Method for removing dialkene from raffinate C4 through selective hydrogenation

Abstract

The invention relates to the technical field of hydrogenation, and discloses a method for removing dialkene from raffinate C4 through selective hydrogenation. The raffinate C4 contains butene and butadiene, and the method comprises the following steps: in the presence of a catalyst, the raffinate C4 is contacted with hydrogen, so that butadiene in the raffinate C4 is subjected to hydrogenation reaction; wherein the catalyst comprises a carrier, Pd and an auxiliary active component, the carrier is composed of Al2O3 and Ag-RexOy which are uniformly distributed, Ag is in a simple substance form, and RexOy is one Re oxide or a mixture of a plurality of Re oxides. According to the method disclosed by the invention, relatively high butene selectivity and relatively high butene yield are maintained by utilizing a synergistic effect of Ag-RexOy and an active component Pd in the carrier.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogenation, and in particular to a method for removing dienes by selective hydrogenation of residual carbon four. Background Art

[0002] The petroleum hydrocarbon cracking ethylene production unit produces a large amount of mixed C4 as a by-product. After the cracked mixed C4 fraction is subjected to solvent extraction of 1,3-butadiene and methyl tert-butyl ether, the remaining C4 raffinate contains 70-80% C4 monoolefins and 0.5%-1.5% diolefins. Diolefins are harmful impurities for the further utilization of olefins, which directly affect the effect of downstream process catalysts and product quality. Therefore, diolefins must be removed before butene separation. In industry, the removal of this part of diolefins mainly involves selective hydrogenation and deep extraction, the latter of which has high investment and energy consumption and poor economic benefits. The selective hydrogenation process has the characteristics of simple process, low reaction temperature and long catalyst life, and is currently the most generally accepted and economical and effective method.

[0003] The selective hydrogenation of C4 fraction to remove dienes is mainly to selectively hydrogenate butadiene to obtain butenes through a catalyst, while preventing the side reaction of butene hydrogenation to produce butane and the hydrogenation coupling of butadiene to produce C8 or hydrocarbons with a larger molecular weight. The challenges faced by the selective hydrogenation reaction of trace butadiene in the C4 fraction are: first, to control the butadiene concentration at the reactor outlet, that is, the butadiene conversion rate; second, to obtain a higher butene yield while ensuring a high conversion rate, that is, product selectivity. Therefore, the ideal C4 hydrocarbon selective hydrogenation catalyst should be able to avoid the deep hydrogenation of butene to produce butane, and at the same time inhibit the process of butadiene hydrogenation coupling on the catalyst surface to produce long-chain hydrocarbons.

[0004] Palladium (Pd) supported catalysts have been widely used in the petrochemical industry as the best active component for the selective hydrogenation of dienes and alkynes. During the reaction, the active component Pd not only catalyzes the selective hydrogenation of butadiene to form butene, but also catalyzes the hydrogenation of butene to form butane. This requires that the palladium catalyst can ensure that butadiene is converted into butene as much as possible at a certain temperature while minimizing over-hydrogenation. In current research, Ag is generally used as an additive to improve the hydrogenation environment and electron cloud distribution of Pd. The energy of the 5s orbital of the Ag atom is close to that of the 4d orbital of the Pd atom. After the Pd-Ag coordination is formed, the 5s electron of the Ag atom will fill the empty 4d electron orbital of the Pd atom, increasing the electron cloud density of the d orbital of the Pd atom, enhancing the binding force of the Pd atom with the H atom, and reducing the binding force with alkynes, dienes and monoolefins. The adsorption of monoolefins on Pd atoms is mainly combined with Pd in ​​the form of σ-Л feedback bonds. The empty 4d orbital of Pd atoms is the key to the formation of σ-Л feedback bonds. The addition of Ag reduces the empty 4d electron orbital of Pd, weakens the adsorption capacity of Pd atoms for olefins, and inhibits the continued over-hydrogenation of olefins.

[0005] Patent US7582805 discloses a catalyst for selective hydrogenation of alkynes and dienes, wherein the catalyst is a palladium-silver catalyst supported by silica, and the carbon deposition and deactivation in the reaction are reduced by increasing the Ag / Pd ratio in the catalyst.

[0006] Patent CN108863697A discloses a palladium-silver-lead selective hydrogenation catalyst, which is prepared by an impregnation method using nickel-containing alumina as a carrier to obtain a palladium-silver-lead selective hydrogenation catalyst, with a palladium content of 0.2-0.7wt%, a silver content of 0.5-3.0wt%, and a lead content of 0.2-2wt%.

