Selective hydrogenation catalyst for carbon four alkyne and preparation method thereof

Abstract

The application discloses a carbon four alkyne selective hydrogenation catalyst and a preparation method thereof. The carrier alumina is a leaf-shaped aggregate structure. The carbon four alkyne selective hydrogenation catalyst comprises 8-25 wt% of nickel oxide, 0.05-5 wt% of silver oxide, 0-1.5 wt% of copper oxide and the rest of the carrier. The carbon four alkyne selective hydrogenation catalyst prepared by the application has the characteristics of high selectivity and good stability, and can be used to effectively reduce the alkyne content in carbon four fractions.

Description

Technical Field

[0001] This invention relates to a selective hydrogenation catalyst for C4 acetylene and its preparation method, specifically to a catalyst for selective hydrogenation of vinyl acetylene from the C4 fraction produced as a byproduct in the process of steam cracking to produce ethylene to recover butadiene. Background Technology

[0002] The C4 fraction, a byproduct of high-temperature hydrocarbon cracking for ethylene production, typically contains 40%–60% butadiene by mass. Butadiene is a crucial monomer in the synthetic rubber industry. Separating butadiene from the C4 fraction primarily employs a two-stage solvent extraction distillation process. Common solvents used include the acetonitrile method, the N-methylpyrrolidone method, and the dimethylformamide method. The first stage of extraction separates butene, butane, and crude butadiene. The second stage removes alkynes (including vinylacetylene (VA), ethylacetylene (MA), and methylacetylene (MA)) from the crude butadiene. Further purification by distillation yields polymer-grade butadiene. Due to the high concentration of alkynes in the extracted C4 fraction, and the fact that they currently have no industrial value, they are typically disposed of by combustion. However, because high concentrations of alkynes pose an explosion hazard, in industrial production, for safety reasons, an equal amount of butadiene must be released during alkyne separation, and the mixture must be diluted with appropriate amounts of butene and butane fractions before being sent to a flare for combustion. This not only results in significant resource waste but also environmental pollution. These factors all contribute to increased energy consumption, significant butadiene loss, and reduced economic viability in traditional C4 solvent extraction units. Due to factors such as cracking depth and cracking technology, the alkyne content in cracked C4 fractions gradually increases, leading to greater butadiene loss and energy consumption during extraction. Furthermore, with the development of organic synthesis technology, restrictions on the alkyne content in butadiene have become more stringent, further deteriorating the economics of butadiene extraction units. Selectively hydrogenating alkynes during butadiene extraction to recover a portion of the butadiene not only achieves the goal of turning waste into treasure but also plays a crucial role in reducing alkyne emissions and preventing environmental pollution.

[0003] The C4 hydrogenation process for removing alkynes is mainly divided into pre-hydrogenation and post-hydrogenation. The pre-hydrogenation process selectively hydrogenates the alkynes in the C4 fraction before extracting butadiene. The post-hydrogenation process selectively hydrogenates the alkyne-rich C4 fraction discharged after butadiene extraction, converting the alkynes into 1,3-butadiene, which is then returned to the extraction unit for butadiene recovery. There are three main types of catalysts for the selective hydrogenation of the C4 fraction: Cu-based, Ni-based, and Pd-based catalysts. These catalysts must not only effectively remove alkynes but also minimize the loss of 1,3-butadiene; therefore, high selectivity is crucial. Simultaneously, high stability is equally important for achieving long-term, low-cost operation of the unit.

[0004] Chinese patent CN201210055071.2 discloses three catalysts for the selective hydrogenation of C4 materials rich in 1,2-butadiene to remove alkynes and their preparation. All catalysts contain a support selected from at least one of alumina, amorphous aluminum silicate, and silicon dioxide. Based on the total weight of the catalyst, one catalyst contains an active component Cu at a content of 2–12 wt% and a metal promoter selected from at least one of Ag, Co, Zr, and Mo at a content of 3–10 wt%. Another catalyst includes components Pd and Pb, with Pd at a content of 0.1–0.6 wt% and Pb at a content of 1–7 wt%; and a metal promoter selected from at least one of Ag, Co, Zr, and Mo at a content of 0.1–1 wt%. The third catalyst includes an active component Ni at a content of 3–15 wt%; and a metal promoter selected from at least one of Ag, Mo, Zr, and Co at a content of 0.1–1 wt%. The patent involves three types of catalysts: Cu-based, Ni-based, and Pd-based catalysts.

[0005] Chinese patent CN109096032A relates to a selective hydrogenation catalyst for cracked C4 and a hydrogenation method for increasing the production of butene-1 from cracked C4. The selective hydrogenation catalyst for cracked C4 is a composite catalyst comprising a first-stage catalyst and a second-stage catalyst. The first-stage catalyst includes a support and the following active components: (a) Ni or its oxide; (b) Ag or its oxide. The second-stage catalyst includes a support and the following active components: (i) Palladium or its oxide; (ii) Group IB metals or their oxides. This process requires the synergistic effect of two-stage hydrogenation and two different catalysts to achieve the desired hydrogenation effect.

[0006] Chinese patent CN102049255A discloses a palladium-based catalyst for selective hydrogenation of cracked C4 fractions and its preparation method. The catalyst consists of an alumina support and a supported component, wherein the supported component comprises 0.05%–5% of the main active component Pd, a Bi co-active component with a Bi / Pd weight ratio of 0.1–20, and one or more rare earth elements La, Pr, and Nd with a total content of 0.01%–5%.

