高選択的に分離するゼオライト膜が設計できることが明らかとなった。
尚、250℃でのアンモニアのパーミエンスは3.0×10-8[mol/(m2・s・Pa)]であり、300℃でのアンモニアのパーミエンスは2.9×10-8[mol/(m2・s・Pa)]であった。
[物性および分離性能の測定]
以下において、ゼオライトあるいはゼオライト膜複合体の物性や分離性能等の測定は実施例Bと同様に行った。
以下の方法により、RHO型ゼオライト膜複合体1、2を製造した。RHO型ゼオライト膜複合体1、2の製造に先立ち、下記の通り、水熱合成用原料混合物1、支持体及び種結晶分散液1を用意した。
6.8gの18-クラウン-6-エーテル(東京化成社製)と2.1gのNaOH(キシダ化学社製)及び4.2gのCsOH・H2O(三津和化学社製)を125.9gの水に溶解し、80℃で3時間撹拌することにより、クラウンエーテル-アルカリ水溶液を得た。その後、8.9gのY型(FAU)ゼオライト(SAR=30、Zeolyst社製 CBV720)に上記クラウンエーテル-アルカリ水溶液を滴下し、水熱合成用原料混合物を調製した。得られた水熱合成用原料混合物1のゲル組成(モル比)はSiO2/Al2O3/NaOH/CsOH/H2O/18-クラウン-6-エーテル=1/0.033/0.36/0.18/50/0.18であった。
多孔質支持体としてはアルミナチューブ(外径6mm、内径4mm、細孔径0.15μm、ノリタケカンパニーリミテド社製)を80mmの長さに切断した後、水で洗浄したのち乾燥させたものを用いた。
23gの18-クラウン-6-エーテル(東京化成社製)と6gのNaOH(キシダ化学社製)及び5gのCsOH・H2O(三津和化学社製)を84gの水に溶解させ、得られた溶液を80℃で3時間撹拌することにより、クラウンエーテル-アルカリ水溶液を得た。
次に、内側を真空に引いた支持体をこの種結晶分散液1に1分間浸し、その後支持体の内側を真空に引いた状態でラビング法により種結晶を支持体に付着させた。
<膜分離性能の評価>
製造例D1に記載のRHO型ゼオライト膜複合体2を用いて、アンモニア/水素/窒素の混合ガスからのアンモニア分離試験を上述の方法により図1の装置を用いて、具体的には下記の方法により行った。
前処理として、250℃の条件下で、供給ガスとして10体積%NH3/20体積%H2/60体積%N2の混合ガスを、耐圧容器とRHOゼオライト膜複合体2との間に導入して、圧力を約0.3MPaに保ち、RHOゼオライト膜複合体2の円筒の内側を0.098MPa(大気圧)として、約120分間乾燥した。
その後、供給ガスとして、12体積%NH3/51体積%N2/37体積%H2の混合ガスを100SCCMで流通させ、背圧を0.4MPaに設定した。この時、RHOゼオライト膜複合体の供給ガス側と透過ガス側の差圧は、0.3MPaであった。また、供給ガス9からスイープガスとしてアルゴンを8.3SCCM供給した。
得られた透過ガスのアンモニアの濃度とアンモニア/水素、アンモニア/窒素のパーミエンス比を表20に示す。表20の結果から、Na+型のRHO型ゼオライト膜を用いることにより、効率良くアンモニアの分離が可能であることが分かる。また、高温条件下においてAl処理したNa+型のRHO型ゼオライト膜は高選択的にアンモニアが分離出来ている事が確認できた。また、250℃でのアンモニアのパーミエンスは4.4×10-8[mol/(m2・s・Pa)]であり、本参考例D1の同等のN原子/Al原子モル比ならびにSi原子/Al原子モル比を示す、アルカリ金属を含有しないRHO型ゼオライト膜複合体3との比較から、アルカリ金属原子を含有させると、同等の高濃度のアンモニアを高い透過性で回収できることが明らかになった。
以下の方法により、RHO型ゼオライト膜複合体3を製造した。なお、支持体は製造例D1と同様の支持体を使用し、種結晶分散液は製造例D1の種結晶分散液1と同様のものを使用した。
水熱合成のための原料混合物2として、以下のものを調製した。
6.8gの18-クラウン-6-エーテル(東京化成社製)と2.1gのNaOH(キシダ化学社製)及び4.2gのCsOH・H2O(三津和化学社製)を125.9gの水に溶解し、80℃で3時間撹拌することにより、クラウンエーテル-アルカリ水溶液を得た。その後、8.9gのY型(FAU)ゼオライト(SAR=30、Zeolyst社製 CBV720)と0.2gの水酸化アルミニウム(Al2O3 53.5質量%、Aldrich社製)に上記クラウンエーテル-アルカリ水溶液を滴下し、水熱合成用原料混合物を調製した。得られた水熱合成用原料混合物2のゲル組成(モル比)はSiO2/Al2O3/NaOH/CsOH/H2O/18-クラウン-6-エーテル=1/0.040/0.36/0.18/50/0.18であった。
