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CN-122006744-A - Catalyst for selective hydrogenation of carbon four fractions, preparation method and application thereof

CN122006744ACN 122006744 ACN122006744 ACN 122006744ACN-122006744-A

Abstract

The invention provides a carbon four-fraction selective hydrogenation catalyst which comprises 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 reagents, the metal composite oxide contains metal elements I, the metal elements I comprise aluminum and titanium, the active component contains metal elements II, the metal elements II comprise main active component copper and optional auxiliary active components, and the auxiliary active components are selected from at least one of Ni and Ru. The invention also provides a preparation method and application of the catalyst for the selective hydrogenation of the carbon four fractions, and a method for removing alkyne in the C4 fraction and increasing butadiene yield by the selective hydrogenation of the carbon four fractions. According to the carbon four-fraction selective hydrogenation catalyst provided by the invention, the specific carrier, the main active component and the auxiliary active component are matched, so that the obtained carbon four-fraction selective hydrogenation catalyst has high reaction activity and selectivity, the problem of green oil is solved, and the service life of the catalyst is prolonged.

Inventors

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

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 (10)

  1. 1. A catalyst for selective hydrogenation of C four fractions is characterized by comprising a carrier and an active component loaded on the carrier, The carrier is a metal composite oxide modified by organic cation quaternary ammonium salt and silane reagent, wherein the metal composite oxide contains metal elements I, and the metal elements I comprise aluminum and titanium; The active component contains a metal element II, wherein the metal element II comprises main active component copper and optional auxiliary active component, and the auxiliary active component is selected from at least one of Ni and Ru.
  2. 2. The catalyst according to claim 1, wherein the organic cationic quaternary ammonium salt comprises a hydrocarbyl quaternary ammonium salt, preferably of the formula R 4 N + X - , wherein X - is selected from the group consisting of halogen ions, acid ions, preferably the halogen ions comprise F - 、Cl - 、Br - and I - , the acid ions comprise nitrate ions and carboxylate ions, each R in the formula R 4 N + X - is the same or different and is each independently selected from the group consisting of alkyl, cycloalkyl, aryl, aralkyl and alkaryl, at least one R, preferably 1 to 2R is selected from the group consisting of C6 and higher alkyl, preferably from the group consisting of C6 to C20 alkyl, the remaining R is preferably selected from the group consisting of C1 to C4 alkyl, C7 to C11 aralkyl; Preferably, the organic cationic quaternary ammonium salt comprises at least one of dioctadecyl dimethyl quaternary ammonium salt, cetyl trimethyl quaternary ammonium salt and C12-18 alkyl dimethyl benzyl quaternary ammonium salt; more 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, hexadecyl dimethyl benzyl ammonium chloride and octadecyl dimethyl benzyl ammonium chloride, and/or The general formula of the silane reagent is SiR 1 x (OR 2 ) y , wherein x and y are respectively and independently selected from integers of 1-3, x+y=4, R 1 is selected from hydrogen, C1-C6 alkyl and C2-C6 alkenyl, and R 2 is selected from C1-C6 alkyl; Preferably, the silane-based reagent comprises at least one of triethoxysilane, trimethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, and/or The organic cation quaternary ammonium salt is used in an amount of 1% -50%, preferably 30% -50%, more preferably 35% -50% of the mass of the metal composite oxide, and/or The silane reagent is used in an amount of 0.5 to 30% by mass, preferably 0.5 to 15% by mass, more preferably 0.5 to 10% by mass, of the metal composite oxide.
  3. 3. The catalyst according to claim 1 or 2, characterized in that the carrier is a SiO 2 -TiO 2 -Al 2 O 3 composite oxide, preferably the carrier comprises 5-25 wt% of TiO 2 , 65-90 wt% of Al 2 O 3 , preferably 80-90 wt% of SiO 2 , 0.5-15 wt% of SiO 2 , and/or The metal composite oxide is Al 2 O 3 -TiO 2 composite oxide, preferably, based on the TiO 2 -Al 2 O 3 composite oxide, the content of Ti in the TiO 2 -Al 2 O 3 composite oxide is 5-30wt%, preferably 8-25wt%, based on TiO 2 , the content of Al in the TiO 2 O 3 composite oxide is 70-95wt%, preferably 75-92 wt%, and/or The specific surface of the carrier is 30-150 m 2 /g, preferably 50-90 m 2 /g, and/or The pore volume of the carrier is 0.2-0.8 mL/g, preferably 0.3-0.5 mL/g.
