A liquid phase selective hydrogenation catalyst for carbon three and its preparation method and application

Abstract

The application provides a carbon three liquid-phase selective hydrogenation catalyst as well as a preparation method and application thereof. The catalyst provided by the application comprises a modified alumina carrier and a Pd metal component loaded on the carrier, wherein the modified alumina carrier is a modified alumina carrier with a surface rich in oxygen-containing groups, which is prepared by heat treatment, crystallization, oxidation and other surface treatment means on components containing alumina and inorganic carbon species. The oxygen-containing groups on the carrier in the catalyst provided by the application can promote the uniform distribution of the metal active component on the surface of the carrier, and improve the catalytic activity and selectivity of the catalyst.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalysts, and in particular relates to a C3 liquid phase selective hydrogenation catalyst, a preparation method and an application thereof. Background Art

[0002] Liquid-phase selective hydrogenation catalysts for C3 are used in steam cracking plants to produce ethylene and propylene. The separated C3 fraction typically contains 2 to 6 mol% of propyne (MA) and propadiene (PD). Trace amounts of propyne and propadiene in propylene can reduce catalyst activity during propylene polymerization, increase polypropylene catalyst consumption, and affect polypropylene product performance. Selective hydrogenation is commonly used industrially to convert propyne and propadiene into propylene, removing impurities while increasing propylene production.

[0003] Liquid-phase selective hydrogenation catalysts for C3 typically use palladium as the primary active component, with metal additives such as silver and copper, and an alumina support. To improve the activity and selectivity of C3 hydrogenation catalysts, the palladium loading method can be optimized, multi-component metal additives can be added, and the chemical adsorption properties and pore structure of the alumina support can be modified. Chinese patent CN101875009A uses ionizing radiation to form uniformly distributed palladium particles on the surface of the alumina support, improving activity while reducing palladium loading. Chinese patent CN107107049A, by adding an organophosphorus compound, alters the palladium catalyst's adsorption capacity for reactants, improving activity and selectivity, and enhancing its resistance to poisons.

[0004] In the preparation of C3 liquid-phase hydrogenation catalysts, the alumina support not only disperses the metal components but also provides a reaction site. Its well-developed pore structure facilitates the diffusion of reactants and products. By optimizing the alumina support's molding method, adding modifying agents, and preparing composite supports based on alumina, the surface chemical adsorption properties and physical pore structure of the alumina support can be improved, thereby enhancing the catalyst's hydrogenation performance.

[0005] Chinese patent CN1958155A discloses an alkyne selective hydrogenation catalyst in which an Al2O3 coating is applied to an inert carrier of talc, refractory clay or silicon carbide, Pd is used as the main active component, and Ag, alkali metals, etc. are used as auxiliary active components. By controlling the thickness of the alumina coating, the distribution of the metal active components on the carrier surface can be promoted, thereby improving the hydrogenation performance.

[0006] Chinese patent CN1279126A discloses a catalyst composed of diatomaceous earth, SiO2, TiO2, Al2O3, etc. as a carrier, loaded with metal components such as Pd and Bi, which has high selectivity and high activity in selective hydrogenation reactions, while reducing the amount of green oil generated and extending the catalyst life.

[0007] Existing C3 liquid-phase selective hydrogenation catalysts and their preparation methods are significantly affected by the properties of the alumina support during mass production. The surface chemical adsorption properties of alumina supports produced from different batches vary, thus affecting the performance of the resulting catalyst. Therefore, there is a need to develop a C3 liquid-phase selective hydrogenation catalyst with a simple preparation method, stable performance during mass production, and excellent activity and selectivity. Summary of the Invention

[0008] To address the problems of the prior art, the present invention provides a C3 liquid-phase selective hydrogenation catalyst, its preparation method, and its application. By utilizing a carrier comprising alumina and carbide, and containing a high content of oxygen-containing groups, the present invention produces a catalyst that exhibits stable performance in mass production, good activity, and high selectivity.

[0009] One of the purposes of the present invention is to provide a C3 liquid-phase selective hydrogenation catalyst, comprising a modified alumina carrier and a Pd metal component loaded on the carrier, wherein the modified alumina carrier is a modified alumina carrier having a surface rich in oxygen-containing groups obtained by surface treatment of components including alumina and inorganic carbon species.

[0010] According to the present invention, the C3 liquid phase selective hydrogenation catalyst:

[0011] The inorganic carbon species is selected from at least one of coke, activated carbon, carbon black, glassy carbon, charcoal, bamboo charcoal, coconut shell charcoal, graphene, graphyne, and diamond; and / or,

[0012] In terms of mass percentage, the inorganic carbon species is 0.5 to 20% of the amount of alumina, preferably 2 to 15%;

[0013] The oxygen-containing group is at least one of a hydroxyl group, a carboxyl group, and a lactone group; wherein the modified alumina support has a carboxyl group content of 1 to 80 mmol / g, preferably 1 to 60 mmol / g; a carboxyl group content of 1 to 80 mmol / g, preferably 1 to 60 mmol / g; and a lactone group content of 1 to 60 mmol / g, preferably 3 to 40 mmol / g;

[0014] The specific surface area of ​​the modified alumina carrier is 10 to 180 m 2 / g, water absorption rate is 30-120%, strength is 30-150N / particle, bulk density is 0.4-1.0g / ml, pore volume is 0.3-1.2ml / g;

