CN-122006743-A - Selective hydrogenation catalyst and preparation method and application thereof

Abstract

The invention discloses a selective hydrogenation catalyst, a preparation method and application thereof. The selective hydrogenation catalyst comprises a carrier and an active component loaded on the carrier, wherein the carrier is a metal composite oxide modified by organic cationic quaternary ammonium salt and silane reagents, the organic cationic quaternary ammonium salt is at least one of long-chain alkyl quaternary ammonium salts with more than 6, the silane reagents are at least one of alkoxy silanes with more than 1 to 4, the active component comprises a main active component and an optional auxiliary active component, the main active component comprises Cu, and the auxiliary active component is one or more of Au, ag and Ru. The selective hydrogenation catalyst has higher crushing strength, higher selectivity and low-temperature reaction activity, and stable hydrogenation activity, can be used for removing the impurity alkyne and the diene through the selective hydrogenation of the low-carbon olefin, and can be used for a long period.

Inventors

• LIU YANHUI
• DU ZHOU
• YANG GUANG
• ZHANG FUCHUN
• REN YUMEI
• DONG LIXIA

Assignees

• 中国石油化工股份有限公司
• 中石化(北京)化工研究院有限公司

Dates

Publication Date

20260512

Application Date

20241111

Claims (16)

1. 1. A selective hydrogenation catalyst is characterized by comprising a carrier and an active component loaded on the carrier, wherein the carrier is a metal composite oxide modified by organic cation quaternary ammonium salt and silane reagent, the organic cation quaternary ammonium salt is at least one of long-chain alkyl quaternary ammonium salt with more than 6, the silane reagent is at least one of alkoxy silane with 1-4 carbon atoms, the active component comprises a main active component and an optional auxiliary active component, the main active component comprises Cu, and the auxiliary active component is one or more of Au, ag and Ru.
2. 2. The selective hydrogenation catalyst according to claim 1, wherein the organic cationic quaternary ammonium salt is selected from at least one of dioctadecyl dimethyl quaternary ammonium salt, cetyl trimethyl quaternary ammonium salt and C12-18 alkyl dimethyl benzyl quaternary ammonium salt, preferably the organic cationic quaternary ammonium salt is selected from at least one of dioctadecyl dimethyl ammonium chloride, cetyl trimethyl ammonium bromide, dodecyl dimethyl benzyl ammonium chloride, tetradecyl dimethyl benzyl ammonium chloride, cetyl dimethyl benzyl ammonium chloride and octadecyl dimethyl benzyl ammonium chloride; and/or the silane-based reagent is selected from at least one of triethoxysilane, trimethoxysilane, methyltriethoxysilane, methyltrimethoxysilane and vinyltrimethylsiloxane, preferably the silane-based reagent is selected from triethoxysilane and/or trimethoxysilane.
3. 3. The selective hydrogenation catalyst according to claim 1 or 2, wherein the mass ratio of the metal composite oxide to the organic cationic quaternary ammonium salt is 1:0.01-1; And/or the mass ratio of the metal composite oxide to the silane reagent is 1:0.01-1.
4. 4. The selective hydrogenation catalyst of any one of claims 1-3, wherein the metal composite oxide comprises Al 2 O 3 and TiO 2 ; Preferably, the metal composite oxide includes 5 to 25 parts of TiO 2 and 75 to 95 parts of Al 2 O 3 in parts by weight.
5. 5. The selective hydrogenation catalyst according to any one of claims 1-4, wherein the specific surface area of the support is 30-150m 2 /g, preferably 50-90m 2 /g; and/or the pore volume of the carrier is 0.2-0.8mL/g, preferably 0.3-0.4mL/g.
6. 6. The selective hydrogenation catalyst according to any one of claims 1 to 5, wherein the main active component Cu is contained in an amount of 1 to 15 parts by weight in terms of its oxide and the co-active component is contained in an amount of 0.1 to 3 parts by weight in terms of its oxide, based on 100 parts by weight of the total weight of the selective hydrogenation catalyst.
7. 7. The selective hydrogenation catalyst of any one of claims 1-6, wherein the active component is distributed on the support in the form of metal clusters, wherein the metal clusters have a particle size of 5nm or less.
8. 8. A method for preparing a selective hydrogenation catalyst, comprising the steps of: (1) Carrying out surface treatment on the metal composite oxide by adopting organic cation quaternary ammonium salt, and then adopting silane reagent to carry out treatment to obtain a modified composite oxide carrier, wherein the organic cation quaternary ammonium salt is at least one of long-chain alkyl quaternary ammonium salts with more than 6C, and the silane reagent is at least one of alkoxy silane with 1-4C; (2) And mixing and impregnating the modified composite oxide carrier and an active component metal salt solution, and then sequentially filtering, drying and roasting.
