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CN-122006730-A - High-activity high-selectivity methanol cracking catalyst and preparation method thereof

CN122006730ACN 122006730 ACN122006730 ACN 122006730ACN-122006730-A

Abstract

The invention belongs to the technical field of synthetic gas chemical industry and catalytic materials, and particularly relates to a copper-based catalyst for preparing hydrogen by methanol pyrolysis and a preparation method thereof. The catalyst comprises a catalyst metal active component, an auxiliary agent and a catalyst carrier, wherein the metal active component is copper, and can be one of copper nitrate/copper carbonate/copper sulfate, and the content is 70-88%. Compared with the prior art, the catalyst provided by the invention provides a strong Lewis acid site, can promote migration and deep dehydrogenation of a methoxy intermediate of methanol dehydrogenation on the surface of Cu metal, remarkably improves the selectivity of main products CO and H 2 , and reduces the selectivity of intermediate products dimethyl ether and methyl formate.

Inventors

  • SHI YULIN
  • LI YANG
  • TAN LI
  • ZHANG HAORAN
  • JIA HAOYANG
  • CHENG XUEBIN
  • ZHANG YU
  • ZHANG LEI

Assignees

  • 浙江思欣通氢能科技有限公司

Dates

Publication Date
20260512
Application Date
20251223

Claims (6)

  1. 1. The high-activity high-selectivity methanol cracking catalyst is characterized by comprising a catalyst metal active component, an auxiliary agent and a catalyst carrier; wherein the metal active component is copper, which can be one of copper nitrate/copper carbonate/copper sulfate, and the content is 70-88%; Wherein the catalyst carrier is SiO 2 , and the Si source content is 1-5%; Wherein the auxiliary agent is at least one of chromium, magnesium and barium, and the content is 1-25%.
  2. 2. The catalyst according to claim 1, wherein the specific surface area of the catalyst is 69-97m 2 /g, the pore volume is 0.49-0.68cm 3 /g, and the pore diameter is 13-26nm.
  3. 3. The catalyst of claim 1, wherein the Si source is one of sodium silicate, potassium silicate, silica sol and diatomaceous earth in an amount of 1% -5%.
  4. 4. A process for preparing the catalyst of any one of claims 1 to 3, comprising the steps of: (1) Weighing Cu 2+ metal salt solution with corresponding mass to prepare salt solution a; (2) Weighing Cr 3+ metal salt solution with corresponding mass to prepare salt solution b, wherein the chromium metal salt is one of chromium nitrate and chromium sulfate, (3) Dissolving a precipitant in water to prepare an alkali solution 1, wherein the precipitant is one of sodium carbonate, sodium bicarbonate and sodium hydroxide; (4) Adding water into a silicon source and a precipitator with corresponding mass for dissolution, and performing ultrasonic treatment to obtain an alkali solution 2 containing silicon; (5) Weighing barium metal salt with corresponding mass, and dissolving to obtain barium metal salt solution 3; (6) Emulsifying and mixing the salt solution a and the alkali solution 2 under a high-speed shearing machine, wherein the shearing speed is 10000-15000r/min, continuously controlling the PH by using the alkali solution 1 after the dripping of the alkali solution 2 is finished, controlling the precipitation condition PH=5-8, and the precipitation temperature is 70-90 ℃ to obtain a precipitate A; (7) At the same time, the salt solution B and the alkali solution 2 are emulsified and mixed under a high-speed shearing machine, the shearing speed is 10000-15000r/min, after the alkali solution 2 is dripped, the alkali solution 1 is used for continuously controlling the PH, the precipitation condition PH=6-10 is controlled, the precipitation temperature is 65-85 ℃, and the precipitate B is obtained; (8) Allowing the slurry of the precipitate A and the slurry of the precipitate B to flow into a reaction kettle in parallel to obtain a precipitate C, dropwise adding an alkali solution 1 to adjust the pH value to 6-9, precipitating at 60-90 ℃, stirring at 200-300r/min, and standing for aging for 4-8h; (9) Drying, namely drying the washed sample at 60-90 ℃ for 12 hours; (10) Soaking, namely adding the barium metal salt solution 3 into the dried powdery catalyst, uniformly mixing, sealing and aging for 2-6 hours, and drying at 90 ℃ for 8 hours; (11) Roasting, namely placing the mixture in a high-temperature furnace, heating the mixture to 250-550 ℃ from room temperature, roasting the mixture for 4-8 hours at constant temperature, cooling the mixture to room temperature to obtain a roasting product, uniformly mixing the roasting product and graphite to obtain a mixture, and tabletting the mixture to form the catalyst.
  5. 5. The method of claim 4, wherein the barium metal salt is one of barium nitrate/barium chloride/barium hydroxide/barium carbonate, and the content is less than 8%.
  6. 6. The method according to claim 4, wherein the mass ratio of Cu/Cr in the salt solution a and the salt solution b is 6.9-10.9.