製造例D1と同様の方法により種結晶及び支持体を用意し、内側を真空に引いた支持体をこの種結晶分散液1に1分間浸し、その後支持体の内側を真空に引いた状態でラビング法により種結晶を支持体に付着させた。
<膜分離性能の評価>
製造例D1に記載のRHO型ゼオライト膜複合体2の代わりに、製造例D2に記載のRHO型ゼオライト膜複合体3を用いた以外は、実施例D1と同様の方法で、RHO型ゼオライト膜複合体3の温度が250℃の条件下において、12体積%NH3/51体積%N2/37体積%H2の混合ガスの分離試験を行った。
以下の方法により、RHO型ゼオライト膜複合体4を製造した。
水熱合成のための原料混合物として、以下のものを調製した。
6.8gの18-クラウン-6-エーテル(東京化成社製)と2.1gのNaOH(キシダ化学社製)及び4.2gのCsOH・H2O(三津和化学社製)を125.9gの水に溶解し、80℃で3時間撹拌することにより、クラウンエーテル-アルカリ水溶液を得た。その後、8.9gのY型(FAU)ゼオライト(SAR=30、Zeolyst社製 CBV720)と0.2gの水酸化アルミニウム(Al2O3 53.5質量%、Aldrich社製)に上記クラウンエーテル-アルカリ水溶液を滴下し、水熱合成用原料混合物を調製した。得られた水熱合成用原料混合物2のゲル組成(モル比)はSiO2/Al2O3/NaOH/CsOH/H2O/18-クラウン-6-エーテル=1/0.040/0.36/0.18/50/0.18であった。
製造例D1と同様の方法により種結晶分散液1及び支持体を用意し、内側を真空に引いた支持体をこの種結晶分散液1に1分間浸し、その後支持体の内側を真空に引いた状態でラビング法により種結晶を支持体に付着させた。
<膜分離性能の評価>
製造例D3に記載のRHO型ゼオライト膜複合体4を用いて、アンモニア/水素/窒素の混合ガスからのアンモニア分離試験を上述の方法により図1の装置を用いて行った。
前処理として、250℃で、供給ガスとして10体積%NH3/20体積%H2/60体積%N2の混合ガスを、耐圧容器とRHOゼオライト膜複合体4との間に導入して、圧力を約0.3MPaに保ち、RHOゼオライト膜複合体4の円筒の内側を0.098MPa(大気圧)として、約120分間乾燥した。
その後、12体積%NH3/51体積%N2/37体積%H2の混合ガスを100SCCMで流通させ、背圧を0.4MPaに設定した。この時、RHOゼオライト膜複合体4の供給ガス側と透過ガス側の差圧は、0.3MPaであった。
ゼオライトの熱膨張率は、以下の条件下での昇温XRD測定法により決定した。
(昇温XRD測定装置仕様)
測定雰囲気:大気
昇温条件 :20℃/min
測定方法 :測定温度で5分間保持後にXRD測定を実施した。
測定データには、可変スリットを用いて固定スリット補正を行った。
熱膨張率の変化率の算出方法:
熱膨張率の変化率=(所定温度で測定した結晶格子定数)÷(30℃で測定した結晶格子定数) - 1 ・・・(1)
(RHO型ゼオライトの製造)
RHO型ゼオライトを次の通り合成した。
SiO2/Al2O3/NaOH/CsOH/H2O/18-クラウン-6-エーテル=1/0.033/0.30/0.06/10/0.18
<RHO型ゼオライト膜複合体1の作製>
多孔質支持体上にRHO型ゼオライトを直接水熱合成することにより多孔質支持体-RHO型ゼオライト膜複合体を作製した。なお、多孔質支持体としてはアルミナチューブ(外径6mm、細孔径0.15μm、ノリタケカンパニーリミテド社製)を40mmの長さに切断した後、水で洗浄したのち乾燥させたものを用いた。
ボールミルの粉砕は以下の通り実施した。500mLのポリビンに、上記種結晶用のRHO型ゼオライト10gと3φmmのHDアルミナボール(ニッカトー社製)300g、水90gを入れ、6時間ボールミル粉砕して10質量%のRHO型ゼオライト分散液とした。このゼオライト分散液に、RHO型ゼオライトが3質量%になるように水を添加して種結晶分散液を得た。
この種結晶分散液を支持体に滴下し、ラビング法により種結晶を支持体に付着させた。
(膜分離性能の評価)
実施例E2に記載のRHO型ゼオライト膜複合体1を用いて、アンモニア/水素/窒素の混合ガスからのアンモニア分離試験を図1の装置を用いて行った。
前処理として、250℃で、供給ガス7として50%H2/50%N2の混合ガスを、耐圧容器2とゼオライト膜複合体1との間に導入して、圧力を約0.3MPaに保ち、ゼオライト膜複合体1の円筒の内側を0.098MPa(大気圧)として、約120分間乾燥した。
その後、12%アンモニア/51%窒素/37%窒素の混合ガスを100SCCMで流通させ、背圧を0.4MPaに設定した。この時、RHO型ゼオライト膜複合体1の供給ガス7側と透過ガス8側の差圧は、0.3MPaであった。
