CA1165749A - Method for carrying out exothermal catalytic gas phase reactions - Google Patents
Method for carrying out exothermal catalytic gas phase reactionsInfo
- Publication number
- CA1165749A CA1165749A CA000377706A CA377706A CA1165749A CA 1165749 A CA1165749 A CA 1165749A CA 000377706 A CA000377706 A CA 000377706A CA 377706 A CA377706 A CA 377706A CA 1165749 A CA1165749 A CA 1165749A
- Authority
- CA
- Canada
- Prior art keywords
- catalyst
- reaction
- respect
- nickel
- particle
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000000034 method Methods 0.000 title claims abstract description 35
- 230000003197 catalytic effect Effects 0.000 title claims abstract description 14
- 238000010574 gas phase reaction Methods 0.000 title claims description 5
- 239000003054 catalyst Substances 0.000 claims abstract description 147
- 238000006243 chemical reaction Methods 0.000 claims abstract description 111
- 239000002245 particle Substances 0.000 claims abstract description 35
- 230000002829 reductive effect Effects 0.000 claims abstract description 21
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 68
- 239000000463 material Substances 0.000 claims description 32
- 229910052759 nickel Inorganic materials 0.000 claims description 29
- 239000011148 porous material Substances 0.000 claims description 23
- 239000010949 copper Substances 0.000 claims description 21
- 229910001868 water Inorganic materials 0.000 claims description 20
- 229910052802 copper Inorganic materials 0.000 claims description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 18
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 17
- 238000007086 side reaction Methods 0.000 claims description 11
- JJLJMEJHUUYSSY-UHFFFAOYSA-L Copper hydroxide Chemical compound [OH-].[OH-].[Cu+2] JJLJMEJHUUYSSY-UHFFFAOYSA-L 0.000 claims description 5
- 239000005750 Copper hydroxide Substances 0.000 claims description 4
- 229910001956 copper hydroxide Inorganic materials 0.000 claims description 4
- 238000001354 calcination Methods 0.000 claims description 2
- 229910000480 nickel oxide Inorganic materials 0.000 claims description 2
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 claims description 2
- 150000001879 copper Chemical class 0.000 claims 1
- 238000001035 drying Methods 0.000 claims 1
- 239000000126 substance Substances 0.000 claims 1
- 230000000694 effects Effects 0.000 abstract description 17
- 230000015572 biosynthetic process Effects 0.000 abstract description 15
- 230000008569 process Effects 0.000 abstract description 11
- 238000003786 synthesis reaction Methods 0.000 abstract description 9
- 229930195733 hydrocarbon Natural products 0.000 abstract description 8
- 150000002430 hydrocarbons Chemical class 0.000 abstract description 8
- 239000004215 Carbon black (E152) Substances 0.000 abstract description 4
- 239000012530 fluid Substances 0.000 abstract description 3
- 239000007792 gaseous phase Substances 0.000 abstract description 2
- 239000007789 gas Substances 0.000 description 36
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 14
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 13
- 238000010790 dilution Methods 0.000 description 12
- 239000012895 dilution Substances 0.000 description 12
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 11
- XTVVROIMIGLXTD-UHFFFAOYSA-N copper(II) nitrate Chemical compound [Cu+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XTVVROIMIGLXTD-UHFFFAOYSA-N 0.000 description 10
- 239000000376 reactant Substances 0.000 description 10
- 239000000395 magnesium oxide Substances 0.000 description 9
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical class [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 8
- 238000009792 diffusion process Methods 0.000 description 8
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 7
- 229910052739 hydrogen Inorganic materials 0.000 description 7
- 239000001257 hydrogen Substances 0.000 description 7
- 239000000203 mixture Substances 0.000 description 7
- 239000000047 product Substances 0.000 description 7
- 229910002091 carbon monoxide Inorganic materials 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- BDAGIHXWWSANSR-UHFFFAOYSA-M Formate Chemical compound [O-]C=O BDAGIHXWWSANSR-UHFFFAOYSA-M 0.000 description 5
- 229910052799 carbon Inorganic materials 0.000 description 5
- 229940105305 carbon monoxide Drugs 0.000 description 5
- 238000002474 experimental method Methods 0.000 description 5
- 239000004312 hexamethylene tetramine Substances 0.000 description 5
- 235000010299 hexamethylene tetramine Nutrition 0.000 description 5
- VKYKSIONXSXAKP-UHFFFAOYSA-N hexamethylenetetramine Chemical compound C1N(C2)CN3CN1CN2C3 VKYKSIONXSXAKP-UHFFFAOYSA-N 0.000 description 5
- 238000005470 impregnation Methods 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 229960004011 methenamine Drugs 0.000 description 5
- 238000002360 preparation method Methods 0.000 description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 4
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- 239000011149 active material Substances 0.000 description 4
- 229910002092 carbon dioxide Inorganic materials 0.000 description 4
- 238000000975 co-precipitation Methods 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 4
- KBJMLQFLOWQJNF-UHFFFAOYSA-N nickel(ii) nitrate Chemical compound [Ni+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O KBJMLQFLOWQJNF-UHFFFAOYSA-N 0.000 description 4
- 238000004064 recycling Methods 0.000 description 4
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 150000001298 alcohols Chemical class 0.000 description 3
- 150000001336 alkenes Chemical class 0.000 description 3
- 229910002090 carbon oxide Inorganic materials 0.000 description 3
- 239000002826 coolant Substances 0.000 description 3
- 239000011777 magnesium Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000036961 partial effect Effects 0.000 description 3
- 239000008188 pellet Substances 0.000 description 3
- 239000012071 phase Substances 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 229910000881 Cu alloy Inorganic materials 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 2
- 229910002651 NO3 Inorganic materials 0.000 description 2
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 2
- URLKBWYHVLBVBO-UHFFFAOYSA-N Para-Xylene Chemical group CC1=CC=C(C)C=C1 URLKBWYHVLBVBO-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 125000000217 alkyl group Chemical group 0.000 description 2
- 239000004411 aluminium Substances 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000004040 coloring Methods 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 229910052593 corundum Inorganic materials 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000005868 electrolysis reaction Methods 0.000 description 2
- 238000011049 filling Methods 0.000 description 2
- 230000000670 limiting effect Effects 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 239000011733 molybdenum Substances 0.000 description 2
- 239000002574 poison Substances 0.000 description 2
- 231100000614 poison Toxicity 0.000 description 2
- 231100000572 poisoning Toxicity 0.000 description 2
- 230000000607 poisoning effect Effects 0.000 description 2
- 230000009257 reactivity Effects 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 239000011029 spinel Substances 0.000 description 2
- 229910052596 spinel Inorganic materials 0.000 description 2
- AKEJUJNQAAGONA-UHFFFAOYSA-N sulfur trioxide Chemical compound O=S(=O)=O AKEJUJNQAAGONA-UHFFFAOYSA-N 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 229910001845 yogo sapphire Inorganic materials 0.000 description 2
- 239000005749 Copper compound Substances 0.000 description 1
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 description 1
- 239000005751 Copper oxide Substances 0.000 description 1
- 101100001675 Emericella variicolor andJ gene Proteins 0.000 description 1
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 239000004115 Sodium Silicate Substances 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 239000013543 active substance Substances 0.000 description 1
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 1
- 239000000292 calcium oxide Substances 0.000 description 1
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 238000003889 chemical engineering Methods 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 150000001880 copper compounds Chemical class 0.000 description 1
- YOCUPQPZWBBYIX-UHFFFAOYSA-N copper nickel Chemical compound [Ni].[Cu] YOCUPQPZWBBYIX-UHFFFAOYSA-N 0.000 description 1
- 229910000431 copper oxide Inorganic materials 0.000 description 1
- AEJIMXVJZFYIHN-UHFFFAOYSA-N copper;dihydrate Chemical compound O.O.[Cu] AEJIMXVJZFYIHN-UHFFFAOYSA-N 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 230000002427 irreversible effect Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- HZPNKQREYVVATQ-UHFFFAOYSA-L nickel(2+);diformate Chemical compound [Ni+2].[O-]C=O.[O-]C=O HZPNKQREYVVATQ-UHFFFAOYSA-L 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000005453 pelletization Methods 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- LGRFSURHDFAFJT-UHFFFAOYSA-N phthalic anhydride Chemical compound C1=CC=C2C(=O)OC(=O)C2=C1 LGRFSURHDFAFJT-UHFFFAOYSA-N 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000012495 reaction gas Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000017557 sodium bicarbonate Nutrition 0.000 description 1
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 1
- 150000003388 sodium compounds Chemical class 0.000 description 1
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 1
- 229910052911 sodium silicate Inorganic materials 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 150000003464 sulfur compounds Chemical class 0.000 description 1
- 238000011282 treatment Methods 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Classifications
-
- 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
- C01C1/0411—Preparation of ammonia by synthesis in the gas phase from N2 and H2 in presence of a catalyst characterised by the catalyst
-
- 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
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
- B01J23/74—Iron group metals
- B01J23/755—Nickel
-
- 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
- B01J33/00—Protection of catalysts, e.g. by coating
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B17/00—Sulfur; Compounds thereof
- C01B17/69—Sulfur trioxide; Sulfuric acid
- C01B17/74—Preparation
- C01B17/76—Preparation by contact processes
- C01B17/78—Preparation by contact processes characterised by the catalyst used
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C1/00—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon
- C07C1/02—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon from oxides of a carbon
- C07C1/04—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon from oxides of a carbon from carbon monoxide with hydrogen
- C07C1/0425—Catalysts; their physical properties
-
- 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
- B01J35/00—Catalysts, in general, characterised by their form or physical properties
- B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
- B01J35/396—Distribution of the active metal ingredient
- B01J35/397—Egg shell like
-
- 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
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/02—Impregnation, coating or precipitation
- B01J37/0201—Impregnation
- B01J37/0205—Impregnation in several steps
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C2523/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00
- C07C2523/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of the iron group metals or copper
- C07C2523/72—Copper
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C2523/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00
- C07C2523/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of the iron group metals or copper
- C07C2523/74—Iron group metals
- C07C2523/755—Nickel
-
- 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
-
- 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
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/40—Bio-organic fraction processing; Production of fertilisers from the organic fraction of waste or refuse
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Catalysts (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
- Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
Abstract
A B S T R A C T
The invention relates to a method of perform-ing exothermal catalytic processes in the gaseous phase using a cooled reactor containing a fixed or fluid bed or a porous, particulate catalyst so that in such a process a reduced reaction rate in the high-temperature range and thereby an improved security against reaction-runaway is obtained by using a catalyst the individual particles of which outermost have a zone of reduced activity, possibly no activity at all, with respect to the desired reaction; the principle of the invention is suitable, for example for hydrocarbon reactions such as methanation or Fischer-Tropsch synthesis.