[0007] Ag is loaded on the carrier surface by traditional impregnation or spraying process, usually in agglomerated flake distribution, which easily covers the surface of Pd particles, causing the catalyst to lose hydrogenation activity and the corresponding ethylene selectivity is also reduced, so it is necessary to improve the distribution state of Ag in the catalyst. Therefore, it is very important to ensure that the catalyst can ensure hydrogenation activity while accurately achieving efficient selective hydrogenation of butadiene, and to provide a selective hydrogenation method with excellent selectivity while ensuring butadiene conversion rate for selective hydrogenation of residual carbon four. Summary of the invention

[0008] The purpose of the present invention is to overcome the above problems in the prior art and provide a method for selectively hydrogenating diolefins from residual carbon four, which can reduce the occurrence of side reactions of excessive hydrogenation while ensuring the conversion rate of butadiene.

[0009] In order to achieve the above object, the present invention provides a method for selectively hydrogenating diolefins from raffinate C4, wherein the raffinate C4 contains butene and butadiene, and the method comprises: contacting the raffinate C4 with hydrogen in the presence of a catalyst to hydrogenate the butadiene in the raffinate C4;

[0010] The catalyst is a supported Pd selective hydrogenation catalyst, comprising a carrier, Pd and an active component, wherein the carrier comprises Al2O3 and Ag-Re x O y Re and Ag have a good synergistic effect. Re can prevent excessive agglomeration of Ag and cover the surface of Pd particles to affect the hydrogenation activity of the catalyst. It can also increase the valence of silver, weaken the degree of Pd-Ag electron transfer, and increase the selectivity for butene.

[0011] Wherein, the Ag-Re x O y Evenly distributed with Al2O3, Ag is in single substance form, Re x O y It is one Re oxide or a mixture of multiple Re oxides, wherein x is 1 or 2, and y is an integer of 1-7.

[0012] The weight proportion of Ag in the carrier is 0.2-3%, the weight proportion of Re is 0.2-5%, and the rest is Al2O3; preferably, the weight proportion of Ag is 0.2-2.5%, the weight proportion of Re is 0.2-4%.

[0013] The Al2O3 crystal form contains at least one of the θ phase, the γ phase and the α phase, wherein the θ phase crystal form accounts for more than 60%, the γ phase crystal form accounts for less than 40%, and the α phase crystal form accounts for less than 10%.

[0014] Wherein, the Pd is the main active component, and its content is 0.02-2wt% of the total mass of the carrier, preferably 0.05-1wt% of the total mass of the carrier, and more preferably 0.1-0.8wt% of the total mass of the carrier.

[0015] Among them, the auxiliary active component is selected from at least one of Zn, Bi, Sn, Mn, Group VIII elements other than palladium, alkali metal elements, alkaline earth metal elements, Group IIIA elements, Group IB elements, rare earth elements and halogen elements, such as Ga, In, La, Ni, Zn, Fe, Bi, Sn, Y, Mn, Cu, Au, etc.

[0016] The content of the auxiliary active component is 0.01 to 5 wt % of the total mass of the carrier, preferably 0.01 to 2 wt %, and more preferably 0.05 to 1 wt %.

[0017] Wherein, the specific surface area of ​​the carrier is 100 to 500 m 2 / g, preferably 200 to 400 m 2 / g, preferably 220~350m 2 / g.

[0018] The butadiene content in the raffinate C4 is 0.01 to 10 mol%, preferably 0.2 to 5 mol%.

[0019] The total content of butene in the raffinate C4 is 30 to 80 mol%, preferably 40 to 75 mol%.

[0020] The raffinate C4 also includes butane, and the total content of butane is 8 to 30 mol%, preferably 10 to 25 mol%.

[0021] The liquid hourly volume space velocity of the extracted carbon four is 5 to 100 h -1 , preferably 6 to 50 hours -1 .

[0022] The contact temperature is 20 to 80° C., preferably 35 to 60° C.; the contact pressure is 0.5 to 4 MPa, preferably 0.6 to 2.5 MPa.

[0023] The molar ratio of hydrogen to butadiene in the extracted carbon tetracarbonate is (0.5-10):1, preferably (0.8-5):1.

[0024] The method of the present invention can make the butadiene content in the hydrogenation reaction product less than 1 μg / g, avoid deep hydrogenation of butene to form butane, and have a high butene yield. At the same time, it can inhibit the excessive hydrogenation process of butadiene and carbon four alkynes on the catalyst surface, reduce coking, and extend the operating time of the hydrogenation reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the X-ray photoelectron spectroscopy (XPS) of Re in the carrier of catalyst C-1 prepared in Preparation Example 1.

[0026] Figure 2 This is the X-ray photoelectron spectroscopy (XPS) of Ag in the carrier of catalyst C-1 prepared in Preparation Example 1. DETAILED DESCRIPTION

[0027] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0028] The pressure in the present invention is absolute pressure.