従って、本発明のゼオライト膜複合体は、熱膨張率の変化率が特定の範囲内に入るゼオライトを種結晶に用いて合成する事により、高温条件下においても安定して高選択的にアンモニアが分離出来る事を示している。
<Na+型RHOの合成>
Na+型RHOゼオライトについては、「Microporous and Mesoporous Materials 132 (2010) 352-356)」に記載の方法で水熱合成を実施した。水熱合成反応後、反応液を冷却して、濾過により生成した結晶を回収した。回収した結晶を100℃で12時間乾燥した。得られたRHO型ゼオライトについて熱膨張率を測定した結果を図2に示した。Na+型RHOの熱膨張率は温度に対して一次直線に近似できることが確認された。本近似式から、30℃に対する300℃の熱膨張率の変化率は0.23%、30℃に対する400℃の熱膨張率の変化率は0.33%と見積もられた。
<RHOゼオライト膜複合体2の合成>
種結晶を付着させた支持体を水熱合成用原料混合物の入ったテフロン(登録商標)製内筒に垂直方向に浸漬してオートクレーブを密閉し、150℃で72時間、自生圧力下で加熱する以外は、実施例E2に記載の方法でNH4 +型のRHO型ゼオライト膜複合体を得た。
NH4 +型のRHO型ゼオライト膜複合体について、1Mの硝酸アルミニウム水溶液45gが入ったテフロン(登録商標)容器製内筒(65ml)に入れた。オートクレーブを密栓し、100℃で1時間、静置状態、自生圧力下で加熱した。
<膜分離性能の評価>
実施例E5に記載のRHO型ゼオライト膜複合体2を用いて、アンモニア/水素/窒素の混合ガスからのアンモニア分離試験を図1の装置を用いて行った。
前処理として、250℃で、供給ガス7として50%H2/50%N2の混合ガスを、耐圧容器2とゼオライト膜複合体1との間に導入して、圧力を約0.3MPaに保ち、ゼオライト膜複合体の円筒の内側を0.098MPa(大気圧)として、約120分間乾燥した。
その後、12%アンモニア/51%窒素/37%窒素の混合ガスを100SCCMで流通させ、背圧を0.4MPaに設定した。この時、RHO型ゼオライト膜複合体2の供給ガス7側と透過ガス8側の差圧は、0.3MPaであった。
従って、ゼオライト膜複合体を構成するゼオライトの熱膨張率の変化率が特定の範囲にある事により、RHO型膜複合体は高温条件下で安定してアンモニアを分離する事を確認した。
<MFI型ゼオライトの製造>
MFI型ゼオライトを次の通り合成した。
50wt%-NaOH水溶液13.65g、水101gを混合したものにアルミン酸ナトリウム(Al2O3-62.2質量%含有)0.15gを加えて10分間室温で撹拌した。これにコロイダルシリカ(日産化学社製 スノーテック-40)32.3gを加えて、50度で5時間撹拌し、水熱反応用原料混合物とした。この反応用原料混合物の組成(モル比)は、SiO2/Al2O3/NaOH/H2O=3.05/0.013/0.193/100、SiO2/Al2O3=239である。
<MFI型ゼオライト膜複合体の作製>
最初に、水熱合成用原料混合物を下記の方法により調製した。
50wt%-NaOH水溶液13.65g、水101gを混合したものにアルミン酸ナトリウム(Al2O3-62.2質量%含有)0.15gを加えて10分間室温で撹拌した。これにコロイダルシリカ(日産化学社製 スノーテック-40)32.3gを加えて、50度で5時間撹拌し、水熱反応用原料混合物とした。この反応用原料混合物の組成(モル比)は、SiO2/Al2O3/NaOH/H2O=3.05/0.013/0.193/100、SiO2/Al2O3=239である。
<膜分離性能の評価>
実施例E8に記載のMFI型ゼオライト膜複合体2の温度を100℃~250℃に変えて12%アンモニア/51%窒素/37%窒素の混合ガスを100SCCMの流量で流通させて、得られた透過ガスのアンモニアの濃度とアンモニア/水素、アンモニア/窒素のパーミエンス比を表27に示した。150℃から250℃に温度を変えても、アンモニアが高い選択性で膜内を透過している事が確認できた。従って、高温条件下においてもゼオライト粒子間に隙間や欠陥が生じる事が無く高選択的にアンモニアが分離出来ている事が確認できたことから、ゼオライトの熱膨張率はRHO型ゼオライト膜複合体と同程度であると考えられる。また、250℃でのアンモニアのパーミエンスは7.5×10-8[mol/(m2・s・Pa)]であった。
<CHA型ゼオライトの製造>
CHA型ゼオライトを次の通り合成した。