The invention relates to a method of perform-ing exothermal catalytic processes in the gaseous phase using a cooled reactor containing a fixed or fluid bed or a porous, particulate catalyst so that in such a process a reduced reaction rate in the high-temperature range and thereby an improved security against reaction-runaway is obtained by using a catalyst the individual particles of which outermost have a zone of reduced activity, possibly no activity at all, with respect to the desired reaction; the principle of the invention is suitable, for example for hydrocarbon reactions such as methanation or Fischer-Tropsch synthesis.
Description
~ 16S7 J~9 15829-15841/KP/io Haldor Tops0e A/S, Lyngby, Denmark.
A method for carrying out exothermal catalytic gas phase reactions.
Field of the invention The present invention relates to a method for carrying out exothermal catalytic gas phase reactions using a cooled reactor containlng a fixed or fluid bad of a porous partlculate catalyst which is active wlth respect to the deslred reaction.
~ackground of the invention A large number of catalytic processes ln the gaseous phase glve a high heat generation, and in many cases they cause considerable rise in temperature. Examples thereof ^;~ are the catalytic conversion of alcohols into hydrocarbons ~ 16574~
by the socalled Mobil synthesis, of carbon oxides by methanation into methane or by the Fischer-Tropsch synthesis into petrol and/or olefins (processes accompanied by the socalled water gas reaction); furthermore ammonia synthesis, preparation of formaldehyde from methanol, natural gas or other hydrocarbons, and preparation of sulfuric acid vapour and sulfur trioxide from sulfur dioxide.
The high temperatures may involve a number of disadvantages. In many cases they can cause damage or destruction of the catalyst, e.g. by sintering of the active catalyst material or the pore system of the catalyst.
Undesired side reactions may often take place, thus decomposition to free carbon by the preparation of hydrocarbons from carbon oxides or alcohols, which carbon may block and destroy the catalyst. In many cases the higher temperatures may shift the reaction equilibrium and -selectivity in an undesired direction; thus in the Fischer-Tropsch synthesis high temperature favours the formation of methane at the expense of the desired products, e.g. ethane, ethene or other olefins or petrol.
Exothermal catalytic processes are often carried out in adlabatic reactors and in such cases one often attempts to llmit the increase in temperature by diluting the reactants, either with gases that are inert under the reaction conditions or by recycling product gas. Dilution with inert gases involves costs of the gases and of separating them from the end product, and recycling of product gas involves loss of energy in the recycling compressors.
In other cases exothermal processes therefore have been carried out in cooled reactors whereby dilution and the use of recycling compressors can be avoided. As cooling medium is used, i.a., air, salt baths, synthetic heat transfer media such as "Dowterm" ~ and in the above-mentioned hydrocarbon formation processes frequently boiling water. In cooled reactors it is possible to obtain a low exit temperature of the product gases and thus an . advantageous reactlon equilibrium in cases where the ' ' ' .
, : ~
1 16574~
desired product is favoured by low temperature. However, in cooled reactors with a catalyst bed it is not possible to avoid that shortly after the "ignition" of the reaction, i.e. a short distance from the inlet to the catalyst bed, a warm zone occurs,a socalled "hot spot" in which the temperature often will be near the temperature thermodynamically determined by the adiabatic temperature increase. Only after this the reaction gas is cooled, i.e.
further on in the catalyst bed. Accordingly, the same problems will occur as mentioned above with respect to the catalyst stability, possibly selectivity and carbon formation in case of hydrocarbon reactions.
The problems regarding the hot spot temperature have been treated in the literature, i.a., by van Welsenaere and Froment (Chemical Engineering Schience, Vol.
25, pp. 1503-1516, 1970) and it appears that hot spot is lnevitable in tube reactors with constant wall temperature and that the hot spot temperature is very sensitive to small variations in the process variables such as inlet temperature, concentration of the reactants and wall j temperature. Accordingly there is a risk that the temperature may increase ln an uncontrollable manner leading to socalled "runaway". Welsenaere and Froment state how the reactions can be controlled under given conditions, for example when carried out in a fixed catalyst bed arranged in tubes surrounded by a cooling medium; a critical factor in thls case ls the tube diameter. In said paper Welsenaere and Froment give results for the oxidation of p-xylene to ; phthalic acid anhydride at atmospheric pressure and with a large excess of alr.
- The calculations have been made for an irreversible ;~ process of first order, but can also be transferred without substantial alterations to reversible reactions which are l~ ~ not of first order. Hereby one finds e.g. for the methanation ;;;l 35 reactions :1 :, 1' 3H2 ~ CH4 + H20 + 49 Kcal/mol,
A method for carrying out exothermal catalytic gas phase reactions.
Field of the invention The present invention relates to a method for carrying out exothermal catalytic gas phase reactions using a cooled reactor containlng a fixed or fluid bad of a porous partlculate catalyst which is active wlth respect to the deslred reaction.
~ackground of the invention A large number of catalytic processes ln the gaseous phase glve a high heat generation, and in many cases they cause considerable rise in temperature. Examples thereof ^;~ are the catalytic conversion of alcohols into hydrocarbons ~ 16574~
by the socalled Mobil synthesis, of carbon oxides by methanation into methane or by the Fischer-Tropsch synthesis into petrol and/or olefins (processes accompanied by the socalled water gas reaction); furthermore ammonia synthesis, preparation of formaldehyde from methanol, natural gas or other hydrocarbons, and preparation of sulfuric acid vapour and sulfur trioxide from sulfur dioxide.
The high temperatures may involve a number of disadvantages. In many cases they can cause damage or destruction of the catalyst, e.g. by sintering of the active catalyst material or the pore system of the catalyst.
Undesired side reactions may often take place, thus decomposition to free carbon by the preparation of hydrocarbons from carbon oxides or alcohols, which carbon may block and destroy the catalyst. In many cases the higher temperatures may shift the reaction equilibrium and -selectivity in an undesired direction; thus in the Fischer-Tropsch synthesis high temperature favours the formation of methane at the expense of the desired products, e.g. ethane, ethene or other olefins or petrol.
Exothermal catalytic processes are often carried out in adlabatic reactors and in such cases one often attempts to llmit the increase in temperature by diluting the reactants, either with gases that are inert under the reaction conditions or by recycling product gas. Dilution with inert gases involves costs of the gases and of separating them from the end product, and recycling of product gas involves loss of energy in the recycling compressors.
In other cases exothermal processes therefore have been carried out in cooled reactors whereby dilution and the use of recycling compressors can be avoided. As cooling medium is used, i.a., air, salt baths, synthetic heat transfer media such as "Dowterm" ~ and in the above-mentioned hydrocarbon formation processes frequently boiling water. In cooled reactors it is possible to obtain a low exit temperature of the product gases and thus an . advantageous reactlon equilibrium in cases where the ' ' ' .
, : ~
1 16574~
desired product is favoured by low temperature. However, in cooled reactors with a catalyst bed it is not possible to avoid that shortly after the "ignition" of the reaction, i.e. a short distance from the inlet to the catalyst bed, a warm zone occurs,a socalled "hot spot" in which the temperature often will be near the temperature thermodynamically determined by the adiabatic temperature increase. Only after this the reaction gas is cooled, i.e.
further on in the catalyst bed. Accordingly, the same problems will occur as mentioned above with respect to the catalyst stability, possibly selectivity and carbon formation in case of hydrocarbon reactions.
The problems regarding the hot spot temperature have been treated in the literature, i.a., by van Welsenaere and Froment (Chemical Engineering Schience, Vol.
25, pp. 1503-1516, 1970) and it appears that hot spot is lnevitable in tube reactors with constant wall temperature and that the hot spot temperature is very sensitive to small variations in the process variables such as inlet temperature, concentration of the reactants and wall j temperature. Accordingly there is a risk that the temperature may increase ln an uncontrollable manner leading to socalled "runaway". Welsenaere and Froment state how the reactions can be controlled under given conditions, for example when carried out in a fixed catalyst bed arranged in tubes surrounded by a cooling medium; a critical factor in thls case ls the tube diameter. In said paper Welsenaere and Froment give results for the oxidation of p-xylene to ; phthalic acid anhydride at atmospheric pressure and with a large excess of alr.
