CN114751426A - Preparation method and application of B-Al-ZSM-5 molecular sieve - Google Patents
Preparation method and application of B-Al-ZSM-5 molecular sieve Download PDFInfo
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- CN114751426A CN114751426A CN202110028657.9A CN202110028657A CN114751426A CN 114751426 A CN114751426 A CN 114751426A CN 202110028657 A CN202110028657 A CN 202110028657A CN 114751426 A CN114751426 A CN 114751426A
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- 239000002808 molecular sieve Substances 0.000 title claims abstract description 133
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 title claims abstract description 133
- 238000002360 preparation method Methods 0.000 title claims abstract description 22
- 238000006243 chemical reaction Methods 0.000 claims abstract description 33
- 229910052796 boron Inorganic materials 0.000 claims abstract description 32
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims abstract description 31
- 239000013078 crystal Substances 0.000 claims abstract description 30
- 239000000654 additive Substances 0.000 claims abstract description 24
- 239000002994 raw material Substances 0.000 claims abstract description 23
- 230000000996 additive effect Effects 0.000 claims abstract description 22
- 239000007787 solid Substances 0.000 claims abstract description 19
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 claims abstract description 18
- CSDREXVUYHZDNP-UHFFFAOYSA-N alumanylidynesilicon Chemical compound [Al].[Si] CSDREXVUYHZDNP-UHFFFAOYSA-N 0.000 claims abstract description 12
- 239000003513 alkali Substances 0.000 claims abstract description 9
- 238000005216 hydrothermal crystallization Methods 0.000 claims abstract description 9
- 238000001035 drying Methods 0.000 claims abstract description 7
- 230000002194 synthesizing effect Effects 0.000 claims abstract description 7
- 238000005406 washing Methods 0.000 claims abstract description 7
- 238000001914 filtration Methods 0.000 claims abstract description 5
- 239000012752 auxiliary agent Substances 0.000 claims abstract description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 45
- 238000000034 method Methods 0.000 claims description 38
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 36
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 35
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 33
- 239000000243 solution Substances 0.000 claims description 32
- 239000000203 mixture Substances 0.000 claims description 31
- 229910052710 silicon Inorganic materials 0.000 claims description 29
- 229910001868 water Inorganic materials 0.000 claims description 29
- 239000010703 silicon Substances 0.000 claims description 28
- 229910052593 corundum Inorganic materials 0.000 claims description 24
- 229910001845 yogo sapphire Inorganic materials 0.000 claims description 24
- KKCBUQHMOMHUOY-UHFFFAOYSA-N Na2O Inorganic materials [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 claims description 22
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 22
- 229910052782 aluminium Inorganic materials 0.000 claims description 20
- 238000002425 crystallisation Methods 0.000 claims description 20
- 230000008025 crystallization Effects 0.000 claims description 20
- 239000000377 silicon dioxide Substances 0.000 claims description 20
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 19
- 229910052681 coesite Inorganic materials 0.000 claims description 19
- 229910052906 cristobalite Inorganic materials 0.000 claims description 19
- 229910052682 stishovite Inorganic materials 0.000 claims description 19
- 229910052905 tridymite Inorganic materials 0.000 claims description 19
- 238000003756 stirring Methods 0.000 claims description 16
- 238000004523 catalytic cracking Methods 0.000 claims description 14
- 239000011259 mixed solution Substances 0.000 claims description 14
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 11
- 150000001335 aliphatic alkanes Chemical class 0.000 claims description 10
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 claims description 9
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims description 8
- -1 polytetrafluoroethylene Polymers 0.000 claims description 8
- 239000011734 sodium Substances 0.000 claims description 8
- 150000001336 alkenes Chemical class 0.000 claims description 7
- 239000003054 catalyst Substances 0.000 claims description 7
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 claims description 7
- 238000005336 cracking Methods 0.000 claims description 6
- 239000008367 deionised water Substances 0.000 claims description 6
- 229910021641 deionized water Inorganic materials 0.000 claims description 6
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 5
- 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 claims description 5
- 239000001257 hydrogen Substances 0.000 claims description 5
- 229910052739 hydrogen Inorganic materials 0.000 claims description 5
- 229910002027 silica gel Inorganic materials 0.000 claims description 5
- 239000000741 silica gel Substances 0.000 claims description 5
- 229910052708 sodium Inorganic materials 0.000 claims description 5
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 claims description 4
- 239000012159 carrier gas Substances 0.000 claims description 4
- 238000005342 ion exchange Methods 0.000 claims description 4
- 239000000843 powder Substances 0.000 claims description 4
- 239000002202 Polyethylene glycol Substances 0.000 claims 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 claims description 3
- 230000007935 neutral effect Effects 0.000 claims description 3
- WXZMFSXDPGVJKK-UHFFFAOYSA-N pentaerythritol Chemical compound OCC(CO)(CO)CO WXZMFSXDPGVJKK-UHFFFAOYSA-N 0.000 claims description 3
- 229920001223 polyethylene glycol Polymers 0.000 claims description 3
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 claims description 3
- 235000012239 silicon dioxide Nutrition 0.000 claims description 3
- 238000005303 weighing Methods 0.000 claims description 3
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical group OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 claims description 2
- 238000002156 mixing Methods 0.000 claims description 2
- 229920000642 polymer Polymers 0.000 claims description 2
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 2
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 2
- 238000000967 suction filtration Methods 0.000 claims description 2
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 claims 2
- 239000010690 paraffinic oil Substances 0.000 claims 2
- 235000019270 ammonium chloride Nutrition 0.000 claims 1
- 229910021536 Zeolite Inorganic materials 0.000 abstract description 19
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 abstract description 19
- 239000010457 zeolite Substances 0.000 abstract description 19
- 239000003795 chemical substances by application Substances 0.000 abstract description 17
- 150000001412 amines Chemical class 0.000 abstract description 9
- 239000002245 particle Substances 0.000 abstract description 3
- 238000001308 synthesis method Methods 0.000 abstract description 3
- 230000008901 benefit Effects 0.000 abstract description 2
- 238000003912 environmental pollution Methods 0.000 abstract description 2
- 239000002243 precursor Substances 0.000 abstract 1
