CN116571260A - Supported molybdenum carbide catalyst and preparation method and application thereof - Google Patents
Supported molybdenum carbide catalyst and preparation method and application thereof Download PDFInfo
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- CN116571260A CN116571260A CN202310408971.9A CN202310408971A CN116571260A CN 116571260 A CN116571260 A CN 116571260A CN 202310408971 A CN202310408971 A CN 202310408971A CN 116571260 A CN116571260 A CN 116571260A
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- catalyst
- metal salt
- molybdenum carbide
- alumina
- carbide catalyst
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- 239000003054 catalyst Substances 0.000 title claims abstract description 140
- QIJNJJZPYXGIQM-UHFFFAOYSA-N 1lambda4,2lambda4-dimolybdacyclopropa-1,2,3-triene Chemical compound [Mo]=C=[Mo] QIJNJJZPYXGIQM-UHFFFAOYSA-N 0.000 title claims abstract description 51
- 229910039444 MoC Inorganic materials 0.000 title claims abstract description 51
- 238000002360 preparation method Methods 0.000 title claims abstract description 33
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 57
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 54
- 229910052751 metal Inorganic materials 0.000 claims abstract description 36
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims abstract description 35
- 239000002184 metal Substances 0.000 claims abstract description 35
- 238000000034 method Methods 0.000 claims abstract description 29
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 29
- 239000000243 solution Substances 0.000 claims abstract description 29
- 239000011733 molybdenum Substances 0.000 claims abstract description 28
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims abstract description 26
- 239000012266 salt solution Substances 0.000 claims abstract description 26
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 22
- 238000001035 drying Methods 0.000 claims abstract description 21
- 150000003839 salts Chemical class 0.000 claims abstract description 21
- 239000002243 precursor Substances 0.000 claims abstract description 16
- 238000002156 mixing Methods 0.000 claims abstract description 13
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims abstract description 9
- 235000011114 ammonium hydroxide Nutrition 0.000 claims abstract description 9
- 230000032683 aging Effects 0.000 claims abstract description 7
- 238000001816 cooling Methods 0.000 claims abstract description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 7
- 238000007598 dipping method Methods 0.000 claims abstract description 4
- 239000007789 gas Substances 0.000 claims description 56
- 230000015572 biosynthetic process Effects 0.000 claims description 51
- 238000003786 synthesis reaction Methods 0.000 claims description 51
- 238000006243 chemical reaction Methods 0.000 claims description 37
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 28
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 14
- 229910052786 argon Inorganic materials 0.000 claims description 14
- VKYKSIONXSXAKP-UHFFFAOYSA-N hexamethylenetetramine Chemical compound C1N(C2)CN3CN1CN2C3 VKYKSIONXSXAKP-UHFFFAOYSA-N 0.000 claims description 14
- 239000002245 particle Substances 0.000 claims description 14
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 claims description 12
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 12
- 239000012018 catalyst precursor Substances 0.000 claims description 12
- 238000010438 heat treatment Methods 0.000 claims description 12
- 239000001301 oxygen Substances 0.000 claims description 12
- 229910052760 oxygen Inorganic materials 0.000 claims description 12
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 11
- 239000001257 hydrogen Substances 0.000 claims description 11
- 229910052739 hydrogen Inorganic materials 0.000 claims description 11
- 238000005470 impregnation Methods 0.000 claims description 11
- 229910010271 silicon carbide Inorganic materials 0.000 claims description 9
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 9
- 239000004312 hexamethylene tetramine Substances 0.000 claims description 7
- 235000010299 hexamethylene tetramine Nutrition 0.000 claims description 7
- 229910052757 nitrogen Inorganic materials 0.000 claims description 7
- 241000282326 Felis catus Species 0.000 claims description 5
- 238000001354 calcination Methods 0.000 claims description 5
- HJXIRCMNJLIHQR-UHFFFAOYSA-N 2-n,2-n-dimethylbenzene-1,2-diamine Chemical compound CN(C)C1=CC=CC=C1N HJXIRCMNJLIHQR-UHFFFAOYSA-N 0.000 claims description 3
- 238000011049 filling Methods 0.000 claims description 3
- -1 molybdenum ions Chemical class 0.000 claims description 3
- 238000002161 passivation Methods 0.000 claims description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 claims description 2
- QGAVSDVURUSLQK-UHFFFAOYSA-N ammonium heptamolybdate Chemical compound N.N.N.N.N.N.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.[Mo].[Mo].[Mo].[Mo].[Mo].[Mo].[Mo] QGAVSDVURUSLQK-UHFFFAOYSA-N 0.000 claims description 2
- 150000001868 cobalt Chemical class 0.000 claims description 2
- 230000002431 foraging effect Effects 0.000 claims description 2
- XAEFZNCEHLXOMS-UHFFFAOYSA-M potassium benzoate Chemical group [K+].[O-]C(=O)C1=CC=CC=C1 XAEFZNCEHLXOMS-UHFFFAOYSA-M 0.000 claims description 2
- 239000011684 sodium molybdate Substances 0.000 claims description 2
- 235000015393 sodium molybdate Nutrition 0.000 claims description 2
- TVXXNOYZHKPKGW-UHFFFAOYSA-N sodium molybdate (anhydrous) Chemical compound [Na+].[Na+].[O-][Mo]([O-])(=O)=O TVXXNOYZHKPKGW-UHFFFAOYSA-N 0.000 claims description 2
- 230000003197 catalytic effect Effects 0.000 abstract description 9
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 abstract description 8
- 230000008569 process Effects 0.000 abstract description 8
- 229910052700 potassium Inorganic materials 0.000 abstract description 5
- 229910052742 iron Inorganic materials 0.000 abstract description 4
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 abstract description 3
- 229910017052 cobalt Inorganic materials 0.000 abstract description 3
- 239000010941 cobalt Substances 0.000 abstract description 3
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 abstract description 3
- 239000006185 dispersion Substances 0.000 abstract description 3
- 239000011591 potassium Substances 0.000 abstract description 3
- 230000002195 synergetic effect Effects 0.000 abstract description 3
- 230000003213 activating effect Effects 0.000 abstract description 2
- 239000000463 material Substances 0.000 abstract description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 57
- 230000000052 comparative effect Effects 0.000 description 33
- 238000012360 testing method Methods 0.000 description 24
- 150000001298 alcohols Chemical class 0.000 description 17
- 238000011156 evaluation Methods 0.000 description 13
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 12
- 229910002091 carbon monoxide Inorganic materials 0.000 description 12
- 239000011148 porous material Substances 0.000 description 12
- 239000010453 quartz Substances 0.000 description 10