[0029] According to a preferred embodiment of the present invention, the method for selective hydrogenation of raffinate C4 comprises: contacting raffinate C4 with hydrogen in the presence of a catalyst to hydrogenate butadiene in the raffinate C4; the raffinate C4 contains butene and butadiene.

[0030] The butadiene content in the raffinate C4 is 0.01 to 10 mol%, preferably 0.2 to 5 mol%; wherein the butadiene includes 1,3-butadiene and / or 1,2-butadiene;

[0031] According to the present invention, preferably, the total content of butene (including at least one of 1-butene, trans-2-butene, cis-2-butene and isobutylene) in the raffinate C4 is 30 to 80 mol%;

[0032] According to the present invention, preferably, the total content of butane (including at least one of normal butane and isobutane) in the residual carbon four is 8 to 30 mol%;

[0033] In the present invention, butane may include isobutane and / or normal butane.

[0034] According to the present invention, preferably, the liquid hourly volume space velocity of the residual carbon four is 5 to 100 h -1 , more preferably 6 to 50 hours -1 , more preferably 8 to 30 hours -1 .

[0035] According to the present invention, preferably, the contact temperature is 20 to 80°C, more preferably 35 to 60°C, and more preferably 45 to 60°C, and the contact pressure is 0.5 to 4 MPa, more preferably 0.6 to 2.5 MPa, and more preferably 1.0 to 2.3 MPa. In the present invention, it is understood that the contact temperature refers to the temperature at the inlet of the hydrogenation reactor.

[0036] According to the present invention, preferably, the molar ratio of hydrogen to 1,3-butadiene in the raffinate C4 is 0.5 to 10:1, more preferably 0.8 to 5:1.

[0037] The supported Pd selective hydrogenation catalyst comprises a carrier, Pd and an active component, wherein the carrier comprises Al2O3 and Ag-Re x O y ; Ag-Re in the carrier x O y Evenly distributed with Al2O3, Ag is in single substance form, Re x O y It is a Re oxide or a mixture of multiple Re oxides, wherein x=1,2, y=1,2...7.

[0038] According to the present invention, the method for preparing the catalyst comprises the following steps:

[0039] Step 1, mixing powdered raw materials;

[0040] Step 2, adding an acidic aqueous solution to the mixture obtained in step 1, and then kneading into a shape;

[0041] Step 3, obtaining the carrier through drying and calcination in a high pressure atmosphere;

[0042] Step 4: Loading Pd and the auxiliary active component on the carrier obtained in step 3, and obtaining the Pd-loaded selective hydrogenation catalyst through drying and calcining.

[0043] In step 1, the powdered raw material includes at least one of aluminum oxide powder, a silver source, a rhenium source, and an optional shaping pore-forming agent, the silver source is selected from at least one of silver perrhenate and silver oxide, and the rhenium source is selected from at least one of silver perrhenate and rhenium oxide. The shaping pore-forming agent can be optionally added to the powdered raw material.

[0044] According to a preferred embodiment of the present invention, the silver source and the rhenium source include silver perrhenate and optionally rhenium oxide.

[0045] According to a preferred embodiment of the present invention, the silver source and the rhenium source include silver oxide and rhenium oxide.

[0046] The rhenium oxide may be at least one of rhenium dioxide and rhenium trioxide.

[0047] The silver perrhenate can be obtained commercially or prepared by conventional methods.

[0048] The method for preparing silver perrhenate may preferably include the following steps: (1) preparing an acidic solution of perrhenic acid or an ammonium perrhenate solution; (2) adding a silver nitrate solution dropwise to the prepared acidic solution of perrhenic acid or an ammonium perrhenate solution under stirring at 30 to 50° C. to produce a white precipitate, and the addition of the silver nitrate solution is completed. After standing for 20 to 40 minutes, the heating is stopped, and the solution is allowed to stand and cool to room temperature; (3) removing the filtrate, washing, vacuum drying, and then setting aside.

[0049] The molar ratio of the silver nitrate to perrhenic acid or ammonium perrhenate is (0.5-1.5):1; the acidic solution is a nitric acid solution.

[0050] The alumina powder is selected from pseudo-boehmite powder and optionally alumina powder.

[0051] The alumina powder is obtained by calcining pseudo-boehmite powder at a temperature selected from 800 to 900° C., and the amount of the alumina powder accounts for 0 to 20% of the total mass of the alumina powder.

[0052] The forming pore-forming agent is selected from at least one of sesbania powder, starch, cellulose, urea, ethylenediamine, and high molecular polymers; the amount of the forming pore-forming agent accounts for 0 to 10 wt% of the total amount of the alumina powder; the cellulose is selected from at least one of methyl cellulose, hydroxypropyl methyl cellulose, and sodium hydroxymethyl cellulose; the high molecular polymer is selected from at least one of polyethylene microspheres, polystyrene, polyethylene glycol, polyvinyl alcohol, and polyethylene glycol.