- 230000015572 biosynthetic process Effects 0.000 description 17
- 238000003786 synthesis reaction Methods 0.000 description 17
- 239000000047 product Substances 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 13
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 13
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 12
- 239000002253 acid Substances 0.000 description 12
- 230000008569 process Effects 0.000 description 10
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 9
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 9
- 238000001878 scanning electron micrograph Methods 0.000 description 7
- 230000008859 change Effects 0.000 description 5
- NQRYJNQNLNOLGT-UHFFFAOYSA-N Piperidine Chemical compound C1CCNCC1 NQRYJNQNLNOLGT-UHFFFAOYSA-N 0.000 description 4
- 238000002441 X-ray diffraction Methods 0.000 description 4
- 238000005265 energy consumption Methods 0.000 description 4
- 239000000499 gel Substances 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 150000005671 trienes Chemical class 0.000 description 4
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 3
- 239000005977 Ethylene Substances 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 230000003197 catalytic effect Effects 0.000 description 3
- 239000007795 chemical reaction product Substances 0.000 description 3
- 230000002349 favourable effect Effects 0.000 description 3
- 238000001027 hydrothermal synthesis Methods 0.000 description 3
- 239000003921 oil Substances 0.000 description 3
- 239000012071 phase Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- BGQMOFGZRJUORO-UHFFFAOYSA-M tetrapropylammonium bromide Chemical compound [Br-].CCC[N+](CCC)(CCC)CCC BGQMOFGZRJUORO-UHFFFAOYSA-M 0.000 description 3
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-Butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 2
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 2
- 150000007513 acids Chemical class 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- IAQRGUVFOMOMEM-UHFFFAOYSA-N butene Natural products CC=CC IAQRGUVFOMOMEM-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000006229 carbon black Substances 0.000 description 2
- 239000000084 colloidal system Substances 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 2
- LPSKDVINWQNWFE-UHFFFAOYSA-M tetrapropylazanium;hydroxide Chemical compound [OH-].CCC[N+](CCC)(CCC)CCC LPSKDVINWQNWFE-UHFFFAOYSA-M 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 1
- 239000004115 Sodium Silicate Substances 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 230000029936 alkylation Effects 0.000 description 1
- 238000005804 alkylation reaction Methods 0.000 description 1
- 150000003863 ammonium salts Chemical class 0.000 description 1
- 238000005280 amorphization Methods 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000005899 aromatization reaction Methods 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 125000004429 atom Chemical group 0.000 description 1
- ZSIQJIWKELUFRJ-UHFFFAOYSA-N azepane Chemical compound C1CCCNCC1 ZSIQJIWKELUFRJ-UHFFFAOYSA-N 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 150000001993 dienes Chemical class 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- IDGUHHHQCWSQLU-UHFFFAOYSA-N ethanol;hydrate Chemical compound O.CCO IDGUHHHQCWSQLU-UHFFFAOYSA-N 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 125000005842 heteroatom Chemical group 0.000 description 1
- 238000003837 high-temperature calcination Methods 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000012229 microporous material Substances 0.000 description 1
- 239000010413 mother solution Substances 0.000 description 1
- 239000002105 nanoparticle Substances 0.000 description 1
- 238000006068 polycondensation reaction Methods 0.000 description 1
- 235000019353 potassium silicate Nutrition 0.000 description 1
- 238000000197 pyrolysis Methods 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical compound [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 229910001388 sodium aluminate Inorganic materials 0.000 description 1
- 229910052911 sodium silicate Inorganic materials 0.000 description 1
- 239000011343 solid material Substances 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000002336 sorption--desorption measurement Methods 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 125000000383 tetramethylene group Chemical group [H]C([H])([*:1])C([H])([H])C([H])([H])C([H])([H])[*:2] 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Images
Classifications
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- 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
- C01B39/36—Pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11
- C01B39/38—Type ZSM-5
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J29/00—Catalysts comprising molecular sieves
- B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
- B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
- B01J29/40—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C4/00—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms
- C07C4/02—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms by cracking a single hydrocarbon or a mixture of individually defined hydrocarbons or a normally gaseous hydrocarbon fraction
- C07C4/06—Catalytic processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
- B01J2229/10—After treatment, characterised by the effect to be obtained
- B01J2229/18—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself
- B01J2229/183—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself in framework positions
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
- C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/01—Particle morphology depicted by an image
- C01P2004/03—Particle morphology depicted by an image obtained by SEM
Abstract
The invention provides a preparation method and application of a B-Al-ZSM-5 molecular sieve, wherein the preparation method comprises the steps of directly introducing a boron source, an MFI type molecular sieve seed crystal auxiliary agent and a solid silicon-aluminum source into an alkali liquor to form a high-concentration system under the condition that organic ammonium is not added, and efficiently synthesizing the B-Al-ZSM-5 molecular sieve with a high silicon-aluminum ratio through hydrothermal crystallization, filtration, washing and drying. The invention synthesizes the small-grain B-Al-ZSM-5 zeolite molecular sieve with high crystallinity, good dispersity, controllable particle size and adjustable acidity by modulating the raw material proportion, reaction conditions or adding an additive under the condition of no organic amine (ammonium) template agent to control the raw material precursor; the preparation method has the advantages of large yield of a single kettle and low cost, and successfully solves the problems of low raw material utilization rate, high cost, emission of a large amount of organic amine (ammonium) template agents, generation of nitric oxides, environmental pollution and the like in the conventional B-Al-ZSM-5 molecular sieve synthesis method.
Description
Technical Field
The invention relates to an efficient green preparation method of a ZSM-5 molecular sieve, in particular to an efficient preparation method and application of a small-grain B-Al-ZSM-5 molecular sieve, belonging to the field of molecular sieve catalysts.