[0015] The modified alumina support further contains an optional inorganic compound other than alumina; preferably, the inorganic compound other than alumina is selected from at least one of silicon oxide, magnesium oxide, barium oxide, calcium oxide, and hydrotalcite, and the mass ratio of the inorganic compound other than alumina to alumina is (0-30):100, preferably (0-28):100;

[0016] Based on the total weight of the catalyst as 100%, the content of the Pd metal component is 0.08-0.8%, preferably 0.08-0.5%;

[0017] The catalyst may optionally further include an auxiliary active metal component, which may be a commonly used auxiliary active metal in the art. Preferably, the auxiliary active metal component is selected from at least one of Ag, Cu, Au, As, Sn, Cr, and Pb. Based on the total weight of the catalyst as 100%, the content of the auxiliary active metal component is 0 to 1%, preferably 0.05 to 0.6%.

[0018] The surface of the aluminum oxide carrier provided by the present invention contains at least one oxygen-containing group selected from hydroxyl, carboxyl and lactone groups, and the density of the oxygen-containing groups is 0.15 to 5 mmol / m 2 The catalyst provided by the present invention optimizes the types and quantities of oxygen-containing groups on the surface of the alumina carrier through heat treatment, crystallization, oxidation and the like, and adds a certain amount of carbon species during molding, thereby promoting the uniform distribution of metal active components on the surface of the alumina carrier and improving the activity and selectivity of the prepared catalyst. The content of Pd metal and co-active metal components in the catalyst can be tested by atomic absorption or ICP methods, and those skilled in the art can select a suitable test method according to the type and content of the metal.

[0019] A second object of the present invention is to provide a method for preparing the above-mentioned C3 liquid phase selective hydrogenation catalyst.

[0020] The preparation method of the catalyst includes two steps: preparation of a modified alumina carrier and loading of active metal components. The preparation of the modified alumina carrier includes kneading the formed powder into a shape, performing surface treatment, and increasing the number of oxygen-containing groups on the surface. In the present invention, the modified alumina carrier and its preparation can refer to patent ZL202311028071.8, and the relevant contents disclosed in the aforementioned document are introduced into the present invention as a reference; the loading of the active metal component includes loading the Pd metal component and the optional auxiliary active metal component on a carrier containing alumina, drying and then high-temperature calcining to obtain a C3 liquid phase selected hydrogenation catalyst. The loading method can adopt the loading method commonly used in the art. The metal components can be loaded on the carrier together, or different metal components can be loaded on the carrier in steps.

[0021] According to the present invention, the preparation method of the C3 liquid-phase selective hydrogenation catalyst comprises: granulating and surface-treating raw materials comprising alumina powder, a forming agent, a pore-forming agent, an inorganic carbon species, and optional inorganic compounds other than alumina to obtain the modified alumina carrier, and then loading the Pd metal component and an optionally added auxiliary active metal component on the carrier to obtain the C3 liquid-phase selective hydrogenation catalyst.

[0022] According to an embodiment of the present invention, the preparation method of the C3 liquid phase selective hydrogenation catalyst specifically comprises:

[0023] (1) mixing alumina powder, a forming agent, a pore-forming agent, an inorganic carbon species, and optionally an inorganic compound other than alumina to obtain a mixed dry material;

[0024] (2) adding an acidic solution and kneading to form a shape, followed by extrusion and granulation;

[0025] (3) drying and surface treating the granulated material to obtain a carrier;

[0026] (4) A solution containing a Pd metal component precursor compound and an optionally added co-active metal component precursor compound is loaded on a carrier, dried, and calcined to obtain the C3 liquid phase selective hydrogenation catalyst.

[0027] According to the present invention, in the method for preparing the C3 liquid phase selective hydrogenation catalyst: the step (1):

[0028] The alumina powder can be any alumina-containing powder material in the prior art. For example, the alumina powder is selected from at least one of pseudo-boehmite powder, alumina trihydrate powder, fast-release alumina powder, and γ-Al2O3 powder. The pseudo-boehmite powder can be commonly used pseudo-boehmite. Preferably, the specific surface area of ​​the pseudo-boehmite powder is 200 to 300 m 2 / g, pore volume 0.5-1.2ml / g, bulk density 0.2-0.4g / ml; the alumina trihydrate powder can be selected from at least one of gibbsite, bayerite, and diaspore; the fast-dehydration alumina powder is obtained by rapid dehydration of aluminum hydroxide, wherein the mass content of Na and Fe is less than 0.1%; the γ-Al2O3 powder can be obtained by high-temperature calcination of commonly used pseudo-boehmite powder;

[0029] The molding agent is selected from at least one of polyethylene glycol cellulose, methyl cellulose, carboxymethyl cellulose, sodium hydroxymethyl cellulose, hydroxypropyl methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, cyanoethyl cellulose, hydroxypropyl cellulose, and starch; the amount of the molding agent is 0.1 to 15 wt%, preferably 0.1 to 10 wt%, based on the total weight of the mixed dry materials;

[0030] The pore forming agent is selected from at least one of polyvinyl alcohol, polyethylene glycol, polyacrylamide, polypropylene glycol, and sesbania gum; the amount of the pore forming agent is 0.1-15wt% of the total weight of the mixed dry materials, preferably 0.1-10wt%;

[0031] The inorganic compound other than alumina is selected from at least one of silicon oxide, magnesium oxide, barium oxide, calcium oxide, and hydrotalcite; the inorganic compound can be optionally added according to the needs of the carrier and can be adjusted in a wide range according to the composition of the modified alumina carrier;

[0032] The inorganic carbon species is selected from at least one of coke, activated carbon, carbon black, glassy carbon, charcoal, bamboo charcoal, coconut shell charcoal, graphene, graphyne, and diamond; the amount of the inorganic carbon species can be adjusted in a wide range according to the composition of the modified alumina carrier.