[0053] In step 2, the acidic aqueous solution is a mixed aqueous solution of perrhenic acid and other acids, and the other acids include at least one of nitric acid, acetic acid, oxalic acid, and citric acid; the weight ratio of the perrhenic acid to the other acids is (0.1-10):1, preferably (0.1-8):1; the weight ratio of the acidic aqueous solution to the powdered raw material is (0.4-2):1, preferably (0.5-1.5):1.

[0054] In step 3, the carrier molding drying temperature is 60-160°C; the carrier molding drying time is 2-24 hours; the carrier molding high-pressure atmosphere calcination temperature is 500-900°C, preferably 550-800°C; the carrier molding high-pressure atmosphere calcination time is 2-20 hours, preferably 3-10 hours; the atmosphere of the carrier molding high-pressure atmosphere calcination is selected from at least one of inert gas, nitrogen, air, and oxygen, and the oxygen content in the atmosphere is 0-40wt%, preferably 15-25wt%; the carrier molding high-pressure atmosphere calcination pressure is 2-5MPa, preferably 3-4MPa.

[0055] In step 4, the Pd is loaded in the form of a solution containing a precursor of Pd; the modifying component is loaded in the form of a solution containing a precursor of the modifying component, and the loading method is spraying or equal volume impregnation.

[0056] The Pd precursor is selected from at least one of palladium chloride, palladium nitrate, palladium acetate, palladium sulfate, palladium oxide and a metal organic compound of palladium.

[0057] The precursor of the co-active component is selected from at least one of the halides, nitrates, acetates, carbonates, sulfates, hydroxides, ammonium compounds or metal organic compounds of the co-active component.

[0058] The palladium and the auxiliary active components are loaded on the carrier, and the drying temperature is 60-160°C, the drying time is 4-12 hours, the roasting temperature is 280-600°C, the roasting time is 4-24 hours, and the roasting atmosphere is selected from at least one of inert gas, nitrogen and air.

[0059] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0060] The present invention will be further described below in conjunction with embodiments, but the scope of the present invention is not limited to these embodiments.

[0061] Unless otherwise specified, in the examples and comparative examples, the reagents used are all reagents conventionally used in the art, and the methods adopted are all conventional methods in the art.

[0062] The pseudo-boehmite powder used below was purchased from Sinopec Catalyst (Beijing) Co., Ltd., with a specific surface area of ​​300 m 2 / g or above.

[0063] Through X-ray electron spectroscopy (XPS) testing, it can be determined that in the carrier of the catalyst provided by the present invention, Ag exists in a simple form, and Re exists in at least one oxidation state. Component content calculation The content of Ag and Re in the catalyst carrier obtained in the preparation example is calculated according to the amount of carrier raw material, and the content of the supported component of the catalyst obtained in the preparation example is calculated according to the content of the active component and the auxiliary active component in the impregnation solution, wherein the content of Ag, Re and the catalyst supported component (Pd and auxiliary active component) are all calculated as elements and calculated based on the total weight of the carrier.

[0064] The crystal phase analysis of alumina carrier was carried out by XRD measurement and quantitative calculation using molecular simulation software Materials Studio.

[0065] Preparation Example 1

[0066] This preparation example is used to illustrate the preparation method of the palladium-supported selective hydrogenation catalyst provided by the present invention.

[0067] Dissolve 5g of silver nitrate in 10ml of deionized water. Dissolve 7.5g of ammonium perrhenate in 25ml of deionized water, slowly add the silver nitrate aqueous solution under stirring at 40℃ to produce a white precipitate, and let it stand for 30 minutes after all the addition is completed. Stop adding and cool to room temperature, remove the filtrate, wash the white precipitate with ether 3 times, and vacuum dry at 80℃ for use.

[0068] Weigh 200 g of pseudo-boehmite powder, 1.5 g of silver perrhenate, 0.1 g of rhenium trioxide, 4 g of sesbania powder, 4 g of methyl cellulose, and 4 g of polyethylene microspheres, and mix them in a mixer to obtain a uniform powdery raw material;

[0069] Weigh 3g of concentrated nitric acid and 0.3g of 75% perrhenic acid and add them into 200g of deionized water to prepare an acidic aqueous solution;

[0070] The uniform powdered raw material is transferred to a kneader, and the acidic aqueous solution is slowly added. After kneading for 1 hour, it is extruded and granulated to obtain toothed ball-shaped carrier particles with a particle size of 4 to 5 mm.