Background
The ZSM-5 molecular sieve is one of the most widely used molecular sieves in the field of petrochemical industry, and has a unique three-dimensional cross channel structure and a ten-membered ring pore structure. The ZSM-5 molecular sieve has high hydrothermal stability, good skeleton stability and strong acidity, so the ZSM-5 molecular sieve is a good catalytic material and plays an important role in important industrial processes such as hydrocarbon catalytic cracking, aromatic alkylation, catalytic cracking, light hydrocarbon aromatization of methanol to gasoline and the like. The ZSM-5 molecular sieve is synthesized by a hydrothermal method, a large amount of water is needed in the synthesis process, the liquid-solid ratio is high (the water-silicon ratio is between 12 and 100), the dosage of a template agent is large, a large amount of waste liquid is generated, the environment is seriously polluted, and if the pyrolysis is incomplete, the solid residues can block the pore channels of the molecular sieve, so that the activity of the catalyst is reduced. In addition, the hydrothermal method has low single-kettle yield (generally about 10%), long crystallization time and high energy consumption, and is not beneficial to industrial production.
In 1980, Taramasso et al (US 4410501) originally tried to introduce boron into ZSM-5 to synthesize a boron-containing molecular sieve, and summarized the synthesis characteristics of the boron-containing molecular sieve. The heteroatom molecular sieve obtained by isomorphously substituting Al or Si in the ZSM-5 molecular sieve by B also shows the application superiority. The introduction of boron adjusts the acidity of the ZSM-5 molecular sieve, so that the catalyst shows higher catalytic activity in reactions such as Methanol To Olefin (MTO), Methanol To Propylene (MTP) and the like. In addition, the synthesis of the Al-free B-ZSM-5 molecular sieve is one of the methods for preparing the TS-1, Ti is replaced by B through a gas-solid phase replacement method to obtain the Ti-ZSM-5 molecular sieve, and the method reduces the cost of the traditional synthesis of the TS-1 molecular sieve.
The synthesis of the B-ZSM-5 molecular sieve is generally hydrothermal synthesis and is carried out in the presence of an alkali source, a sodium source, a silicon source and a boron source and under the condition of adding an organic template agent. However, the cost of the organic template is high, the pollution emission in the preparation process of the molecular sieve is serious, especially the commonly used tetrapropylammonium hydroxide (TPAOH), and the zeolite synthesized by the organic template needs to be roasted to obtain the microporous material. The high temperature calcination process requires high energy consumption, not only reduces the properties of the zeolite (such as removal of framework atoms, partial amorphization, grain aggregation, and lattice collapse), but also generates harmful gases. Therefore, it is a consistent pursuit of researchers to find an inexpensive method for synthesizing ZSM-5 molecular sieves and modulating their acid properties by compositional changes.
Zhaijiao et al (CN101519216B) uses cheap cyclic molecular amine, Hexamethyleneimine (HMI) or Piperidine (PI) or a mixture of the two as an organic alkali template agent to prepare a directing agent, mixes a boron source, a silicon source and a sodium source in a certain proportion, and carries out hydrothermal crystallization to obtain the (aluminum-free) B-ZSM-5 molecular sieve, but the feeding water-silicon ratio of the (aluminum-free) B-ZSM-5 molecular sieve is 10-40.
Tangyi et Al (CN 103708497A) introduce boron source and MFI type zeolite seed crystal in a ZSM-5 zeolite synthesis system (silicon source, aluminum source, alkali source, template agent and water), and the synthesized nano-particle stacked B-Al-ZSM-5 zeolite has high crystallinity and controllable particle size, and can improve the diffusion rate and the anti-carbon deposition capability when used in the reaction of preparing olefin (MTP) from methanol, improve the acid property of the ZSM-5 molecular sieve, and is favorable for enhancing the propylene selectivity and prolonging the service life of the catalyst. However, the borosilicate molecular sieve is synthesized under the conditions of high water-silicon ratio (10-100) and the presence of an organic ammonium template (the silicon-template ratio is 0.6), and the template agent needs to be removed by roasting at high temperature (520 ℃ C. and 580 ℃ C.), thereby causing pollution and high energy consumption.
The method comprises the steps of synthesizing a ZSM-5 molecular sieve with high crystallinity by using a mixture of amorphous silica solid and solid sodium silicate crystals as a double silicon source and using no inorganic alkali without using an organic template and a seed crystal, such as Duangang et al (CN101177282A), wherein the water-silicon ratio of the molecular sieve is 10-25, the crystallization temperature is 180-200 ℃, and the silicon-aluminum ratio of the synthesized molecular sieve is lower; liuhuachang et al (CN102757068A) also realized amine-free synthesis of ZSM-5 by mixing silica gel with water glass as the silicon source.
A large number of researches show that the synthesis phase region of a system for synthesizing the molecular sieve without adding an organic amine (ammonium) template agent is narrow, and the selection of synthesis conditions is more rigorous. Especially for the synthesis of general ZSM-5 molecular sieve, the silica-alumina ratio is generally lower (generally 20-40) and the solid content of the system is lower, so that the preparation efficiency is low (the yield is 10-20%). In order to improve the crystallization capacity of the molecular sieve, a proper amount of ZSM-5 molecular sieve seed crystals are added in the synthesis process to enable a primary structural unit to grow by taking the seed crystals as centers, on the other hand, the addition of the seed crystals promotes the purposes of accelerating crystallization and improving crystallinity, and can enhance the stability of a crystallized product in a mother solution and inhibit the crystal transformation of zeolite.
In a word, the synthesis efficiency of synthesizing the ZSM-5 molecular sieve without the organic template in the prior art is low, and the silicon-aluminum ratio of the molecular sieve is low. The invention designs a ZSM-5 molecular sieve with part B replacing aluminum, namely the B-Al-ZSM-5 molecular sieve is directly synthesized under the condition of no organic amine (ammonium) template agent. In a solid-like (high solid content) system, a high solid content preparation system is easier and more flexible to configure by using a solid silicon source, the synthesis efficiency of the molecular sieve is improved, the acidity of the molecular sieve is modified, and the ratio of weak acid to strong acid is adjusted when the silicon-aluminum ratio of the molecular sieve is high.