- The calculations have been made for an irreversible ;~ process of first order, but can also be transferred without substantial alterations to reversible reactions which are l~ ~ not of first order. Hereby one finds e.g. for the methanation ;;;l 35 reactions :1 :, 1' 3H2 ~ CH4 + H20 + 49 Kcal/mol,
(2) 2CO + 2H2 ~ ` CH4 + C02 + 59 Kcal/mol, and
(3) C2 + 4H2 ~ ` CH4 + 2H20 + 39 Kcal/mol, :, '' ~,. -- ' '~
, . , ~ 165'~49 - that the diameter of the catalyst tubes cannot be more than a few millimeters if there shall be complete security against runaway under any conditions. Such small tube diameter is inapplicabLe to industrial operation. The most important difference between the example of Welsenaere and Froment and the methanation reactions seems to be the high pressure and the high molar concentration in the latter and the resulting high production of heat per catalyst volume unit. Similar conditions apply to other hydrocarbon-forming reactions, e.g. the Fischer-Tropsch synthesis for the formation of petrol and/or olefins:
.
, . , ~ 165'~49 - that the diameter of the catalyst tubes cannot be more than a few millimeters if there shall be complete security against runaway under any conditions. Such small tube diameter is inapplicabLe to industrial operation. The most important difference between the example of Welsenaere and Froment and the methanation reactions seems to be the high pressure and the high molar concentration in the latter and the resulting high production of heat per catalyst volume unit. Similar conditions apply to other hydrocarbon-forming reactions, e.g. the Fischer-Tropsch synthesis for the formation of petrol and/or olefins:
.
(4) nCO + 2nH2~ (CH2)n + H2O + ablut 40 Kcal/gram atom C
or the socalled Mobil synthesis for the formation of hydrocarbons from alcohols, e.g.
or the socalled Mobil synthesis for the formation of hydrocarbons from alcohols, e.g.
(5) nCH3OH ~ (CH2)n + nH2O + about 12 Kcal/gram atom C
Thus, it is not possible without special measures to prevent an increase of temperature to that or a value near that determined by the adiabatic temperature increase for such reactions. Welsenaere and Froment suggest a dilution of the catalyst filling in the catalyst bed, e.g.
with catalytically inert filler bodies whereby the amount of heat produced per reactor unit volume decreases. However, it is found that a relatively high degree of dilution of the catalyst is necessary, which necessitates an increase of the catalyst volume itself in order to ~ignite;' the reaction.
Thus, this method has the drawback of demanding an enlargement of the reactor and thus an increase of the capital costs; more important ls often the fact that the dilution has the disadvantage of decreasing the resistance of the catalyst filling or its adsorption capaclty for catalyst poisons carrled on with the reactlon flow.
Therefore, such dilution of the catalyst is not a satisfactory solutlon of the temperature control problems in the cooled exothermal catalytic processes.
~''~'' ~
':
.
,: , . - : :
~ 165749 In order to study the problems further some experiments were carried out in an air-cooled methanation reactor with a catalyst having the manufacturing designation MCR-2X. This is a microporous, temperature-stable, mechanically strong catalyst~with nickel crystallites of the same order of magnitude as the pore diameter,on a support of y-alumina (see Karsten Pedersen, Allan Skov and J.R. Rostrup-Nielsen, ACS Symposium, Houston, March 1980).
The catalyst was used in the form of cylinders with height and diameter 4.3 mm. In some of the experiments the catalyst was diluted with catalytically inactive cylinders of same geometric shape. The pressure in the reactor was maintained at 26 kg/cm2 and a feed gas was used of the composition 70% H2, 93 CO, 10% CO2 and 11% CH4. These experimental conditions will give thermodynamically determined adiabatic increases of temperature of between 380 and 400C
irrespective of the degree of dilution of the catalyst.
It was found that without dilution of the catalyst it was not possible to limit the temperature increase which accordingly became the sald 380 to 400C. With dilution ratios of 1:3 and 1:5 (i.e. a volume of inert cylinders 3 and 5 times, respectively, that of catalyst bodies) actual increases of temperature were measured that were until 50C
less than the expected adiabatic temperature increases of 380 to 400& . In these experiments the temperature of the tube wall in the hot spot area was about 600C or more, which would be an unrealistic high tube wall temperature ln industrial operation; in an industrial cooled reactor the highest tube wall temperature would not exceed 400C.
The limitatlon of temperature increase obtained can be considered substantial although in ltself it has no big ; practical lndustrial importance, and although catalyst ~ ~ dilution ln this manner for the above reasons is not-very ; ~ expedient.
i 35 However, a detailed analysis of the reduced temperature increase demonstrated that the reduced temperature increase resulted from the fact that the reaction velocity had not increased as much as was to be ., - :
expected according to the reaction kinetics, and surprisingly - ~ -it was found that this reduced reaction velocity was due to the fact that the calculated reaction velocity at high temperature exceeds the velocity of diffusion of the reactants through the gas film surrounding the catalyst particles. Since the gas phase diffusion is almost independent of the temperature (activation energy 1-2 Kcal/mol), the reaction velocity ran against a barrier caused by the lacking presence of reactants at the actual reaction sites, the interior of the catalyst bodies, and therefore the reaction is prevented from runaway.
Summary of the -invention It is the object of the invention to utilize this surprising observation to indicate how one can generally prevent runaway in catalyzed exothermal gas phase reactions in cooled reactors containing a bed of a porous particulate catalyst which is active with respect to the desired reaction. In accordance with the invention this is achieved when each of the ir.dividual particles of the catalyst outermost has a zone of reduced catalytic activity with respect to the desired reactlon.
Detailed description of the invention The outermost part of each individual catalyst particle thus can consist of a completsly inert layer or of a layer with reduced activity for the strongly exothermal reaction in question. In case of simultaneously occurrence of a strongly exothermal main reaction together wlth one or more side reactions (which may be less exothermal, or even thermally neutral or endothermal), the outer layer may, if desired, be catalytically active for the side reaction but not for the main reaction; as an example can be mentioned that the above reactions (1), ~2) and (4), which are catalyzed by nickel, are accompanied by the water gas reaction, also called the shift reaction:
~ , ~ 35 (6) C0 + H20 = C02 + H2 + 10 Kcal/mol, '' ' ' . ' . ~:
~ 165749 which, i.a., is catalyzed by copper.
- Whether the outer layer is catalytically inert or catalytically active with respect to a side reaction but inactive with respect to the main reaction, the abovementioned film diffusion is extended to also include diffusion through the inert outer layer of the catalyst. Therefore, it will be possible to determine the ma~imum reaction rate in the reactor since it is determined by the thickness of the inert layer. The thickness of the layer inert to the main reaction in practice will be from one to a few orders of magnitude bigger than the thickness of the surrounding gas film; on basis of calculations the thickness of this gas film can be estimated at about 1 ~ at normal industrial conditions;
according to the invention said outer zone of the catalyst particles therefore can suitably have a thickness of 0.01-2 mm. Thicknesses of said layer of more than about 0.5 or 1 mm will in practice only come into question when using comparatively large catalyst particles.
A general explanation of the invention as defined is that a given catalyst body with homogeneous activity and a homogeneous pore system exposed to a given mixture of reactants ls subjected to various reaction restrictions as the reaction temperature is changed (increased).
At low temperature the reaction rate is limited by the catalyst material. Here, the reaction is in the socalled intrinsic velocity range in which there is almost no concentration gradient of the reactants through the pore system of the catalyst body. As the temperature increases the catalyst activity increases, and this imparts an increased gradient o the reactants through the catalyst bodies. At some point a temperature range is reached where the diffusion of the reactants through the catalyst bodies becomes the limiting parameter for the reaction rate;
in effect this means that not all of the catalyst material is used in the reaction; the efficiency factor becomes ~1.
When the temperature is further increased, the parameter determing the reaction rate will be the mass '"
' ':
':
, i, ~ 165749 transport through the gas film surrounding the catalyst - bodies. Normally this rate is too large for the cooling surface of the reactor to limit the hot spot temperature to a level substantially below that determined by the adiabatic temperature increase, which in many cases means that a thermal sintering cannot be avoided or in case of certain methanation reactions that carbon formation cannot be prevented.
According to the invention, however, a restrictive surface is incorporated into the individual catalyst bodies by increasing the gas film or by decreasing in some way the penetrative power of the reactants whereby the reaction rate and accordingly also the temperature increase is limited.
It could be expected that the incorporation of such inert layer, "delaying layer", would cause diffic-ulties in the start or "ignition" of the exothermal reactions.
However, this does not happen because the reaction rate is slow in the ignition zone under any circumstances so that the gas diffusion through the inert layer will not be restrictive (determining) for the reaction rate. This layer will only become a limiting factor, i.e. virtually it will only begin to be effective when the reaction rate becomes so high that it is deslred to slow it down. As the inert layer constitutes or.ly a small part of the catalyst pellet the resistance of the catalyst against poisoning is retained.
In thls connection it can be mentioned that said outer layer on very small catalyst pellets may constitute above 50% of thelr volume; but normally its share will be conslderably less, for instance for cylindrical catalyst bodies with height and dlameter of 4.2 mm typically 1-10%, especially 2-10% and frequently 2-5% of the volume.
' The reactor may be any type of cooled reactor for ~ exothermal reactions, for example a tubular reaator or a reactor ;- 35 having a larger space of optional shape and containing cooling tubes wherein a cooling medium flows. The catalyst bed usually will be a socalled fixed bed but the invention -~ can also be used in connection with catalysts in fluid bed.