[0033] According to the present application, in the preparation method of the carbon three liquid phase selective hydrogenation catalyst, step (2) is as follows:

[0034] The concentration of the acidic solution can be adjusted in a wide range, preferably, the concentration of the acidic solution is 0.001-1mol / L;

[0035] The solvent in the acidic solution is selected from water or a mixed solution of water and an organic solvent, preferably, the organic solvent is selected from at least one of methanol, ethanol, and ethylene glycol; when the solvent in the acidic solution is a mixed solution of water and an organic solvent, the volume ratio of the organic solvent to water is (0.05-1.5):1;

[0036] The acidic compound in the acidic solution is selected from at least one of an organic acid and an inorganic acid, preferably at least one of acetic acid, maleic acid, malic acid, citric acid, oxalic acid, formic acid, tartaric acid, ascorbic acid, salicylic acid, succinic acid, nitric acid, sulfuric acid, hydrochloric acid, hypochlorous acid, and phosphoric acid;

[0037] In step (2), the amount of the acid in the acidic aqueous solution can be adjusted by the person skilled in the art according to the required specific surface area, strength, bulk density, and other data of the alumina carrier; the kneading forming time and the extrusion forming pressure are related to the size of the used equipment, the composition of the alumina powder, and the composition of the acid solution, and can be specifically determined by the person skilled in the art according to experience.

[0038] According to the present application, in the preparation method of the carbon three liquid phase selective hydrogenation catalyst, step (3) is as follows:

[0039] The surface treatment is selected from at least one of heat treatment, crystallization, oxidation, alkalization, and irradiation treatment; preferably,

[0040] The heat treatment conditions include: the heat treatment atmosphere includes a first atmosphere and a second atmosphere, the first atmosphere is selected from at least one of carbon dioxide, water vapor, acetylene, ethylene, and methane, the second atmosphere is selected from at least one of air, nitrogen, argon, and helium, the volume ratio of the first atmosphere to the second atmosphere is (0.05-1):1, the heat treatment temperature is 300-1200° C., the heat treatment time is 1-24 hours, and the pressure is 0.1-3 MPa;

[0041] The crystallization conditions are: temperature of 120-250° C., pressure of 0.2-15 MPa, time of 4-18 h, and the solvent used for crystallization is at least one selected from water, ethanol, ethylene glycol, and ethylenediamine;

[0042] The oxidation conditions are as follows: temperature of 30-110° C., time of 0.2-10 h, the oxidant used for oxidation is at least one selected from nitric acid, sulfuric acid, ammonium persulfate, hydrogen peroxide, potassium permanganate, and ascorbic acid, and the concentration of the oxidant solution is 0.1-10 mol / L;

[0043] The alkalization conditions are as follows: a temperature of 30 to 110° C., a time of 0.2 to 10 hours, an alkaline compound used for alkalization is selected from at least one of sodium hydroxide, sodium bicarbonate, sodium carbonate, sodium acetate, sodium oxalate, sodium citrate, potassium hydroxide, potassium bicarbonate, potassium carbonate, potassium acetate, and potassium citrate, and the concentration of the alkaline compound solution is 0.1 to 10 mol / L;

[0044] The irradiation treatment conditions are as follows: the ray source is selected from gamma rays and / or microwaves, wherein the gamma ray irradiation dose rate is 2-90 kGy / min, and the irradiation time is 0.2-24 h; the microwave power is 50-1000 W, and the irradiation time is 0.5-60 min.

[0045] According to the present invention, in the preparation method of the C3 liquid phase selective hydrogenation catalyst:

[0046] When the inorganic carbon species is at least one of coke, activated carbon, carbon black, and glassy carbon, heat treatment is performed, or surface treatment is performed by crystallization and oxidation;

[0047] When the inorganic carbon species is at least one of charcoal, bamboo charcoal, and coconut shell charcoal, heat treatment is performed, or heat treatment and irradiation are performed for surface treatment;

[0048] When the inorganic carbon species is at least one of graphene, graphyne, and diamond, the surface treatment is performed by crystallization and oxidation, or by heat treatment and alkalization, or by heat treatment, alkalization, and irradiation.

[0049] According to the present invention, in step (4) of the method for preparing the C3 liquid phase selective hydrogenation catalyst:

[0050] The Pd metal component precursor compound is selected from at least one soluble compound of palladium, preferably at least one selected from palladium chloride, palladium nitrate, palladium acetate, and palladium sulfate;

[0051] The auxiliary active metal component precursor compound is selected from at least one of the chlorides, nitrates, acetates, sulfates, oxides, and metal organic compounds of Ag, Cu, Au, As, Sn, Cr, and Pb, and is preferably selected from at least one of the chlorides, nitrates, and acetates of Ag, Cu, Au, As, Sn, Cr, and Pb;

[0052] The solvent in the solution is selected from at least one of water, hydrochloric acid, nitric acid, acetic acid, and alcohol, preferably water;

[0053] The metal concentration in the solution containing the metal compound can be adjusted within a wide range. For example, the total metal content in the solution is 0.01 to 500 mg / mL.