Disclosure of Invention
The invention aims to provide a preparation method and application of a B-Al-ZSM-5 molecular sieve, wherein the preparation method of the B-Al-ZSM-5 molecular sieve does not need to add an organic template, and the catalytic cracking stability of the B-Al-ZSM-5 molecular sieve synthesized in an organic amine (ammonium) -free solid-like (high solid content) high-efficiency system is better than that of the molecular sieve synthesized by adding traditional organic template tetrapropylammonium bromide, and the molecular sieve has the characteristics of high silica-alumina ratio and the like.
The preparation scheme of the invention can be carried out in two ways, one way is to keep the silicon-aluminum ratio in the composition of the ZSM-5 molecular sieve unchanged, and B with different contents can be introduced; and the other is to keep the ratio of Si to B + Al unchanged, change the ratio of B to Al, and increase the silicon-aluminum ratio of the feed of the ZSM-5 molecular sieve synthesis system to different degrees because the aluminum source in the feed amount reduces the increase of the boron source, and the silicon-aluminum ratio of the product is theoretically higher than that of the ZSM-5 molecular sieve. The former molecular sieve has little change in strong acidity, but the introduction of B brings about a large change in weak acid content. In the latter case, the acidity changes significantly for different B/Al ratios for both strong and weak acids. The flexible modulation of the element composition in the formula of the molecular sieve mixed glue can be realized. The system of the invention has important significance for finely adjusting the acid property of the molecular sieve.
In order to achieve the purpose, the invention provides a solid-like preparation system, and a preparation method of a B-Al-ZSM-5 molecular sieve under the condition of not adding an organic amine (ammonium) template agent, wherein the preparation method is characterized in that a high-concentration system formed by a boron source, an MFI type molecular sieve seed crystal auxiliary agent and a solid silica-alumina source is directly introduced into an alkali liquor under the condition of not adding organic ammonium, and the B-Al-ZSM-5 molecular sieve with high silica-alumina ratio is efficiently synthesized through hydrothermal crystallization, filtration, washing and drying processes, and specifically comprises the following steps: step (1): weighing a certain amount of solid NaOH, and dissolving the solid NaOH in deionized water to prepare a NaOH solution. Further adding a certain amount of aluminum source and boron source into the NaOH solution, wherein the three raw materials of the NaOH source, the aluminum source and the boron source are added in a ratio to the waterThe relationship of the molar ratio of (A) to (B) is: h2O:Al2O3:Na2O:B2O3At 80-2000:1:8-80:0.01-100, stirring well to clarify, to give solution M1.
Step (2): adding a certain amount of MFI type molecular sieve seed crystal and additive into the prepared solution M1, and fully stirring to obtain a mixed solution M2.
And (3): adding a silicon source into the mixed solution M2 to obtain a final mixed sol M3, wherein the composition and the proportion of the final mixed sol M3 are H2O:SiO2:Al2O3:Na2O:B2O3Keeping the low water-silicon ratio of the system at 80-2000:20-300:1:8-80: 0.01-100.
And (4): and (3) transferring the prepared final mixed sol M3 into a high-pressure reaction kettle, preferably a polytetrafluoroethylene reaction kettle, and crystallizing in two sections.
And (5): and (4) performing reduced pressure suction filtration on the mixture after crystallization in the step (4), washing the mixture to be neutral by using deionized water, and drying the mixture in a constant temperature box at the temperature of 100 ℃ and 120 ℃, preferably at the temperature of 110 ℃ to obtain the molecular sieve raw powder.
And (6): and (4) carrying out primary ion exchange on the molecular sieve raw powder obtained in the step (5) by adopting ammonium salt solution ions to form ammonium type B-Al-ZSM-5, and roasting to obtain the hydrogen type B-Al-ZSM-5 molecular sieve.
The system adopts a solid-like high-solid-content system, and the molar ratio of water to silicon oxide in the final mixed sol M3 is 2-12 by adjusting the addition amount of solid materials in the preparation step.
In the step (2), the additive is an alcohol compound or a polymer; the MFI type molecular sieve crystal seed comprises the following components in percentage by mass: additive: solution M1-1: 0.1-1: 80-2100.
The alcohol compound is at least one of ethanol, glycol, glycerol, pentaerythritol and polyethylene glycol. The aluminum source of the invention is one or two of sodium metaaluminate, aluminum sulfate and aluminum trichloride.
The boron source of the invention can be selected from H3BO3、Na3BO3Or B2O3One or two ofAnd (4) seed preparation.
The silicon source substance can be one or more of coarse silica gel, silicic acid and white carbon black.
In step (3) of the present invention, the mass ratio of the silicon source to the mixed solution M2 is SiO2: mixed solution M2 is 0.2-1: 1.
In the step (2), the stirring time is 0.5-3 h; in the step (3), the stirring time is 1-10 h.
In the step (4), the two-stage crystallization conditions are as follows: the first section of crystallization is carried out in a constant temperature box at 70-120 ℃ for 5-30h, and the second section of crystallization is carried out in a constant temperature box at 140-180 ℃ for 4-40 h.
The invention also provides application of the B-Al-ZSM-5 molecular sieve obtained by the preparation method of the B-Al-ZSM-5 molecular sieve in the reaction of preparing olefin by catalytic cracking of alkane oil products.
The application of the invention is that the olefin reaction prepared by catalytic cracking of the alkane oil is that the alkane oil such as naphtha and the like is used as raw material, B-Al-ZSM-5 molecular sieve is used as catalyst, N2As carrier gas, the alkane partial pressure is 3-13kPa, and the alkane mass space velocity is 2-12h-1The cracking reaction temperature is 550-700 ℃.