0.6gのNaOH(キシダ化学社製)及び1.1gのKOH(キシダ化学社製)、水10gを混合したものに水酸化アルミニウム(Al2O3-53.5質量%含有、アルドリッチ社製)0.5gを加えて撹拌し溶解させ、透明溶液とした。これに有機テンプレートとして、N,N,N-トリメチル-1-アダマンタンアンモニウムヒドロキシド(以下これを「TMADAOH」と称する。)25質量%水溶液を5.4gを加え、さらにコロイダルシリカ(日産化学社製スノーテック-40)12gを加えて2時間撹拌し、水熱合成用原料混合物とした。この混合物の組成(モル比)は、SiO2/Al2O3/NaOH/KOH/H2O/TMADAOH=1/0.033/0.2/0.2/15/0.08、SiO2/Al2O3は30である。
<CHA型ゼオライト膜複合体の作製>
最初に、水熱合成用原料混合物を以下のとおり調製した。
1mol/L-NaOH水溶液1.45g、1mol/L-KOH水溶液5.78g、水114.6gを混合したものに水酸化アルミニウム(Al2O3-53.5質量%含有、アルドリッチ社製)0.19gを加えて撹拌し溶解させ、透明溶液とした。これに有機テンプレートとして、TMADAOH25質量%水溶液を2.43g加え、さらにコロイダルシリカ(日産化学社製、スノーテック-40)10.85gを加えて2時間撹拌し、水熱合成用原料混合物とした。この混合物の組成(モル比)は、SiO2/Al2O3/N
aOH/KOH/H2O/TMADAOH=1/0.018/0.02/0.08/100/0.04、SiO2/Al2O3=58である。
乾燥後の膜複合体を、空気中、電気炉で、450℃にて10時間、500℃で5時間焼成した。このときの室温から450度までの昇温速度と降温速度はともに0.5℃/分、450度から500度までの昇温速度と降温速度はともに0.1℃/分とした。焼成後の膜複合体の質量と支持体の質量の差から求めた、支持体上に結晶化したCHA型ゼオライトの質量は約0.279~0.289gであった。また、焼成後の膜複合体の空気透過量は2.4~2.9cm3/分であった。
<膜分離性能の評価>
参考例E2に記載のCHA型ゼオライト膜複合体3の温度を100℃~250℃に変えて12%アンモニア/51%窒素/37%窒素の混合ガスを100SCCMの流量で流通させて、得られた透過ガスのアンモニアの濃度とアンモニア/水素、アンモニア/窒素のパーミエンス比を表28に示した。150℃から250℃に温度を変えると、温度が高くなるほど膜内を透過したガス中のアンモニアガス濃度が低下する事が分かった。また、250℃でのアンモニアのパーミエンスは7.2×10-7[mol/(m2・s・Pa)]であった。これはRHO型およびMFI型ゼオライト膜複合体よりも高いパーミエンスであるが、アンモニア/窒素あるいはアンモニア/水素のパーミエンス比が小さい事から、アンモニアの透過選択性が低く、ゼオライト粒子間の隙間や欠陥からガスが透過していると考えられた。
2 耐圧容器
3 支持体先端の封止部
4 ゼオライト膜複合体と透過ガス回収管との接合部
5 圧力計
6 背圧弁
7 供給ガス(試料ガス)
8 透過ガス
9 スィープガス
10 非透過ガス
11 透過ガス回収管
12 スィープガス供給管
Claims (10)
- ゼオライト膜を用いて、少なくとも、アンモニアガスと、水素ガスと、窒素ガスと、を含有する混合ガスからアンモニアガスを選択的に透過させてアンモニアを分離する方法であって、
前記混合ガス中のアンモニアガス濃度が1.0体積%以上である、アンモニアの分離方法。 - 前記混合ガス中の水素ガス/窒素ガスの体積比が0.2以上、3以下である、請求項1に記載のアンモニアの分離方法。
- アンモニアガスを分離する際の温度が、50℃より高く、500℃以下である、請求項1または2に記載のアンモニアの分離方法。
- 前記ゼオライト膜を構成するゼオライトが、RHO型ゼオライトまたはMFI型ゼオライトである、請求項1~3のいずれか1項に記載のアンモニアの分離方法。
- 水素ガスと窒素ガスからアンモニアを製造する工程を含み、該製造工程で得られるアンモニアガスを含む混合ガスからアンモニアを請求項1~4のいずれか1項に記載のアンモニアの分離方法により分離する、アンモニアの分離方法。
- ゼオライトを含むゼオライト膜であって、X線光電子分光法により決定されるAl元素に対する窒素元素のモル比が0.01以上、4以下であることを特徴とするゼオライト膜。
- ゼオライトを含むゼオライト膜であって、X線光電子分光法により決定されるAl元素に対するSi元素のモル比が2.0以上、10以下であることを特徴とするゼオライト膜。
- ゼオライトを含むゼオライト膜であって、X線光電子分光法により決定されるAl元素に対するアルカリ金属元素のモル比が0.01以上、0.070以下であることを特徴とするゼオライト膜。