[0007] US Patent 4547600 discloses a Pd noble metal catalyst. This catalyst has a decent single-cycle operating capability and some application value when the alkyne content of the feedstock and the requirements for hydrogenation efficiency are not very high. However, the catalyst has low activity, and the alkyne content after hydrogenation remains relatively high. Furthermore, the catalyst exhibits poor selectivity, with significant loss of 1,3-butadiene during hydrogenation. Additionally, after 720 hours of reaction, the active component Pd is lost, with the Pd content in the catalyst decreasing from 0.3 wt% to 0.12 wt%, leading to a decline in catalyst activity that cannot be restored through regeneration.

[0008] The Cu-based catalyst invented in US Patent 4440956 exhibits good selectivity and minimal or almost no loss of butadiene during the reaction; however, its reactivity is very low, resulting in a very low volume hourly space velocity (typically less than 3 h⁻¹). -l This requires a very large catalyst volume, and because the catalyst deactivates quickly and requires frequent regeneration, multiple reactors are needed.

[0009] US Patent 3912789 discloses a Cu-based catalyst for liquid-phase hydrogenation. The catalyst support is γ-alumina, the active component is Cu, and the promoters include Ag, Pt, Pd, Mg, Ni, Co, Cr, Mo, etc. The Cu content is 3-13% of the alumina content, and the promoter content is preferably 1-20% of the total Cu and promoter content. However, the catalyst has a short activity cycle, with a lifespan of 175-200 hours, requiring repeated regeneration. Furthermore, this catalyst is suitable for treating C4 fractions with an alkyne content of less than 0.2 wt%.

[0010] Chinese patent CN109092298B relates to a selective hydrogenation catalyst for cracked C4 and a hydrogenation treatment method for increasing the production of butene-1 from cracked C4. The technical solution employing a two-stage composite palladium-based catalyst for selective hydrogenation of cracked C4, comprising a first-stage catalyst and a second-stage catalyst, wherein the first-stage catalyst includes a support and palladium or a compound thereof, and cerium or a compound thereof, and the second-stage catalyst includes a support and palladium or an oxide thereof, and a Group IB metal or a compound thereof, can be used to increase the production of butene-1 from butadiene-containing C4 materials.

[0011] Chinese patent CN101428228B discloses a selective hydrogenation catalyst and its preparation method. The catalyst uses alumina as a support and contains the active component palladium, the auxiliary agent copper, and auxiliary agents X1 and X2. Based on 100% of the total catalyst mass, it contains 0.1–0.5% palladium, 0.1–6% copper, 0.5–15% X1, 0.5–5% X2, and 0–2% of one or more auxiliary metals selected from cobalt, nickel, molybdenum, tungsten, lanthanum, silver, cerium, samarium, and neodymium. X1 is selected from IVA elements, and X2 is selected from alkali metals, alkaline earth metals, or mixtures thereof. The catalyst is suitable for the selective hydrogenation of alkyne-rich residues after butadiene extraction, but it is only suitable for processing C4 materials with high alkyne content and very low butadiene content.

[0012] Chinese patent CN100558684C discloses a palladium-based catalyst for the selective hydrogenation of acetylene. This catalyst uses La, Ti, and Nb as promoters and SiO2 as a support. The catalyst must be reduced at 300–600 °C before use. Its main function is to reduce the oxidized states of Pd, La, Ti, and Nb in the catalyst to their metallic states, thereby modifying the Pd surface and exhibiting a strong metal-support interaction (SMSI) phenomenon.

[0013] Chinese patent CN102886262A discloses a catalyst using a Ni-Cu bimetallic active element, wherein the Ni content is 10-20%, the Cu content is 3-10%, and the remainder is an alumina support. This catalyst achieves selectivity of 90% for EA (butyne) and 84.1% for VA (vinylacetylene), but also suffers significant butadiene loss, with a 67.5% reduction in butadiene content during the entire reaction.

[0014] In summary, both copper-based and palladium-based catalysts have certain limitations and are unsuitable for processing C4 fractions with high yethiamine content. Therefore, it is essential to find a catalyst that can selectively and stably process C4 fractions with high yethiamine content.

[0015] The microstructure and surface properties of alumina significantly influence the performance of supported catalysts, thus the controllable synthesis of alumina morphology and size has attracted considerable research interest. Currently, researchers have prepared alumina morphologies including flakes, rods, and spheres using various methods. Nanosheet alumina possesses a large specific surface area and high surface energy, exhibiting high dispersibility for the active metals in catalysts and a high diffusion rate for reactants, significantly reducing diffusion resistance. Therefore, as a support, it can greatly improve catalyst activity and anti-coking properties, demonstrating superior performance compared to traditional alumina. Currently, flake alumina research mainly focuses on the synthesis of micron-sized flake alumina, primarily for preparing flake alumina ceramics. The synthesis routes for nanosheet alumina are mostly developed based on surfactants as templates, resulting in higher costs and a tendency to agglomerate during high-temperature calcination, which limits its industrialization.

[0016] Chinese patent CN201710944136.1 discloses a method for preparing a nano-alumina carrier with a surface rich in defect sites: the steps are as follows: (1) Inorganic aluminum salt and precipitant are dissolved in a water-ethylene glycol mixed solvent at a molar ratio of 1:5 to 1:9, and stirred to obtain a transparent solution. The solution is then transferred to a hydrothermal reactor. The hydrothermal reaction temperature is 100 to 200°C, and the reaction time is 12 to 48 hours. (2) After the reaction is completed, the reaction material is filtered, washed, dried, and calcined to obtain a nano-alumina carrier rich in surface defects with a specific surface area of ​​150 to 400 m². 2 / g, pore volume is 0.34~0.62cm³ 3 / g. However, ethylene glycol in the mixed solvent is easily oxidized by hydrothermal metabolism to produce toxic oxalic acid, thus it cannot be widely used as a solvent and is not conducive to promotion.