9. 9. The preparation method according to claim 8, wherein the organic cationic quaternary ammonium salt is at least one selected from dioctadecyl dimethyl quaternary ammonium salt, cetyl trimethyl quaternary ammonium salt and C12-18 alkyl dimethyl benzyl quaternary ammonium salt, preferably at least one selected from dioctadecyl dimethyl ammonium chloride, cetyl trimethyl ammonium bromide, dodecyl dimethyl benzyl ammonium chloride, tetradecyl dimethyl benzyl ammonium chloride, cetyl dimethyl benzyl ammonium chloride and octadecyl dimethyl benzyl ammonium chloride; and/or the silane-based reagent is selected from at least one of triethoxysilane, trimethoxysilane, methyltriethoxysilane, methyltrimethoxysilane and vinyltrimethylsiloxane, preferably, the silane-based reagent is selected from triethoxysilane and/or trimethoxysilane; And/or the mass ratio of the metal composite oxide to the organic cation quaternary ammonium salt is 1:0.01-1; And/or the mass ratio of the metal composite oxide to the silane reagent is 1:0.01-1; And/or the metal composite oxide comprises Al 2 O 3 and TiO 2 , preferably, 5-25 parts by weight of TiO 2 and 75-95 parts by weight of Al 2 O 3 ; And/or, the active component metal salt solution comprises a main active component salt solution and a co-active component salt solution; wherein the primary active ingredient salt is selected from at least one of a sulfate, nitrate, soluble carboxylate, phosphate and halide of copper, preferably at least one of copper sulfate, copper nitrate, copper chloride and copper acetate; the auxiliary active component salt is selected from at least one of nitrate, soluble carboxylate and halide of auxiliary active components, and the auxiliary active components are selected from at least one of Au, ag and Ru, preferably at least one of gold nitrate, silver nitrate and ruthenium nitrate; and/or the volume of the active component metal salt solution is 0.8-2.5 times of the equivalent volume of the pore volume of the modified composite oxide carrier.
10. 10. The preparation method according to claim 8 or 9, wherein the surface treatment conditions comprise a temperature of 60-150 ℃, preferably 90-120 ℃, a time of 1-12 hours, preferably 2-8 hours; And/or the conditions of the treatment include a temperature of 60-150 ℃, preferably 90-120 ℃, and a time of 1-12 hours, preferably 2-8 hours; And/or the conditions of the mixed impregnation comprise the temperature of 20-60 ℃ and the time of 1-12h; and/or the drying conditions include a temperature of 60-150 ℃, preferably 90-120 ℃, and a time of 1-12 hours, preferably 2-8 hours; And/or the roasting conditions comprise a temperature of 300-800 ℃, preferably 350-600 ℃, a time of 1-12 hours, preferably 2-8 hours, and an atmosphere of air and/or nitrogen.
11. 11. A selective hydrogenation catalyst made by the process of any one of claims 8-10.
12. 12. Use of a selective hydrogenation catalyst according to any one of claims 1-7 and 11 in the selective hydrogenation of C2-4 fractions.
13. 13. Use according to claim 12, wherein the C2-4 fraction contains C2-4 olefins and/or C2-4 alkanes; Preferably, the C2-4 olefin content is from 0 to 99.99wt%; Preferably, the C2-4 alkane is present in an amount of 0 to 99.99wt%.
14. 14. The use according to claim 13, wherein the C2-4 fraction further comprises impurities comprising C2-4 alkynes and optionally C3 dienes; preferably, the content of the C2-4 alkyne is 0.01-5wt%; Preferably, the C3 diolefin is present in an amount of 0 to 5wt%.
15. 15. A process for the selective hydrogenation of a C2-4 fraction, which comprises contacting the C2-4 fraction with a selective hydrogenation catalyst under hydrogenation reaction conditions, wherein the selective hydrogenation catalyst is the selective hydrogenation catalyst according to any one of claims 1 to 7 and 11.
16. 16. The process according to claim 20, wherein the hydrogenation reaction conditions comprise using a fixed bed reactor, a temperature of 20-50 ℃, preferably 20-25 ℃, a pressure of 0.5-0.8MPa, preferably 0.5-0.7MPa; And/or the molar ratio of hydrogen to the total amount of alkyne to diene contained in the C 2-4 fraction is 1-2.5:1, preferably 1.5-2:1; and/or the recycle ratio of hydrogen to the total amount of alkyne to diene contained in the C 2-4 fraction is from 10 to 30:1, preferably from 20 to 25:1.