- 多孔質支持体及びその表面にゼオライトを含むゼオライト膜を備えるアンモニア分離用ゼオライト膜複合体であって、前記ゼオライトの30℃における熱膨張率に対する300℃における熱膨張率の変化率が±0.25%以内であり、30℃における熱膨張率に対する400℃における熱膨張率の変化率が±0.35%以内である、アンモニア分離用ゼオライト膜複合体。
- 前記ゼオライトの30℃における熱膨張率に対する300℃における該熱膨張率の変化率に対する、30℃における熱膨張率に対する400℃における該熱膨張率の変化率が、±120%以内である、請求項9に記載のアンモニア分離用ゼオライト膜複合体。
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Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2019014826A (ja) * | 2017-07-07 | 2019-01-31 | 旭化成株式会社 | 複合体 |
JP6986613B1 (ja) * | 2020-11-04 | 2021-12-22 | 日立造船株式会社 | 分離部材および分離方法 |
WO2022172893A1 (ja) * | 2021-02-10 | 2022-08-18 | 日本碍子株式会社 | ゼオライト膜複合体およびゼオライト膜複合体の製造方法 |
WO2023153172A1 (ja) * | 2022-02-08 | 2023-08-17 | 日本碍子株式会社 | 分離膜複合体、混合ガス分離装置および分離膜複合体の製造方法 |
Families Citing this family (7)
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---|---|---|---|---|
JP6757606B2 (ja) * | 2016-06-21 | 2020-09-23 | 日立造船株式会社 | Mfi型ゼオライト(シリカライト)を用いた分離膜の製造方法 |
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AU2018286313B2 (en) | 2017-06-15 | 2023-11-23 | Mitsubishi Chemical Corporation | Ammonia separation method and zeolite |
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KR102205266B1 (ko) * | 2018-12-28 | 2021-01-20 | 고려대학교 산학협력단 | Cha 제올라이트 분리막 및 그 제조방법 |
FR3098795B1 (fr) * | 2019-07-18 | 2021-10-15 | Dassault Aviat | Systeme d'inertage et aeronef et methode d'inertage associes |
CN113571698B (zh) * | 2021-09-23 | 2021-12-28 | 中南大学 | 一种碳点调控的金属硒化物/碳复合材料及其制备方法和应用 |
Citations (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10506363A (ja) | 1994-07-08 | 1998-06-23 | エクソン リサーチ アンド エンジニアリング カンパニー | 本来の場所で結晶化されたゼオライト含有組成物(lai−isc) |
JP2000507909A (ja) | 1996-03-14 | 2000-06-27 | エクソン ケミカル パテンツ インコーポレイテッド | モレキュラーシーブフィルムの調製方法 |
JP2008247654A (ja) | 2007-03-29 | 2008-10-16 | Hiroshima Univ | アンモニアの分離方法、製造方法、及び気体分離膜 |
JP2009545511A (ja) * | 2006-08-03 | 2009-12-24 | ユーオーピー エルエルシー | Uzm−22アルミノシリケートゼオライト、その調製方法およびuzm−22の使用方法 |
JP2011121040A (ja) | 2009-02-27 | 2011-06-23 | Mitsubishi Chemicals Corp | 無機多孔質支持体−ゼオライト膜複合体、その製造方法およびそれを用いた分離方法 |
JP2011121045A (ja) | 2009-11-11 | 2011-06-23 | Mitsubishi Chemicals Corp | 含水有機化合物の分離方法および分離装置 |