[0017] Chinese patent CN201210427889.2 discloses a method for preparing an alumina carrier, comprising the following steps: taking an appropriate amount of aluminum salt solution with a concentration of 0.5-2.5 mol / L, adding an appropriate amount of urea to the aluminum salt solution and stirring until completely dissolved, wherein the amount of urea added is equal to the ratio of urea to Al. 3+ The molar ratio is 2-10:1; the above solution is placed in a sealed reaction vessel and reacted at 140℃-200℃ for 2-12 hours, followed by direct calcination to prepare the alumina support. Although the support prepared by this method has a high specific surface area and large pore size, the alumina support is obtained by directly drying and calcining the material after the reaction without filtration and washing, resulting in a high content of amorphous alumina and a dispersed pore distribution, which limits its further application.

[0018] Chinese patent CN201110351132.5 provides an improved hydrothermal method for preparing porous alumina ultrafine powder. The method uses aluminum inorganic salt as raw material and urea as co-precipitant to generate a precursor under hydrothermal conditions. The precursor is then centrifuged, washed, dried, and calcined to obtain porous alumina ultrafine powder with high purity, narrow particle size distribution, and high porosity.

[0019] Chinese patent CN107540007A discloses a method for preparing nanosheet mesoporous alumina: using inorganic aluminum salt as the aluminum source, triethanolamine as an additive, and ethylenediamine as a precipitant, nanosheet mesoporous alumina is obtained by hydrothermal aging treatment. The thickness of the nanosheet alumina sheets is 1-10 nm and the width is 0.1-0.5 μm.

[0020] Chinese patent CN107777713A discloses a γ-alumina hexagonal nanosheet material and its preparation method, with a size of 50-500 nm and a thickness of 5-10 nm. This invention uses aluminum alkoxides as raw materials, controls the two-dimensional growth of its intermediate alumina hydroxide through organic amines, and prepares γ-alumina hexagonal nanosheets using chemical precipitation and hydrothermal methods.

[0021] Chinese patent CN104961146A discloses a nanosheet aluminum hydroxide colloid and its preparation method, which involves directly hydrothermating anhydrous ethanol and anhydrous aluminum chloride at 220-300℃ to obtain a nanosheet gel with a thickness of 3-20 nm.

[0022] Chinese patent CN106276992A discloses a method for preparing leaf-shaped nano-γ-alumina. The method involves dissolving inorganic aluminum salts and urea in water to obtain a transparent solution, transferring the solution to a high-pressure reactor, and then introducing hydrogen gas into the reactor to maintain a certain pressure and temperature for the reaction to obtain leaf-shaped nano-γ-alumina. However, the leaf-shaped nano-γ-alumina is in a dispersed state and does not accumulate. It is prone to agglomeration during high-temperature calcination. When used as a catalyst support to load active metals, it reduces the dispersion of the active metals on the support surface. Furthermore, the use of hazardous hydrogen gas during the preparation process is detrimental to production safety.

[0023] The article by Li Jinlin et al., “Controllable Synthesis and Characterization of γ-Al2O3 Nanocrystals with Specific Morphology, Journal of South-Central University for Nationalities (Natural Science Edition), 2016, 35: 1-4,” prepared alumina nanosheets with a length of 60-100 nm using acetic acid and isopropanol as raw materials and hydrothermally at 200℃. The main exposed crystal plane was the (110) crystal plane. The article by Yuguo Xia et al., “Synthesis of AlOOH nanocrystals with different morphologies due to the effect of sulfate ions and the corresponding formation mechanism study, Phys. Chem. Chem. Phys., 2013, 15, 18290,” used nano-AlOOH as raw material, added sodium sulfate and sulfuric acid, and hydrothermally treated at 200℃ for 24 hours to obtain alumina nanosheets with a size of 60-100 nm. The alumina prepared by this method has a small specific surface area (<100 nm). 2 Moreover, the preparation process uses dilute acid, and the high-temperature hydrothermal process places high demands on the reactor material, which is not conducive to large-scale production. Summary of the Invention

[0024] The purpose of this invention is to provide a selective hydrogenation catalyst for C4 acetylenes and its preparation method. The selective hydrogenation catalyst for C4 acetylenes contains active components nickel and silver, and uses alumina with a leaf-like aggregate structure as a support. The prepared selective hydrogenation catalyst for C4 acetylenes has the characteristics of high selectivity and good stability, and can be used to effectively reduce the acetylene content in C4 fractions.

[0025] To achieve the above objectives, the present invention provides a selective hydrogenation catalyst for C4-acetylenes, comprising: 8-25 wt% nickel oxide, 0.05-5 wt% silver oxide, 0-1.5 wt% copper oxide, 0.1-4 wt% alkali metal and / or alkaline earth metal oxides, 0-3 wt% cerium oxide and / or lanthanum oxide, with the balance being a support, based on 100% of the total catalyst weight; the catalyst has a specific surface area of ​​60-160 m².2 / g, with a pore volume of 0.35~0.65ml / g; the carrier alumina has a leaf-like aggregate structure and is prepared by hydrothermal synthesis.