Compared with the prior art, the invention has the following beneficial effects:
the invention relates to a synthesis method for efficiently synthesizing a small-grain B-Al-ZSM-5 molecular sieve by an organic amine (ammonium) -free system and a solid-like phase (high solid content), which is characterized in that zeolite seed crystals and an auxiliary agent with an MFI structure are added in the solid-like phase (high solid content) system without adding an organic template, a boron source enters a framework to synthesize the ZSM-5 molecular sieve in the hydrolysis and polycondensation process of a solid silicon source under the action of alkali, and the B-Al-ZSM-5 molecular sieve is obtained by one-step synthesis. On the other hand, the B element is introduced into the ZSM-5 molecular sieve to partially replace the Al element so as to improve the silica-alumina ratio of the ZSM-5 molecular sieve synthesized without the template and simultaneously adjust the silica-alumina ratio, namely acidity, of the molecular sieve. Compared with ZSM-5 molecular sieve synthesized without template agent, the introduced crystal morphology, the grain size and the acid property of B have obvious influence by adjusting the synthesis condition or adding additives.
The invention synthesizes the small crystal grain B-Al-ZSM-5 zeolite molecular sieve (crystal grain-1 micron) with complete crystallization, good particle dispersibility and adjustable silicon-aluminum ratio (20-300) by adjusting the raw material proportion and the reaction condition or adding additives under the condition without a template agent, and the dispersibility of the crystal grain of the molecular sieve is higher.
The B-Al-ZSM-5 zeolite molecular sieve synthesized by the method has high efficiency, and the single kettle yield is high (25-30%), so that the problems of low raw material utilization rate, high cost, large amount of organic amine (ammonium) template agent emission, nitrogen oxide generation, environmental pollution and the like in the conventional B-Al-ZSM-5 molecular sieve synthesis method are successfully solved. Thirdly, the silica-alumina ratio of B-Al-ZSM-5 synthesized by the system without the organic template is adjustable in a larger range, the acidity is adjusted, the traditional process of removing the template agent by roasting is eliminated during use, the process is simplified, and the energy is saved and the efficiency is high; fourthly, the synthesized B-Al-ZSM-5 is used for the normal hexane catalytic cracking reaction, and the low-carbon olefin (particularly propylene and triene) has high selectivity, long service life and good stability.
The B-Al-ZSM-5 molecular sieve synthesized by the method does not need to be roasted at high temperature to remove the template agent, and the sodium type B-Al-ZSM-5 molecular sieve can be obtained after being washed by water, so the cost of raw materials is low, and the energy consumption is reduced. Further carrying out ammonium ion exchange, roasting and the like to obtain the hydrogen type molecular sieve. The acid properties of the molecular sieve synthesized by the system are finely modulated, such as the same SiO2/Al2O3In this case, the ratio of weak acid to strong acid can be adjusted.
The hydrogen type B-Al-ZSM-5 molecular sieve is used in the process of preparing olefin by cracking reaction of alkane such as naphtha and the like, the catalytic cracking reaction is subjected to reaction evaluation in a small micro-reaction device, and N2As carrier gas, the mass space velocity of alkane is 2-12h-1The alkane partial pressure is 2-13kPa, the cracking reaction temperature is 550-700 ℃, the propylene selectivity is high, the catalytic cracking reaction life is long, and the stability is better. The ZSM-5 molecular sieve synthesized by the system without the template agent has the characteristic of a molecular sieve with silicon-rich outer surface, and the catalytic cracking stability of the molecular sieve is better than that of the molecular sieve synthesized by the common traditional tetrapropylammonium bromide and the like.
Drawings
FIG. 1 is an SEM image of the product of example 1 of the present invention;
FIG. 2 is an X-ray diffraction (XRD) pattern (left) and a corresponding regio-enlarged XRD pattern (right) of the products of the examples and comparative examples of the present invention;
the sample A is Al-ZSM-5 which is synthesized in comparative example 1 without organic template and does not contain B; b and C are respectively samples of the B-Al-ZSM-5 molecular sieve in the examples 1 and 3.
FIG. 3 is a plot of temperature programmed adsorption-desorption (NH3-TPD) of ammonia gas as a product of examples and comparative examples of the present invention, illustrating the change in the amount of strong and weak acids after different modes of adding B in a template-free system;
wherein, the sample A is Al-ZSM-5 synthesized by comparative example 1 without organic template; the B sample is the B-Al-ZSM-5 molecular sieve sample in the example 1; the C sample is the B-Al-ZSM-5 molecular sieve sample in example 10.
FIG. 4 is an SEM image of the product of example 3 of the present invention;
FIG. 5 is an XRD spectrum of the products of examples 5, 6, 7 and 8 of the present invention;
wherein A, B, C, D in the figure is a sample of the B-Al-ZSM-5 molecular sieve in examples 5, 6, 7 and 8 respectively.
FIG. 6 is an SEM image of the product of example 5 of the present invention;
FIG. 7 is an SEM image of the product of example 6 of the present invention;
FIG. 8 is an SEM image of the product of example 7 of the present invention;
FIG. 9 is an SEM image of the product of example 8 of the present invention;
FIG. 10 is a graph of example 1 versus comparative example 1 and comparative example 2 showing the change in catalyzed hexane conversion over time. Showing the changes of catalytic activity and reaction stability of each typical sample;
Detailed Description
The present invention will be described in further detail with reference to specific embodiments. It should not be understood that the scope of the above-described subject matter of the present invention is limited to the following examples.
Example 1
The preparation process and steps of this example are as follows:
weighing oneDissolving a certain amount of solid NaOH in deionized water to prepare a NaOH solution. Adding a certain amount of aluminum source and a certain amount of boron source into the prepared NaOH solution respectively to provide Al2O3The aluminum source substance is NaAlO2Providing B2O3The boron source is H3BO3The molar ratio of the three raw materials to water is as follows: h2O:Al2O3:Na2O:B2O3Stirring thoroughly until clear 1000:1:8:2 gave solution M1.
(1) Adding a certain amount of MFI type zeolite seed crystal (namely ZSM-5 seed crystal of pure silicon) and an additive into the prepared solution M1, wherein the additive is ethanol, and the mass ratio of the two raw materials to the M1 solution is MFI type zeolite seed crystal: additive: when the M1 solution was stirred thoroughly for 1.5h, a mixture M2 was obtained.