JP2012066242A (ja) | 2010-08-26 | 2012-04-05 | Mitsubishi Chemicals Corp | ガス分離用ゼオライト膜複合体 |
JP2013534896A (ja) * | 2010-06-21 | 2013-09-09 | ユーオーピー エルエルシー | Uzm−35ゼオライト組成物、調製方法及びプロセス |
JP2014058433A (ja) | 2012-09-19 | 2014-04-03 | Mitsubishi Chemicals Corp | アンモニアの分離方法 |
WO2015020014A1 (ja) | 2013-08-05 | 2015-02-12 | 三菱化学株式会社 | ゼオライト及びその製造方法と用途 |
WO2015129471A1 (ja) | 2014-02-27 | 2015-09-03 | 国立研究開発法人科学技術振興機構 | 担持金属触媒及び該触媒を用いるアンモニア合成法 |
Family Cites Families (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4762535A (en) * | 1987-06-02 | 1988-08-09 | Air Products And Chemicals, Inc. | Ammonia separation using semipermeable membranes |
US4814303A (en) * | 1987-09-25 | 1989-03-21 | E. I. Du Pont De Nemours And Company | Anorthite-cordierite based ceramics from zeolites |
US5824617A (en) | 1994-07-08 | 1998-10-20 | Exxon Research & Engineering Company | Low alkaline inverted in-situ crystallized zeolite membrane |
GB9600082D0 (en) * | 1996-01-04 | 1996-03-06 | Exxon Chemical Patents Inc | Molecular sieves and processes for their manufacture |
JP3316173B2 (ja) | 1997-11-06 | 2002-08-19 | 株式会社ノリタケカンパニーリミテド | ゼオライト膜担持用基材 |
AU754663B2 (en) * | 1998-10-20 | 2002-11-21 | Ngk Insulators, Ltd. | Zeolite composite film and process for producing the same |
WO2005021141A1 (ja) | 2003-08-27 | 2005-03-10 | Ngk Insulators, Ltd. | ガス分離体、及びその製造方法 |
US8349291B2 (en) | 2006-08-03 | 2013-01-08 | Uop Llc | Calcined UZM-22 and UZM-22HS aluminosilicate zeolites |
KR100978490B1 (ko) * | 2008-05-21 | 2010-08-30 | 서강대학교산학협력단 | 다양한 두께를 갖는 모든 b-축이 기질에 대해서 수직으로배향된 MFI형 제올라이트 박막 및 그의 제조방법 |
US20100071559A1 (en) * | 2008-09-19 | 2010-03-25 | Sylvain Miachon | Membranes and devices for gas separation |
JP2011012104A (ja) | 2009-06-30 | 2011-01-20 | Sekisui Plastics Co Ltd | 住宅の床下用断熱材 |
JP6163715B2 (ja) * | 2012-03-30 | 2017-07-19 | 三菱ケミカル株式会社 | ゼオライト膜複合体 |
JP6167489B2 (ja) | 2012-03-30 | 2017-07-26 | 三菱ケミカル株式会社 | ゼオライト膜複合体 |
JP6107000B2 (ja) * | 2012-03-30 | 2017-04-05 | 三菱化学株式会社 | ゼオライト膜複合体 |
JP6213062B2 (ja) * | 2013-08-28 | 2017-10-18 | 三菱ケミカル株式会社 | 気体の分離または濃縮方法、および高酸素濃度混合気体の製造方法 |