[0026] The selective hydrogenation catalyst for C4-tetrayne of the present invention is prepared by the following method:

[0027] Step (1): Add the compound that can decompose into NH3 and CO2 in the subsequent hydrothermal treatment in step (2) to the inorganic aluminum salt aqueous solution, and stir until completely dissolved to form a mixed solution;

[0028] Step (2): CO2 gas at a pressure of 0.1-2 MPa is introduced into the mixed solution, followed by hydrothermal treatment. The obtained product is filtered to separate solid and liquid. The obtained solid is washed, dried and calcined to obtain alumina carrier with a leaf-like aggregate structure.

[0029] The C4-acetylenic selective hydrogenation catalyst of the present invention is used in step (2) where the hydrothermal treatment is carried out in a hydrothermal reactor or a high-pressure reactor.

[0030] The C4-acetylenic selective hydrogenation catalyst of the present invention, wherein the compound that can decompose into CO2 and NH3 in the subsequent hydrothermal treatment in step (1) is selected from one or more of ammonium carbonate, ammonium bicarbonate, urea and ammonium oxalate.

[0031] In the selective hydrogenation catalyst for C4 acetylene of the present invention, the molar ratio of aluminum ions of inorganic aluminum salt to compound in step (1) is 0.1 to 4.0, preferably 0.5 to 3.

[0032] In the C4 acetylene selective hydrogenation catalyst of the present invention, the inorganic aluminum salt in step (1) can be one or more of aluminum sulfate, aluminum nitrate and aluminum chloride.

[0033] The C4-tetrylene selective hydrogenation catalyst of the present invention allows for hydrothermal treatment in step (2) using conventional process conditions in the art. The recommended process conditions of the present invention are: hydrothermal temperature of 100–300°C, hydrothermal treatment for 2–48 h; preferably, the hydrothermal temperature is 120–200°C, the hydrothermal time is 4–24 h, and drying is carried out at 80–120°C for 2–10 h.

[0034] Before molding, the carrier of the present invention can be supplemented with adhesives, extrusion aids, etc., as needed. The specific substances used and the amounts added can be determined according to existing knowledge in the art. For example, the adhesive can be one or more of nitric acid, phosphoric acid, hydrochloric acid, and sulfuric acid, and the amount added is 3 to 10 wt% of the total weight of the sample to be molded; the extrusion aid can be guar gum powder, etc., and its amount is generally 2 to 6 wt% of the total weight of the sample to be molded.

[0035] The C4-acetylene selective hydrogenation catalyst of the present invention may further contain rare earth elements cerium and / or lanthanum (in oxide form), preferably in a content of 0.1–1.5 wt%. The addition of cerium and / or lanthanum to the catalyst can suppress the growth of catalyst support grains during high-temperature calcination, improve the dispersion of the active component nickel, and thus improve the hydrogenation selectivity and stability of the catalyst. In the present invention, cerium and / or lanthanum are preferably added in the form of soluble nitrates.

[0036] The selective hydrogenation catalyst for C4-acetylenes of the present invention may further contain alkali metals and / or alkaline earth metals (in oxide form) at a content of 0.1–4 wt%, preferably 0.3–2 wt%. The alkali metal and / or alkaline earth metal is at least one selected from Li, Na, K, Ca, Mg, Sr, and Be, preferably one or two selected from Li, K, and Mg. When the catalyst is used for the selective hydrogenation of C4-acetylenes, the addition of alkali metals and / or alkaline earth metals can regulate the acidity or alkalinity of the catalyst support surface. Adjusting the acidity or alkalinity of the catalyst surface can improve hydrogenation activity and stability, and help reduce the deposition of carbon and colloids during hydrogenation, thereby extending the catalyst's lifespan. In the present invention, the alkali metals and / or alkaline earth metals are preferably added in the form of soluble nitrates, acetates, or citrates.

[0037] Rare earth elements cerium and / or lanthanum, as well as alkali metals and / or alkaline earth metals, can be added during the carrier molding process; they can also be added to the carrier after molding and before impregnation of the active component; they can also be added simultaneously with the active component impregnation solution during the impregnation of the active component; or they can be added after impregnation of the active component.

[0038] Rare earth elements cerium and / or lanthanum, as well as alkali metals and / or alkaline earth metals, are added during the carrier molding process. The calcination temperature after carrier drying is the calcination temperature for the final-shape carrier. Alternatively, rare earth elements cerium and / or lanthanum, as well as alkali metals and / or alkaline earth metals, are added to the carrier after molding but before impregnation with the active components. The calcination temperature after carrier drying is 400–800℃, and the calcination time is 3–10 h, preferably 500–700℃, and the calcination time is 4–6 h. Or, rare earth elements cerium and / or lanthanum, as well as alkali metals and / or alkaline earth metals, are added after impregnation with the active components. The calcination temperature is 300–550℃, and the calcination time is 3–8 h.

[0039] The calcination method and conditions described are commonly used for catalyst support calcination. Vertical furnaces, converters, and mesh belt kilns can be used. The calcination temperature of the support is the same as that before impregnation with the active components Ni and Ag, to ensure the required specific surface area and pore volume of the catalyst. Before or after calcination at this temperature, the support may be prepared through low-temperature calcination, but these are all intermediate transitional calcination steps. The calcination temperature for the shaping support is 620–1050℃, and the calcination time is 3–10 h, preferably 700–1000℃ and 4–6 h. The catalyst calcination temperature is 300–550℃, and the calcination time is 3–8 h.