1. , , :
, ' : .
~ ' .
3 ~5749 As mentioned theouter layer must have reduced ~ catalytic activity and although it will often in accordance with the invention be suitable to use a catalyst the individual particles of which outermost have a zone which is inactive with respe~t to the desired reaction ~or main reaction), it may in some cases be expedient to use a catalyst wherein said outer zone has some yet reduced activity with respect to the reaction (or main reaction).
The outer zone can be provided in various ways, frequently in analogy with technique known from the pharmaceutical industry where tablets are prepared with more layers of varying composition or varying concentrations of an active substance.
Thus, it is possible to first prepare catalyst bodies of the normal kind, consisting of a porous support containing catalytically active material in the pore-system.
This can be prepared by known technique, for example by coprecipitation or by first preparing porous support bodies which are then impregnated with the catalytically active material. The catalyst thus prepared is then immersed in a gel or sol of lnert support material of the same or another kind as that of the catalyst support itself. If the outer layer should not be completely catalytically lnert but should have restricted catalytical activity, it can then be impregnated whlle ensurlng that the concentration of catalytically active material becomes lower than that in the inner layer.
Alternating impregnations, washing out and treatments with chemicalscan be combined whereby a desired structure and combination of structures can be obtained. On a finished catalyst an inert layer or even a catalytically active layer partially clogging the pore orifices can be applied, e.g.
by electrolysis or depositing from the vapour phase, whereby catalyst activity in the outer layer and the diffusion rate into the interior of the catalyst are reduced. A special structure can be obtained by pelletizing a mixture of disintegrated catalyst particles with an inert support material. Hereby the diffusion effect is combined with a dilution of the catalyst, whereby the degree of dilution can be reduced substantially.
~ 1~5'749 Practical embodiments of these methods and combinations thereof will be obvious to those skilled in the art.
As mentioned the principle disclosed may be utilized not only in case of a single exothermal reaction but-also in cases where an exothermal ma$n reaction and one or more side reactions occur simultaneously in the same reactor which contains a bed of a particulate catalyst which is active with respect to the main reaction. In that case each of the individual particles of said catalyst according to the invention outermost has a zone of a material which is at least partially inactive with respect to the main reaction but catalytically active with respect to one or more side reactions.
A practical embodiment of such a catalyst~ or generally of catalysts in accordance with the principles of the invention, is a catalyst whose particles consist of a porous support material which is catalytically inactive with respect to the desired reaction or main reaction (but possibly catalytically active with respect to a side reactlon) and contain in part of the pore~system a material which is catalytically active with respect to the desired reaction or main reactlon, in such a manner that the pores ln the outer zone of the support particles are free of the material which i8 catalytically active with respect to the desired reaction or main reaction. The content in the pores of catalytically active material may for example be provided by co-precipitation, by electrolysis, by depositing from the vapour phase or by impregnation from the liquid phase.
In cases where the catalyst is only to be catalytically active with respect to one reaction, the catalyst particles may according to the invention consist of a porous, inactive material which contains ln part of the pore system a material which is catalytically active with respect to the desired reaction, the pores in the outer zone of the support being partially blocked by catalytically inactive material.
In another embodiment of the method, which is applicable both in cases where only one reaction is catalyzed and in cases where a main reaction as well as one or more side reactions are catalyzed by different components of the catalyst, the catalyst employed has the structure of "islets" embedded in the main structure of the porous support.
In that case the catalyst particles in accordance with the invention consist of a porous support material which may in itself be catalytically active or may comprise a component which is catalytically active with respect to one or more desired side reactions, the particles having such a structure that "islets" of the support having a high content in tha pore~ of a material which is active with respect to the desired reaction or main reaction are statistically evenly distributed in the interior of the catalyst, but more sparingly present or absent in the outer zone of the catalyst.
Catalysts prepared according to the described principles can be used with particular advantage for hydrocarbon reactions such as those shown hereinbefore, especially methanation reactions. The catalyst may then consist of a known support material, e.g. y-alumina, magneslum aluminium spinel, silica, zirconia, titania or combinations of two or more of these materials, together with catalytically active nickel, whereby there outermost is a zone without nickel or with a reduced concentration of nickel. In this way the desired shell éffect is obtained directly.
However, the principle may be used even more elegantly; as mentioned above reactions (1), (2) and (4) are accompanied by the water gas reaction (6). The reactions (1)-(4) and also th water gas reaction are catalyzed by nickel whereas the water gas reaction is also catalyzed, i.a., by copper. It is advantageous to have the methanation reactions accompanied by the water gas or shift reaction insuch a manner that the partial pressure of carbon - monoxide is reduced before it comes too much into contact ;~ 35 with the catalyst nickel since CO to some extent is a catalyst poison for nickel and the poisoning can be reduced by reducing the partial pressure of CO. It should be noted that it is nickel metal and copper metal that catalyze the .~ .
, .
-- .
~ ~8~'74~
reactions whereas the catalyst metal is applied in the form of a compound, commonly a nitrate or hydroxide, which is later oxygenated, e.g. by calcination, and finally reduced to the free metal, frequently during the start of the desired reaction by the aid of hydrogen present amongst the reactants; these circumstances will be ignored hereinafter and the specification will only deal with the free metals.
It is known that alloys of copper and nickel above a certain copper content show a very poor activity for methanation (see M. Araki and V. Ponec, J. Catalysis 44, 439 (1976)); this is further illustrated in Example 1 hereinafter. However, the Ni/Cu-catalyst still has activity for the conversion of carbon monoxide into carbon dioxide by the water gas reaction (6). This can be utilized in connection with the present invention by the preparation of a nickel catalyst outermost having a shell of the nickel-copper alloy. In this way there is firstly obtained a slowing down of the strongly heat-evolving methanation reaction but also a reduction of the partial pressure of the carbon monoxide by the water gas reaction, whereby the nickel-contalning catalyst core is spared the socalled ~-desactivation (see the abovementioned paper by Karsten Pedersen, Allan Skov andJ.R. Rostrup-Nielsen in ACS-symposium).
By the ~3-desactivation the adsorbed carbon monoxide is slowly converted into deposits of carbon having low reactivity, which desactivates the catalyst, but this is avoided when using according to the invention nickel-containing porous catalyst particles containing copper in the outer layer of each particle.
The outer copper-containing catalyst film can be formed by various means. For example one can first prepare particles of a nickel catalyst in known manner, e.g. by lmpregnation or co-precipitation, and then immerse the particles in water or other liguid and subseguently in an impregnation liquid containing a copper compound, e.g.
copper nitrate or copper hydroxide.
Another method consists in precipitating copper hydroxide from copper nitrate in the outer parts of the - pore system of the catalyst. In this method it is ,. .
' ` ' '' . . ' : -3~7 advantageous if the support material is basic, for example contains free magnesium oxide. This can for instance be obtained by using a support of magnesium aluminium spinel which is burned at such temperature (about 1100C) that unreacted magnesium oxide still possesses some reactivity. Alternatively, the pore system is first filled with suspended magnesium oxide or other base such as calcium oxide or solutions of an alkali metal hydroxide. Copper hydroxide will be pre-cipitated in the outer part of the pore system accordingto the reaction (7) Cu(NO3)2 + MgO + H2O > Cu(OH)2 + Mg(N3)2 The method described can be used with nickel catalysts wherein the nickel has been evenly distributed by other means, as mentioned for example by co-precipi-tation, impregnation with nickel nitrate without the presence of MgO or other alkaline compounds in the pore system. If the catalyst support contains free magnesium oxide or other alkaline compounds, nickel can be applied before or after copper by impregnation with nickel hex-amine formate, which in itself is alkaline but does not cause precipitation of nickel by contact with alkaline compounds. In this way it is possible to control the ratio nickel to copper in the outer zone of the catalyst and at the same time obtain an even distribution of the nickel content.
The reaction velocity in methanation and thereby the reaction temperature can be controlled according to similar principles using a vanadium- or molybdenum-based catalyst in a sulfur-containing atmosphere as described in Canadian patent application Serial No. 366,677.
, ,, , !~ D, ,~..
' 1~ .
' '. . .
. .
- 13a -It may be particularly useful to utilize the principle of the present invention in connection with the process described in Canadian patent application Serial No. 366,674 for preparing a gas mixture having a high content of C2-hydrocarbons by reacting a feed gas mixture containing hydrogen and carbon oxides by means of a catalyst containing molybdenum and/or vanadium and iron and/or nickel in the presence of gaseous sulfur compounds. This reaction is a /
/
~ B
., 1 1657~9 Fischer-Tropsch synthesis and it is very important to - maintain the temperature relatively low because higher temperatures will shift the equilibrium towaxds the production of methane. Therefore, in accordance with the present invention the catalyst bodies may be provided with a shell of inactive support material or a shell containing copper to synthesize the simultaneous water gas reaction.
The method of the invention will be illustrated in the following by some Examples.
Example 1 _________ A. A series of catalysts were prepared by co-precipitating sodium silicate and varying amounts of copper and nickel nitrates with sodium hydrogen carbonate.
The precipitated product was shaped to particles which were washed out to remove sodium compounds, dried at 120C, calcined at 500C and reduced in hydrogen at 500C.