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 10
- 230000000694 effects Effects 0.000 description 9
- 239000000843 powder Substances 0.000 description 8
- 238000003756 stirring Methods 0.000 description 7
- 229910017116 Fe—Mo Inorganic materials 0.000 description 4
- UFMZWBIQTDUYBN-UHFFFAOYSA-N cobalt dinitrate Chemical compound [Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O UFMZWBIQTDUYBN-UHFFFAOYSA-N 0.000 description 4
- 229910001981 cobalt nitrate Inorganic materials 0.000 description 4
- 239000008367 deionised water Substances 0.000 description 4
- 229910021641 deionized water Inorganic materials 0.000 description 4
- 238000000227 grinding Methods 0.000 description 4
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 4
- 238000002791 soaking Methods 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid group Chemical group C(CC(O)(C(=O)O)CC(=O)O)(=O)O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 230000001976 improved effect Effects 0.000 description 3
- 239000012071 phase Substances 0.000 description 3
- PAYRUJLWNCNPSJ-UHFFFAOYSA-N Aniline Chemical compound NC1=CC=CC=C1 PAYRUJLWNCNPSJ-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- AFCARXCZXQIEQB-UHFFFAOYSA-N N-[3-oxo-3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(CCNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 AFCARXCZXQIEQB-UHFFFAOYSA-N 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 125000004432 carbon atom Chemical group C* 0.000 description 2
- 238000012512 characterization method Methods 0.000 description 2
- 239000003245 coal Substances 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- 238000004108 freeze drying Methods 0.000 description 2
- 238000011068 loading method Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229910000027 potassium carbonate Inorganic materials 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- ONDPHDOFVYQSGI-UHFFFAOYSA-N zinc nitrate Chemical group [Zn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ONDPHDOFVYQSGI-UHFFFAOYSA-N 0.000 description 2
- 239000002028 Biomass Substances 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 238000003763 carbonization Methods 0.000 description 1
- 238000010000 carbonizing Methods 0.000 description 1
- 238000004587 chromatography analysis Methods 0.000 description 1
- KYYSIVCCYWZZLR-UHFFFAOYSA-N cobalt(2+);dioxido(dioxo)molybdenum Chemical compound [Co+2].[O-][Mo]([O-])(=O)=O KYYSIVCCYWZZLR-UHFFFAOYSA-N 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- XTVVROIMIGLXTD-UHFFFAOYSA-N copper(II) nitrate Chemical group [Cu+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XTVVROIMIGLXTD-UHFFFAOYSA-N 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000002816 fuel additive Substances 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 238000005984 hydrogenation reaction Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 238000003760 magnetic stirring Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- MEFBJEMVZONFCJ-UHFFFAOYSA-N molybdate Chemical compound [O-][Mo]([O-])(=O)=O MEFBJEMVZONFCJ-UHFFFAOYSA-N 0.000 description 1
- KBJMLQFLOWQJNF-UHFFFAOYSA-N nickel(ii) nitrate Chemical group [Ni+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O KBJMLQFLOWQJNF-UHFFFAOYSA-N 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 239000012450 pharmaceutical intermediate Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 239000010948 rhodium Substances 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 238000005987 sulfurization reaction Methods 0.000 description 1
- 230000008093 supporting effect Effects 0.000 description 1
Classifications
-
- 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
- B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
- B01J27/20—Carbon compounds
- B01J27/22—Carbides
-
- 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
-
- 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
- B01J37/08—Heat treatment
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/15—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively
- C07C29/151—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively with hydrogen or hydrogen-containing gases
- C07C29/153—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively with hydrogen or hydrogen-containing gases characterised by the catalyst used
- C07C29/156—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively with hydrogen or hydrogen-containing gases characterised by the catalyst used containing iron group metals, platinum group metals or compounds thereof
-
- 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
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Catalysts (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention relates to the technical field of catalytic material preparation, and particularly discloses a supported molybdenum carbide catalyst, and a preparation method and application thereof. The preparation method comprises the following steps: dissolving a molybdenum source in ammonia water, adding an organic carbon source, and uniformly mixing to obtain a precursor solution; adding alumina into the precursor solution, dipping and drying to obtain dipped alumina; dissolving metal salt in water to obtain a metal salt solution; and adding the impregnated alumina into a metal salt solution, standing for ageing, drying, roasting, cooling and passivating to obtain the supported molybdenum carbide catalyst. The supported molybdenum carbide catalyst provided by the invention has the advantages that each active component in the carrier keeps a higher dispersion state, the binding force between the active component and the carrier is higher, the active component is not easy to run off in the catalytic process, the aim of preparing low-carbon alcohol by efficiently activating and converting synthetic gas under mild conditions is fulfilled by the synergistic effect of molybdenum carbide and a plurality of active components of potassium, iron or cobalt, the industrialized application prospect is high, and the practical value is higher.
Description
Technical Field
The invention relates to the technical field of catalytic material preparation, in particular to a supported molybdenum carbide catalyst and a preparation method and application thereof.
Background
Lower alcohols are generally defined as alcohols containing two or more carbon atoms, mainly monohydric alcohols having less than 6 carbon atoms, and are useful as fuel additives, lubricants or pharmaceutical intermediates, which have been receiving attention from researchers because of their high economic added value. It is especially notable that the low carbon alcohol has excellent performance and also has the characteristic of environmental friendliness. The synthesis gas extracted from coal, biomass, shale gas and carbon dioxide is used as raw materials to directly synthesize the low-carbon alcohol (HAS), so that the current situation of petroleum resource shortage can be relieved, and the synthesis gas is one of the most practical and feasible ways for realizing efficient and clean conversion of coal resources and HAS a very development prospect.