[0040] The C4-acetylene selective hydrogenation catalyst of the present invention, based on 100% of the total catalyst weight, preferably contains 10-19 wt% nickel oxide, preferably 0.1-1.5 wt% silver oxide, and preferably 0.3-0.8 wt% copper oxide.

[0041] In the C4-acetylene selective hydrogenation catalyst of the present invention, the nickel, silver, and copper are added in the form of soluble salts. The soluble salt of nickel is selected from at least one of nickel nitrate, nickel acetate, nickel chloride, and nickel sulfate, preferably nickel nitrate or nickel acetate. The soluble salt of silver is preferably silver nitrate. The soluble salt of copper is preferably copper nitrate.

[0042] The selective hydrogenation catalyst for C4 acetylenes of the present invention is preferably reduced with hydrogen at 250–450°C for 6–24 hours before use.

[0043] This invention also provides a method for preparing the above-mentioned selective hydrogenation catalyst for C4-acetylenes, but the preparation method of this invention is not limited thereto. Preferably, the preparation method of this invention includes the following steps:

[0044] A soluble salt solution containing nickel, silver, and copper is impregnated onto a support in one or more steps, dried, and calcined at 300–450°C for 3–8 hours to obtain a C4-acetylene selective hydrogenation catalyst; the alumina support has a leaf-like aggregate structure.

[0045] The selective hydrogenation catalyst for C4-acetylenes of this invention uses alumina with a leaf-like aggregate structure as the support. This alumina uses inexpensive aluminum as a raw material and does not add a template agent. Hydrothermal treatment yields alumina with a regular leaf-like aggregate structure. The preparation method of this invention has advantages such as low cost, simple operation, and simple synthesis conditions. Furthermore, the alumina prepared by this invention has a leaf-like aggregate structure, which is easy to separate and does not agglomerate during high-temperature calcination, maintaining its nanosheet morphology.

[0046] The alumina used in the catalyst of this invention has a leaf-like aggregate structure, characterized by regular morphology, uniform particle size, high crystallinity, and high thermal stability. This leaf-like aggregate structure overcomes the drawbacks of conventional nano-sheet alumina products, such as difficulty in separation and easy agglomeration at high temperatures. The alumina with this leaf-like aggregate structure is easy to separate and does not agglomerate during high-temperature calcination, maintaining its nano-sheet morphology. Therefore, it can serve as an excellent catalyst support for the selective hydrogenation of C4-acetylenes. During the preparation process, CO2 gas is introduced, which effectively neutralizes the number of surface hydroxyl groups on the alumina leaves during crystallization. This reduces leaf curling caused by hydroxyl condensation during crystallization and effectively controls the width of the alumina leaves. Furthermore, it reduces the saturation of hydroxyl groups with aluminum ions, making the sheet-like alumina more conducive to chelation coordination with active metals. In addition, this invention uses a high molar ratio of aluminum ions to compounds, which improves the yield per batch and effectively reduces production costs. This preparation method is also low-cost and simple to operate.

[0047] The inventors of this invention unexpectedly discovered that a catalyst prepared using sheet-like alumina as a support, with Ni as the main active component and Ag as the second active component, not only exhibits high selectivity but also good stability, thus solving the problem of mutual constraints among activity, selectivity, and stability. The catalyst of this invention exhibits high selectivity; that is, during the hydrogenation reaction of C4-tetrayne, butadiene does not undergo hydrogenation or only undergoes a very small portion of hydrogenation. This is likely due to the high dispersion of Ni and Ag on the sheet-like alumina support, fully utilizing their synergistic effect. Furthermore, when the support is treated with alkali metals or alkaline earth metals or mixtures thereof, this invention can effectively control the acidity of the support surface, which is beneficial for inhibiting the polymerization reaction of dienes and reducing butadiene loss. Attached Figure Description

[0048] Figure 1 This is a SEM image of the leaf-shaped aggregate structure of alumina obtained in Example 1 of the present invention.

[0049] Figure 2 This is a SEM image of the alumina used in Comparative Example 1 of this invention. Detailed Implementation

[0050] The present invention will be specifically described below through embodiments. These embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments based on the above description of the present invention.

[0051] Example 1

[0052] (1) Carrier preparation

[0053] Aluminum nitrate and urea (molar ratio of aluminum ions to urea of ​​1.5) were added to deionized water, stirred until dissolved, and then transferred to a hydrothermal reactor. CO2 gas was introduced to 0.8 MPa, and the reaction was carried out at 180°C for 10 h. After cooling to room temperature, the precipitate was filtered, washed, and dried. The obtained product was mixed with nitric acid, phosphoric acid, guar gum powder, and water to form a plastic body, extruded into strips, dried at 120°C for 4 h, and calcined at 600°C for 4 h to obtain a leaf-shaped aggregate alumina support precursor. An aqueous solution of lithium carbonate and citric acid was prepared and impregnated onto the support using an equal-volume impregnation method. The mixture was dried at 120°C for 4 h and calcined at 920°C for 4 h to obtain a lithium-containing leaf-shaped aggregate alumina support.

[0054] (2) Catalyst preparation

[0055] Nickel nitrate, silver nitrate, and copper nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) using an equal-volume impregnation method. The solution was dried at 120°C and calcined at 350°C for 4 hours to obtain catalyst C1.

[0056] Based on the total weight of the catalyst (100%), catalyst C1 contains 16.5 wt% nickel oxide, 0.5 wt% silver oxide, 0.3 wt% copper oxide, 0.6 wt% lithium oxide, with the balance being the support, and has a specific surface area of ​​107 m². 2 / g, pore volume is 0.48ml / g.