  4. 4. A catalyst according to any of claims 1-3, characterized in that the content of the carrier in the selective hydrogenation catalyst is 70-95 wt%, the content of the main active component is 5-25 wt%, the content of the co-active component is 0-5 wt%, preferably 0.1-5 wt%, and/or based on the selective hydrogenation catalyst The active component is distributed on the carrier in the form of nanoclusters, wherein the nanoclusters have a particle size of 5nm or less, and/or In the selective hydrogenation catalyst, the main active component and the auxiliary active component are each independently present in the form of their simple substances or oxides.
  5. 5. The method for preparing the carrier according to any one of claims 1 to 4, wherein the preparation of the carrier comprises the steps of performing a first treatment on the metal composite oxide by using an organic cation quaternary ammonium salt solution, and performing a second treatment on the metal composite oxide by using a silane reagent to obtain the carrier; Preferably, the first treatment comprises first dipping and first drying which are sequentially carried out, and/or the second treatment comprises dripping a solution of a silane reagent into the metal composite oxide subjected to the first treatment, and then stirring, second drying and first roasting, wherein the stirring time is 1 min-60 min; Preferably, the solvent of the solution of the organic cationic quaternary ammonium salt comprises at least one of water, methanol, ethanol, benzene, toluene, ethyl chloride, isopropanol, acetone, sulfuric acid, hydrochloric acid, nitric acid, sodium hydroxide, potassium hydroxide; preferably, the concentration of the organic cation quaternary ammonium salt solution is 0.1-10wt%, preferably 0.2-10wt%, and more preferably 1-5wt%; preferably, the solution of the silane reagent is an aqueous solution of the silane reagent, and the concentration of the aqueous solution is 0.1-10wt%, preferably 1-10wt%; preferably, the first impregnation condition comprises an impregnation temperature of 10-50 ℃ and an impregnation time of 1-12 hours, preferably 1-8 hours; preferably, the conditions of the first drying and the second drying are the same or different, and each independently comprises a drying temperature of 60-150 ℃, preferably 60-110 ℃ and a drying time of 4-12 h, and/or The first roasting condition comprises a roasting temperature of 300-1100 ℃, preferably 500-900 ℃ and a roasting time of 4-12 hours.
  6. 6. A process for preparing a catalyst for selective hydrogenation of carbon four fractions according to any of claims 1 to 5, which comprises the steps of impregnating the support with a copper salt solution and optionally with a nickel salt solution and/or a ruthenium salt solution, followed by a third drying and a second calcination.
  7. 7. The method according to claim 6, wherein the second impregnation conditions comprise a temperature of 20-70 ℃, preferably 20-40 ℃, for a period of 1-12 hours, preferably 1-4 hours, and/or The third drying condition comprises a temperature of 60-150 ℃, preferably 100-150 ℃ for 1-8 hours, preferably 4-8 hours, and/or The second roasting condition comprises the temperature of 300-600 ℃, preferably 400-500 ℃ and the time of 4-12 hours.
  8. 8. The method according to claim 6 or 7, wherein the copper salt comprises at least one of a sulfate, nitrate, soluble carboxylate, hypophosphite and halide of copper, preferably at least one of copper sulfate, copper nitrate, copper chloride and copper acetate, and/or The ruthenium salt comprises at least one of nitrate, soluble carboxylate and halide of ruthenium, preferably at least one of nitrate, hydrochloride, oxalate and acetate of ruthenium, and/or The nickel salt comprises at least one of nitrate, soluble carboxylate and halide of nickel, preferably at least one of nitrate, hydrochloride, oxalate and acetate of nickel, and/or The copper salt solution, ruthenium salt solution and nickel salt solution are at least one of water, methanol, ethanol, benzene, toluene and chloroethane respectively and/or The concentration of the copper salt solution is 0.1-0.6 mol/L, and/or The concentration of the ruthenium salt solution is 0.005-0.01 mol/L, and/or The concentration of the nickel salt solution is 0.1-0.3 mol/L.
  9. 9. Use of the carbon four-fraction selective hydrogenation catalyst according to any one of claims 1 to 5 or the preparation method according to any one of claims 6 to 8 for selective hydrogenation to remove alkynes from C4 fractions and increase butadiene production, preferably, the selective hydrogenation conditions comprise a reaction temperature of 20 ℃ to 40 ℃, a pressure of 0.5mpa to 0.8mpa, a molar ratio of hydrogen to alkynes of 1 to 2.5:1, and a circulation ratio of 10 to 30:1.
  10. 10. A method for removing alkyne in C4 fraction and increasing yield of butadiene by selective hydrogenation of C4 fraction comprises the step of carrying out selective hydrogenation reaction on the C4 fraction and hydrogen in the presence of the C4 fraction selective hydrogenation catalyst prepared by the preparation method of any one of claims 1-5 or the C4 fraction selective hydrogenation catalyst prepared by the preparation method of any one of claims 6-8, wherein the condition of the selective hydrogenation reaction preferably comprises the reaction temperature of 20-40 ℃, the pressure of 0.5-0.8 MPa, the molar ratio of hydrogen to alkyne is 1-2.5:1, and the circulation ratio is 10-30:1.