The methanation activi*y was measured at 1 atm and 250C by passing a gas conqisting of 1% CO in H2 in an amount of lO0 Nl/h over the catalyst in form of irregular bodies having the slze ~det~rmined by sieve) of 0.3-0.5 mm. The following results were obtained:
Catalyst Weight % Atomic ratio Act~vity No. Ni Cu Ni/Cu + Ni 10 mol/g/h l 68.50 l.0 93.75 2 54.2 14.6 0.8 22.32 3 40.2 29.0 0.6 8.93 4 26.5 43.0 0.4 3 57 13.1 56.7 0.2 0.89
Thus, it is not possible without special measures to prevent an increase of temperature to that or a value near that determined by the adiabatic temperature increase for such reactions. Welsenaere and Froment suggest a dilution of the catalyst filling in the catalyst bed, e.g.
with catalytically inert filler bodies whereby the amount of heat produced per reactor unit volume decreases. However, it is found that a relatively high degree of dilution of the catalyst is necessary, which necessitates an increase of the catalyst volume itself in order to ~ignite;' the reaction.
Thus, this method has the drawback of demanding an enlargement of the reactor and thus an increase of the capital costs; more important ls often the fact that the dilution has the disadvantage of decreasing the resistance of the catalyst filling or its adsorption capaclty for catalyst poisons carrled on with the reactlon flow.
Therefore, such dilution of the catalyst is not a satisfactory solutlon of the temperature control problems in the cooled exothermal catalytic processes.
~''~'' ~
':
.
,: , . - : :
~ 165749 In order to study the problems further some experiments were carried out in an air-cooled methanation reactor with a catalyst having the manufacturing designation MCR-2X. This is a microporous, temperature-stable, mechanically strong catalyst~with nickel crystallites of the same order of magnitude as the pore diameter,on a support of y-alumina (see Karsten Pedersen, Allan Skov and J.R. Rostrup-Nielsen, ACS Symposium, Houston, March 1980).
The catalyst was used in the form of cylinders with height and diameter 4.3 mm. In some of the experiments the catalyst was diluted with catalytically inactive cylinders of same geometric shape. The pressure in the reactor was maintained at 26 kg/cm2 and a feed gas was used of the composition 70% H2, 93 CO, 10% CO2 and 11% CH4. These experimental conditions will give thermodynamically determined adiabatic increases of temperature of between 380 and 400C
irrespective of the degree of dilution of the catalyst.
It was found that without dilution of the catalyst it was not possible to limit the temperature increase which accordingly became the sald 380 to 400C. With dilution ratios of 1:3 and 1:5 (i.e. a volume of inert cylinders 3 and 5 times, respectively, that of catalyst bodies) actual increases of temperature were measured that were until 50C
less than the expected adiabatic temperature increases of 380 to 400& . In these experiments the temperature of the tube wall in the hot spot area was about 600C or more, which would be an unrealistic high tube wall temperature ln industrial operation; in an industrial cooled reactor the highest tube wall temperature would not exceed 400C.
The limitatlon of temperature increase obtained can be considered substantial although in ltself it has no big ; practical lndustrial importance, and although catalyst ~ ~ dilution ln this manner for the above reasons is not-very ; ~ expedient.
i 35 However, a detailed analysis of the reduced temperature increase demonstrated that the reduced temperature increase resulted from the fact that the reaction velocity had not increased as much as was to be ., - :
expected according to the reaction kinetics, and surprisingly - ~ -it was found that this reduced reaction velocity was due to the fact that the calculated reaction velocity at high temperature exceeds the velocity of diffusion of the reactants through the gas film surrounding the catalyst particles. Since the gas phase diffusion is almost independent of the temperature (activation energy 1-2 Kcal/mol), the reaction velocity ran against a barrier caused by the lacking presence of reactants at the actual reaction sites, the interior of the catalyst bodies, and therefore the reaction is prevented from runaway.
Summary of the -invention It is the object of the invention to utilize this surprising observation to indicate how one can generally prevent runaway in catalyzed exothermal gas phase reactions in cooled reactors containing a bed of a porous particulate catalyst which is active with respect to the desired reaction. In accordance with the invention this is achieved when each of the ir.dividual particles of the catalyst outermost has a zone of reduced catalytic activity with respect to the desired reactlon.
Detailed description of the invention The outermost part of each individual catalyst particle thus can consist of a completsly inert layer or of a layer with reduced activity for the strongly exothermal reaction in question. In case of simultaneously occurrence of a strongly exothermal main reaction together wlth one or more side reactions (which may be less exothermal, or even thermally neutral or endothermal), the outer layer may, if desired, be catalytically active for the side reaction but not for the main reaction; as an example can be mentioned that the above reactions (1), ~2) and (4), which are catalyzed by nickel, are accompanied by the water gas reaction, also called the shift reaction:
~ , ~ 35 (6) C0 + H20 = C02 + H2 + 10 Kcal/mol, '' ' ' . ' . ~:
~ 165749 which, i.a., is catalyzed by copper.
- Whether the outer layer is catalytically inert or catalytically active with respect to a side reaction but inactive with respect to the main reaction, the abovementioned film diffusion is extended to also include diffusion through the inert outer layer of the catalyst. Therefore, it will be possible to determine the ma~imum reaction rate in the reactor since it is determined by the thickness of the inert layer. The thickness of the layer inert to the main reaction in practice will be from one to a few orders of magnitude bigger than the thickness of the surrounding gas film; on basis of calculations the thickness of this gas film can be estimated at about 1 ~ at normal industrial conditions;
according to the invention said outer zone of the catalyst particles therefore can suitably have a thickness of 0.01-2 mm. Thicknesses of said layer of more than about 0.5 or 1 mm will in practice only come into question when using comparatively large catalyst particles.
A general explanation of the invention as defined is that a given catalyst body with homogeneous activity and a homogeneous pore system exposed to a given mixture of reactants ls subjected to various reaction restrictions as the reaction temperature is changed (increased).
At low temperature the reaction rate is limited by the catalyst material. Here, the reaction is in the socalled intrinsic velocity range in which there is almost no concentration gradient of the reactants through the pore system of the catalyst body. As the temperature increases the catalyst activity increases, and this imparts an increased gradient o the reactants through the catalyst bodies. At some point a temperature range is reached where the diffusion of the reactants through the catalyst bodies becomes the limiting parameter for the reaction rate;
in effect this means that not all of the catalyst material is used in the reaction; the efficiency factor becomes ~1.
When the temperature is further increased, the parameter determing the reaction rate will be the mass '"
' ':
':
, i, ~ 165749 transport through the gas film surrounding the catalyst - bodies. Normally this rate is too large for the cooling surface of the reactor to limit the hot spot temperature to a level substantially below that determined by the adiabatic temperature increase, which in many cases means that a thermal sintering cannot be avoided or in case of certain methanation reactions that carbon formation cannot be prevented.
According to the invention, however, a restrictive surface is incorporated into the individual catalyst bodies by increasing the gas film or by decreasing in some way the penetrative power of the reactants whereby the reaction rate and accordingly also the temperature increase is limited.
It could be expected that the incorporation of such inert layer, "delaying layer", would cause diffic-ulties in the start or "ignition" of the exothermal reactions.
However, this does not happen because the reaction rate is slow in the ignition zone under any circumstances so that the gas diffusion through the inert layer will not be restrictive (determining) for the reaction rate. This layer will only become a limiting factor, i.e. virtually it will only begin to be effective when the reaction rate becomes so high that it is deslred to slow it down. As the inert layer constitutes or.ly a small part of the catalyst pellet the resistance of the catalyst against poisoning is retained.
In thls connection it can be mentioned that said outer layer on very small catalyst pellets may constitute above 50% of thelr volume; but normally its share will be conslderably less, for instance for cylindrical catalyst bodies with height and dlameter of 4.2 mm typically 1-10%, especially 2-10% and frequently 2-5% of the volume.
' The reactor may be any type of cooled reactor for ~ exothermal reactions, for example a tubular reaator or a reactor ;- 35 having a larger space of optional shape and containing cooling tubes wherein a cooling medium flows. The catalyst bed usually will be a socalled fixed bed but the invention -~ can also be used in connection with catalysts in fluid bed.
1. , , :
, ' : .
~ ' .
3 ~5749 As mentioned theouter layer must have reduced ~ catalytic activity and although it will often in accordance with the invention be suitable to use a catalyst the individual particles of which outermost have a zone which is inactive with respe~t to the desired reaction ~or main reaction), it may in some cases be expedient to use a catalyst wherein said outer zone has some yet reduced activity with respect to the reaction (or main reaction).
The outer zone can be provided in various ways, frequently in analogy with technique known from the pharmaceutical industry where tablets are prepared with more layers of varying composition or varying concentrations of an active substance.
Thus, it is possible to first prepare catalyst bodies of the normal kind, consisting of a porous support containing catalytically active material in the pore-system.
This can be prepared by known technique, for example by coprecipitation or by first preparing porous support bodies which are then impregnated with the catalytically active material. The catalyst thus prepared is then immersed in a gel or sol of lnert support material of the same or another kind as that of the catalyst support itself. If the outer layer should not be completely catalytically lnert but should have restricted catalytical activity, it can then be impregnated whlle ensurlng that the concentration of catalytically active material becomes lower than that in the inner layer.
Alternating impregnations, washing out and treatments with chemicalscan be combined whereby a desired structure and combination of structures can be obtained. On a finished catalyst an inert layer or even a catalytically active layer partially clogging the pore orifices can be applied, e.g.
by electrolysis or depositing from the vapour phase, whereby catalyst activity in the outer layer and the diffusion rate into the interior of the catalyst are reduced. A special structure can be obtained by pelletizing a mixture of disintegrated catalyst particles with an inert support material. Hereby the diffusion effect is combined with a dilution of the catalyst, whereby the degree of dilution can be reduced substantially.