The selectivity of the synthesis gas reaction for the production of lower alcohols is largely dependent on the type of catalyst and the reaction conditions, and therefore, research on the catalyst is currently the focus of researchers. There are four main types of catalysts reported in the literature for the production of lower alcohols from synthesis gas, including copper-based catalysts, FT catalysts, rhodium-based catalysts and molybdenum-based catalysts. Wherein, the molybdenum-based catalyst has stable physical properties, good hydrogenation activity and unique anti-sulfuration performance. And researches show that the low-carbon alcohol selectivity of the molybdenum carbide catalyst is higher than that of other molybdenum-based catalysts, and the catalyst has the most development prospect in a low-carbon alcohol catalytic system prepared from synthesis gas.
The single molybdenum carbide has poor activity and selectivity when being applied to the synthesis gas to prepare the low-carbon alcohol, and various components are required to be added to modify the molybdenum carbide. However, the existing method for preparing the multi-component molybdenum carbide catalyst has poor dispersibility of each component and poor binding force among each component in the prepared catalyst, so that the activity and stability of the catalyst are poor, and the remarkable improvement of the activity of the catalyst is limited.
Disclosure of Invention
Aiming at the problems of low catalytic activity, low stability, complex preparation method and the like of the existing method for preparing the multi-component molybdenum carbide catalyst, the invention provides a supported molybdenum carbide catalyst, and a preparation method and application thereof. The specific carbon source is selected in the preparation process, and potassium, cobalt and/or iron are adopted to modify the molybdenum carbide, so that the prepared catalyst has excellent activity, selectivity and stability of preparing low-carbon alcohol from the synthetic gas, and has low preparation cost, simple operation and good practical application value.
In order to solve the technical problems, the technical scheme provided by the embodiment of the invention is as follows:
in a first aspect, the present invention provides a method for preparing a supported molybdenum carbide catalyst, comprising the steps of:
step a, dissolving a molybdenum source in ammonia water to obtain a molybdenum source solution; adding an organic carbon source into the molybdenum source solution, and uniformly mixing to obtain a precursor solution; wherein the organic carbon source is at least one of hexamethylenetetramine or N, N-dimethylbenzenediamine;
step b, adding alumina into the precursor solution, dipping and drying to obtain dipped alumina;
step c, dissolving metal salt in water to obtain a metal salt solution; adding the impregnated alumina into a metal salt solution, standing for aging, and drying to obtain a catalyst precursor; the metal salt comprises a first metal salt and a second metal salt, wherein the first metal salt is potassium salt, and the second metal salt is one or two of ferric salt and cobalt salt;
and d, crushing, roasting, cooling and passivating the catalyst precursor to obtain the supported molybdenum carbide catalyst.
Compared with the prior art, the preparation method of the supported molybdenum carbide catalyst provided by the invention adopts a step-by-step impregnation method, and the molybdenum source and a specific organic carbon source are complexed before the Mo source is loaded on the surface of the alumina, so that the uniform loading of Mo on the surface of the alumina is realized, the problem of Mo agglomeration on the surface of the alumina is avoided, and the mixing of Mo and the organic carbon source in a molecular level is also realized, thereby avoiding the problem of serious carbon accumulation on the surface of the catalyst caused by insufficient contact between the carbon source and the molybdenum source in the subsequent roasting process; meanwhile, after the complex impregnation of Mo and a specific carbon source is completed, the modified metal salt solution is impregnated, so that the problems of reduced catalyst activity, unstable catalyst activity and the like caused by the fact that by-products such as ferric molybdate or cobalt molybdate are generated by the reaction of Mo and the modified metal salt solution are avoided.
The preparation method provided by the invention can be used for preparing the multi-component uniformly-dispersed supported molybdenum carbide catalyst, the activity of the catalyst is obviously improved through the synergistic effect of a plurality of active centers of Mo, K, co or Fe, and the preparation method of the catalyst is simple, does not need high-temperature high-pressure conditions and the like, and is suitable for large-scale industrial preparation and application.
Preferably, in the step a, the molybdenum source is at least one of sodium molybdate, ammonium heptamolybdate or ammonium tetramolybdate.
Preferably, in the step a, the concentration of molybdenum ions in the molybdenum source solution is 0.1mol/L to 0.4mol/L.
Preferably, in the step a, the mass concentration of the ammonia water is 10% -15%.
Preferably, in the step a, the molar ratio of the organic carbon source to Mo in the molybdenum source is 7-10:1.
The optimized organic carbon source can be used as a carbon source for roasting and carbonizing to obtain carbon, and can complex Mo, so that the mixing degree of the molybdenum source and the carbon source is improved, the chelating effect is moderate, the side reaction of Mo and a modified salt solution during subsequent dipping of the modified metal salt solution can be avoided, the pure-phase molybdenum carbide is ensured, and the catalytic activity is remarkably improved.
Preferably, in step b, the alumina is impregnated with the precursor solution, which further comprises: calcining the alumina carrier at 450-600 ℃ for 3-5 h.
Further, in the step b, the particle diameter of the alumina carrier is 5 μm to 20 μm.
The specific surface area of the alumina can be increased by calcining the alumina before impregnating the alumina with the molybdenum source, and impurities in the alumina carrier can be removed, so that the loading of molybdenum and modified metal elements (such as K, fe or Co) can be increased.
Illustratively, in step a, in order to ensure that the organic carbon source and the molybdenum source solution are sufficiently mixed, the organic carbon source and the molybdenum source solution may be mixed by ultrasonic, heating or magnetic stirring.
Preferably, in step b, the molar ratio of alumina to Mo in the molybdenum source is 4-6:1.
Preferably, in the step b, the impregnation is ultrasonic impregnation, the impregnation temperature is 20-40 ℃, and the impregnation time is 1-2 h.
Illustratively, in the step b, the drying is performed by freeze drying, the drying temperature is-80 ℃ to 0 ℃, the vacuum degree is less than 48mTorr, and the drying time is 10h to 20h.
The preferred drying means is advantageous in maintaining the structural integrity and valence stability of the multiple components in the catalyst.
Preferably, in the step c, the molar ratio of the first metal salt to the second metal salt is 1:1.5-2.5 in terms of metal element; the concentration of the second metal salt in the metal salt solution is 1.1mol/L-1.8mol/L.