[0057] Example 2

[0058] (1) Carrier preparation

[0059] Aluminum chloride and ammonium carbonate (molar ratio of aluminum ions to ammonium carbonate of 2.0) were added to deionized water, stirred until dissolved, and then transferred to a hydrothermal reactor. CO2 gas was introduced to 1.5 MPa, and the reaction was carried out at 220°C for 14 h. After cooling to room temperature, the precipitate was filtered, washed, and dried. The obtained product was mixed with nitric acid, phosphoric acid, guar gum powder, lanthanum nitrate, potassium nitrate, and water to form a plastic body, which was then extruded into strips. The strips were then dried at 120°C for 4 h and calcined at 880°C for 4 h to obtain a lanthanum and potassium-containing leaf-shaped aggregate alumina support.

[0060] (2) Catalyst preparation

[0061] Nickel acetate, silver nitrate, and copper nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) using an equal-volume impregnation method. The solution was dried at 120°C and calcined at 400°C for 4 hours to obtain catalyst C2.

[0062] Based on the total weight of the catalyst (100%), catalyst C2 contains 15.9 wt% nickel oxide, 0.3 wt% silver oxide, 0.5 wt% copper oxide, 0.5 wt% potassium oxide, 0.2 wt% lanthanum oxide, with the balance being the support, and has a specific surface area of ​​138 m². 2 / g, pore volume is 0.51ml / g.

[0063] Example 3

[0064] (1) Carrier preparation

[0065] Aluminum sulfate and ammonium bicarbonate (molar ratio of aluminum ions to ammonium bicarbonate of 2.5) were added to deionized water, stirred until dissolved, and then transferred to a hydrothermal reactor. CO2 gas was introduced to 1.7 MPa, and the reaction was carried out at 140°C for 17 h. After cooling to room temperature, the precipitate was filtered, washed, and dried. The obtained product was mixed with nitric acid, phosphoric acid, guar gum powder, and water to form a plastic body, which was then extruded into strips and dried at 120°C for 4 h and calcined at 560°C for 4 h to obtain a leaf-shaped aggregate alumina carrier precursor. A potassium hydroxide aqueous solution was prepared and impregnated onto the carrier using an equal-volume impregnation method. The carrier was dried at 120°C for 4 h and calcined at 850°C for 5 h to obtain a potassium-containing leaf-shaped aggregate alumina carrier.

[0066] (2) Catalyst preparation

[0067] The catalyst was prepared by a two-step impregnation method. In the first step, nickel acetate was dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) using an equal-volume impregnation method. The total nickel content of the impregnated catalyst was 35%. The solution was dried at 120°C and calcined at 350°C for 4 hours to obtain catalyst precursor Q1. In the second step, nickel nitrate and silver nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto Q1 using an equal-volume impregnation method. The solution was dried at 120°C and calcined at 430°C for 4 hours to obtain catalyst C3.

[0068] Based on the total weight of the catalyst (100%), catalyst C3 contains 18.4 wt% nickel oxide, 0.7 wt% silver oxide, 1 wt% potassium oxide, with the balance being the support, and has a specific surface area of ​​151 m². 2 / g, pore volume is 0.55ml / g.

[0069] Example 4

[0070] (1) Carrier preparation

[0071] Aluminum sulfate, aluminum nitrate, and urea (molar ratio of aluminum ions to urea of ​​1.0) were added to deionized water and stirred until dissolved. The mixture was then transferred to a hydrothermal reactor, and CO2 gas was introduced to a pressure of 1.2 MPa. The reaction was carried out at 150°C for 20 h. After cooling to room temperature, the precipitate was filtered, washed, and dried. The obtained product was mixed with nitric acid, phosphoric acid, guar gum powder, and water to form a plastic body. The mixture was extruded into strips, dried at 120°C for 4 h, and calcined at 590°C for 4 h to obtain a leaf-shaped aggregate alumina support precursor. An aqueous solution of lithium carbonate and citric acid was prepared and impregnated onto the support using an equal-volume impregnation method. The mixture was dried at 120°C for 4 h and calcined at 950°C for 4 h to obtain a lithium-containing leaf-shaped aggregate alumina support.

[0072] (2) Catalyst preparation

[0073] Nickel nitrate, silver nitrate, copper nitrate, and cerium nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) using an equal-volume impregnation method. The solution was dried at 120°C and calcined at 400°C for 3 hours to obtain catalyst C4.

[0074] Based on the total weight of the catalyst (100%), catalyst C4 contains 17.6 wt% nickel oxide, 1 wt% silver oxide, 0.8 wt% copper oxide, 0.3 wt% lithium oxide, 0.1 wt% cerium oxide, with the balance being the support, and a specific surface area of ​​95 m². 2 / g, pore volume is 0.39ml / g.

[0075] Example 5

[0076] (1) Carrier preparation

[0077] Aluminum nitrate, urea, and ammonium oxalate (the molar ratio of aluminum ions to the sum of the molar numbers of urea and ammonium oxalate was 3.0) were added to deionized water and stirred until dissolved. The mixture was then transferred to a hydrothermal reactor, and CO2 gas was introduced to a pressure of 2.0 MPa. The reaction was carried out at 160°C for 23 hours. After cooling to room temperature, the precipitate was filtered, washed, and dried. The obtained product was mixed with nitric acid, phosphoric acid, guar gum powder, and water to form a plastic mass. This mass was extruded into strips, dried at 120°C for 4 hours, and calcined at 550°C for 4 hours to obtain a leaf-shaped aggregate alumina support precursor. A lanthanum nitrate aqueous solution was prepared and impregnated onto the support using an equal-volume impregnation method. The mixture was dried at 110°C for 5 hours and calcined at 980°C for 4 hours to obtain a lanthanum-containing leaf-shaped aggregate alumina support.