(2) Adding a silicon source into the mixed solution to provide SiO2The silicon source substance is coarse silica gel, and the mixture is fully stirred for 8 hours to obtain viscous colloid M3 which is uniformly mixed. The molar ratio of the components of the M3 mixture in this example was H2O:SiO2:Al2O3:Na2O:B2O3＝1000:150:1:8:2。
(3) And (3) transferring the prepared colloid M3 into a high-pressure reaction kettle, carrying out first hydrothermal crystallization in a constant temperature box at 100 ℃ for 5 hours, and transferring to the constant temperature box at 150 ℃ for second hydrothermal crystallization for 18 hours.
(4) And filtering the crystallized mixture under reduced pressure, washing the mixture to be neutral by deionized water, and drying the mixture in a thermostat at 110 ℃.
(5) And roasting the obtained product in a muffle furnace at 550 ℃ after ammonium ion exchange to obtain the hydrogen type B-Al-ZSM-5 molecular sieve.
Example 2
The general procedure of this example is exactly the same as in example 1 above.
The difference is that: 1) when adding boron source, Na is adopted3BO3As provision of B2O32) aluminum sulfate is adopted when an aluminum source is added, and the molar ratio of the three raw materials to water is H2O:Al2O3:Na2O:B2O31000:1:12: 5; 3) in thatWhen a silicon source is added, silicic acid is used as a silicon source for providing SiO2The mass ratio of the silicon source to the mixed solution of M2 is SiO2M2 mixed solution was 0.5:1, and stirred thoroughly for 5h to obtain a viscous gel M3. The molar ratio of the components of the M3 mixture in this example was H2O:SiO2:Al2O3:Na2O:B2O3＝1000:150:1:12:5。
Example 3
The general procedure of this example is exactly the same as in example 1 above.
The difference is that: 1) when adding boron source, use B2O3As provision of B2O3The molar ratio of the three raw materials to water, namely H2O:Al2O3:Na2O:B2O31000:1:8: 10; 2) adding an aluminum source which is aluminum trichloride; 3) when a silicon source is added, white carbon black is adopted as SiO supply2The mass ratio of the silicon source to the mixed solution of M2 is SiO2: m2 mixed solution was stirred thoroughly for 10h at 0.5:1 to give a uniformly mixed viscous gel M3. The molar ratio of the components of the M3 mixture in this example was H2O:SiO2:Al2O3:Na2O:B2O3＝1000:150:1:8:10。
Example 4
The general procedure of this example is exactly the same as example 1 above.
The difference is that: 1) when the aluminum source and the boron source are added, the molar ratio of the three raw materials to the water is H2O:Al2O3:Na2O:B2O3Stirring thoroughly until clear 1000:0.75:8:2.25 to give solution M1; 2) when the additive is added, glycerol is used as the additive, and the mass ratio of the added raw materials is MFI type zeolite seed crystal: additive: m1 was stirred thoroughly for 1h at a ratio of 1:0.1:1000 to give a mixture M2. The molar ratio of the components of the M3 mixture in this example was H2O:SiO2:Al2O3:Na2O:B2O3＝1333:200:1:11:3。
Example 5
The general procedure of this example is exactly the same as example 1 above.
The difference is that: 1) when the aluminum source and the boron source are added, the molar ratio of the three raw materials to the water is H2O:Al2O3:Na2O:B2O3Stirring thoroughly to clarify to obtain solution M1, 1000:0.5:8: 2.5; 2) when the additive is added, pentaerythritol is used as the additive, and the mass ratio of the added raw materials is MFI type zeolite seed crystal: additive: the M1 solution was stirred thoroughly for 3h at 1:0.2:1000 to give a mixed solution M2. The molar ratio of the components of the M3 mixture in this example was H2O:SiO2:Al2O3:Na2O:B2O3＝2000:300:1:16:5。
Example 6
The general procedure of this example is exactly the same as in example 1 above.
The difference is that: in the crystallization process, the first reaction is carried out in a constant temperature box at 100 ℃ for 12 hours, and the reaction product is transferred to a constant temperature box at 140 ℃ again for second hydrothermal crystallization for 24 hours.
Example 7
The general procedure of this example is exactly the same as in example 1 above.
The difference is that: 1) when an aluminum source and a boron source are added, the molar ratio of the three raw materials to water is as follows: h2O：Al2O3：Na2O:B2O3Stirring thoroughly until clear to give solution M1 at 600:1:8: 2. 2) Adding a certain amount of MFI type zeolite seed crystals and an additive into the prepared solution M1, wherein the additive is polyethylene glycol, and the mass ratio of the two raw materials to the M1 solution is MFI type zeolite seed crystals: additive: when the M1 solution was stirred thoroughly for 1.5h, a mixture M2 was obtained. The molar ratio of the components of the M3 mixture in this example was H2O:SiO2:Al2O3:Na2O:B2O3＝600:150:1:8:2。
Example 8
The general procedure of this example is exactly the same as example 1 above.
The difference is that: 1) when an aluminum source and a boron source are added, the molar ratio of the three raw materials to water is as follows: h2O：Al2O3：Na2O:B2O3Stirring thoroughly until clear to give solution M1, 1200:1:8: 2. 2) Adding a certain amount of MFI type zeolite seed crystals and an additive into the prepared solution M1, wherein the additive is ethylene glycol, and the mass ratio of the two raw materials to the M1 solution is MFI type zeolite seed crystals: additive: m1 was stirred thoroughly for 1.5h at a ratio of 1:0.3:1200 to give a mixture M2. The molar ratio of the components of the M3 mixture in this example was H2O:SiO2:Al2O3:Na2O:B2O3＝1200:150:1:8:2。
Example 9
The general procedure of this example is exactly the same as in example 1 above.