Preferably, in the step c, the volume-mass ratio of the metal salt solution to the alumina is 1:1.5-3.0, wherein the volume unit is milliliter and the mass unit is gram.
Preferably, in the step c, the temperature of standing and ageing is 20-40 ℃ and the time is 3-5 h.
Illustratively, in the step c, the drying is performed by freeze drying, the drying temperature is-80 ℃ to 0 ℃, the vacuum degree is less than 48mTorr, and the drying time is 10h to 20h.
Preferred impregnation conditions are favorable for uniformly supporting the modified metal on the alumina carrier, and the catalyst has excellent CO/H by selecting K, fe or Co and Mo to cooperate 2 Catalytic activity of synthesis gas to make lower alcohols.
Preferably, in the step d, the specific steps of roasting are as follows: heating to 500-600 ℃ at a speed of 3-5 ℃/min under the atmosphere of hydrogen and nitrogen, and preserving heat for 2-4 h; then, the temperature is raised to 600 ℃ to 800 ℃ at a speed of 1 to 2 ℃/min under the atmosphere of ethane and argon, and the temperature is kept for 4 to 10 hours.
Further preferably, the hydrogen and nitrogen are present in the calcination atmosphere in an amount of 10 to 35% by volume.
It is further preferable that the ethane and argon are contained in a firing atmosphere in which the ethane is contained in an amount of 5 to 15% by volume.
The preferred roasting process is beneficial to realizing full carbonization of molybdenum through control of multi-stage temperature and roasting atmosphere, so that the formed molybdenum carbide has better crystal form, and is also beneficial to keeping other active components in a higher dispersion state, avoiding loss of the active components, reducing aggregation of the molybdenum carbide, and further beneficial to improving the catalytic activity of the prepared catalyst.
Preferably, in the step d, the specific steps of passivation are as follows: passivating the cooled carrier for 4-8 h under the atmosphere of argon and oxygen.
Further preferably, the volume content of oxygen in the mixture of argon and oxygen is 1% -10%.
Further, the flow rate of the mixed gas in the roasting and passivation processes is 75-85 mL/min.
In a second aspect, the invention also provides a supported molybdenum carbide catalyst, which is prepared by the preparation method of the supported molybdenum carbide catalyst.
The invention provides the loaded carbonMolybdenum-carbide catalyst with excellent CO/H 2 The catalyst has the advantages of simple preparation process, wide raw material sources and low cost, and has wide application prospect in the field of preparing low-carbon alcohol from the synthetic gas.
In a third aspect, the invention also provides application of the supported molybdenum carbide catalyst in preparation of low-carbon alcohol from synthesis gas.
In a fourth aspect, the invention also provides a method for preparing low-carbon alcohol from synthesis gas, which comprises the following steps:
adding silicon carbide particles into the reactor catalyst bed layer from top to bottom, filling mixed particles of the supported molybdenum carbide catalyst and the silicon carbide particles in the middle layer, and introducing synthesis gas to react to obtain the low-carbon alcohol.
Preferably, the synthesis gas is H in a molar ratio of 1-2:1 2 And CO, the reaction temperature is 310-330 ℃, the reaction pressure is 3.0-3.5 MPa, and the airspeed is 3800 mL.g cat -1 ·h -1 -4200mL·g cat -1 ·h -1 。
Further, the particle size of the silicon carbide particles added on the upper and lower parts of the catalyst bed layer is 10-30 meshes.
Further, the particle size of the silicon carbide particles used in combination with the supported molybdenum carbide catalyst is 80-100 mesh.
Further, the volume of the 80-100 mesh silicon carbide particles is 3 times the mass of the supported molybdenum carbide catalyst, wherein the volume is in milliliters and the mass is in grams.
The supported molybdenum carbide catalyst provided by the invention has the advantages that each active component in the carrier keeps a higher dispersion state, the binding force between the active component and the carrier is higher, the active component is not easy to run off in the catalytic process, the aim of preparing low-carbon alcohol by efficiently activating and converting synthetic gas under mild conditions is fulfilled by the synergistic effect of molybdenum carbide and a plurality of active components of potassium, iron or cobalt, the industrialized application prospect is high, and the practical value is higher.
Drawings
FIG. 1 is KCo-Mo prepared in example 1 2 C/Al 2 O 3 XRD characterization of the catalyst;
FIG. 2 is KCo-Mo prepared in example 1 2 C/Al 2 O 3 The catalyst is used for evaluating data of preparing low-carbon alcohol from synthesis gas.
Detailed Description
The present invention will be described in further detail with reference to the following examples in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
In order to better illustrate the present invention, the following examples are provided for further illustration.
The alumina supports used in the following examples and comparative examples were each gamma-Al obtained by firing at 600℃for 4 hours 2 O 3 A carrier.
Example 1
The embodiment provides a preparation method of a supported molybdenum carbide catalyst, which comprises the following steps:
step one, 2.48g (NH) 4 ) 6 Mo 7 O 24 ·4H 2 Adding O into 40mL of 15% ammonia water solution, uniformly mixing, adding 17.72g of hexamethylenetetramine, and stirring and uniformly mixing to obtain a precursor solution;
step two, 6.0g of gamma-Al 2 O 3 Adding the carrier into the precursor solution, soaking for 1h at 30 ℃, and then drying for 20h at-20 ℃ under the vacuum degree of 48mTorr to obtain impregnated alumina;
step three, 1.68g Co (NO) 3 ) 2 ·6H 2 O and 0.23. 0.23g K 2 CO 3 Dissolving in 4mL of deionized water to obtain a mixed salt solution; dropwise adding the mixed salt solution onto the impregnated alumina sample, fully stirring in the process until the mixed salt solution is added completely, standing and aging for 5 hours at 30 ℃, and then drying for 20 hours at-20 ℃ under the vacuum degree of 48mTorr to obtain a catalyst precursor;
grinding the catalyst precursor into powder, placing the powder into a quartz boat, placing the quartz boat into a tube furnace, and heating the quartz boat to 500 ℃ at a speed of 4 ℃/min to ensure that the quartz boat is stableThe temperature is 3h, the protection gas at the stage is the mixed gas of hydrogen and nitrogen, the hydrogen content is 20%, and the flow is 80mL/min; then switching the shielding gas into a mixed gas of ethane and argon, wherein the content of ethane is 10 percent, the flow is 80mL/min, heating to 600 ℃ at the speed of 1 ℃/min, preserving heat for 5 hours, naturally cooling to room temperature, and then switching into a mixed gas of argon and oxygen, wherein the content of oxygen is 2 percent, the flow is 80mL/min, and the time lasts for 4 hours to obtain KCo-Mo 2 C/Al 2 O 3 A catalyst.