[0078] (2) Catalyst preparation

[0079] The catalyst was prepared by a two-step impregnation method. In the first step, nickel chloride and magnesium nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) using an equal-volume impregnation method. The total nickel content of the impregnated catalyst was 45%. The solution was dried at 110°C and calcined at 380°C for 4 hours to obtain catalyst precursor Q2. In the second step, nickel nitrate, silver nitrate and copper nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto Q2 using an equal-volume impregnation method. The solution was dried at 120°C and calcined at 420°C for 4 hours to obtain catalyst C5.

[0080] Based on the total weight of the catalyst (100%), catalyst C5 contains 20.1 wt% nickel oxide, 0.2 wt% silver oxide, 0.2 wt% copper oxide, 0.3 wt% magnesium oxide, 0.3 wt% lanthanum oxide, with the balance being the support, and has a specific surface area of ​​91 m². 2 / g, pore volume is 0.41ml / g.

[0081] Example 6

[0082] (1) Carrier preparation

[0083] Aluminum chloride, aluminum nitrate, urea, and ammonium carbonate (the molar ratio of the sum of the molar numbers of aluminum ions and urea to ammonium carbonate is 0.5) were added to deionized water and stirred until dissolved. The mixture was then transferred to a hydrothermal reactor, and CO2 gas was introduced to a pressure of 0.3 MPa. The reaction was carried out at 240°C for 4 hours. After cooling to room temperature, the precipitate was filtered, washed, and dried. The obtained product was mixed with nitric acid, phosphoric acid, guar gum powder, and water to form a plastic body. The mixture was then extruded into strips, dried at 120°C for 4 hours, and calcined at 1000°C for 4 hours to obtain a leaf-shaped aggregate alumina carrier.

[0084] (2) Catalyst preparation

[0085] The catalyst was prepared by a two-step impregnation method. In the first step, nickel acetate and copper nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) by an equal-volume impregnation method. The solution was dried at 110°C and calcined at 380°C for 4 hours to obtain the catalyst precursor Q3. In the second step, silver nitrate and magnesium nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto Q3 by an equal-volume impregnation method. The solution was dried at 120°C and calcined at 480°C for 4 hours to obtain the catalyst C6.

[0086] Based on the total weight of the catalyst (100%), catalyst C6 contains 12.9 wt% nickel oxide, 1.5 wt% silver oxide, 0.4 wt% copper oxide, 1.2 wt% magnesium oxide, with the balance being the support, and a specific surface area of ​​88 m². 2 / g, pore volume is 0.37ml / g.

[0087] Example 7

[0088] (1) Carrier preparation

[0089] Aluminum nitrate, aluminum sulfate, and urea (molar ratio of aluminum ions to urea of ​​3.2) were added to deionized water and stirred until dissolved. The mixture was then transferred to a hydrothermal reactor, and CO2 gas was introduced to a pressure of 1.8 MPa. The reaction was carried out at 200°C for 8 hours. After cooling to room temperature, the precipitate was filtered, washed, and dried. The obtained product was mixed with nitric acid, phosphoric acid, citric acid, lithium carbonate, guar gum powder, and water to form a plastic body. The mixture was then extruded into strips, dried at 110°C for 6 hours, and calcined at 900°C for 4 hours to obtain a lithium-containing leaf-like aggregate structure alumina carrier.

[0090] (2) Catalyst preparation

[0091] Nickel nitrate, silver nitrate, copper nitrate, and cerium nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) using an equal-volume impregnation method. The solution was dried at 120°C and calcined at 400°C for 3 hours to obtain catalyst C7.

[0092] Based on the total weight of the catalyst (100%), catalyst C7 contains 14.3 wt% nickel oxide, 1.2 wt% silver oxide, 0.7 wt% copper oxide, 0.2 wt% lithium oxide, 1.0 wt% cerium oxide, with the balance being the support, and a specific surface area of ​​127 m². 2 / g, pore volume is 0.45ml / g.

[0093] Comparative Example 1

[0094] (1) Carrier preparation

[0095] Boehmite (specific surface area 328 m²) prepared using commercially available carbonization method 2 / g (pore volume 0.98ml / g), mixed with nitric acid, phosphoric acid, guar gum powder and water to form a plastic body, extruded into strips, and then dried at 120℃ for 4h and calcined at 600℃ for 4h to obtain an alumina support precursor. An aqueous solution of lithium carbonate and citric acid was prepared and impregnated onto the support using an equal-volume impregnation method. The solution was dried at 120℃ for 4h and calcined at 920℃ for 4h to obtain a lithium-containing alumina support. The structure of this alumina support is as follows. Figure 2 As shown, the alumina carrier does not have a leaf-like aggregate structure.

[0096] (2) Catalyst preparation

[0097] Nickel nitrate, silver nitrate, and copper nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) using an equal-volume impregnation method. The solution was dried at 120°C and calcined at 350°C for 4 hours to obtain catalyst D1.

[0098] Based on the total weight of the catalyst (100%), catalyst D1 contains 16.5 wt% nickel oxide, 0.5 wt% silver oxide, 0.3 wt% copper oxide, 0.6 wt% lithium oxide, with the balance being the support, and has a specific surface area of ​​113 m². 2 / g, pore volume is 0.49ml / g.