~ 1~5'749 Practical embodiments of these methods and combinations thereof will be obvious to those skilled in the art.
As mentioned the principle disclosed may be utilized not only in case of a single exothermal reaction but-also in cases where an exothermal ma$n reaction and one or more side reactions occur simultaneously in the same reactor which contains a bed of a particulate catalyst which is active with respect to the main reaction. In that case each of the individual particles of said catalyst according to the invention outermost has a zone of a material which is at least partially inactive with respect to the main reaction but catalytically active with respect to one or more side reactions.
A practical embodiment of such a catalyst~ or generally of catalysts in accordance with the principles of the invention, is a catalyst whose particles consist of a porous support material which is catalytically inactive with respect to the desired reaction or main reaction (but possibly catalytically active with respect to a side reactlon) and contain in part of the pore~system a material which is catalytically active with respect to the desired reaction or main reactlon, in such a manner that the pores ln the outer zone of the support particles are free of the material which i8 catalytically active with respect to the desired reaction or main reaction. The content in the pores of catalytically active material may for example be provided by co-precipitation, by electrolysis, by depositing from the vapour phase or by impregnation from the liquid phase.
In cases where the catalyst is only to be catalytically active with respect to one reaction, the catalyst particles may according to the invention consist of a porous, inactive material which contains ln part of the pore system a material which is catalytically active with respect to the desired reaction, the pores in the outer zone of the support being partially blocked by catalytically inactive material.
In another embodiment of the method, which is applicable both in cases where only one reaction is catalyzed and in cases where a main reaction as well as one or more side reactions are catalyzed by different components of the catalyst, the catalyst employed has the structure of "islets" embedded in the main structure of the porous support.
In that case the catalyst particles in accordance with the invention consist of a porous support material which may in itself be catalytically active or may comprise a component which is catalytically active with respect to one or more desired side reactions, the particles having such a structure that "islets" of the support having a high content in tha pore~ of a material which is active with respect to the desired reaction or main reaction are statistically evenly distributed in the interior of the catalyst, but more sparingly present or absent in the outer zone of the catalyst.
Catalysts prepared according to the described principles can be used with particular advantage for hydrocarbon reactions such as those shown hereinbefore, especially methanation reactions. The catalyst may then consist of a known support material, e.g. y-alumina, magneslum aluminium spinel, silica, zirconia, titania or combinations of two or more of these materials, together with catalytically active nickel, whereby there outermost is a zone without nickel or with a reduced concentration of nickel. In this way the desired shell éffect is obtained directly.
However, the principle may be used even more elegantly; as mentioned above reactions (1), (2) and (4) are accompanied by the water gas reaction (6). The reactions (1)-(4) and also th water gas reaction are catalyzed by nickel whereas the water gas reaction is also catalyzed, i.a., by copper. It is advantageous to have the methanation reactions accompanied by the water gas or shift reaction insuch a manner that the partial pressure of carbon - monoxide is reduced before it comes too much into contact ;~ 35 with the catalyst nickel since CO to some extent is a catalyst poison for nickel and the poisoning can be reduced by reducing the partial pressure of CO. It should be noted that it is nickel metal and copper metal that catalyze the .~ .
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~ ~8~'74~
reactions whereas the catalyst metal is applied in the form of a compound, commonly a nitrate or hydroxide, which is later oxygenated, e.g. by calcination, and finally reduced to the free metal, frequently during the start of the desired reaction by the aid of hydrogen present amongst the reactants; these circumstances will be ignored hereinafter and the specification will only deal with the free metals.
It is known that alloys of copper and nickel above a certain copper content show a very poor activity for methanation (see M. Araki and V. Ponec, J. Catalysis 44, 439 (1976)); this is further illustrated in Example 1 hereinafter. However, the Ni/Cu-catalyst still has activity for the conversion of carbon monoxide into carbon dioxide by the water gas reaction (6). This can be utilized in connection with the present invention by the preparation of a nickel catalyst outermost having a shell of the nickel-copper alloy. In this way there is firstly obtained a slowing down of the strongly heat-evolving methanation reaction but also a reduction of the partial pressure of the carbon monoxide by the water gas reaction, whereby the nickel-contalning catalyst core is spared the socalled ~-desactivation (see the abovementioned paper by Karsten Pedersen, Allan Skov andJ.R. Rostrup-Nielsen in ACS-symposium).
By the ~3-desactivation the adsorbed carbon monoxide is slowly converted into deposits of carbon having low reactivity, which desactivates the catalyst, but this is avoided when using according to the invention nickel-containing porous catalyst particles containing copper in the outer layer of each particle.
The outer copper-containing catalyst film can be formed by various means. For example one can first prepare particles of a nickel catalyst in known manner, e.g. by lmpregnation or co-precipitation, and then immerse the particles in water or other liguid and subseguently in an impregnation liquid containing a copper compound, e.g.
copper nitrate or copper hydroxide.
Another method consists in precipitating copper hydroxide from copper nitrate in the outer parts of the - pore system of the catalyst. In this method it is ,. .
' ` ' '' . . ' : -3~7 advantageous if the support material is basic, for example contains free magnesium oxide. This can for instance be obtained by using a support of magnesium aluminium spinel which is burned at such temperature (about 1100C) that unreacted magnesium oxide still possesses some reactivity. Alternatively, the pore system is first filled with suspended magnesium oxide or other base such as calcium oxide or solutions of an alkali metal hydroxide. Copper hydroxide will be pre-cipitated in the outer part of the pore system accordingto the reaction (7) Cu(NO3)2 + MgO + H2O > Cu(OH)2 + Mg(N3)2 The method described can be used with nickel catalysts wherein the nickel has been evenly distributed by other means, as mentioned for example by co-precipi-tation, impregnation with nickel nitrate without the presence of MgO or other alkaline compounds in the pore system. If the catalyst support contains free magnesium oxide or other alkaline compounds, nickel can be applied before or after copper by impregnation with nickel hex-amine formate, which in itself is alkaline but does not cause precipitation of nickel by contact with alkaline compounds. In this way it is possible to control the ratio nickel to copper in the outer zone of the catalyst and at the same time obtain an even distribution of the nickel content.
The reaction velocity in methanation and thereby the reaction temperature can be controlled according to similar principles using a vanadium- or molybdenum-based catalyst in a sulfur-containing atmosphere as described in Canadian patent application Serial No. 366,677.
, ,, , !~ D, ,~..
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- 13a -It may be particularly useful to utilize the principle of the present invention in connection with the process described in Canadian patent application Serial No. 366,674 for preparing a gas mixture having a high content of C2-hydrocarbons by reacting a feed gas mixture containing hydrogen and carbon oxides by means of a catalyst containing molybdenum and/or vanadium and iron and/or nickel in the presence of gaseous sulfur compounds. This reaction is a /
/
~ B
., 1 1657~9 Fischer-Tropsch synthesis and it is very important to - maintain the temperature relatively low because higher temperatures will shift the equilibrium towaxds the production of methane. Therefore, in accordance with the present invention the catalyst bodies may be provided with a shell of inactive support material or a shell containing copper to synthesize the simultaneous water gas reaction.
The method of the invention will be illustrated in the following by some Examples.
Example 1 _________ A. A series of catalysts were prepared by co-precipitating sodium silicate and varying amounts of copper and nickel nitrates with sodium hydrogen carbonate.
The precipitated product was shaped to particles which were washed out to remove sodium compounds, dried at 120C, calcined at 500C and reduced in hydrogen at 500C.
The methanation activi*y was measured at 1 atm and 250C by passing a gas conqisting of 1% CO in H2 in an amount of lO0 Nl/h over the catalyst in form of irregular bodies having the slze ~det~rmined by sieve) of 0.3-0.5 mm. The following results were obtained:
Catalyst Weight % Atomic ratio Act~vity No. Ni Cu Ni/Cu + Ni 10 mol/g/h l 68.50 l.0 93.75 2 54.2 14.6 0.8 22.32 3 40.2 29.0 0.6 8.93 4 26.5 43.0 0.4 3 57 13.1 56.7 0.2 0.89
6 0 70.1 0 0 It appears that even a small amount of copper drastically reduces the methanation activity.
B. 3 Catalysts were prepared by impregnating a support of y-alumina having an internal surface area of about 40 m2/g in solutions of copper nitrate, nickel nitrate and 1 1~S74~
a mixture of nickel nitrate and copper nitrate, respectively.
The impregnated supports were calcined at 550C and reduced ~ in hydrogen at 720C. The catalysts were tested in a reactorat a pressure of 1 atm with 53.5 Nl/h gas consisting of 61.8% by volume of H2, 18.2% by volume of H2O and 20.~ by volume of C0, over 0.2 g catalyst as particles of 0.3-0.5 mm.
In this way the following rate-s for carbon monoxide `~
conversion (water gas reaction, shift reaction) and methanation, were measured:
reaction rate at 375C, 10 3 mol/g/h shift methanation Cu1.05 0 Ni,Cu 73 5.2 15 Ni ) Ni ) 1431 1608 +) measured at 311C as reactor temperature could not be controlled at 375C
++) measured on the above mentioned catalyst MCR-2X.
It appears that the Nl,Cu-catalyst has a good activity for the water gas reaction whereas none of the Cu-containing catalysts have any slgnificant activity for methanation.