KCo-Mo prepared in this example 2 C/Al 2 O 3 The XRD characterization diagram of the catalyst is shown in figure 1, and according to the XRD diagram, the main phase of the catalyst is Al 2 O 3 、Mo 2 C and Co.
KCo-Mo prepared in this example 2 C/Al 2 O 3 The BET test results of the catalysts are shown in Table 1.
TABLE 1 KCo-Mo 2 C/Al 2 O 3 BET test results of catalyst
| Specific surface area (m) 2 ·g -1 ) | Pore volume V BJH (cm 3 ·g -1 ) | Aperture D (nm) |
| 106.2 | 0.78 | 29.3 |
KCo-Mo prepared in this example 2 C/Al 2 O 3 The catalyst is used for preparing low-carbon alcohol from synthesis gas:
both above and below the catalyst bedAdding 6mL of 15 mesh silicon carbide particles, taking 1g of KCo-Mo 2 C/Al 2 O 3 After the catalyst and 3mL of 80 mesh silicon carbide particles are uniformly mixed, filling the catalyst into the middle layer of the catalyst bed layer, installing a reaction tube, checking the air tightness of the device, and after the air tightness is qualified, introducing synthesis gas, wherein the reaction conditions are as follows: h 2 Co=2, temperature 320 ℃, pressure 3.0MPa, space velocity 4000ml·g cat -1 ·h -1 . The gas phase product was analyzed by on-line chromatography and the liquid phase product was analyzed by off-line gas chromatography.
The reaction was carried out under these conditions for 80 hours, and evaluation data of the catalyst was obtained. The carbon monoxide conversion was 63.6%, as shown in fig. 2, and it can be seen that the catalyst was excellent in stability during the reaction; the selectivity of the total alcohol was 67.6%, C 2+ The alcohol selectivity was 74.3% and the total alcohol space time yield was 364.2mg/g/h.
H for preparing low-carbon alcohol from the synthesis gas 2 The molar ratio to CO becomes 1, and the other conditions are unchanged. The reaction was carried out under these conditions for 80 hours, and evaluation data of the catalyst was obtained. Carbon monoxide conversion was 59.3%, total alcohol selectivity 64.2%, C 2+ The alcohol selectivity was 69.1% and the total alcohol space time yield was 308.7mg/g/h.
Example 2
The embodiment provides a preparation method of a supported molybdenum carbide catalyst, which comprises the following steps:
step one, 2.48g (NH) 4 ) 6 Mo 7 O 24 ·4H 2 Adding O into 100mL of ammonia water solution with the mass concentration of 13%, uniformly mixing, adding 14.15g of hexamethylenetetramine, and stirring and uniformly mixing to obtain a precursor solution;
step two, 7.5g of gamma-Al 2 O 3 Adding the carrier into the precursor solution, soaking for 2 hours at 20 ℃, and then drying for 20 hours at-15 ℃ under the vacuum degree of 48mTorr to obtain impregnated alumina;
step three, 2.05g Fe (NO) 3 ) 3 ·9H 2 O and 0.23. 0.23g K 2 CO 3 Dissolving in 4mL of deionized water to obtain a mixed salt solution; the mixed salt solution is completely dripped on the impregnated alumina sample and is fully used in the processStirring until the mixed salt solution is fully added, standing and aging for 5 hours at 20 ℃, and then drying for 20 hours at-15 ℃ under the vacuum degree of 48mTorr to obtain a catalyst precursor;
grinding the catalyst precursor to powder, placing the powder into a quartz boat, placing the quartz boat into a tube furnace, heating to 600 ℃ at a speed of 3 ℃/min, and preserving heat for 2 hours, wherein the shielding gas at the stage is a mixed gas of hydrogen and nitrogen, the hydrogen content is 20%, and the flow is 80mL/min; then switching the shielding gas into a mixed gas of ethane and argon, wherein the ethane content is 10 percent, the flow is 80mL/min, heating to 800 ℃ at the speed of 1 ℃/min, preserving heat for 5 hours, naturally cooling to room temperature, and then switching into a mixed gas of argon and oxygen, wherein the oxygen content is 2 percent, the flow is 80mL/min, and the duration is 4 hours, thus obtaining KFE-Mo 2 C/Al 2 O 3 A catalyst.
KFe-Mo prepared in this example 2 C/Al 2 O 3 The BET test results of the catalysts are shown in Table 2.
TABLE 2 KFE-Mo 2 C/Al 2 O 3 BET test results of catalyst
| Specific surface area (m) 2 ·g -1 ) | Pore volume V BJH (cm 3 ·g -1 ) | Aperture D (nm) |
| 98.3 | 0.37 | 16.1 |
KFe-Mo obtained in this example 2 C/Al 2 O 3 Catalyst for synthesis gasThe synthesis conditions for the preparation of lower alcohols were exactly the same as in example 1.
The reaction was carried out under these conditions for 80 hours, and evaluation data of the catalyst was obtained. The carbon monoxide conversion was 84.7%, the total alcohol selectivity was 58.6%, C 2+ The alcohol selectivity was 71.0% and the total alcohol space time yield was 325.2mg/g/h.