[0071] Dry at 110°C for 16 hours;

[0072] Al2O3-Ag-Re was obtained by calcining at 680℃ for 4 hours in air atmosphere at a pressure of 3MPa. x O y The carrier has a θ phase crystal type of 68.9%, a γ phase crystal type of 25.7%, and the rest is an α phase crystal type. The carrier has a specific surface area of ​​331m 2 / g, Ag content is 0.23wt%, Re content is 0.47wt%;

[0073] Prepare 250 mL of aqueous solution containing 0.6 g Pd in ​​Pd(NO3)2 and 0.4 g Ga in Ga(NO3)3, and mix Al2O3-Ag-Re x O y 200 g of the carrier was immersed in the solution, dried at 140 °C for 8 h, and calcined at 320 °C for 8 h to obtain Pd-Ga / Al2O3-Ag-Re x O y The catalyst, denoted as A, contains 0.3% Pd, 0.2% Ga, 0.23% Ag and 0.47% Re by weight.

[0074] Preparation Example 2

[0075] Preparation steps (1-6) are the same as in Preparation Example 1

[0076] Prepare 180 mL of aqueous solution containing 0.4 g Pd in ​​Pd(NO3)2 and 0.2 g La in La(NO3)3. x O y 200 g of the carrier was immersed in the solution, dried at 140 °C for 8 h, and calcined at 350 °C for 6 h to obtain Pd-La / Al2O3-Ag-Re x O y The catalyst, denoted as B, contains, by weight, 0.2% Pd, 0.1% La, 0.23% Ag and 0.47% Re.

[0077] Preparation Example 3

[0078] Dissolve 10g of silver nitrate in 20ml of deionized water. Prepare 55g of 25% perrhenic acid aqueous solution, slowly add the silver nitrate aqueous solution under stirring at 40℃ to produce a white precipitate, and let it stand for 30 minutes until all the addition is completed. Stop adding and cool to room temperature, remove the filtrate, wash the white precipitate with acetone 3 times, and vacuum dry at 80℃ for use.

[0079] Weigh 200 g of pseudo-boehmite powder, 2.0 g of silver perrhenate, 0.7 g of rhenium dioxide, 8 g of sesbania powder, 3 g of sodium hydroxymethylcellulose, and 10 g of polystyrene, and mix them in a mixer to obtain a uniform powdery raw material;

[0080] Weigh 2g of concentrated nitric acid and 0.5g of 75% perrhenic acid, add them into 220g of deionized water to prepare an acidic aqueous solution;

[0081] The uniform powdered raw material is transferred into a kneader, and the acidic aqueous solution is slowly added. After kneading for 1 hour, it is extruded and granulated to obtain spherical carrier particles with a particle size of 4 to 5 mm.

[0082] Dry at 120°C for 8 hours;

[0083] Al2O3-Ag-Re was obtained by calcining at 710℃ for 3 hours in a nitrogen-oxygen mixed atmosphere with a pressure of 2.56MPa and an oxygen content of 35%. x O y The carrier has a θ phase crystal type of 72.88%, a γ phase crystal type of 25.66%, and the rest is an α phase crystal type. The carrier has a specific surface area of ​​289m 2 / g, Ag content is 0.3wt%, Re content is 0.9wt%;

[0084] Prepare 220 mL of aqueous solution containing 1 g of Pd in ​​Pd(NO3)2 and 1 g of NaNO3, and mix Al2O3-Ag-Re x O y 200 g of the carrier was immersed in the solution, dried at 100 °C for 4 h, and calcined at 550 °C for 4 h to obtain Pd-Na / Al2O3-Ag-Re x O y The catalyst, denoted as C, contains, by weight, 0.5% Pd, 0.5% Na, 0.3% Ag and 0.9% Re.

[0085] Preparation Example 4

[0086] Preparation steps (1-6) are the same as in Preparation Example 3

[0087] Prepare 200 ml of aqueous solution containing 2 g Pd in ​​PdCl2 solution and 0.2 g Cu in CuCl2 to make Al2O3-Ag-Re x O y The support was impregnated in the solution, dried at 105°C for 2 h, and calcined at 380°C for 15 h to obtain Pd-Cu / Al2O3-Ag-Re x O y The catalyst, denoted as D, contains 1% Pd, 0.1% Cu, 0.3% Ag and 0.9% Re by weight.

[0088] Preparation Example 5

[0089] Weigh 200 g of pseudo-boehmite powder, 2.3 g of silver oxide, 0.6 g of rhenium dioxide, 5 g of sesbania powder, 7 g of hydroxypropyl methylcellulose, and 2 g of polyvinyl alcohol, and mix them in a mixer to obtain a uniform powdery raw material;

[0090] Weigh 4 g of citric acid and 0.9 g of 75% perrhenic acid, add them to 180 g of deionized water to prepare an acidic aqueous solution;

[0091] The uniform powdered raw material is transferred into a kneader, and the acidic aqueous solution is slowly added. After kneading for 2 hours, it is extruded and granulated to obtain columnar carrier particles with a particle size of 3 to 4 mm.