[0054] The drying process and drying conditions commonly used in the art can be used. The drying process allows the solvent used for impregnation to fully volatilize. The drying time can be selected according to the amount of solvent used and the drying temperature. For example, the drying conditions are: a drying temperature of 40 to 190° C. and a drying time of 4 to 48 hours; preferably, a drying temperature of 50 to 140° C. and a drying time of 4 to 24 hours.

[0055] The calcination can adopt the calcination process and calcination conditions commonly used in the art. The calcination time varies according to the content of the metal active component. As the content of the metal active component increases, the calcination time can be appropriately increased. For example, the calcination conditions are: calcination temperature of 300-700°C, and calcination time of 2-24h.

[0056] A third object of the present invention is to provide an application of the above-mentioned C3 liquid phase selective hydrogenation catalyst or the C3 liquid phase selective hydrogenation catalyst obtained by the above-mentioned preparation method in the hydrogenation reaction of a C3 fraction.

[0057] According to the present invention, in the application:

[0058] The C3 liquid phase selective hydrogenation catalyst is subjected to a reduction treatment before use. Preferably, the gas used for reduction includes hydrogen and other gases, the other gases are nitrogen or methane, and the molar percentage of hydrogen in the gas is 10-90%; the reduction temperature is 90-350° C.; and the reduction time is 2-24 hours.

[0059] In the C3 liquid phase fraction, the molar percentage of propyne and propadiene is 0.5-6%;

[0060] The conditions of the hydrogenation reaction are: reaction temperature of 25-70°C, reaction space velocity of 5-120h -1 .

[0061] The catalyst of the present invention utilizes heat treatment, crystallization, oxidation, and irradiation during the preparation of the alumina-containing support to increase the number of oxygen-containing groups on the alumina-containing support. The introduction of carbon species enriches the types and number of oxygen-containing groups on the support. The increased oxygen-containing groups on the surface of the alumina support allow for a more uniform distribution of active metal components and a controllable thickness, resulting in a catalyst with improved activity and selectivity. Furthermore, the surface modification of the alumina-containing support after molding ensures more consistent physical properties across batches, leading to more stable catalyst performance. DETAILED DESCRIPTION

[0062] The present invention will be described in detail below with reference to specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made by those skilled in the art to the present invention based on the contents of the present invention still fall within the scope of protection of the present invention.

[0063] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, for example, they can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0064] Example 1

[0065] Carrier preparation: take a specific surface area of ​​150.3m 2 100g of pseudo-boehmite powder (with a pore volume of 0.75ml / g and a bulk density of 0.22g / ml), 5g of sesbania powder, 8g of carboxymethyl cellulose, and 4g of bamboo charcoal were mixed evenly. 1.8g of concentrated nitric acid was added to 150g of deionized water to prepare a mixed solution. The mixed solution was added to the mixed powders, and the mixture was then thoroughly kneaded in a kneader. Afterwards, the mixture was extruded and pelletized to obtain cylindrical particles with a particle size of 2-4mm. The particles were dried at 80°C for 8h and then heat-treated at 1200°C and 0.1MPa for 24h using air and water vapor (volume ratio 0.8:1) to obtain an alumina support.

[0066] Active metal component loading method: 0.395 g of silver nitrate was added to 25 mL of a 10 mg Pd / mL palladium nitrate solution, diluted to 65 mL with deionized water, and impregnated onto 100 g of the alumina support prepared by the above method. The impregnated sample was dried at 120°C for 4 hours and calcined at 500°C for 4 hours to obtain catalyst S1, which had a Pd loading of 0.25% and an Ag loading of 0.25% by weight.

[0067] Example 2

[0068] Support preparation: Take 100 g of pseudo-boehmite powder (same as in Example 1), 10 g of silicon oxide, 8 g of coconut shell carbon, 5 g of sesbania powder, and 10 g of ethyl cellulose, and mix them uniformly. Take 1.8 g of concentrated nitric acid and add it to 150 g of deionized water to prepare a mixed solution. Add the mixed solution to the mixed powder and put them together into a kneader for sufficient kneading, and then extrude and pelletize them to obtain cylindrical pellets with a particle size of 2-4 mm. Then, heat-treat them at 600 °C and 1.5 MPa for 12 h in air and water vapor (volume ratio 0.8:1) to obtain an alumina support.

[0069] Active metal component loading method: Take 18 mL of a palladium nitrate solution of 10 mg Pd / mL, dilute it to 58 mL with deionized water, and impregnate it into 100 g of the alumina support prepared by the above method, dry it at 110 °C for 6 h, and calcine it at 500 °C for 8 h to obtain a Pd-containing catalyst precursor. Take 0.333 g of copper chloride, add it to 58 mL of deionized water, and use the prepared Cu solution to impregnate the Pd-containing catalyst precursor, and then dry it at 110 °C for 6 h and calcine it at 500 °C for 8 h to obtain catalyst S2, which has a Pd loading of 0.18% and a Cu loading of 0.15% by mass content.