Example 3
The embodiment provides a preparation method of a supported molybdenum carbide catalyst, which comprises the following steps:
step one, 2.48g (NH) 4 ) 6 Mo 7 O 24 ·4H 2 Adding O into 60mL of ammonia water solution with the mass concentration of 12%, uniformly mixing, adding 19.12g of N, N-dimethylbenzenediamine, and stirring and uniformly mixing to obtain a precursor solution;
step two, 8.5g of gamma-Al 2 O 3 Adding the carrier into the precursor solution, soaking for 1h at 40 ℃, and then drying for 15h at-25 ℃ under the vacuum degree of 48mTorr to obtain impregnated alumina;
step three, 2.41g Co (NO) 3 ) 2 ·9H 2 O and 0.23. 0.23g K 2 CO 3 Dissolving in 4mL of deionized water to obtain a mixed salt solution; dropwise adding the mixed salt solution onto the impregnated alumina sample, fully stirring in the process until the mixed salt solution is added completely, standing and aging for 3 hours at 40 ℃, and then drying for 15 hours at-25 ℃ under the vacuum degree of 48mTorr to obtain a catalyst precursor;
grinding the catalyst precursor to powder, placing the powder into a quartz boat, placing the quartz boat into a tube furnace, heating to 600 ℃ at a speed of 5 ℃/min, and preserving heat for 2 hours, wherein the shielding gas at the stage is a mixed gas of hydrogen and nitrogen, the hydrogen content is 20%, and the flow is 80mL/min; then switching the shielding gas into a mixed gas of ethane and argon, wherein the content of ethane is 10 percent, the flow is 80mL/min, heating to 700 ℃ at the speed of 2 ℃/min, preserving heat for 4 hours, naturally cooling to room temperature, and then switching into a mixed gas of argon and oxygen, wherein the content of oxygen is 2 percent, the flow is 80mL/min, and the time lasts for 6 hours to obtain KCo-Mo 2 C/Al 2 O 3 A catalyst.
KCo-Mo prepared in this example 2 C/Al 2 O 3 The BET test results of the catalysts are shown in Table 3.
TABLE 3 KCo-Mo 2 C/Al 2 O 3 BET test results of catalyst
| Specific surface area (m) 2 ·g -1 ) | Pore volume V BJH (cm 3 ·g -1 ) | Aperture D (nm) |
| 108.6 | 0.61 | 22.6 |
KCo-Mo prepared in this example 2 C/Al 2 O 3 The catalyst was used for synthesis of lower alcohols from synthesis gas, and the synthesis conditions were exactly the same as in example 1.
The reaction was carried out under these conditions for 80 hours, and evaluation data of the catalyst was obtained. The carbon monoxide conversion was 59.5%, the total alcohol selectivity was 73.4%, C 2+ The alcohol selectivity was 68.3% and the total alcohol space time yield was 293.8mg/g/h.
Example 4
The embodiment provides a preparation method of a supported molybdenum carbide catalyst, which comprises the following steps:
step one, 2.48g (NH) 4 ) 6 Mo 7 O 24 ·4H 2 Adding O into 36mL of 10% ammonia water solution, uniformly mixing, adding 16.25g of hexamethylenetetramine, and stirring and uniformly mixing to obtain a precursor solution;
step two, 7.0g of gamma-Al 2 O 3 Carrier bodyAdding the precursor solution, soaking for 1h at 30 ℃, and then drying for 10h at-30 ℃ under the vacuum degree of 48mTorr to obtain impregnated alumina;
step three, 1.85g Co (NO) 3 ) 2 ·9H 2 O and 0.23. 0.23g K 2 CO 3 Dissolving in 4mL of deionized water to obtain a mixed salt solution; dropwise adding the mixed salt solution onto the impregnated alumina sample, fully stirring in the process until the mixed salt solution is added completely, standing and aging for 4 hours at 30 ℃, and then drying for 10 hours at-30 ℃ under the vacuum degree of 48mTorr to obtain a catalyst precursor;
grinding the catalyst precursor to powder, placing the powder into a quartz boat, placing the quartz boat into a tube furnace, heating to 600 ℃ at a speed of 3 ℃/min, and preserving heat for 3 hours, wherein the shielding gas at the stage is a mixed gas of hydrogen and nitrogen, the hydrogen content is 20%, and the flow is 80mL/min; then switching the shielding gas into a mixed gas of ethane and argon, wherein the content of ethane is 10 percent, the flow is 80mL/min, heating to 650 ℃ at the speed of 1 ℃/min, preserving heat for 7 hours, naturally cooling to room temperature, and then switching into a mixed gas of argon and oxygen, wherein the content of oxygen is 2 percent, the flow is 80mL/min, and the time lasts for 5 hours to obtain KCo-Mo 2 C/Al 2 O 3 A catalyst.
KCo-Mo prepared in this example 2 C/Al 2 O 3 The BET test results of the catalysts are shown in Table 4.
TABLE 4 KCo-Mo 2 C/Al 2 O 3 BET test results of catalyst
| Specific surface area (m) 2 ·g -1 ) | Pore volume V BJH (cm 3 ·g -1 ) | Aperture D (nm) |
| 103.8 | 0.77 | 29.8 |
KFe-Mo obtained in this example 2 C/Al 2 O 3 The catalyst was used for synthesis of lower alcohols from synthesis gas, and the synthesis conditions were exactly the same as in example 1.
The reaction was carried out under these conditions for 80 hours, and evaluation data of the catalyst was obtained. The carbon monoxide conversion was 60.9%, the total alcohol selectivity was 61.2%, C 2+ The alcohol selectivity was 73.5% and the total alcohol space time yield was 298.7mg/g/h.
Comparative example 1
This comparative example provides a method for preparing a supported molybdenum carbide catalyst, which is identical to example 1 in preparation steps except that cobalt nitrate in example 1 is replaced with copper nitrate in equimolar amount to obtain KCu-Mo 2 C/Al 2 O 3 A catalyst.
KCu-Mo prepared in this comparative example 2 C/Al 2 O 3 The BET test results of the catalysts are shown in Table 5.
TABLE 5 KCu-Mo 2 C/Al 2 O 3 BET test results of catalyst
| Specific surface area (m) 2 ·g -1 ) | Pore volume V BJH (cm 3 ·g -1 ) | Aperture D (nm) |
| 107.5 | 0.74 | 27.6 |
KCu-Mo prepared in this comparative example 2 C/Al 2 O 3 The catalyst was used for synthesis of lower alcohols from synthesis gas, and the synthesis conditions were exactly the same as in example 1.