The difference is that: 1) when an aluminum source and a boron source are added, the molar ratio of the three raw materials to water is as follows: h2O：Al2O3：Na2O:B2O3When stirred well at 1000:1:8:0.5, a solution M1 was obtained. 2) The molar ratio of the components of the M3 mixture in this example was H2O:SiO2:Al2O3:Na2O:B2O31000:150:1:8: 0.5. 3) In the crystallization process, the first reaction is carried out for 5 hours in a thermostat with the temperature of 110 ℃, and the reaction product is transferred to a thermostat with the temperature of 180 ℃ again for second hydrothermal crystallization for 5 hours.
Example 10
The general procedure of this example is exactly the same as in example 1 above.
The difference is that: 1) when an aluminum source and a boron source are added, the molar ratio of the three raw materials to water is as follows: h2O：Al2O3：Na2O:B2O3When the ratio is 1000:0.5:8:2.5, the mixture is sufficiently stirred until the mixture is clear, so that a solution M1 is obtained. 2) The molar ratio of the components of the M3 mixture in this example was H2O:SiO2:Al2O3:Na2O:B2O31000:150:0.5:8: 2.5. 3) In the crystallization process, the first reaction is carried out for 15 hours in a thermostat with the temperature of 70 ℃, and the reaction product is transferred to a thermostat with the temperature of 160 ℃ again for the second hydrothermal crystallization for 20 hours.
Product of the above example B-Al-ZSMThe yield of the-5 single kettle is 25-30%. Both have similar XRD spectrogram and IR spectrogram, complete crystallization with the crystallinity of 95-100%, obvious small-grain ZSM-5 molecular sieve morphology and controllable grain size in SEM image, and the specific surface area determined by BET analysis is 330-360 m-2The concentration is/g, and the microporous molecular sieve has a more typical adsorption and desorption curve. According to the embodiment of the invention, the B-Al-ZSM-5 molecular sieve with high crystallinity and high yield is obtained under the condition that the feeding silica-alumina ratio is 150-300, wherein the introduction of the B element is more favorable for improving the silica-alumina ratio of the molecular sieve.
Comparative example 1
The silicon-aluminum composition of this example was exactly the same as in example 1. Except that no boron source is added, and the Al-ZSM-5 molecular sieve without a template system is synthesized. At room temperature, dissolving NaOH in an ethanol water solution, adding an aluminum source to dissolve until the solution is clear, slowly adding silica gel, stirring for 1h, adding MFI type zeolite seed crystal (silicalite-1) seed crystal, continuously stirring for 1h to obtain gel, placing the gel in a crystallization kettle, and crystallizing for 3 days at 140 ℃. After crystallization, the ZSM-5 molecular sieve is obtained through procedures of filtering, washing, drying and the like. The H-type ZSM-5 molecular sieve (marked as ZSM-5-W) is obtained through the treatment projects of ammonium exchange, roasting and the like.
Comparative example 2
The general procedure of this example is exactly the same as comparative example 1 above. In contrast, the TPA + templated sample only exchanged an equimolar amount of ethanol for TPA +, and the molar composition and synthesis of the other starting materials were identical. Namely, the Al-ZSM-5 molecular sieve with the template system is synthesized by adopting the same amount of template tetrapropylammonium bromide without adding an alcohol assistant in the system and removing the template through baking at 550 ℃. The H-type ZSM-5 molecular sieve (marked as ZSM-5-N) is obtained through the treatment projects of ammonium exchange, roasting and the like.
Example 11
The hydrogen-type B-Al-ZSM-5 molecular sieve obtained in example (example 1, 3, 6, 8) was used in the catalytic cracking reaction of N-hexane, the amount of the molecular sieve used was 0.5g, and N was added2As a carrier gas, the hexane partial pressure is 12kPa, and the mass space velocity of the n-hexane is 6h-1The cracking reaction temperature was 625 ℃. And compared with the synthesized samples in comparative example 1 and comparative example 2 for evaluation, the specific reaction numberSee table 1 and fig. 10.
TABLE 1 comparison of catalytic cracking Performance of ZSM-5 and B-Al-ZSM-5 molecular sieves
And (4) supplementary notes: 1) P/E ═ propylene selectivity/ethylene selectivity; 2) triene: ethylene + propylene + butylene (C2 ═ + C3 ═ + C4 ═)
Research shows that compared with the template ZSM-5-N, the selectivity of methane and ethane of the template-free ZSM-5-W is reduced, the selectivity of ethylene is increased, and the selectivity of methane and ethane of the B-Al-ZSM-5 molecular sieve synthesized after adding boron is reduced more obviously; in the selectivity of the propylene, the ZSM-5-N molecular sieve reaches 23.16 percent, the ZSM-5-W molecular sieve reaches 22.27 percent, the optimized sample of the B-Al-ZSM-5 molecular sieve is increased to 32.08 percent, and the selectivity of the propylene is increased by nearly 10 percent compared with the ZSM-5 molecular sieve in a comparative example, which indicates that the yield of the propylene can be greatly increased by introducing boron in the method; compared with ZSM-5-N and ZSM-5-W, the yield of butene of the B-Al-ZSM-5 molecular sieve is also improved by 5.18 percent to the maximum; the BTX yield of the B-Al-ZSM-5 molecular sieve is obviously reduced and is only 9.17%, 7.63%, 7.48% and 9.37% respectively, which shows that the introduction of boron is favorable for reducing the BTX yield; the P/E ratio of n-hexane cracking reaction on the B-Al-ZSM-5 molecular sieve increased from 0.90 and 0.82 of the comparative example ZSM-5 molecular sieve to 1.62 (highest), and the overall yield of ethylene, propylene and butene (triene) increased.
In conclusion, the invention successfully synthesizes the B-Al-ZSM-5 molecular sieve under the conditions of no template system and high solid content. The system has high economic value and environmental protection benefit, and the potential application value is remarkable; when the B-Al-ZSM-5 molecular sieve is synthesized in a template-free system and used for a normal hexane catalytic cracking reaction, compared with the ZSM-5 molecular sieve without a template or with a template system, the yield and selectivity of diene and triene are obviously increased, the BTX selectivity is reduced, the reaction life (the conversion rate is more than 90 percent) of the molecular sieve is about three times of that of the other molecular sieve, and the stability is better.
