Search

CN-121972169-A - Copper-zinc catalyst, preparation method thereof and application thereof in preparing ethanol by methyl acetate hydrogenation

CN121972169ACN 121972169 ACN121972169 ACN 121972169ACN-121972169-A

Abstract

The application discloses a copper-zinc catalyst, a preparation method thereof and application thereof in preparing ethanol by methyl acetate hydrogenation. The method comprises the steps of (1) mixing water, a silicon source, an aluminum source and alkali, stirring I, crystallizing in a closed container to obtain a solution A, (2) mixing the solution A and the alkali solution, stirring II to obtain a solution B, (3) mixing water, a copper source, a zinc source and an auxiliary agent source to obtain a solution C, and (4) mixing the solution B and the solution C, controlling the pH value to be 6.5-9.5, aging, washing, drying and roasting to obtain the copper-zinc catalyst. And (3) carrying out hydrogen reduction on the copper-zinc catalyst, and carrying out hydrogenation reaction. The catalyst prepared by the preparation method provided by the application has the advantages of increased specific surface area, smaller Cu particle size of an active species, contribution to improving the thermal stability of the catalyst, obviously improved catalytic activity and higher methyl acetate conversion rate and ethanol selectivity.

Inventors

  • LV XINXIN
  • PEI RENYAN
  • YU WEICHEN
  • XU SHANGJUN
  • LI XUDONG
  • SONG ZHIJIA
  • WANG HUI

Assignees

  • 延长中科（大连）能源科技股份有限公司

Dates

Publication Date
20260505
Application Date
20251204

Claims (10)

  1. 1. The preparation method of the copper-zinc catalyst is characterized by comprising the following steps of: (1) Mixing water, a silicon source, an aluminum source and alkali, stirring the mixture I, and crystallizing the mixture in a closed container to obtain a solution A; (2) Mixing the solution A with an alkali solution, and stirring the solution II to obtain a solution B; (3) Mixing water, a copper source, a zinc source and an auxiliary agent source to obtain a solution C; (4) Mixing the solution B and the solution C, controlling the pH value to be 6.5-9.5, aging, washing, drying to obtain a catalyst precursor, and roasting to obtain the copper-zinc catalyst.
  2. 2. The method according to claim 1, wherein in the step (1), the silicon source is at least one selected from the group consisting of silica sol, methyl orthosilicate, ethyl orthosilicate, sodium silicate, and diatomaceous earth; the aluminum source is at least one selected from sodium aluminate, aluminum isopropoxide, aluminum hydroxide, aluminum sol and pseudo-boehmite; the alkali is at least one selected from sodium carbonate, sodium bicarbonate, ammonium carbonate, sodium hydroxide, potassium hydroxide, ammonia water and the like.
  3. 3. The method according to claim 1, wherein in the step (1), the molar ratio of the silicon source to the aluminum source in the solution a is SiO 2 :Al 2 O 3 =100:1-5; The molar ratio of the silicon source to the alkali is SiO 2 :M 2 O=100:3-6; The molar ratio of the silicon source to water is SiO 2 :H 2 O=1:15-40; Wherein the number of moles of the silicon source is calculated as the number of moles of SiO 2 contained in the silicon source, the number of moles of the aluminum source is calculated as the number of moles of Al 2 O 3 contained in the aluminum source, and the number of moles of the base is calculated as M 2 O contained in the base.
  4. 4. The method of claim 1, wherein in step (3), the copper source is selected from at least one of nitrate, sulfate, carbonate, chloride, acetate of copper; The zinc source is selected from at least one of nitrate, sulfate, carbonate, chloride and acetate of zinc; The auxiliary source is selected from at least one of nitrate, carbonate and chloride corresponding to auxiliary elements; the auxiliary element is at least one selected from calcium, nickel, barium, iron, molybdenum, aluminum, cerium, chromium, palladium, magnesium and manganese.
  5. 5. The method according to claim 1, wherein in the step (1), the crystallization temperature is 40 to 150 ℃; the crystallization time is 2-240 h; preferably, in the step (1), the stirring time is 20-240 min.
  6. 6. The method according to claim 1, wherein in the step (3), the aging temperature is 20 ℃ to 100 ℃; The aging time is 0-300 min; Preferably, in the step (3), the temperature of the drying is 20 ℃ to 200 ℃; the drying time is 0-30 h; The roasting temperature is 200-600 ℃; the roasting time is 0-10 h; The temperature rising rate of the roasting is 0.01-30 ℃ per minute.
  7. 7. The method of claim 1, wherein in step (4), a lamellar structure crystalline phase is present in the catalyst precursor.
  8. 8. The copper-zinc catalyst prepared by the preparation method according to any one of claims 1 to 7, wherein the mass ratio of CuO to ZnO in the copper-zinc catalyst is 1:0.01 to 5; in the copper-zinc catalyst, the auxiliary element accounts for 0.1-10wt% of the mass of the catalyst based on the mass of the oxide; Preferably, the specific surface area of the copper-zinc catalyst is 50-150 m 2 /g, the pore diameter is 5-50 nm, the pore volume is 0.2-1.0 mL/g, the crystallite size of CuO is 1.0-8.0 nm, and the crystallite size of ZnO is 1.0-8.0 nm.
  9. 9. A method for preparing ethanol by hydrogenating methyl acetate is characterized by comprising the following steps of carrying out hydrogen reduction treatment on the copper-zinc catalyst according to claim 8; And (3) contacting the raw material gas containing methyl acetate and hydrogen with the copper-zinc catalyst after reduction treatment, and reacting to obtain the ethanol.
  10. 10. The method of claim 9, wherein the hydrogen reduction temperature is 20 ℃ to 400 ℃; The temperature rising rate of the hydrogen reduction is 0.01-30 ℃ per minute; the hydrogen reduction time is 0.01-300 min; preferably, the molar ratio of the methyl acetate to the hydrogen is 1:2-50, the mass airspeed of the methyl acetate is 0.2-10 h -1 , the reaction temperature is 100-600 ℃, and the reaction pressure is 1-10 MPa.