The reaction was carried out under these conditions for 80 hours, and evaluation data of the catalyst was obtained. Carbon monoxide conversion 25.2%, total alcohol selectivity 53.4%, C 2+ The alcohol selectivity was 43.9% and the total alcohol space time yield was 201.5mg/g/h.
Comparative example 2
This comparative example provides a method for preparing a supported molybdenum carbide catalyst, which is identical to example 1 in preparation steps except that cobalt nitrate in example 1 is replaced with zinc nitrate in equimolar amount to obtain KZn-Mo 2 C/Al 2 O 3 A catalyst.
KZn-Mo prepared in this comparative example 2 C/Al 2 O 3 The BET test results of the catalysts are shown in Table 6.
TABLE 6 KZn-Mo 2 C/Al 2 O 3 BET test results of catalyst
| Specific surface area (m) 2 ·g -1 ) | Pore volume V BJH (cm 3 ·g -1 ) | Aperture D (nm) |
| 108.9 | 0.73 | 27.0 |
KZn-Mo prepared in this comparative example 2 C/Al 2 O 3 The catalyst was used for synthesis of lower alcohols from synthesis gas, and the synthesis conditions were exactly the same as in example 1.
The reaction was carried out under these conditions for 80 hours, and evaluation data of the catalyst was obtained. Carbon monoxide conversion was 18.6%, total alcohol selectivity was 42.9%, C 2+ The alcohol selectivity was 39.6% and the total alcohol space time yield was 183.4mg/g/h.
Comparative example 3
The comparative example provides a method for preparing a supported molybdenum carbide catalyst, which has the same preparation steps as those of example 2, except that potassium carbonate is not added to obtain Fe-Mo 2 C/Al 2 O 3 A catalyst.
Fe-Mo prepared in this comparative example 2 C/Al 2 O 3 The BET test results of the catalysts are shown in Table 7.
TABLE 7 Fe-Mo 2 C/Al 2 O 3 BET test results of catalyst
| Specific surface area (m) 2 ·g -1 ) | Pore volume V BJH (cm 3 ·g -1 ) | Aperture D (nm) |
| 102.9 | 0.44 | 17.2 |
Fe-Mo prepared in this comparative example 2 C/Al 2 O 3 Catalyst for synthesis gas productionThe synthesis conditions of the carbon alcohol were exactly the same as those of example 1.
The reaction was carried out under these conditions for 80 hours, and evaluation data of the catalyst was obtained. The conversion of carbon monoxide was 68.1%, the selectivity to total alcohol was 53.9%, C 2+ The alcohol selectivity was 42.6% and the total alcohol space time yield was 256.6mg/g/h.
Comparative example 4
The comparative example provides a method for preparing a supported molybdenum carbide catalyst, which has the same preparation steps as those of example 1, except that potassium carbonate is not added to obtain Co-Mo 2 C/Al 2 O 3 A catalyst.
Co-Mo prepared in this comparative example 2 C/Al 2 O 3 The BET test results of the catalysts are shown in Table 8.
TABLE 8 Co-Mo 2 C/Al 2 O 3 BET test results of catalyst
| Specific surface area (m) 2 ·g -1 ) | Pore volume V BJH (cm 3 ·g -1 ) | Aperture D (nm) |
| 111.0 | 0.72 | 26.0 |
Co-Mo prepared in this comparative example 2 C/Al 2 O 3 The catalyst was used for synthesis of lower alcohols from synthesis gas, and the synthesis conditions were exactly the same as in example 1.
The reaction was carried out under these conditions for 80 hours, and evaluation data of the catalyst was obtained. Conversion of carbon monoxide92.5% and total alcohol selectivity 45.3%, C 2+ The alcohol selectivity was 26.1% and the total alcohol space time yield was 167.6mg/g/h.
Comparative example 5
The comparative example provides a method for preparing a supported molybdenum carbide catalyst, which has the same preparation steps as those of the example 1, except that cobalt nitrate is not added to obtain K-Mo 2 C/Al 2 O 3 A catalyst.
K-Mo prepared in this comparative example 2 C/Al 2 O 3 The BET test results of the catalysts are shown in Table 9.
TABLE 9K-Mo 2 C/Al 2 O 3 BET test results of catalyst
| Specific surface area (m) 2 ·g -1 ) | Pore volume V BJH (cm 3 ·g -1 ) | Aperture D (nm) |
| 119.0 | 0.76 | 25.0 |
K-Mo prepared in this comparative example 2 C/Al 2 O 3 The catalyst was used for synthesis of lower alcohols from synthesis gas, and the synthesis conditions were exactly the same as in example 1.
The reaction was carried out under these conditions for 80 hours, and evaluation data of the catalyst was obtained. Carbon monoxide conversion 68.3%, total alcohol selectivity 58.6%, C 2+ The alcohol selectivity was 58.1% and the total alcohol space time yield was 284.2mg/g/h.
Comparative example 6
This comparative example provides a method for preparing a supported molybdenum carbide catalyst, which has the same preparation steps as example 1, except that cobalt nitrate of example 1 is replaced with nickel nitrate to obtain KNi-Mo 2 C/Al 2 O 3 A catalyst.
KNi-Mo prepared in this comparative example 2 C/Al 2 O 3 The BET test results of the catalysts are shown in Table 10.
TABLE 10 KNI-Mo 2 C/Al 2 O 3 BET test results of catalyst
| Specific surface area (m) 2 ·g -1 ) | Pore volume V BJH (cm 3 ·g -1 ) | Aperture D (nm) |
| 102.0 | 0.77 | 26.9 |
KNi-Mo prepared in this comparative example 2 C/Al 2 O 3 The catalyst was used for synthesis of lower alcohols from synthesis gas, and the synthesis conditions were exactly the same as in example 1.
The reaction was carried out under these conditions for 80 hours, and evaluation data of the catalyst was obtained. The conversion of carbon monoxide was 32.9%, the selectivity to total alcohols was 48.6%, C 2+ The alcohol selectivity was 38.1% and the total alcohol space time yield was 192.6mg/g/h.
Comparative example 7
This comparative example provides a method for preparing a supported molybdenum carbide catalyst, the preparation steps are exactly the same as in example 1,except that hexamethylenetetramine in example 1 was replaced with an equal proportion of aniline to give KCo-Mo 2 C/Al 2 O 3 A catalyst.