[0070] Example 3

[0071] Support preparation: Take 100 g of alumina trihydrate powder with a specific surface area of 200.3 m 2 / g, a pore volume of 1.42 ml / g, and a bulk density of 0.15 g / ml, 5 g of polyethylene glycol cellulose, 5 g of polyvinyl alcohol, and 12 g of graphyne, and mix them uniformly. Take 2.2 g of concentrated sulfuric acid and add it to 125 g of deionized water to prepare a mixed solution. Add the mixed solution to the mixed powder and put them together into a kneader for sufficient kneading, and then extrude and pelletize them to obtain cylindrical pellets with a particle size of 2-4 mm, dry them at 80 °C for 8 h, heat-treat them at 300 °C and 3 MPa in carbon dioxide and nitrogen (volume ratio 0.5:1) for 1 h, immerse them in a 5 mol / L potassium carbonate solution at 60 °C for 6 h, and then irradiate them with γ rays at a dose of 2 kGy / min for 24 h to obtain an alumina support.

[0072] Active metal component loading method: Take 30 mL of a palladium chloride solution of 10 mg Pd / mL, dilute it to 71 mL with deionized water, add 0.521 g of chloroauric acid to it, stir it uniformly, and then impregnate it into 100 g of the alumina support prepared by the above method, dry it at 100 °C for 12 h, and calcine it at 450 °C for 12 h to obtain catalyst S3, which has a Pd loading of 0.30% and an Au loading of 0.25% by mass content.

[0073] Example 4

[0074] Support preparation: Take 120 g of pseudo-boehmite powder (same physical properties as in Example 1), 20 g of γ-Al2O3 powder, 10 g of fast deoxidized aluminum powder, 4.5 g of sesbania powder, 5 g of starch, 3.7 g of carbon black, and mix them uniformly. Take 2.5 g of concentrated hydrochloric acid and 1.2 g of acetic acid, add them to 160 g of deionized water to prepare a mixed solution. Add the mixed solution to the mixed powder, and then put them together into a kneader to be kneaded thoroughly. Then, extrude and cut them to obtain cylindrical particles with a particle size of 2-4 mm. Dry them at 80°C for 8 h, crystallize them at 120°C and 0.2 MPa for 18 h, then immerse them in a mixed solution of 0.1 mol / L nitric acid and 0.1 mol / L hydrogen peroxide at 80°C for 10 h, and freeze-dry them at -40°C for 8 h to obtain an alumina support.

[0075] Active metal component loading method: Take 20 mL of 10 mg Pd / mL palladium nitrate solution, dilute it to 65 mL with deionized water, add 0.158 g of silver nitrate to it, stir it uniformly, and then immerse it into 100 g of the alumina support prepared by the above method. Dry it at 140°C for 4 h, and calcine it at 520°C for 4 h to obtain a catalyst precursor containing Pd and Ag. Take 0.413 g of chromium nitrate, dissolve it in 65 mL of deionized water, immerse the catalyst precursor containing Pd and Ag, then dry it at 120°C for 12 h, and calcine it at 550°C for 6 h to obtain catalyst S4. According to the mass content, the Pd loading is 0.20%, the Ag loading is 0.10%, and the Cr loading is 0.05%.

[0076] Example 5

[0077] Support preparation: Take 120 g of pseudo-boehmite powder (same physical properties as in Example 1), 20 g of γ-Al2O3 powder, 10 g of barium oxide, 5.8 g of cyanoethyl cellulose, 4.8 g of polypropylene glycol, and 30 g of diamond, and mix them uniformly. Take 6.9 g of ascorbic acid and 1.2 g of concentrated hydrochloric acid, add them to 175 g of a solvent of ethanol and deionized water (volume ratio 5:1) to prepare a mixed solution. Add the mixed solution to the mixed powder, and then put them together into a kneader to be kneaded thoroughly. Then, extrude and cut them to obtain cylindrical particles with a particle size of 2-4 mm. Dry them at 100°C for 4 h, heat-treat them at 350°C and 0.2 MPa for 3 h in an ethyne and argon gas (volume ratio 0.05:1) atmosphere, immerse them in a 0.1 mol / L sodium hydroxide solution at 40°C for 10 h, and then irradiate them with a 50W microwave for 60 min to obtain an alumina support.

[0078] Active metal component loading method: Take 10 mg Pd / mL of palladium chloride solution 25 mL, dilute to 70 mL with deionized water, dry at 110°C for 12 h, and calcine at 450°C for 8 h to obtain a Pd-containing catalyst precursor. Take 0.189 g of lead acetate, add to 70 mL of deionized water, impregnate the Pd-containing catalyst precursor, then dry at 100°C for 6 h and calcine at 450°C for 8 h to obtain catalyst S5, with a Pd loading of 0.25% and a Pb loading of 0.10% by mass content.

[0079] Comparative Example 1

[0080] Carrier preparation: Take 100 g of pseudoboehmite powder (with the same properties as in Example 1), 5 g of sesbania powder, 8 g of carboxymethyl cellulose, and 4 g of bamboo charcoal, mix well. Take 1.8 g of concentrated nitric acid, add to 150 g of deionized water to prepare a mixed solution. Add the mixed solution to the mixed powder, and then put them together into a kneader for thorough kneading, then extrude and cut into particles to obtain cylindrical particles with a particle size of 2-4 mm. After drying and air heat treatment (operation temperature, pressure, and time are the same as in Example 1), an alumina carrier is obtained.