US10005067B2 (en) | 2014-05-27 | 2018-06-26 | Danmarks Tekniske Universitet | Use of catalysts, method and apparatus for selective oxidation of ammonia in a gas containing hydrogen |
EP3388135B1 (en) | 2015-12-07 | 2022-09-28 | Showa Denko K.K. | Ammonia removal equipment, ammonia removal method, and hydrogen gas production method |
US20190366276A1 (en) * | 2017-01-18 | 2019-12-05 | Sumitomo Electric Industries, Ltd. | Zeolite membrane and separation membrane |
AU2018286313B2 (en) * | 2017-06-15 | 2023-11-23 | Mitsubishi Chemical Corporation | Ammonia separation method and zeolite |
WO2019040707A2 (en) * | 2017-08-24 | 2019-02-28 | Purafil, Inc. | METHOD FOR REMOVING GASEOUS CONTAMINANTS FROM A FLUID STREAM |
-
2018
- 2018-06-15 AU AU2018286313A patent/AU2018286313B2/en active Active
- 2018-06-15 EP EP23181169.6A patent/EP4234493A3/en active Pending
- 2018-06-15 WO PCT/JP2018/023042 patent/WO2018230737A1/ja active Application Filing
- 2018-06-15 JP JP2019525591A patent/JP7056658B2/ja active Active
- 2018-06-15 EP EP18818324.8A patent/EP3640209A4/en active Pending
- 2018-06-15 CN CN201880039137.4A patent/CN110740973B/zh active Active
-
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- 2019-12-13 US US16/713,360 patent/US10946333B2/en active Active
- 2019-12-14 SA SA519410807A patent/SA519410807B1/ar unknown
-
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- 2021-01-21 US US17/153,961 patent/US11628395B2/en active Active
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- 2022-03-29 JP JP2022052996A patent/JP7380736B2/ja active Active
- 2022-05-24 AU AU2022203499A patent/AU2022203499B2/en active Active
- 2022-06-02 US US17/830,375 patent/US11833468B2/en active Active
-
2023
- 2023-10-31 JP JP2023186630A patent/JP2024016125A/ja active Pending
Patent Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10506363A (ja) | 1994-07-08 | 1998-06-23 | エクソン リサーチ アンド エンジニアリング カンパニー | 本来の場所で結晶化されたゼオライト含有組成物(lai−isc) |
JP2000507909A (ja) | 1996-03-14 | 2000-06-27 | エクソン ケミカル パテンツ インコーポレイテッド | モレキュラーシーブフィルムの調製方法 |