KCo-Mo prepared in this comparative example 2 C/Al 2 O 3 The BET test results of the catalysts are shown in Table 11.
TABLE 11 KCo-Mo 2 C/Al 2 O 3 BET test results of catalyst
| Specific surface area (m) 2 ·g -1 ) | Pore volume V BJH (cm 3 ·g -1 ) | Aperture D (nm) |
| 104.1 | 0.81 | 29.5 |
KCo-Mo prepared in this comparative example 2 C/Al 2 O 3 The catalyst was used for synthesis of lower alcohols from synthesis gas, and the synthesis conditions were exactly the same as in example 1.
The reaction was carried out under these conditions for 80 hours, and evaluation data of the catalyst was obtained. Carbon monoxide conversion was 42.9%, total alcohol selectivity was 51.1%, C 2+ The alcohol selectivity was 53.9% and the total alcohol space time yield was 245.3mg/g/h.
Comparative example 8
This comparative example provides a method for preparing a supported molybdenum carbide catalyst, which has the same preparation steps as in example 1, except that hexamethylenetetramine in example 1 is replaced with citric acid in equal proportion to obtain KCo-Mo 2 C/Al 2 O 3 A catalyst.
KCo-Mo prepared in this comparative example 2 C/Al 2 O 3 The BET test results of the catalysts are shown in Table 12.
TABLE 12 KCo-Mo 2 C/Al 2 O 3 BET test results of catalyst
| Specific surface area (m) 2 ·g -1 ) | Pore volume V BJH (cm 3 ·g -1 ) | Aperture D (nm) |
| 102.7 | 0.73 | 29.4 |
KCo-Mo prepared in this comparative example 2 C/Al 2 O 3 The catalyst was used for synthesis of lower alcohols from synthesis gas, and the synthesis conditions were exactly the same as in example 1.
The reaction was carried out under these conditions for 80 hours, and evaluation data of the catalyst was obtained. Carbon monoxide conversion was 20.3%, total alcohol selectivity was 36.8%, C 2+ The alcohol selectivity was 14% and the total alcohol space time yield was 103.3mg/g/h.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, or alternatives falling within the spirit and principles of the invention.
Claims (10)
1. The preparation method of the supported molybdenum carbide catalyst is characterized by comprising the following steps:
step a, dissolving a molybdenum source in ammonia water to obtain a molybdenum source solution; adding an organic carbon source into the molybdenum source solution, and uniformly mixing to obtain a precursor solution; wherein the organic carbon source is at least one of hexamethylenetetramine or N, N-dimethylbenzenediamine;
step b, adding alumina into the precursor solution, dipping and drying to obtain dipped alumina;
step c, dissolving metal salt in water to obtain a metal salt solution; adding the impregnated alumina into a metal salt solution, standing for aging, and drying to obtain a catalyst precursor; the metal salt comprises a first metal salt and a second metal salt, wherein the first metal salt is potassium salt, and the second metal salt is one or two of ferric salt and cobalt salt;
and d, crushing, roasting, cooling and passivating the catalyst precursor to obtain the supported molybdenum carbide catalyst.
2. The method for preparing a supported molybdenum carbide catalyst according to claim 1, wherein in step a, the molybdenum source is at least one of sodium molybdate, ammonium heptamolybdate or ammonium tetramolybdate; and/or
In the step a, the concentration of molybdenum ions in the molybdenum source solution is 0.1mol/L-0.4mol/L; and/or
In the step a, the mass concentration of the ammonia water is 10% -15%; and/or
In the step a, the molar ratio of the organic carbon source to Mo in the molybdenum source is 7-10:1.
3. The method of preparing a supported molybdenum carbide catalyst according to claim 1, wherein in step b, the alumina is impregnated with a precursor solution further comprising: calcining the alumina carrier at 450-600 ℃ for 3-5 h.
4. The method of preparing a supported molybdenum carbide catalyst according to claim 1 or 3, wherein in step b, the molar ratio of alumina to Mo in the molybdenum source is 4-6:1; and/or
In the step b, the impregnation is ultrasonic impregnation, the impregnation temperature is 20-40 ℃, and the impregnation time is 1-2 h.
5. The method for preparing a supported molybdenum carbide catalyst according to claim 1, wherein in the step c, the molar ratio of the first metal salt to the second metal salt is 1:1.5-2.5 in terms of metal element; the concentration of the second metal salt in the metal salt solution is 1.1mol/L-1.8mol/L; and/or
In the step c, the volume-mass ratio of the metal salt solution to the alumina is 1:1.5-3.0, wherein the volume unit is milliliter, and the mass unit is gram; and/or
In the step c, the temperature of standing and ageing is 20-40 ℃ and the time is 3-5 h.
6. The method for preparing a supported molybdenum carbide catalyst according to claim 1, wherein in the step d, the specific steps of calcining are: heating to 500-600 ℃ at a speed of 3-5 ℃/min under the atmosphere of hydrogen and nitrogen, and preserving heat for 2-4 h; then, under the atmosphere of ethane and argon, heating to 600-800 ℃ at a speed of 1-2 ℃/min, and preserving heat for 4-10 h; and/or
In the step d, the specific steps of passivation are as follows: passivating the cooled carrier for 4-8 h under the atmosphere of argon and oxygen.
7. A supported molybdenum carbide catalyst prepared by the method of any one of claims 1-6.
8. The use of the supported molybdenum carbide catalyst of claim 7 in the preparation of low carbon alcohols from synthesis gas.
9. The method for preparing the low-carbon alcohol from the synthesis gas is characterized by comprising the following steps of:
adding silicon carbide particles into the reactor catalyst bed up and down, filling mixed particles of the supported molybdenum carbide catalyst and the silicon carbide particles in the middle layer, and introducing synthesis gas to react to obtain the low-carbon alcohol.
10. The method for preparing low-carbon alcohol from synthesis gas according to claim 9, wherein the synthesis gas is H with a molar ratio of 1-2:1 2 And CO, the reaction temperature is 310-330 ℃, the reaction pressure is 3.0-3.5 MPa, and the airspeed is 3800 mL.g cat -1 ·h -1 -4200mL·g cat -1 ·h -1 。
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