[0092] Dry at 120°C for 8 hours;

[0093] Al2O3-Ag-Re was obtained by calcining at 780℃ for 6 hours in a nitrogen-oxygen mixed atmosphere with a pressure of 3MPa and an oxygen content of 15%. x O y The carrier has a θ phase crystal type of 74.55%, a γ phase crystal type of 23.58%, and the rest is an α phase crystal type. The carrier has a specific surface area of ​​267m 2 / g, Ag content is 1wt%, Re content is 0.5wt%;

[0094] Prepare 300 mL of aqueous solution containing 1.4 g Pd in ​​PdCl2 and 0.2 g Zn in ZnCl2, and mix Al2O3-Ag-Re x O y 200 g of the carrier was immersed in the solution, dried at 120 °C for 8 h, and calcined at 480 °C for 6 h to obtain Pd-Zn / Al2O3-Ag-Re x O y The catalyst, denoted as E, contains, by weight, 0.7% Pd, 0.1% Zn, 1% Ag and 0.5% Re.

[0095] Preparation Example 6

[0096] Weigh 200 g of pseudo-boehmite powder, 2.3 g of silver oxide, 0.25 g of rhenium trioxide, 8 g of starch, 2 g of methyl cellulose, and 8 g of polyethylene microspheres, and mix them in a mixer to obtain a uniform powdery raw material;

[0097] Weigh 10g of oxalic acid and 1.5g of 75% perrhenic acid, add them to 230g of deionized water to prepare an acidic aqueous solution;

[0098] The uniform powdered raw material is transferred to a kneader, and the acidic aqueous solution is slowly added. After kneading for 10 hours, it is extruded and granulated to obtain toothed ball-shaped carrier particles with a particle size of 3 to 4 mm.

[0099] Dry at 105°C for 4 hours;

[0100] Al2O3-Ag-Re was obtained by calcining at 680℃ for 6 hours in air atmosphere at a pressure of 3MPa. x O y The carrier has a θ phase crystal type of 71.21%, a γ phase crystal type of 28.12%, and the rest is an α phase crystal type. The carrier has a specific surface area of ​​315m 2 / g, Ag content is 1wt%, Re content is 0.5wt%;

[0101] Prepare 240 mL of aqueous solution containing 1.2 g Pd in ​​Pd(NO3)2 and 0.2 g Fe in Fe(NO3)3. x O y 200 g of the carrier was immersed in the solution, dried at 120 °C for 8 h, and calcined at 290 °C for 12 h to obtain Pd-Fe / Al2O3-Ag-Re x O y The catalyst, denoted as F, contains, by weight, 0.6% Pd, 0.1% Fe, 1% Ag and 0.5% Re.

[0102] Preparation Example 7

[0103] Weigh 200 g of pseudo-boehmite powder, 2.3 g of silver oxide, 0.59 g of rhenium dioxide, 0.63 g of rhenium trioxide, 8 g of urea, 4 g of hydroxypropyl methylcellulose, and 4 g of polyethylene microspheres, and mix them in a mixer to obtain a uniform powdery raw material;

[0104] Weigh 3 g of acetic acid and 0.5 g of 75% perrhenic acid and add them to 200 g of deionized water to prepare an acidic aqueous solution;

[0105] The uniform powdered raw material is transferred to a kneader, and the acidic aqueous solution is slowly added. After kneading for 10 hours, it is extruded and granulated to obtain toothed ball-shaped carrier particles with a particle size of 3 to 4 mm.

[0106] Dry at 150°C for 2 hours;

[0107] Al2O3-Ag-Re was obtained by calcining at 750℃ for 3 hours in air atmosphere at a pressure of 4MPa. x O y The carrier has a θ phase crystal type of 72.3%, a γ phase crystal type of 23.8%, and the rest is an α phase crystal type. The carrier has a specific surface area of ​​282m 2 / g, Ag content is 1wt%, Re content is 0.64wt%;

[0108] Prepare 320 mL of PdCl2 containing 0.8 g Pd and HAuCl4 aqueous solution containing 0.1 g Au, and mix Al2O3-Ag-Re x O y The support was immersed in the solution, dried at 120°C for 8 h, and calcined at 440°C for 8 h to obtain Pd-Au / Al2O3-Ag-Re x O y The catalyst, denoted as G, contains, by weight, 0.4% Pd, 0.05% Au, 1% Ag and 0.64% Re.