Description

Selective hydrogenation catalyst and preparation method and application thereof Technical Field The invention relates to the technical field of catalyst preparation, in particular to a selective hydrogenation catalyst, a preparation method and application thereof. Background The low-carbon olefin generally refers to olefin with carbon number of C 2-C4, such as ethylene, propylene, butylene and the like, is the most basic raw material for petrochemical production, can be used for producing polyethylene, polypropylene, acrylonitrile, ethylene oxide and the like, and has wide application in the fields of plastics, rubber, resin, high polymer, medicines, pesticides and the like. Also included in the lower hydrocarbons are some alkynes and dienes, which are separated from petrochemical plants. In general, a small amount of alkyne contained in C 2-C4 low-carbon olefin is poisoned and deactivated in downstream reaction, the reaction rate is reduced or the product quality is reduced, and the like, and the catalyst for polymerization of mono-olefins is poisoned by the impurities, so that the low-carbon olefin is used as a raw material in the petrochemical production process, and the small amount of alkyne contained therein is subjected to selective catalytic hydrogenation at first. The selective hydrogenation of lower hydrocarbons to remove acetylenes ensures that the lower olefins, the main components of which are not converted or have a lower conversion rate, which requires a higher low temperature activity and a higher selectivity of the catalyst. The traditional carbon three-hydrogenation catalyst adopts Al 2O3 as a carrier, pd as an active component and Ag as an auxiliary active component. The preparation method of the catalyst adopts an impregnation method. The effect of the surface tension and solvation effect of the impregnation liquid is particularly evident during the impregnation and drying treatment of the catalyst, and the metal active component precursor is deposited on the surface of the carrier in the form of aggregates. In addition, the distribution state between Pd and Ag is not ideal, the catalyst activity is not easy to control, the selectivity of the catalyst is mainly controlled by the pore diameter of the catalyst and the dispersion state of the active components, and the dispersion of the active components is influenced by the number of surface groups of a carrier and the solvation in the preparation process of the catalyst, so that the randomness of the dispersion of the active components of the catalyst is large, the preparation repeatability is poor, and the catalytic reaction effect is not ideal. CN101433845A discloses an unsaturated hydrocarbon selective hydrogenation catalyst and a preparation method thereof. The catalyst takes alumina as a carrier and palladium as an active component, and the rare earth, alkaline earth metal and fluorine are added to improve the impurity resistance and coking resistance of the catalyst, but the selectivity of the catalyst is not ideal. CN104096572a discloses a hydrogenation catalyst, the active components in the catalyst are Pd, ag and Ni, wherein the Pd and Ag are loaded by an aqueous solution impregnation method, and the Ni is loaded by a W/O microemulsion impregnation method. After the method is adopted, pd/Ag and Ni are positioned in pore channels with different pore diameters, green oil generated by the reaction is subjected to saturated hydrogenation in macropores, and the coking amount of the catalyst is reduced. However, the reduction temperature of Ni often reaches about 500 ℃, and Pd atoms in a reduced state are easily aggregated at the temperature, so that the activity of the catalyst is greatly reduced, and the activity loss is compensated by greatly increasing the amount of active components, but the selectivity is reduced. Disclosure of Invention The invention aims to solve the problems of low-temperature activity, poor selectivity, poor stability and the like of a selective hydrogenation catalyst in the prior art, and provides the selective hydrogenation catalyst, a preparation method and application thereof, the invention can obviously improve the dispersity of the active components on the surface of the carrier by modifying the carrier, and the catalyst prepared by the method has the advantages of high crushing strength, high selectivity, high low-temperature activity, stable hydrogenation activity and the like, and can be used for a long period. In order to achieve the aim, the first aspect of the invention provides a selective hydrogenation catalyst, which comprises a carrier and an active component supported on the carrier, wherein the carrier is a metal composite oxide modified by organic cation quaternary ammonium salt and silane reagent, the organic cation quaternary ammonium salt is at least one of long-chain alkyl quaternary ammonium salt with more than 6, the silane reagent is at least one of alkoxy silane with 1 to 4 carbon a