Description

High-activity high-selectivity methanol cracking catalyst and preparation method thereof Technical Field The invention belongs to the technical field of synthetic gas chemical industry and catalytic materials, and particularly relates to a copper-based catalyst for preparing hydrogen by methanol pyrolysis and a preparation method thereof. Background Hydrogen energy is a high-efficiency renewable clean energy source with high specific heat capacity, but serious potential safety hazards exist in hydrogen storage and transportation. Means for producing hydrogen from liquid fuels that are stable and easy to transport have been developed. Methanol is a promising liquid organic hydrogen carrier, is safe and cheap, has high hydrogen-carbon ratio, can be hydrogenated by using carbon dioxide to produce methanol, the methanol produced can be transferred to a place needing hydrogen, and the carbon dioxide can be hydrogenated for the next time, thereby realizing the feasible transportation and utilization of hydrogen. In the hydrogen production of methanol, the copper-based catalyst has the advantages of higher catalytic activity, simple preparation process, low price, easy realization of industrialization and the like, and the commercial Cu/ZnO/Al 2O3 catalyst has the problems of low activity, easy carbon deposition and sintering and the like at present, and the dimethyl ether, methyl formate and the like in methanol pyrolysis byproducts have high ratio, so that the reaction device is very easy to block. For this reason, preparing Cu-based catalysts with high activity and low by-products becomes a great challenge for current Cu-based catalysts. Disclosure of Invention The invention aims to solve the technical problem of providing a catalyst which can obviously improve the catalytic performance of the catalyst, has better catalytic activity, H 2 and CO selectivity and lower ether and ester selectivity, and can meet the requirement of large-scale methanol hydrogen production. A high-activity high-selectivity methanol cracking catalyst comprises a catalyst metal active component, an auxiliary agent and a catalyst carrier; wherein the metal active component is copper, which can be one of copper nitrate/copper carbonate/copper sulfate, and the content is 70-88%; Wherein the catalyst carrier is SiO 2, and the Si source content is 1-5%; Wherein the auxiliary agent is at least one of chromium, magnesium and barium, and the content is 1-25%. Further, the specific surface area of the catalyst is 69-97m 2/g, the pore volume is 0.49-0.68cm 3/g, and the pore diameter is 13-26nm. Further, the Si source is one of sodium silicate, potassium silicate, silica sol and diatomite, and the content is 1% -5%. In order to achieve the above object, the present invention further provides a method for preparing a high activity and high selectivity methanol cracking catalyst, wherein the method comprises the steps of: (1) Weighing Cu 2+ metal salt solution with corresponding mass to prepare salt solution a; (2) And weighing Cr 3+ metal salt solution with corresponding mass to prepare a salt solution b, wherein the chromium metal salt is one of chromium nitrate and chromium sulfate, the mass ratio of Cu/Cr in the salt solution a and the salt solution b is 6.9-10.9, and when the mass ratio of Cu/Cr is controlled within a corresponding range, cu at a Cu-Cr 2O3 interface promotes the initial activation decomposition of methanol, so that the selectivity of H 2 and CO is greatly improved, and the generation of byproducts such as methane, dimethyl ether and the like is inhibited. (3) Dissolving a precipitant in water to prepare an alkali solution 1, wherein the precipitant is one of sodium carbonate, sodium bicarbonate and sodium hydroxide; (4) Adding water into corresponding amounts of silicon source and precipitant to dissolve, and performing ultrasonic treatment to obtain an alkali solution 2 containing silicon; (5) And weighing barium metal salt with corresponding mass, and dissolving to obtain barium metal salt solution 3, wherein the barium metal salt is one of barium nitrate/barium chloride/barium hydroxide/barium carbonate, and the content is less than 8%. (6) Emulsifying and mixing the salt solution a and the alkali solution 2 under a high-speed shearing machine, wherein the shearing speed is 10000-15000r/min, continuously controlling the PH by using the alkali solution 1 after the dripping of the alkali solution 2 is finished, controlling the precipitation condition PH=5-8, and the precipitation temperature is 70-90 ℃ to obtain a precipitate A; (7) At the same time, the salt solution B and the alkali solution 2 are emulsified and mixed under a high-speed shearing machine, the shearing speed is 10000-15000r/min, after the dripping of the alkali solution 2 is finished, the alkali solution 1 is used for continuously controlling the PH=6-10, the precipitation temperature is 65-85 ℃, and the precipitate B is obtained; (8) Allowing the slurry of th