[0109] Comparative Example 1

[0110] Weigh 200 g of pseudo-boehmite powder, 10 g of sesbania powder, and 5 g of starch, and mix them in a mixer to obtain a uniform powdery raw material;

[0111] Weigh 2g of citric acid and 2g of concentrated nitric acid, add them into 150g of deionized water to prepare an acidic aqueous solution; transfer the uniform powdered raw materials into a kneader, and slowly add the acidic aqueous solution, knead for 2 hours, and then perform extrusion molding and pelletizing to obtain columnar carrier particles with a particle size of 4 to 5mm;

[0112] Dry at 120°C for 8 hours;

[0113] The Al2O3 carrier was obtained by calcining at 1000℃ for 6 hours under normal pressure and air atmosphere;

[0114] Prepare 100 mL of an aqueous solution of Pd(NO3)2 containing 1.5 g of Pd and AgNO3 containing 1 g of Ag, soak 200 g of the obtained Al2O3 carrier in the solution, dry at 100°C for 8 h, and calcine at 500°C for 12 h to obtain a Pd-Ag / Al2O3 catalyst, denoted as H, in which Pd is 0.75% and Ag is 0.5%.

[0115] Comparative Example 2

[0116] Weigh 200 g of pseudo-boehmite powder, 2.3 g of silver oxide, 10 g of sesbania powder, and 5 g of starch, and mix them in a mixer to obtain a uniform powdery raw material;

[0117] Weigh 2g of citric acid and 2g of concentrated nitric acid, add them into 150g of deionized water to prepare an acidic aqueous solution; transfer the uniform powdered raw materials into a kneader, and slowly add the acidic aqueous solution, knead for 2 hours, and then perform extrusion molding and pelletizing to obtain columnar carrier particles with a particle size of 4 to 5mm;

[0118] Dry at 120°C for 8 hours;

[0119] The Al2O3-Ag carrier was obtained by calcining at 1000°C for 6 hours under normal pressure and air atmosphere;

[0120] Prepare 100 mL of an aqueous solution of Pd(NO3)2 containing 1.5 g of Pd, soak 200 g of the obtained Al2O3 carrier in the solution, dry at 100°C for 8 h, and calcine at 500°C for 12 h to obtain a Pd-Ag / Al2O3 catalyst, denoted as J, in which Pd is 0.75% and Ag is 1%.

[0121] Test Example 1

[0122] The catalysts of the above-mentioned preparation examples 1-7 were subjected to X-ray photoelectron spectroscopy test. The valence of Ag and Re was determined according to the XPS test results, and the main Re xO y The percentage distribution is shown in Table 1 below.

[0123] Table 1

[0124]

[0125]

[0126] Example 1

[0127] A single-stage adiabatic fixed bed reactor was used for hydrogenation reaction. First, the palladium catalyst was reduced with hydrogen. During the reaction, the residual carbon tetrachloride (the composition of the residual carbon tetrachloride is shown in Table 2) and hydrogen were mixed in proportion and introduced into the adiabatic fixed bed reactor filled with the catalyst. The liquid volume space velocity of the residual carbon tetrachloride at the inlet was 20h -1 The molar ratio of inlet hydrogen to butadiene (including 1,2-butadiene and 1,3-butadiene) in the raffinate C4 is 1.0-1.5:1, and the inlet temperature of the reactor is 35-45°C. The pressure in the reactor is 2.1MPa. By adjusting the reaction temperature and the amount of hydrogen to ensure that the outlet butadiene is <1μg / g, the average yield of butene (including 1-butene) in the hydrogenation reaction within 150h of reaction operation is calculated as shown in Table 3.

[0128] Table 2

[0129]

[0130] Butene yield = (butene molar amount at the inlet - butene molar amount at the outlet) / butene molar amount at the inlet × 100%.

[0131] Table 3

[0132]

[0133] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for selectively hydrogenating diolefins from raffinate C4, comprising contacting raffinate C4 with hydrogen in the presence of a catalyst to hydrogenate butadiene in the raffinate C4; wherein: The residual carbon four contains butene and butadiene, the catalyst comprises a carrier, Pd and an auxiliary active component, the carrier comprises Al2O3 and Ag-Re x O y , Ag is in single substance form, Re x O y is a Re oxide or a mixture of multiple Re oxides, x is 1 or 2, and y is an integer of 1-7.

2. The method according to claim 1, characterized in that: The butadiene content in the raffinate C4 is 0.01 to 10 mol%, preferably 0.2 to 5 mol%; and / or, The total content of butene in the raffinate C4 is 30 to 80 mol%, preferably 40 to 75 mol%; and / or, The raffinate C4 also includes butane, and the total content of butane is 8 to 30 mol%, preferably 10 to 25 mol%.

