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CN-122006728-A - Bimetallic composite catalyst for catalytic deoxidation of fatty acid and preparation method and application thereof

CN122006728ACN 122006728 ACN122006728 ACN 122006728ACN-122006728-A

Abstract

The invention discloses a bimetallic composite catalyst for catalytic deoxidation of fatty acid, and a preparation method and application thereof. The catalyst comprises a carrier, cu-Ce bimetallic loaded on the carrier and an in-situ carbon layer uniformly attached to the surface of a bimetallic element, wherein the carrier is a biomass carbon material, and the Cu-Ce bimetallic accounts for 1-8wt% of the total mass of the composite catalyst. The preparation process of the catalyst comprises the steps of dissolving soluble copper salt and soluble cerium salt in deionized water, adding a carrier under a stirring state, then fully soaking in a sealed shade to obtain a precursor, drying the precursor, and carbonizing in a reducing atmosphere. The catalyst is used for catalyzing and deoxidizing diesel oil grade hydrocarbon-rich fuel by fatty acid, can realize deep deoxidization of fatty acid in a low-hydrogen or no-hydrogen state, has a raw material conversion rate of 65%, a target product selectivity of more than 85%, and an activity retention rate of about 90% after multiple cycles, thereby fundamentally eliminating the cost and safety problems caused by hydrogen supply and high-pressure reaction.

Inventors

  • LIN BAINING
  • LIU RUKUAN
  • ZHANG AIHUA
  • XIAO ZHIHONG
  • LI YIYANG

Assignees

  • 湖南省林业科学院

Dates

Publication Date
20260512
Application Date
20260130

Claims (10)

  1. 1. A bimetallic composite catalyst for catalytic deoxidation of fatty acid is characterized by comprising a carrier, cu-Ce bimetallic loaded on the carrier and an in-situ carbon layer uniformly attached to the surface of a bimetallic element, wherein the carrier is a biomass carbon material, and the Cu-Ce bimetallic accounts for 1-8wt% of the total mass of the composite catalyst.
  2. 2. The bimetal composite catalyst for fatty acid catalytic deoxidation of claim 1, wherein the biomass carbon material is a shell and/or cake, and the molar ratio of Cu to Ce in the Cu-Ce bimetal is 1:0.5-2.
  3. 3. The bimetal composite catalyst for catalytic deoxygenation of fatty acid of claim 1, wherein the in-situ carbon layer is obtained by pyrolysis of biomass carbon material and has a thickness of 0.5-4 nm.
  4. 4. A preparation method of the bimetallic composite catalyst for catalytic deoxidation of fatty acid, as claimed in any one of claims 1-3, comprises the steps of dissolving soluble copper salt and soluble cerium salt in deionized water, adding a carrier in a stirring state, fully soaking in a sealed shade to obtain a precursor, drying the precursor, and carbonizing in a reducing atmosphere.
  5. 5. The preparation method of the bimetallic composite catalyst for fatty acid catalytic deoxygenation, which is disclosed in claim 4, comprises the steps that the soluble copper salt is at least one of copper chloride, copper nitrate and copper acetate, and the soluble cerium salt is at least one of cerium chloride, cerium nitrate and cerium acetate.
  6. 6. The method for preparing a bimetallic composite catalyst for catalytic deoxygenation of fatty acid, as set forth in claim 4, wherein the sufficient impregnation is performed by overdose impregnation, and the condition is that the carrier is completely impregnated in the solution, and the impregnation is performed for more than 10d in a sealed state at 15-25 ℃.
  7. 7. The preparation method of the bimetallic composite catalyst for fatty acid catalytic deoxygenation, which is disclosed in claim 4, comprises the following steps of stirring at a rotating speed of 100-300 r/min, and drying at 15-40 ℃ to constant weight under an inert atmosphere.
  8. 8. The preparation method of the bimetallic composite catalyst for catalytic deoxidation of fatty acid, which is disclosed in claim 4, comprises the steps of placing a precursor in a muffle furnace, introducing the reducing atmosphere to thoroughly replace air in the furnace, then heating the precursor to 180-200 ℃ from room temperature at 3-5 ℃ for 1-3 h, and then heating the precursor to 260-280 ℃ from normal temperature at 10-15 ℃ per min for 5-15 min, wherein the reducing atmosphere is a mixed gas of nitrogen and hydrogen, and the volume ratio of the nitrogen to the hydrogen is 80-98:2-20.
  9. 9. The application of the bimetallic composite catalyst for catalytic deoxygenation of fatty acid, which is disclosed in any one of claims 1-3, is characterized in that the bimetallic composite catalyst is used for preparing diesel-grade hydrocarbon-rich fuel through catalytic deoxygenation of fatty acid.
  10. 10. The application of the bimetallic composite catalyst for catalytic deoxygenation of fatty acid, which is disclosed in claim 9, is characterized in that the process of preparing diesel-grade hydrocarbon-rich fuel by catalytic deoxygenation of fatty acid comprises the steps of adding 3-10wt% of catalyst, reacting at 400-420 ℃ under normal pressure of protective atmosphere, and reacting for 1-2 h.