Description

Catalyst for selective hydrogenation of carbon four fractions, preparation method and application thereof Technical Field The invention relates to the technical field of carbon four-fraction selective hydrogenation, in particular to a carbon four-fraction selective hydrogenation catalyst and a preparation method and application thereof. Background The carbon four fraction refers to a mixture of various alkanes, alkenes, dienes and alkynes containing four carbon atoms, and is mainly derived from refinery gas generated in the petroleum refining process and byproducts in the ethylene preparation process by cracking petroleum hydrocarbons, wherein the cracked carbon four contains saturated hydrocarbons and unsaturated hydrocarbons such as n-butane, isobutane, 1-butene, trans-2-butene, cis-2-butene, isobutene, 1, 2-butadiene, 1, 3-butadiene, methylacetylene, ethylacetylene, vinylacetylene and the like, and the cracked carbon four is mainly used for producing 1, 3-butadiene, isobutene and 1-butene in industry. The cracking carbon four fraction of the byproduct of ethylene preparation by hydrocarbon high-temperature cracking usually contains 40-60% of butadiene by mass, the butadiene is an important monomer in the synthetic rubber industry, and solvent extraction methods such as an acetonitrile method, an N-methylpyrrolidone method and a dimethylformamide method are usually adopted for extracting butadiene from the cracking carbon four fraction, so that the methods basically meet the requirement on the purity of butadiene at present. Due to the influence of factors such as cracking depth, cracking technology and the like, the alkyne content in the cracked carbon four fraction gradually increases, so that the loss of butadiene in the extraction process is increased and the energy consumption is increased. Meanwhile, with the development of the organic synthesis industrial technology, the limitation on the alkyne content in butadiene is stricter, and the factors all lead to the deterioration of the economy of a butadiene extraction device, when the butadiene is extracted, the alkyne is selectively hydrogenated and then part of butadiene is recovered, so that the aim of changing waste into valuables can be achieved, and the reduction of alkyne emission and the prevention of environmental pollution also play an important role. At present, alkyne in the mixed carbon tetrahydrocarbon fraction can be removed by adopting a catalytic selective hydrogenation method. The catalyst used is mainly intended to use noble metal catalysts typified by palladium, platinum, silver, etc., and secondly non-noble metal catalysts typified by copper, nickel. The selective hydrogenation of alkynes in hydrocarbon streams varies with the composition of the feedstock and the desired product, as well as the catalyst and reaction conditions chosen. In addition to higher hydrogenation activity, a good selective hydrogenation catalyst should have good stability, i.e., the catalyst should have anti-impurity and anti-colloid capabilities, so as to prolong the service life of the catalyst. Thus, the support is required to have lower acidity, smaller specific surface area and larger pore size. In addition, in the preparation of the catalyst, the addition of some auxiliary agents can also prolong the service life of the catalyst. Noble metal catalysts generally employ a large amount of palladium catalyst supported on a carrier (typically alumina) with the addition of other promoter components such as gold, silver, chromium, copper, iron, rhodium, lithium, potassium, and also lead or zinc. Noble metal catalysts have good low-temperature activity and mild reaction conditions, but have the defects of easy loss of active components of the catalyst, high price, difficult regeneration and poor hydrogenation selectivity. The non-noble metal catalyst needs to react at a higher temperature, and hydrogenation conditions are more severe, but the preparation is simple, the repeated regeneration is convenient, and the cost is relatively low, so that the catalyst still has a certain research and development value. In the hydrogenation reaction process, semi-hydrogenated free radicals adsorbed on the catalyst react with adjacent alkyne or diene to generate a viscous polymer (commonly called green oil), which mainly comprises compounds with more than C6, and the semi-hydrogenated free radicals cover the surface of the catalyst to block micropores on the surface of the catalyst, so that the activity of the catalyst is reduced, and the service life of the catalyst is influenced. In particular, in the case of conjugated dienes (e.g., 1, 3-butadiene), polymerization is more easily performed, so that the catalyst is deactivated in a short period of time, and thus the catalyst must be frequently regenerated to be reused. In the application research in the field of selective hydrogenation of carbon tetrayne, it is realized that the use of nickel-based selective hydrogenation