',, Example 2 _________ A support consisting of magnesia with a minor content of alumina (ratio Mg/Al 7:1) in the form of cylinders with height and diameter 4.5 mm was impregnated with a saturatet aqueous solution of o~er nitrate. The impregnated support was calcined at -~ 550C. When the particles were broken it could be clearly seen that copper had accumulated as a thin black shell on the outside of the support. Mlcroscopic examination showed that i the thickness of the layer was about 50 ~.
The copper-impregnated support was impregnated with ~1 a saturated aqueous solution of nickel hexanine formate prepared by ; J~ dissolving 23 g nickel formate in 50 ml concentrated aqueous ,~, ~, - ^- - - . - . , ~ 1~5749 ammonia. The impregnated catalyst was calcined at 300C. The broken particles showed even colouring and thus even ; distribution of nickel. By analysis 0.6% by weight of Cu and 2.7% by weiyht of Ni were found.
A corresponding catalyst was prepared by impregnating first in nickel hexamine formate and then copper nitrate. The copper shell appeared as a dark colouring of the outer zone of the particles. This catalyst is designated catalyst A and as reference a copper free methanation catalyst, designated catalyst B, was prepared by impregnating the support in nickel hexamine formate.
Example 3 A methanation catalyst containing about 25% by weight of nickel on a stabilized support of alumina was impregnated lS in the form af 4.2 x 4.2 mm cylinders in a gel of alumina prepared by suspending 11 g alumina in 180 ml water and gelled with 5.6 ml concentrated nitric acid. The impregnated catalyst was calcined at 550C.
A corresponding preparation was carried out with the ~,, 20 difference that, 10 ml of the alumina gel was mixed at "', beforehand with a solution of copper nitrate. The impregnated 1'' and calcined catalyst showed an outer shell containing ~-~, copper,by microscopic examination estimated at a thickness - of about O.S mm. Minor amounts of copper nitrate had ` 25 penetrated into the interior of the catalyst but the ratio j between the copper content in the outer zone and that of the interior could be estimated at about 3:1. This catalyst ls designated C.
Example 4 ________ , 1' 30 This experiment shows how a coating on a catalyst , applied by means of a gel can reduce the reaction rate at ,~', high temperature.
A methanation catalyst with nickel in form of l~l 4.2 x 4.2 mm cylinders was coated with a gel of alumina and ,',1 , 35 then dried. Then the catalyst was reduced in pure hydrogen '- at 800C for 2 hours. This catalyst is designated D.
'",.,,1, -~
, ~ 16S7~9 A catalyst without such coating was activated - (reduced) in the same manner. It is designated E and is identical with the abovementioned catalyst MCR-2X.
Example 5 __ ___ __ __ The present example illustrates the testing of catalyst A-E mentioned in Examples 2 to 4.
The catalyst pellet to be tested was fixed between two thermoelements in a tube reactor having an internal diameter of 6 mm. Then it was heated in pure hydrogen to about 300C in order to eliminate possible traces of nickel oxide. Thereafter the hydrogen supply was cut off and the system fed with a synthesis gas consisting of 9~ CO in H2 at a rate of about 100 Nl/h during the entire experiment.
At about 300C the product gas stream was analyzed on a lS gas chromatograph and the amount of methane produced determlned. Then the temperature was increased stepwise and ~' the methanation rate determined at each step.
,~l The table below demonstrates that catalysts having ' an inert outer layer applied with the gel have a reduced reaction rate at high temperature as compared with the homogenous reference catalyst.
, Table 3 Catalyst Oest temp. Methanation C activlty millimol~g~h__ I
'~ A 300 1.4 -.MgO support 360 4 , impregnated with 417 6 -~ copper nitrate and 518 12 nlckél hexamine formate 603 11 A1203-MgO support 389 60 impregnated with 482 180 nickel hexamine ~ormate 577 250 i: :
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i 165749 Table 3 (contd.) NiO.Al2O3 catalyst 425 95 coated with A12O3 570 130 _ 741 95 D 243 3.5 NiO.A12O3 catalyst 295 30 coated with a shell 336 50 containing copper oxide 440 65 and A 2 3 60 NiO.Al2O3 catalyst 323 180 (the above mentioned known 379 250 catalyst MCR-2X without 438 270 restrictions) 508 315 The reason why catalysts B and E have maximum activities in the temperature range considered is the thickness of the gas film during the test, wherein the gas veloclties have been considerably lower than by industrial operation; in normal lndustrial operation with the higher gas velocities, the gas film would become thinner and thereby slow the aiffusion down to a le~ser degree. The mass transfer value for the gas film is estimated at about
B. 3 Catalysts were prepared by impregnating a support of y-alumina having an internal surface area of about 40 m2/g in solutions of copper nitrate, nickel nitrate and 1 1~S74~
a mixture of nickel nitrate and copper nitrate, respectively.
The impregnated supports were calcined at 550C and reduced ~ in hydrogen at 720C. The catalysts were tested in a reactorat a pressure of 1 atm with 53.5 Nl/h gas consisting of 61.8% by volume of H2, 18.2% by volume of H2O and 20.~ by volume of C0, over 0.2 g catalyst as particles of 0.3-0.5 mm.
In this way the following rate-s for carbon monoxide `~
conversion (water gas reaction, shift reaction) and methanation, were measured:
reaction rate at 375C, 10 3 mol/g/h shift methanation Cu1.05 0 Ni,Cu 73 5.2 15 Ni ) Ni ) 1431 1608 +) measured at 311C as reactor temperature could not be controlled at 375C
++) measured on the above mentioned catalyst MCR-2X.
It appears that the Nl,Cu-catalyst has a good activity for the water gas reaction whereas none of the Cu-containing catalysts have any slgnificant activity for methanation.
',, Example 2 _________ A support consisting of magnesia with a minor content of alumina (ratio Mg/Al 7:1) in the form of cylinders with height and diameter 4.5 mm was impregnated with a saturatet aqueous solution of o~er nitrate. The impregnated support was calcined at -~ 550C. When the particles were broken it could be clearly seen that copper had accumulated as a thin black shell on the outside of the support. Mlcroscopic examination showed that i the thickness of the layer was about 50 ~.
The copper-impregnated support was impregnated with ~1 a saturated aqueous solution of nickel hexanine formate prepared by ; J~ dissolving 23 g nickel formate in 50 ml concentrated aqueous ,~, ~, - ^- - - . - . , ~ 1~5749 ammonia. The impregnated catalyst was calcined at 300C. The broken particles showed even colouring and thus even ; distribution of nickel. By analysis 0.6% by weight of Cu and 2.7% by weiyht of Ni were found.
A corresponding catalyst was prepared by impregnating first in nickel hexamine formate and then copper nitrate. The copper shell appeared as a dark colouring of the outer zone of the particles. This catalyst is designated catalyst A and as reference a copper free methanation catalyst, designated catalyst B, was prepared by impregnating the support in nickel hexamine formate.
Example 3 A methanation catalyst containing about 25% by weight of nickel on a stabilized support of alumina was impregnated lS in the form af 4.2 x 4.2 mm cylinders in a gel of alumina prepared by suspending 11 g alumina in 180 ml water and gelled with 5.6 ml concentrated nitric acid. The impregnated catalyst was calcined at 550C.
A corresponding preparation was carried out with the ~,, 20 difference that, 10 ml of the alumina gel was mixed at "', beforehand with a solution of copper nitrate. The impregnated 1'' and calcined catalyst showed an outer shell containing ~-~, copper,by microscopic examination estimated at a thickness - of about O.S mm. Minor amounts of copper nitrate had ` 25 penetrated into the interior of the catalyst but the ratio j between the copper content in the outer zone and that of the interior could be estimated at about 3:1. This catalyst ls designated C.
Example 4 ________ , 1' 30 This experiment shows how a coating on a catalyst , applied by means of a gel can reduce the reaction rate at ,~', high temperature.
A methanation catalyst with nickel in form of l~l 4.2 x 4.2 mm cylinders was coated with a gel of alumina and ,',1 , 35 then dried. Then the catalyst was reduced in pure hydrogen '- at 800C for 2 hours. This catalyst is designated D.
'",.,,1, -~
, ~ 16S7~9 A catalyst without such coating was activated - (reduced) in the same manner. It is designated E and is identical with the abovementioned catalyst MCR-2X.
Example 5 __ ___ __ __ The present example illustrates the testing of catalyst A-E mentioned in Examples 2 to 4.
The catalyst pellet to be tested was fixed between two thermoelements in a tube reactor having an internal diameter of 6 mm. Then it was heated in pure hydrogen to about 300C in order to eliminate possible traces of nickel oxide. Thereafter the hydrogen supply was cut off and the system fed with a synthesis gas consisting of 9~ CO in H2 at a rate of about 100 Nl/h during the entire experiment.
At about 300C the product gas stream was analyzed on a lS gas chromatograph and the amount of methane produced determlned. Then the temperature was increased stepwise and ~' the methanation rate determined at each step.
,~l The table below demonstrates that catalysts having ' an inert outer layer applied with the gel have a reduced reaction rate at high temperature as compared with the homogenous reference catalyst.
, Table 3 Catalyst Oest temp. Methanation C activlty millimol~g~h__ I
'~ A 300 1.4 -.MgO support 360 4 , impregnated with 417 6 -~ copper nitrate and 518 12 nlckél hexamine formate 603 11 A1203-MgO support 389 60 impregnated with 482 180 nickel hexamine ~ormate 577 250 i: :
~:: .
