CN-122006745-A - Carbon three-fraction selective hydrogenation catalyst and preparation method and application thereof

CN122006745ACN 122006745 ACN122006745 ACN 122006745ACN-122006745-A

Abstract

The invention provides a carbon three-fraction selective catalyst. The catalyst 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, a metal element I in the metal composite oxide comprises aluminum and titanium, a metal element II in the active component comprises noble metal Pd as a main active component and optional auxiliary active components, the auxiliary active components comprise transition metals and/or alkaline earth metals, the transition metals are selected from one or more of Cu, mn, ni, zn, and the alkaline earth metals are selected from one or more of Ca, mg and Ba. The carrier is modified by the organic cation quaternary ammonium salt and the silane reagent, so that the dispersity of the active components on the surface of the carrier can be obviously improved, and the problem of low crushing strength of the metal composite oxide is solved. The invention also provides a preparation method and application of the carbon three-fraction selective catalyst, and also provides a method for generating propylene by carbon three-fraction selective hydrogenation.

Inventors

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

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. A catalyst for selective hydrogenation of three carbon 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 a main active component Pd and an optional auxiliary active component, the auxiliary active component comprises transition metal and/or alkaline earth metal, the transition metal is selected from one or more of Cu, mn, ni, zn, and the alkaline earth metal is selected from one or more of Ca, mg and Ba.
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. Catalyst according to claim 1 or 2, characterized in that the support is a SiO 2 -TiO 2 -Al 2 O 3 composite oxide, preferably the support has a Ti content of 5-25 wt.% based on TiO 2 , an Al content of 65-90 wt.% based on Al 2 O 3 , preferably 80-90 wt.%, an Si content of 0.5-15 wt.% based on SiO 2 , and/or The metal composite oxide is Al 2 O 3 -TiO 2 composite oxide, preferably, based on the metal composite oxide, the content of Ti in the metal composite oxide is 5-30wt%, preferably 8-25wt%, based on TiO 2 , the content of Al in the metal composite oxide is 70-95wt%, preferably 75-92 wt%, based on Al 2 O 3 , 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. A catalyst according to any one of claims 1 to 3, characterized in that the noble metal content is 0.1 to 0.5 parts by oxide based on 100 parts by mass of the catalyst, and/or the transition metal content is 1 to 5 parts by oxide, and/or the alkaline earth metal content is 1 to 5 parts by oxide, preferably 3 to 5 parts, and/or 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 The catalyst is subjected to activation treatment by adopting hydrogen before use, and preferably, the activation treatment conditions comprise an activation temperature of 300-600 ℃, an activation pressure of 0-3.0 MPa, a flow rate of the hydrogen relative to the catalyst of 1-15 mL/min g and an activation time of 6-18 h.
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 cation quaternary ammonium salt is at least one of water, methanol, ethanol, benzene, toluene, chloroethane, isopropanol, acetone, hydrochloric acid, sulfuric acid, nitric acid, sodium hydroxide and 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. A process for preparing a carbon three-fraction selective hydrogenation catalyst according to any one of claims 1 to 5, comprising the steps of: S1, adopting an optional auxiliary active component-containing solution to impregnate a carrier for the second time, and then carrying out third drying and second roasting to obtain a catalyst precursor; s2, adopting a solution containing the main active component to third impregnate the catalyst precursor, and then carrying out fourth drying and third roasting to obtain the catalyst.
7. The method according to claim 6, wherein the conditions of the second impregnation and the third impregnation are the same or different and each independently comprises a temperature of 20 ℃ to 70 ℃, preferably 20 ℃ to 40 ℃, for a period of 1h to 12h, preferably 1 to 4h, and/or The conditions of the third drying and the fourth drying are the same or different, and each independently comprise a temperature of 60-150 ℃, preferably 100-150 ℃ for 1-8 hours, preferably 4-8 hours, and/or The conditions of the second roasting and the third roasting are the same or different, and each independently comprise the temperature of 300-600 ℃, preferably 400-500 ℃ and the time of 4-12 hours, and/or the roasting atmosphere is air and/or nitrogen.
8. The method according to claim 6 or 7, wherein the volume of the solution containing the auxiliary active ingredient is 0.8 to 2.5 times the equivalent volume of the pore volume of the carrier, and/or The concentration of the alkaline earth metal-containing solution is 0.1 to 0.6mol/L, preferably 0.5 to 2.5mol/L, and/or The concentration of the transition metal-containing solution is 0.1-1.5 mol/L, and/or The concentration of the solution containing the main active component is 0.01-0.3 mol/L, preferably 0.01-0.15 mol/L, and/or The solution containing the auxiliary active component is hydrochloride solution, sulfate solution or nitrate solution, and/or The solution containing main active component is hydrochloride solution, sulfate solution or nitrate solution, and/or The solvent of the auxiliary active component-containing solution and the solvent of the main active component-containing solution are the same or different, and each independently comprise at least one of water, hydrochloric acid, sulfuric acid, nitric acid, methanol and ethanol.
9. Use of a hydrogenation catalyst according to any one of claims 1 to 5 or a hydrogenation catalyst prepared by a process according to any one of claims 6 to 8 in the selective hydrogenation of carbon three cuts to propylene; Preferably, the carbon three fraction comprises propylene and propane; Preferably, the carbon three fraction contains impurities, which are propyne and/or propadiene; Preferably, the carbon three-fraction comprises 80-99.99 wt% of propylene and/or 0-19.99 wt% of propane and/or 0.01-5 wt% of propyne and/or 0-5% of allene; Preferably, the hydrogenation reaction conditions comprise that a fixed bed reactor is adopted, the temperature of an inlet of the reactor is 20-50 ℃, the molar ratio of hydrogen to (alkyne+diene) is 1-2.5:1, the pressure is 0.5-0.8 MPa, the circulation ratio is 10-30:1, and the volume space velocity is 1-3 h -1 .
10. A method for producing propylene by selective hydrogenation of carbon three fractions, which is characterized by comprising the steps of carrying out selective hydrogenation reaction of propyne and propadiene in the carbon three fractions and hydrogen in the presence of the carbon three fraction selective hydrogenation catalyst according to any one of claims 1 to 5 or the carbon three fraction selective hydrogenation catalyst prepared by the preparation method according to any one of claims 6 to 8 to produce propylene; preferably, the hydrogenation catalyst is subjected to activation reduction, and preferably, the activation reduction conditions comprise that hydrogen is adopted for activation reduction, the flow of the hydrogen relative to the catalyst is 1-15 mL/min & g, the activation temperature is 300-600 ℃, the activation pressure is 0-3.0 MPa, and the activation time is 6-18 h; Preferably, the condition of the selective hydrogenation reaction comprises the following steps of adopting a fixed bed reactor, wherein the inlet temperature of the reactor is 20-50 ℃, the molar ratio of hydrogen to (alkyne+diene) is 1-2.5:1, the pressure is 0.5-0.8 MPa, the circulation ratio is 10-30:1, and the volume space velocity is 1-3 h -1 ; Preferably, the carbon three fraction contains impurities, which are propyne and/or propadiene; Preferably, the carbon three fraction comprises 80-99.99 wt% of propylene and/or 0-19.99 wt% of propane and/or 0.01-5 wt% of propyne and/or 0-5% of allene.