Description

Bimetallic composite catalyst for catalytic deoxidation of fatty acid and preparation method and application thereof Technical Field The invention relates to a fatty acid deoxidizing catalyst, in particular to a bimetal composite catalyst for fatty acid catalytic deoxidization, and a preparation method and application thereof, and belongs to the technical field of biological fuels. Background Fatty acid catalytic deoxygenation is the core process of biomass grease to petroleum-like based hydrocarbon fuels. At present, the most intuitive reaction paths are mainly two process systems of hydrodeoxygenation and non-hydrodeoxygenation. Wherein, the hydrodeoxygenation process generally adopts noble metal, cobalt molybdenum or nickel-based sulfide catalyst, operates under high-temperature and high-pressure hydrogen environment, and realizes deoxygenation by hydrocracking fatty acid molecules. Although the technology can realize higher conversion rate, the hydrogen consumption accounts for 30-50% of the total production cost, and the high-pressure reactor greatly increases equipment investment and safety risks. Although the non-hydrodeoxygenation route avoids hydrogen dependence, the non-hydrodeoxygenation route is limited by the performance of catalyst materials, particularly the transition metal oxide is easy to sinter and deactivate in the reaction, and has the bottleneck of poor sulfur resistance and the like, and the problems of permanent poisoning failure and the like caused by trace sulfur impurities. More serious, if the pore channel structure of the traditional catalyst carrier (such as molecular sieve, alumina and silicon carbide) is unreasonable in design, the diffusion resistance of fatty acid molecules is easily increased, the reaction can be completed in 4-6 hours, and the selectivity of the target product of diesel-grade hydrocarbon-rich fuel (C 15-C18) is low. In addition, under the high-temperature operating environment, the metal active sites are rapidly deactivated due to sintering agglomeration, and the fatty acid deoxidization process is accompanied by severe coking tendency, so that the active sites are covered and carrier pore channels are blocked, the stability and the service life of the catalyst are greatly reduced, and the continuous production and the economy of industrial devices are seriously restricted. These drawbacks together lead to difficulties in balancing activity, cost and sustainability in the prior art, impeding the large-scale industrialization of biofuels. In summary, the problems in the prior art are mainly that 1, high activity metal (such as noble metal) and cost efficiency are not compatible, 2, reaction kinetic efficiency is limited by mass transfer obstruction and side reaction runaway, and 3, the catalyst structure lacks a long-acting stabilizing mechanism in a high-temperature reducing environment, so that the prior art needs a catalytic deoxidizing catalyst with high catalytic activity, long catalytic life and low price so as to meet the industrialization requirement of preparing biomass fuel by fatty acid deoxidization. Disclosure of Invention Aiming at the problems existing in the prior art, the first object of the invention is to provide a bimetallic composite catalyst for catalytic deoxidation of fatty acid. The catalyst is based on the active site of Cu-Ce bimetal, and utilizes a cell wall chamber in a biomass carbon material as a micro-channel reactor, so that the deep deoxidation of fatty acid is realized and the isomerization and cyclization selectivity of the catalyst is greatly improved on the premise of greatly improving the dispersibility, stability and catalytic activity of the catalyst. The second purpose of the invention is to provide a preparation method of the bimetallic composite catalyst for catalytic deoxidation of fatty acid. The method adopts a long-time impregnation period to enable the Cu-Ce bimetallic system to deeply permeate into the multistage pore canal of the carrier, and adopts a low-temperature and high-temperature two-stage carbonization process under a reducing atmosphere, so that the high dispersion and the space limitation of the Cu-Ce bimetallic system are realized while the collapse of the pore canal of the carrier is avoided, and the structural stability and the catalytic activity of the catalyst are further effectively improved. The third purpose of the invention is to provide an application of the bimetallic composite catalyst for catalytic deoxidation of fatty acid, which is used for preparing diesel-grade hydrocarbon-rich fuel by catalytic deoxidation of fatty acid. Based on the characteristics of the catalyst, the deep deoxidization of fatty acid can be realized in a low-hydrogen or hydrogen-free state in the process of preparing diesel-grade hydrocarbon-rich fuel by using the catalyst in fatty acid catalytic deoxidization, and the deoxidization conversion rate of fatty acid of more than or equal to 65% can be realized in