~.";,. :
! .:
i 165749 Table 3 (contd.) NiO.Al2O3 catalyst 425 95 coated with A12O3 570 130 _ 741 95 D 243 3.5 NiO.A12O3 catalyst 295 30 coated with a shell 336 50 containing copper oxide 440 65 and A 2 3 60 NiO.Al2O3 catalyst 323 180 (the above mentioned known 379 250 catalyst MCR-2X without 438 270 restrictions) 508 315 The reason why catalysts B and E have maximum activities in the temperature range considered is the thickness of the gas film during the test, wherein the gas veloclties have been considerably lower than by industrial operation; in normal lndustrial operation with the higher gas velocities, the gas film would become thinner and thereby slow the aiffusion down to a le~ser degree. The mass transfer value for the gas film is estimated at about
7 kmol/h/m2, whereas this value would be about 100 kmol/h/m2 under industrial conditions. This involves that the difference in high-temperature activity with and without shell wlll be hlgher th~n shown ln table 3.
..
, . ,-, "
..
, . ,-, "
Claims (11)
1. In a method for carrying out a catalytic exothermal gas phase reaction in a cooled reactor containing a bed of a porous particulate catalyst which is active with respect to the desired reaction, the improvement that each individual particle of the catalyst outermost has a zone of reduced catalytic activity with respect to the desired reaction.
2. A method as claimed in claim 1, wherein each of the individual particles of the catalyst outermost has a zone which is inactive with respect to the desired reaction.
3. A method as claimed in claim 2, wherein said outer zone of each catalyst particle has a thickness of 0.01-2 mm.
4. A method as claimed in claim 1, wherein the catalyst particles consist of a porous, catalytically inactive support material which contains in part of the pore system a material which is catalytically active with respect to the desired reaction, the pores in the outer zone of the support being partically blocked by a catalytically inactive material.
5. A method as claimed in claim 1, wherein each catalyst particle consists of a porous support material which is catalytically inactive with respect to the desired reaction, the structure of each particle being such that "islets" of the support material having a high content in the pores of a material which is catalytically active with respect to the desired reaction are statistically evenly distributed in the interior of the catalyst but more sparingly present or absent in the outer zone of the catalyst.
6. In a method for simultaneously carrying out an exothermal catalytic gas phase main reaction and at least one catalytic gas phase side reaction, said reactions taking place in one cooled reactor containing a bed of a porous particulate catalyst which is active with respect to said reactions, the improvement that each individual particle of the catalyst outermost has a zone containing a material which is at least partically inactive with respect to the main reaction and catalytically active with respect to at least one side reaction.
7. A method as claimed in claim 6, wherein said outer zone of each catalyst particle has a thickness of 0.01-2 mm.
8. A method as claimed in claim 6, wherein the catalyst particles consist of a porous support material which is catalytically inactive with respect to the main reaction and which contains in part of the pore system a material which is catalytically active with respect to the main reaction, the pores in the outer zone of the support being free of the material which is catalytically active with respect to the main reaction.
9. A method as claimed in claim 6, wherein each catalyst particle consists of a porous support material which is catalytically inactive with respect to the main reaction and optionally active with respect to at least one side reaction, the structure of each particle being such that "islets" of the support material having a high content on the pores of a material which is catalytically active with respect to the main reaction are statistically evenly distributed in the interior of the catalyst but more sparingly present or absent in the outer zone of the catalyst.
10. A method as claimed in claim 6 for carrying out methanation reactions accompanied by the water gas reaction in a cooled reactor by the aid of a particulate catalyst containing nickel in the pores of the porous support, wherein the nickel-containing porous catalyst contains copper in the outer layer of each particle, said outer layer having a thickness of at least 0.01 mm.
11. A method for preparing the catalyst defined in claim 10, comprising the steps of (a) preparing a porous support containing a substance selected from the class consisting of nickel and nickel oxide in the pores, said porous support comprising an alkaline material, (b) treating the thus-prepared nickel based catalyst with a solution of a copper salt to precipitate copper hydroxide in an outer zone thereof having a thickness of at least 0.01 mm, (c) drying, (d) calcining and (e) reducing said catalyst.
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DK216980A DK144996C (en) | 1980-05-19 | 1980-05-19 | PROCEDURE FOR CARRYING OUT THE CATALYTIC EXOTHERMY GAS PHASE PROCESS AND PROCEDURE FOR THE PREPARATION OF A CATALYST |
DK2169/80 | 1980-05-19 |
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JP2752438B2 (en) * | 1989-06-19 | 1998-05-18 | 富士機器工業株式会社 | Paperwork |
DK173917B1 (en) * | 1998-07-02 | 2002-02-18 | Topsoe Haldor As | Process for producing ammonia |
EP1454671A1 (en) * | 2003-03-07 | 2004-09-08 | Karsten Pedersen | A catalyst for use in production of hydrogen by conversion of organic matter in water |
CN103055874A (en) * | 2011-10-21 | 2013-04-24 | 中国石油化工股份有限公司 | Methanation catalyst used for preparing substitute natural gas from synthesis gas, and preparation method and application thereof |
EP2893977B1 (en) * | 2012-09-04 | 2019-07-03 | University of Yamanashi | Co-selective methanation catalyst |
WO2014158095A1 (en) | 2013-03-28 | 2014-10-02 | Agency For Science, Technology And Research | Methanation catalyst |
SG2013050877A (en) | 2013-06-28 | 2015-01-29 | Agency Science Tech & Res | Methanation catalyst |
WO2015012189A1 (en) * | 2013-07-23 | 2015-01-29 | 三井金属鉱業株式会社 | Carbon monoxide methanation catalyst composition, and carbon monoxide methanation catalyst |
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DE2212964C3 (en) * | 1972-03-17 | 1980-01-31 | Basf Ag, 6700 Ludwigshafen | Supported catalyst containing vanadium pentoxide, titanium dioxide and optionally zirconium dioxide, phosphorus and other metal oxides |
JPS5831978B2 (en) * | 1972-08-10 | 1983-07-09 | フジミケンマザイコウギヨウ カブシキガイシヤ | Kinobutsutsushihogokouzotai |
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US4002658A (en) * | 1975-05-01 | 1977-01-11 | Ford Motor Company | Methanation catalyst and process of using the same |
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US4206087A (en) * | 1977-01-06 | 1980-06-03 | Engelhard Minerals & Chemicals Corporation | Catalyst for reducing pollutants in waste gas streams and process for preparing the catalyst |
US4128506A (en) * | 1978-01-23 | 1978-12-05 | General Motors Corporation | Platinum-rhodium catalyst for automotive emission control |
US4196100A (en) * | 1978-01-10 | 1980-04-01 | The International Nickel Co., Inc. | Catalyst useful for methanation and preparation thereof |
DE2925682A1 (en) * | 1979-06-26 | 1981-01-29 | Basf Ag | VANADINE PENTOXIDE, TITANIUM DIOXIDE, PHOSPHORUS, RUBIDIUM AND / OR CAESIUM AND Possibly. ZIRCONDIOXIDE CONTAINING CARRIER CATALYST |
-
1980
- 1980-05-19 DK DK216980A patent/DK144996C/en not_active IP Right Cessation
-
1981
- 1981-05-11 GB GB8114368A patent/GB2077613B/en not_active Expired
- 1981-05-11 ZA ZA00813117A patent/ZA813117B/en unknown
- 1981-05-12 SE SE8102986A patent/SE448684B/en not_active IP Right Cessation
- 1981-05-15 CA CA000377706A patent/CA1165749A/en not_active Expired
- 1981-05-18 NL NL8102436A patent/NL8102436A/en not_active Application Discontinuation
- 1981-05-18 FR FR8109828A patent/FR2482473B1/en not_active Expired
- 1981-05-18 NO NO811683A patent/NO155916C/en unknown
- 1981-05-18 AU AU70674/81A patent/AU542846B2/en not_active Ceased
- 1981-05-19 IT IT2181581A patent/IT1136615B/en active
- 1981-05-19 IN IN529/CAL/81A patent/IN155291B/en unknown
- 1981-05-19 JP JP7434981A patent/JPS5715834A/en active Granted
- 1981-05-19 DE DE3119887A patent/DE3119887A1/en active Granted
Also Published As
Publication number | Publication date |
---|---|
SE448684B (en) | 1987-03-16 |
NO155916B (en) | 1987-03-16 |
AU7067481A (en) | 1981-11-26 |
FR2482473A1 (en) | 1981-11-20 |
NO811683L (en) | 1981-11-20 |
AU542846B2 (en) | 1985-03-21 |
GB2077613B (en) | 1985-03-06 |
DE3119887C2 (en) | 1992-09-24 |
JPH0420656B2 (en) | 1992-04-06 |
NO155916C (en) | 1987-06-24 |
IT1136615B (en) | 1986-09-03 |
DK144996C (en) | 1982-12-20 |
ZA813117B (en) | 1982-05-26 |
JPS5715834A (en) | 1982-01-27 |
NL8102436A (en) | 1981-12-16 |
DE3119887A1 (en) | 1982-03-25 |
IT8121815A0 (en) | 1981-05-19 |
FR2482473B1 (en) | 1987-06-26 |
DK144996B (en) | 1982-07-26 |
DK216980A (en) | 1981-11-20 |
IN155291B (en) | 1985-01-19 |
SE8102986L (en) | 1981-11-20 |
GB2077613A (en) | 1981-12-23 |
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