Description

Carbon three-fraction selective hydrogenation catalyst and preparation method and application thereof Technical Field The invention relates to the technical field of carbon three-fraction selective hydrogenation, in particular to a carbon three-fraction selective hydrogenation catalyst, a preparation method thereof and application of the catalyst in propylene production by carbon three-fraction selective hydrogenation. Background Propylene is an important basic chemical raw material, propylene is one of the basic raw materials of three synthetic materials, the maximum dosage of the propylene is polypropylene production, the propylene can be also used for producing acrylonitrile, propylene oxide, acrolein, acrylic acid, phenol, acetone and the like, and downstream products of the propylene can be widely applied to the fields of films, fibers, rubber, resin, paint and the like. At present, with the continuous expansion of the propylene production, the propylene production reaches 5600 ten thousand tons per year by 2022 years, the annual consumption reaches 4800 ten thousand tons per year, the propylene supply is gradually replaced by domestic production from import, the structural productivity of the propylene is excessive, the requirements on the industrial status of downstream products of the propylene are correspondingly improved, and the requirements on refining propylene raw materials are more strict. Propylene is usually obtained in an ethylene production device by petroleum pyrolysis, and the composition of carbon three fractions in pyrolysis gas is usually 92-96% of propylene, 2.9-3.5% of propane, and 1-5% of propyne (MA) and Propadiene (PD). Wherein MAPD is a toxic substance affecting downstream propylene applications, so that obtaining high purity propylene first removes MAPD. MAPD in the carbon three fraction is easily polymerized into colloid at high temperature, and is deposited on the surface of the catalyst, so that the catalyst is deactivated quickly, and the catalyst has to be activated and regenerated frequently. It is therefore important in industrial applications that the hydrogenation catalyst has a high low temperature activity, and that the catalyst maintains a suitable gel capacity so that the activity of the polymer on the surface of the catalyst is unchanged before being washed, thereby extending the service life of the catalyst. The industrial apparatus for removing MAPD from carbon three fractions mainly comprises gas phase catalytic selective hydrogenation, liquid phase catalytic selective hydrogenation and catalytic rectification methods. At present, a liquid phase selective hydrogenation method is generally adopted in the market, and the method has the advantages of simple process flow, low reaction temperature, low energy consumption, safety, environmental protection and easy operation. The selective hydrogenation of the carbon three fractions has higher requirements on the selection of the catalyst and the control of the reaction process. The existing industrial carbon three-fraction selective hydrogenation catalyst is a supported catalyst which takes noble metal palladium as a main active component and alumina as a carrier, and some of the supported catalyst also add assistants such as silver, gold, copper and the like to improve propylene selectivity. However, the existing industrial carbon three-fraction selective hydrogenation catalyst for removing propyne and propadiene has the problems of low activity, poor stability, low propylene selectivity and the like. Disclosure of Invention In order to solve at least one of the problems in the prior art, the invention provides a carbon three-fraction selective hydrogenation catalyst, a preparation method thereof and application of the catalyst in the production of propylene by carbon three-fraction selective hydrogenation. The hydrogenation catalyst can convert propyne and propadiene into propylene in the selective hydrogenation process, and can inhibit the further hydrogenation reaction of propylene into propane. To this end, in a first aspect, the present invention provides a carbon three-cut selective hydrogenation catalyst comprising a support and an active component supported on the support, 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 metal element II in the active component comprises a main active component Pd and an optional auxiliary active component, the auxiliary active component comprises transition metal and/or alkaline earth metal, the transition metal is selected from one or more of Cu, mn, ni, zn, and the alkaline earth metal is selected from one or more of Ca, mg and Ba. The carrier is treated by the organic cation quaternary ammonium salt and the silane reagent, so that the problem of low crushing strength of the metal composite