[0081] Active metal component loading method: Take 10 mg Pd / mL of palladium nitrate solution 35 mL, dilute to 65 mL with deionized water, dry at 120°C for 12 h, and calcine at 500°C for 8 h to obtain catalyst D1, with a Pd loading of 0.35% by mass content.

[0082] Comparative Example 2

[0083] Carrier preparation: Take 100 g of pseudoboehmite powder (with the same properties as in Example 1), 10 g of silicon oxide, 5 g of sesbania powder, and 10 g of ethyl cellulose, mix well. Then take 1.8 g of concentrated nitric acid, add to 150 g of deionized water to prepare a mixed solution. Add the mixed solution to the mixed powder, and then put them together into a kneader for thorough kneading, then extrude and cut into particles to obtain cylindrical particles with a particle size of 2-4 mm. After drying and air heat treatment (operation conditions are the same as in Example 2), an alumina carrier is obtained.

[0084] Active metal component loading method is the same as in Comparative Example 1 to obtain catalyst D2.

[0085] Comparative Example 3

[0086] Carrier preparation: Take 100 g of pseudoboehmite powder (with the same properties as in Example 1), 5 g of sesbania powder, 8 g of carboxymethyl cellulose, and 4 g of bamboo charcoal, mix well. Take 1.8 g of concentrated nitric acid, add to 150 g of deionized water to prepare a mixed solution. Add the mixed solution to the mixed powder, and then put them together into a kneader for thorough kneading, then extrude and cut into particles to obtain cylindrical particles with a particle size of 2-4 mm. After drying and air heat treatment (operation temperature, pressure, and time are the same as in Example 1), an alumina carrier is obtained. 2 / g, pore volume 0.8ml / g, bulk density 0.16g / ml 20g alumina trihydrate powder, 80g α-Al2O3 powder, 6g polyethylene glycol, 7g methylcellulose, are mixed uniformly. Take 4g oxalic acid and 4g acetic acid, add 150g deionized water to prepare a mixed solution. The mixed solution is added to the mixed powders, and then put into a kneader and fully kneaded. After extrusion and pelletization, cylindrical particles with a particle size of 2-4mm are obtained. After drying, crystallization and oxidation (operating conditions are the same as in Example 3), an alumina support is obtained.

[0087] The active metal component loading method was the same as that of Comparative Example 1 to obtain catalyst D3.

[0088] Test Example 1 Carrier Characterization

[0089] Determination of oxygen groups on alumina supports: The nature and quantity of oxygen groups on the supports were determined using the Boehm method. Three 0.6g portions of the supports were each soaked for 24 hours in 40ml of 0.05mol / L NaHCO3, Na2CO3, and NaOH solutions. 10ml of the soaking solution was titrated with 0.05mol / L hydrochloric acid. Each sample was titrated three times, and the arithmetic mean was taken. The number of each oxygen group on the supports was calculated based on the base consumption. The oxygen group density was then calculated based on the support specific surface area data. The results are listed in Table 1.

[0090] Table 1. Test results of oxygen-containing groups on alumina supports in Examples and Comparative Examples

[0091]

[0092] As shown in Table 1, the content and density of oxygen-containing groups on the surface of the alumina support prepared using the method of the present invention are significantly higher than those of the alumina support prepared in the comparative example. By adjusting the raw material ratio, preparation process parameters, and conditions, the method of the present invention can regulate the number and type of oxygen-containing groups on the surface of the alumina support.

[0093] Test Example 2 Catalyst Performance Evaluation

[0094] The above catalyst was used to carry out C3 liquid phase selective hydrogenation reaction, and the experimental conditions were as follows:

[0095] 50 ml of catalyst was loaded into a stainless steel tubular reactor. After nitrogen displacement, hydrogen was introduced for activation at 120°C for 4 hours. After cooling to room temperature, the atmosphere was purged with nitrogen and the liquid C3 reaction feedstock was introduced. The molar composition of the reaction materials was: 5.12% propane, 92.3% propylene, 1.19% propadiene, and 1.39% propyne. The molar ratio of hydrogen to alkyne (propyne and propadiene) was 1.5. The reactor inlet temperature was 35°C and the reaction pressure was 1.8 MPa. The conversion and selectivity of each catalyst were evaluated under the same reaction conditions. The results are shown in Table 2.

[0096] The conversion (%) and selectivity (%) of propyne and propadiene (collectively referred to as MAPD in the table) are calculated as follows:

[0097]

[0098]

[0099] Wherein, MAPD stands for propyne and propadiene, (MAPD) in is the content of MAPD at the reactor inlet, (MAPD) out is the content of MAPD at the reactor outlet, (C2H6) in is the content of C2H6 at the reactor inlet, (C2H6) out is the content of C2H6 at the reactor outlet, and the contents of the above components are measured by a gas chromatograph equipped with a FID detector.

[0100] Table 2. Evaluation results of catalysts obtained in Examples and Comparative Examples

[0101] catalyst MAPD conversion rate (%) Selectivity (%) S1 97.1 83.4 S2 94.2 80.5 S3 99.5 81.3 S4 96.5 85.3 S5 98.3 83.2 D1 88.5 80.1 D2 87.2 81.2 D3 89.2 79.3

[0102] According to the evaluation reaction results in Table 2, the catalysts of Examples 1-5 achieved significantly higher conversions than those of Comparative Examples 1-3 for the liquid-phase selective hydrogenation of C3. Furthermore, selectivity was also high at higher MAPD (propyne and propadiene) conversions. This indicates that the catalysts comprising alumina and carbide of the present invention exhibit superior catalytic activity and selectivity.