3. The method according to claim 1, characterized in that: The liquid hourly volume space velocity of the extracted carbon four is 5 to 100 h -1 , preferably 6 to 50 hours -1 and / or, The contact temperature is 20 to 80° C., preferably 35 to 60° C.; the contact pressure is 0.5 to 4 MPa, preferably 0.6 to 2.5 MPa; and / or, The molar ratio of hydrogen to butadiene in the extracted carbon tetracarbonate is (0.5-10):1, preferably (0.8-5):

1.

4. The method according to claim 1, characterized in that: The auxiliary active component is selected from at least one of Zn, Bi, Sn, Mn, Group VIII elements other than palladium, alkali metal elements, alkaline earth metal elements, Group IIIA elements, Group IB elements, rare earth elements, and halogen elements.

5. The method according to claim 1, characterized in that: Pd is 0.02-2 wt% of the total mass of the carrier, preferably 0.05-1 wt%, more preferably 0.1-0.8 wt%; The auxiliary active component is 0.01 to 5 wt % of the total weight of the carrier, preferably 0.01 to 2 wt %, more preferably 0.05 to 1 wt %.

6. The method according to claim 1, characterized in that: The Al2O3 crystal form includes at least one of the θ phase, the γ phase and the α phase, wherein the θ phase crystal form accounts for more than 60%, the γ phase crystal form accounts for less than 40%, and the α phase crystal form accounts for less than 10%; and / or, The weight percentage of Ag in the carrier is 0.2-3%, preferably 0.2-2.5%; and / or, The weight percentage of Re in the carrier is 0.2-5%, preferably 0.2-4%; and / or, The specific surface area of ​​the carrier is 100 to 500 m 2 / g, preferably 200 to 400 m 2 / g, more preferably 220 to 350 m 2 / g.

7. The method according to claim 1, characterized in that The catalyst is prepared by the following steps: Step 1, mixing powdered raw materials; Step 2, adding an acidic aqueous solution to the mixture obtained in step 1, and then kneading into a shape; Step 3, obtaining the carrier through drying and calcination in a high pressure atmosphere; Step 4, loading Pd and the auxiliary active components on the carrier obtained in step 3, and drying and calcining; The powdered raw material comprises at least one of aluminum oxide powder, a silver source, a rhenium source, and an optional forming pore-forming agent, the silver source is selected from at least one of silver perrhenate and silver oxide, and the rhenium source is selected from at least one of silver perrhenate and rhenium oxide.

8. The method according to claim 7, characterized in that: The alumina powder is selected from at least one of pseudo-boehmite powder and optional alumina powder; the alumina powder is obtained by calcining pseudo-boehmite powder at 800-900° C., and the amount of the alumina powder accounts for 0-20% of the total mass of the alumina powder; and / or, The shaping pore-forming agent is selected from at least one of sesbania powder, starch, cellulose, urea, ethylenediamine, and high molecular polymers; the amount of the shaping pore-forming agent accounts for 0 to 10 wt % of the total amount of the alumina powder.

9. The method according to claim 7, characterized in that In step 2: The acidic aqueous solution is a mixed aqueous solution of perrhenic acid and other acids, wherein the other acids are selected from at least one of nitric acid, acetic acid, oxalic acid and citric acid; and / or, The weight ratio of the perrhenic acid to the other acid is (0.1-10):1, preferably (0.1-8):1; and / or, The weight ratio of the acidic aqueous solution to the powdered raw material is (0.4-2):1, preferably (0.5-1.5):

1.

10. The method according to claim 7, characterized in that In step 3: The molding and drying temperature is 60 to 120°C; the drying time is 8 to 24 hours; and / or, The high pressure atmosphere calcination temperature is 500 to 900° C., preferably 550 to 800° C.; the high pressure atmosphere calcination time is 2 to 20 hours, preferably 3 to 10 hours; and / or, The atmosphere of high pressure atmosphere calcination is selected from at least one of inert gas, nitrogen, air and oxygen, and the oxygen content in the atmosphere is 0 to 40 wt %, preferably 15 to 25 wt %; and / or, The pressure of high-pressure atmosphere calcination is 2 to 5 MPa, preferably 3 to 4 MPa.

11. The method according to claim 7, characterized in that In step 4: The Pd is loaded in the form of a solution containing a Pd precursor; the co-active component is loaded in the form of a solution containing a co-active component precursor, and the loading method is spraying or equal volume impregnation; and / or, The Pd precursor is selected from at least one of palladium chloride, palladium nitrate, palladium acetate, palladium sulfate, palladium oxide, and a metal organic compound of palladium; and / or, The precursor of the auxiliary active component is selected from at least one of the halides, nitrates, acetates, carbonates, sulfates, hydroxides, ammonium compounds and metal organic compounds of the auxiliary active component; and / or, The drying temperature is 60-160° C., the calcination temperature is 280-600° C., and the calcination atmosphere is selected from at least one of an inert gas, nitrogen, and air.

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