Description

Copper-zinc catalyst, preparation method thereof and application thereof in preparing ethanol by methyl acetate hydrogenation Technical Field The application relates to a copper-zinc catalyst, a preparation method thereof and application thereof in preparing ethanol by hydrogenating methyl acetate, belonging to the field of catalysts. Background Ethanol is an important industrial chemical, has wide application in a plurality of industrial fields such as chemical industry, medicine, material science and the like by virtue of the unique chemical and physical properties, and plays an irreplaceable key role. At present, the production of ethanol mainly depends on two traditional technical routes of biomass fermentation and chemical synthesis. Among them, the biomass fermentation technology is relatively mature, but it uses grain crops as main raw materials, resulting in a series of significant problems. From economic analysis, the comprehensive cost generated in links such as raw material purchase, processing loss and supply chain management is high, so that the overall economy of the process route is at a low level, and continuous pressure is formed for related production enterprises. In contrast, methyl acetate hydrogenation to ethanol technology provides a new path to address the challenges described above. The process effectively avoids dependence on grain raw materials through a catalytic hydrogenation process, and reduces production cost from the source. Meanwhile, by virtue of a high-selectivity reaction mechanism and optimized process conditions, the technology can realize efficient synthesis of the ethanol and improve the purity and quality of the product. Because of these significant advantages, the technology of preparing ethanol by hydrogenating methyl acetate has recently received extensive attention from academia and industry, and is a new strategy for synthesizing ethanol with important development potential. With the deep and continuous progress of related basic research and engineering application technology, the process route is expected to realize large-scale industrial application in the future, and plays an important role in the ethanol production technology pattern, so that the ethanol industry is promoted to develop towards more green, efficient and sustainable directions. In an acetate hydrogenation reaction system, carbon deposition caused by sintering of active components of a catalyst and side reaction is a key factor influencing the performance and service life of the catalyst. Firstly, the active component copper particles are easy to migrate and aggregate in the reaction process. Under the drive of energy, the brownian motion of copper atoms is exacerbated, resulting in particles approaching and fusing with each other, forming larger sized particles. The process accords with the basic principle of molecular dynamics, and as a result, the specific surface area of the catalyst is obviously reduced, and the pore channel structure collapses and narrows. Especially under the high temperature condition, the thermal motion kinetic energy of copper and auxiliary metal particles is increased, the collision frequency and the effective collision probability are increased, and the agglomeration and growth of the particles are further enhanced. Secondly, while the main reaction is carried out, various side reactions occur in the system. From the organic reaction mechanism perspective, the reactant molecules are subjected to nonselective adsorption and activation on the active sites, and unsaturated hydrocarbon intermediates can be generated through cracking. Such species are highly reactive and readily form carbonaceous polymers on the catalyst surface by free radical polymerization or condensation mechanisms and gradually deposit as soot. The above phenomena can lead to the coverage of active sites or the destruction of the structure, the reduction of the number of active sites, the drastic reduction of catalytic performance, the final deactivation of the catalyst and the significant shortening of the service life thereof. From the industrial application point of view, the reduction of the catalyst life not only increases the purchasing and replacing costs, but also adversely affects the process continuity and the operation stability, thereby increasing the running cost and the production risk. To solve this problem, we have focused on developing a new catalyst preparation strategy. The method is based on the systematic understanding of the interaction among the active components, the auxiliary agent and the carrier, and by accurately regulating and controlling the composition and the microstructure of the catalyst, the sintering resistance and the carbon deposition resistance of the catalyst under the severe reaction condition are improved, the service life is prolonged, and the support is provided for the efficient and stable operation of the process for preparing ethanol by hydrogenating th