Claims (12)
1. A preparation method of a B-Al-ZSM-5 molecular sieve is characterized by directly introducing a high-concentration system formed by a boron source, an MFI type molecular sieve seed crystal auxiliary agent and a solid silicon-aluminum source into an alkali liquor without adding organic ammonium, and efficiently synthesizing the B-Al-ZSM-5 molecular sieve with a high silicon-aluminum ratio through hydrothermal crystallization, filtration, washing and drying processes, and specifically comprises the following steps:
step (1): weighing NaOH, dissolving the NaOH in deionized water to prepare NaOH alkali solution, adding a boron source and an aluminum source, fully stirring until the solution is clear to obtain a solution M1, wherein the composition and the molar ratio of the solution M1 are H2O:Al2O3:Na2O:B2O3＝80-2000:1:8-80:0.01-100；
Step (2): adding a certain amount of MFI type molecular sieve seed crystal and an additive into the solution M1, and fully stirring to obtain a mixed solution M2;
and (3): slowly adding a silicon source into the mixed solution M2, and stirring to obtain the final mixed sol M3, wherein the mixed sol M3 has the composition and the molar ratio of H2O:SiO2:Al2O3:Na2O:B2O3Keeping the low water-silicon ratio of the system at 80-2000:20-300:1:8-80: 0.01-100;
and (4): transferring the final mixed sol M3 to a polytetrafluoroethylene reaction kettle for crystallization in two sections;
and (5): separating the product obtained in the step (4), performing reduced pressure suction filtration, washing the product to be neutral by using deionized water, and drying the product at the temperature of 100-120 ℃ to obtain molecular sieve raw powder;
and (6): and (4) carrying out ion exchange on the molecular sieve raw powder obtained in the step (5) by using an ammonium chloride solution to form ammonium type B-Al-ZSM-5, and roasting to obtain the hydrogen type B-Al-ZSM-5 molecular sieve.
2. The method of claim 1, wherein the system is a solid-like high-solid-content system, and the final mixing is performedH in Sync Sol M32O and SiO2In a molar ratio of 2 to 12.
3. The method for preparing the B-Al-ZSM-5 molecular sieve of claim 1, wherein in the step (2), the additive is an alcohol compound or a polymer; the MFI type molecular sieve crystal seed comprises the following components in percentage by mass: additive: solution M1-1: 0.1-1: 80-2100.
4. The method of claim 3, wherein the alcohol compound is at least one of ethanol, ethylene glycol, glycerol, pentaerythritol, and polyethylene glycol.
5. The method of claim 1, wherein the silicon source is at least one of a coarse silica gel, silicic acid, and silica white.
6. The method for preparing the B-Al-ZSM-5 molecular sieve of claim 1, wherein in the step (3), the mass ratio of the silicon source to the mixed solution M2 is SiO2: mixed solution M2 is 0.2-1: 1.
7. The method of preparing the B-Al-ZSM-5 molecular sieve of claim 1, wherein the aluminum source is at least one of sodium metaaluminate, aluminum chloride, aluminum sulfate and the like.
8. The method of claim 1, wherein the boron source is H3BO3、Na3BO3And B2O3At least one of (1).
9. The method for preparing the B-Al-ZSM-5 molecular sieve of claim 1, wherein in the step (2), the stirring time is 0.5-3 h; in the step (3), the stirring time is 1-10 h.
10. The method for preparing the B-Al-ZSM-5 molecular sieve of claim 1, wherein in the step (4), two-stage crystallization is carried out as follows: the first stage crystallization temperature is 70-120 ℃, and the crystallization time is 5-30 h; the second-stage crystallization temperature is 140-.
11. The use of the B-Al-ZSM-5 molecular sieve of any of claims 1-10 in the reaction of producing olefins by catalytic cracking of paraffinic oils.
12. The application of claim 11, wherein the olefin production reaction by catalytic cracking of the paraffinic oil product comprises using naphtha as a raw material, using a B-Al-ZSM-5 molecular sieve as a catalyst, and using N as a catalyst2As carrier gas, the alkane partial pressure is 3-13kPa, and the alkane mass space velocity is 2-12h-1The cracking reaction temperature is 550-700 ℃.
Priority Applications (1)
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| CN115385357A (en) * | 2022-08-25 | 2022-11-25 | 山东京博石油化工有限公司 | HZSM-5 molecular sieve, preparation method thereof and application thereof in light hydrocarbon catalytic cracking |
| CN116119681A (en) * | 2023-01-11 | 2023-05-16 | 中国石油大学(华东) | Preparation method for rapidly synthesizing ZSM-5 molecular sieve by inducer |
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| CN106745049A (en) * | 2016-12-30 | 2017-05-31 | 神华集团有限责任公司 | A kind of molecular sieves of boron modification HZSM 5, preparation method and its usage |
| CN108190913A (en) * | 2018-03-02 | 2018-06-22 | 浙江大学 | The method of method synthesis Silicon-rich ZSM-5 zeolite molecular sieve is oriented to using crystal seed |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106745049A (en) * | 2016-12-30 | 2017-05-31 | 神华集团有限责任公司 | A kind of molecular sieves of boron modification HZSM 5, preparation method and its usage |
| CN108190913A (en) * | 2018-03-02 | 2018-06-22 | 浙江大学 | The method of method synthesis Silicon-rich ZSM-5 zeolite molecular sieve is oriented to using crystal seed |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115385357A (en) * | 2022-08-25 | 2022-11-25 | 山东京博石油化工有限公司 | HZSM-5 molecular sieve, preparation method thereof and application thereof in light hydrocarbon catalytic cracking |
| CN116119681A (en) * | 2023-01-11 | 2023-05-16 | 中国石油大学(华东) | Preparation method for rapidly synthesizing ZSM-5 molecular sieve by inducer |
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