Claims

1. A C3 liquid-phase selective hydrogenation catalyst comprising a modified alumina support and a Pd metal component supported on the support, wherein the modified alumina support is a modified alumina support having a surface rich in oxygen-containing groups obtained by surface treatment of components including alumina and an inorganic carbon species, wherein the inorganic carbon species is selected from at least one of coke, activated carbon, carbon black, glassy carbon, charcoal, bamboo charcoal, coconut shell charcoal, graphene, graphyne, and diamond; and the surface treatment is selected from at least one of heat treatment, crystallization, oxidation, alkalization, and irradiation.

2. The catalyst according to claim 1, characterized in that In terms of mass percentage, the inorganic carbon species is 0.5-20% of the amount of alumina; and / or, The oxygen-containing group is at least one of a hydroxyl group, a carboxyl group, and a lactone group; and / or, The specific surface area of ​​the modified alumina carrier is 10-180 m 2 / g, water absorption rate of 30-120%, strength of 30-150N / particle, bulk density of 0.4-1.0g / ml, pore volume of 0.3-1.2ml / g; and / or, The modified alumina support further contains an optional inorganic compound other than alumina; and / or, Based on the total weight of the catalyst as 100%, the content of the Pd metal component is 0.08-0.8%; and / or, Optionally, a co-active metal component is added to the catalyst.

3. The catalyst according to claim 2, characterized in that In terms of mass percentage, the inorganic carbon species is 2-15% of the amount of alumina; and / or, The modified alumina carrier has a hydroxyl content of 3 to 60 mmol / g; and / or The modified alumina carrier has a carboxyl content of 1 to 80 mmol / g; and / or The content of lactone groups in the modified alumina carrier is 1 to 60 mmol / g; and / or, The inorganic compound other than aluminum oxide is selected from at least one of silicon oxide, magnesium oxide, barium oxide, calcium oxide and hydrotalcite; and / or In the modified alumina carrier, the mass ratio of the inorganic compound other than alumina to alumina is (0-30):100; and / or, Based on the total weight of the catalyst as 100%, the content of the Pd metal component is 0.08-0.5%; and / or, The auxiliary active metal component is selected from at least one of Ag, Cu, Au, As, Sn, Cr, and Pb; and / or, Based on the total weight of the catalyst being 100%, the content of the active metal component is 0-1%.

4. The catalyst according to claim 3, characterized in that The modified alumina carrier has a hydroxyl content of 5 to 40 mmol / g; and / or The modified alumina carrier has a carboxyl content of 1 to 60 mmol / g; and / or The content of lactone groups in the modified alumina carrier is 3 to 40 mmol / g; and / or, In the modified alumina carrier, the mass ratio of the inorganic compound other than alumina to alumina is (0-28):100; and / or, Based on the total weight of the catalyst being 100%, the content of the active metal component is 0.05-0.6%.

5. A method for preparing the C3 liquid phase selective hydrogenation catalyst according to any one of claims 1 to 4, comprising: The raw materials including alumina powder, a forming agent, a pore-forming agent, an inorganic carbon species and optional inorganic compounds other than alumina are granulated and surface-treated to obtain a modified alumina carrier, and then the Pd metal component and the optionally added auxiliary active metal component are loaded on the carrier to obtain the C3 liquid phase selective hydrogenation catalyst.

6. The preparation method according to claim 5, characterized in that The preparation method specifically comprises: (1) mixing alumina powder, a forming agent, a pore-forming agent, an inorganic carbon species, and optionally an inorganic compound other than alumina to obtain a mixed dry material; (2) After adding acidic solution, kneading into shape and extruding into granules; (3) Drying and surface treating the granulated material to obtain a modified alumina carrier; (4) A solution containing a Pd metal component precursor compound and an optionally added co-active metal component precursor compound is loaded on a carrier, dried, and calcined to obtain the C3 liquid phase selective hydrogenation catalyst.

7. The preparation method according to claim 6, characterized in that In step (1): The alumina powder is selected from at least one of pseudo-boehmite powder, alumina trihydrate powder, fast-deoxidizing alumina powder, and γ-Al2O3 powder; and / or, The forming agent is selected from at least one of polyethylene glycol cellulose, methyl cellulose, carboxymethyl cellulose, sodium hydroxymethyl cellulose, hydroxypropyl methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, cyanoethyl cellulose, hydroxypropyl cellulose and starch; and / or, The amount of the forming agent is 0.1-15 wt% of the total weight of the mixed dry materials; and / or, The pore-forming agent is selected from at least one of polyvinyl alcohol, polyethylene glycol, polyacrylamide, polypropylene glycol, and sesbania powder; and / or, The amount of the pore-forming agent is 0.1-15 wt% of the total weight of the mixed dry materials; and / or, The inorganic compound other than aluminum oxide is selected from at least one of silicon oxide, magnesium oxide, barium oxide, calcium oxide and hydrotalcite; and / or The inorganic carbon species is selected from at least one of coke, activated carbon, carbon black, glassy carbon, charcoal, bamboo charcoal, coconut shell charcoal, graphene, graphyne, and diamond.