JP2009545511A (ja) * | 2006-08-03 | 2009-12-24 | ユーオーピー エルエルシー | Uzm−22アルミノシリケートゼオライト、その調製方法およびuzm−22の使用方法 |
JP2008247654A (ja) | 2007-03-29 | 2008-10-16 | Hiroshima Univ | アンモニアの分離方法、製造方法、及び気体分離膜 |
JP2011121040A (ja) | 2009-02-27 | 2011-06-23 | Mitsubishi Chemicals Corp | 無機多孔質支持体−ゼオライト膜複合体、その製造方法およびそれを用いた分離方法 |
JP2011121045A (ja) | 2009-11-11 | 2011-06-23 | Mitsubishi Chemicals Corp | 含水有機化合物の分離方法および分離装置 |
JP2011121854A (ja) | 2009-11-11 | 2011-06-23 | Mitsubishi Chemicals Corp | 多孔質支持体−ゼオライト膜複合体の製造方法 |
JP2013534896A (ja) * | 2010-06-21 | 2013-09-09 | ユーオーピー エルエルシー | Uzm−35ゼオライト組成物、調製方法及びプロセス |
JP2012066242A (ja) | 2010-08-26 | 2012-04-05 | Mitsubishi Chemicals Corp | ガス分離用ゼオライト膜複合体 |
JP2014058433A (ja) | 2012-09-19 | 2014-04-03 | Mitsubishi Chemicals Corp | アンモニアの分離方法 |
WO2015020014A1 (ja) | 2013-08-05 | 2015-02-12 | 三菱化学株式会社 | ゼオライト及びその製造方法と用途 |
WO2015129471A1 (ja) | 2014-02-27 | 2015-09-03 | 国立研究開発法人科学技術振興機構 | 担持金属触媒及び該触媒を用いるアンモニア合成法 |
Non-Patent Citations (9)
Title |
---|
"ATLAS OF ZEOLITE FRAMEWORK TYPES Fifth Revised", 2007, ELSEVIER |
"Chemical Handbook, Applied Chemistry I", 2003, MARUZEN CO., LTD., article "The Chemical Society of Japan", pages: 581 |
"Japan, Compilation of Chemical Processes", TOKYO KAGAKU DOZIN, article "The Society of Chemical Engineers", pages: 1 53 |
CAMUS, OLIVER ET AL.: "Ceramic Membranes for Ammonia Recovery", AICHE JOURNAL, vol. 52, no. 6, 2006, pages 2055 - 2065, XP055565458, ISSN: 0001-1541 * |
CHEMICAL, COMMUNICATIONS, 2000, pages 2221 - 2222 |
D.R. CORBIN. ET AL., J. AM. CHEM. SOC, vol. 112, pages 4821 - 4830 |
MICROPOROUS AND MESOPOROUS MATERIALS, vol. 132, 2010, pages 352 - 356 |
NAONOBU KATADAMIKI NIWA: "Zeolite", vol. 21, 2004, JAPAN ZEOLITE ASSOCIATION, pages: 45 - 52 |
PARKS. H. ET AL., STUD. SURF. SCI. CATAL., vol. 105, 1997, pages 1989 - 1994 |
Cited By (5)
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JP2019014826A (ja) * | 2017-07-07 | 2019-01-31 | 旭化成株式会社 | 複合体 |
JP6986613B1 (ja) * | 2020-11-04 | 2021-12-22 | 日立造船株式会社 | 分離部材および分離方法 |
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