8. The preparation method according to claim 7, characterized in that In step (1): The amount of the forming agent is 0.1-10 wt % of the total weight of the mixed dry materials; and / or, The amount of the pore-forming agent used accounts for 0.1-10 wt % of the total weight of the mixed dry materials.

9. The preparation method according to claim 6, characterized in that In step (2): The concentration of the acidic solution is 0.001 to 1 mol / L; and / or, The solvent in the acidic solution is selected from water or a mixed solution of water and an organic solvent; and / or, The acidic compound in the acidic solution is selected from at least one of an organic acid and an inorganic acid.

10. The preparation method according to claim 9, characterized in that In step (2): The organic solvent is selected from at least one of methanol, ethanol, and ethylene glycol; and / or, when the solvent in the acidic solution is a mixed solution of water and an organic solvent, the volume ratio of the organic solvent to water is (0.05-1.5):1; and / or, The acidic compound in the acidic solution is selected from at least one of acetic acid, maleic acid, malic acid, citric acid, oxalic acid, formic acid, tartaric acid, ascorbic acid, salicylic acid, succinic acid, nitric acid, sulfuric acid, hydrochloric acid, hypochlorous acid, and phosphoric acid.

11. The preparation method according to claim 6, characterized in that In step (3): The surface treatment is selected from at least one of heat treatment, crystallization, oxidation, alkalization, and irradiation treatment.

12. The preparation method according to claim 11, characterized in that In step (3): The heat treatment conditions include: the heat treatment atmosphere includes a first atmosphere and a second atmosphere, the first atmosphere is selected from at least one of carbon dioxide, water vapor, acetylene, ethylene, and methane, the second atmosphere is selected from at least one of air, nitrogen, argon, and helium, the volume ratio of the first atmosphere to the second atmosphere is (0.05-1):1, the heat treatment temperature is 300-1200°C, the heat treatment time is 1-24h, and the pressure is 0.1-3MPa; and / or, The crystallization conditions are: temperature of 120-250°C, pressure of 0.2-15 MPa, time of 4-18 h, and the solvent used for crystallization is at least one selected from water, ethanol, ethylene glycol, and ethylenediamine; and / or, The oxidation conditions are: temperature of 30-110°C, time of 0.2-10 h, the oxidant used for oxidation is at least one selected from nitric acid, sulfuric acid, ammonium persulfate, hydrogen peroxide, potassium permanganate, and ascorbic acid, and the concentration of the oxidant solution is 0.1-10 mol / L; and / or, The alkalization conditions are as follows: temperature of 30-110°C, time of 0.2-10 h, the alkaline compound used for alkalization is selected from at least one of sodium hydroxide, sodium bicarbonate, sodium carbonate, sodium acetate, sodium oxalate, sodium citrate, potassium hydroxide, potassium bicarbonate, potassium carbonate, potassium acetate, and potassium citrate, and the concentration of the alkaline compound solution is 0.1-10 mol / L; and / or, The irradiation treatment conditions are as follows: the ray source is selected from gamma rays and / or microwaves, wherein the gamma ray irradiation dose rate is 2-90 kGy / min, and the irradiation time is 0.2-24 h; the microwave power is 50-1000 W, and the irradiation time is 0.5-60 min.

13. The preparation method according to claim 6, characterized in that In step (4): The Pd metal component precursor compound is selected from at least one soluble compound of palladium; and / or, The auxiliary active metal component precursor compound is selected from at least one of chlorides, nitrates, acetates, sulfates, oxides, and metal organic compounds of Ag, Cu, Au, As, Sn, Cr, and Pb; and / or, The solvent in the solution is selected from at least one of water, hydrochloric acid, nitric acid, acetic acid, and alcohol; and / or, The total metal content in the solution is 0.01 to 500 mg / mL; and / or, The drying conditions are: drying temperature of 40-190° C., drying time of 4-48 hours; and / or, The calcination conditions are as follows: calcination temperature is 300-700° C., and calcination time is 2-24 hours.

14. The preparation method according to claim 13, characterized in that In step (4): The Pd metal component precursor compound is selected from at least one of palladium chloride, palladium nitrate, palladium acetate, and palladium sulfate; and / or, The auxiliary active metal component precursor compound is selected from at least one of chlorides, nitrates and acetates of Ag, Cu, Au, As, Sn, Cr and Pb; and / or, The solvent in the solution is water; and / or, The drying conditions are as follows: drying temperature is 50-140° C., and drying time is 4-24 hours.

15. Use of the C3 liquid phase selective hydrogenation catalyst according to any one of claims 1 to 4 or the C3 liquid phase selective hydrogenation catalyst obtained by the preparation method according to any one of claims 5 to 14 in a C3 fraction hydrogenation reaction.

16. The use according to claim 15, characterized in that The C3 liquid phase selective hydrogenation catalyst is subjected to reduction treatment before use; and / or, In the C3 liquid fraction, the molar percentage of propyne and propadiene is 0.5-6%; and / or, The conditions of the hydrogenation reaction are: reaction temperature of 25-70°C, and / or reaction space velocity of 5-120h -1 .

17. The use according to claim 16, characterized in that The gas used for reduction includes hydrogen and other gases, the other gas is nitrogen or methane, the molar percentage of hydrogen in the gas is 10-90%; and / or the reduction temperature is 90-350° C.; and / or the reduction time is 2-24 hours.

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