[0099] Comparative Example 2

[0100] (1) Carrier preparation

[0101] Boehmite (specific surface area 340 m²) prepared using commercially available sulfuric acid method 2 A mixture of potassium hydroxide (1.02 ml / g, pore volume 1.02 ml / g) with nitric acid, phosphoric acid, guar gum powder, and water was kneaded into a plastic mass, extruded into strips, and then dried at 120°C for 4 hours and calcined at 560°C for 4 hours to obtain an alumina carrier precursor. A potassium hydroxide aqueous solution was prepared and impregnated onto the carrier using an equal-volume impregnation method. The substrate was then dried at 120°C for 4 hours and calcined at 850°C for 5 hours to obtain a potassium-containing alumina carrier that did not possess a leaf-like aggregate structure.

[0102] (2) Catalyst preparation

[0103] The catalyst was prepared by a two-step impregnation method. In the first step, nickel acetate was dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) using an equal-volume impregnation method. The total nickel content of the impregnated catalyst was 35%. The solution was dried at 120°C and calcined at 350°C for 4 hours to obtain catalyst precursor Q4. In the second step, nickel nitrate and silver nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) using an equal-volume impregnation method. The solution was dried at 120°C and calcined at 430°C for 4 hours to obtain catalyst D2.

[0104] Based on the total weight of the catalyst (100%), catalyst D2 contains 18.4 wt% nickel oxide, 0.7 wt% silver oxide, 1 wt% potassium oxide, with the balance being the support, and has a specific surface area of ​​155 m². 2 / g, pore volume is 0.55ml / g.

[0105] Comparative Example 3

[0106] (1) Carrier preparation

[0107] Chinese patent CN106276992B discloses a method for preparing leaf-shaped nano-γ-alumina: 7.5g of aluminum nitrate and 6g of urea are added to 70mL of deionized water and magnetically stirred for 20 minutes to obtain a colorless and transparent solution. The solution is then transferred to a high-pressure reactor, and hydrogen gas is introduced to purge the air from the reactor. The hydrogen pressure in the reactor is then set to 0.4MPa, and the reactor is sealed. The reactor is heated to 140℃ and reacted for 12 hours. After the reaction, the reactor is allowed to cool naturally to room temperature, the gas inside the reactor is released, the reactor is opened, and the reaction slurry is collected. The slurry is filtered and dried to obtain boehmite monohydrate, which is mixed with nitric acid, phosphoric acid, guar gum powder, and water to form a plastic body. This body is then extruded into strips, dried at 120℃ for 4 hours, and calcined at 550℃ for 4 hours to obtain a leaf-shaped alumina carrier precursor. A lanthanum nitrate aqueous solution was prepared and impregnated onto a support using an equal-volume impregnation method. The support was dried at 110°C for 5 hours and calcined at 980°C for 4 hours to obtain a lanthanum-containing alumina support. This alumina support does not have a leaf-like aggregate structure.

[0108] (2) Catalyst preparation

[0109] The catalyst was prepared by a two-step impregnation method. In the first step, nickel chloride and magnesium nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) using an equal-volume impregnation method. The total nickel content of the impregnated catalyst was 45%. The solution was dried at 110°C and calcined at 380°C for 4 hours to obtain catalyst precursor Q5. In the second step, nickel nitrate, silver nitrate and copper nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) using an equal-volume impregnation method. The solution was dried at 120°C and calcined at 420°C for 4 hours to obtain catalyst D3.

[0110] Based on the total weight of the catalyst (100%), catalyst D3 contains 20.1 wt% nickel oxide, 0.2 wt% silver oxide, 0.2 wt% copper oxide, 0.3 wt% magnesium oxide, 0.3 wt% lanthanum oxide, with the balance being the support, and a specific surface area of ​​87 m². 2 / g, pore volume is 0.40ml / g.

[0111] Comparative Example 4

[0112] (1) Carrier preparation

[0113] Boehmite (specific surface area 310 m²) prepared using commercially available carbonization method 2 / g, pore volume 1.05ml / g), mixed with nitric acid, phosphoric acid, citric acid, lithium carbonate, guar gum powder and water to form a plastic body, extruded into strips, and then dried at 110℃ for 6h and calcined at 900℃ for 4h to obtain a lithium-containing alumina support, which does not have a leaf-like aggregate structure.

[0114] (2) Catalyst preparation

[0115] Nickel nitrate, silver nitrate, copper nitrate, and cerium nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) using an equal-volume impregnation method. The solution was dried at 120°C and calcined at 400°C for 3 hours to obtain catalyst D4.

[0116] Based on the total weight of the catalyst (100%), catalyst D4 contains 14.3 wt% nickel oxide, 1.2 wt% silver oxide, 0.7 wt% copper oxide, 0.2 wt% lithium oxide, 1.0 wt% cerium oxide, with the balance being the support, and a specific surface area of ​​131 m². 2 / g, pore volume is 0.45ml / g.

[0117] Table 1. Properties and composition of catalysts in the examples and comparative catalysts.

[0118]

[0119] Example 8

[0120] Characterization of active metal dispersion in catalysts:

[0121] Metal dispersion was determined using a CO pulse titration test on a Micromeritics Autochem 2920 chemisorption analyzer. 0.1 g of catalyst samples from Examples 1, 3, 5, and 7, and Comparative Examples 1–4 were weighed, reduced at 800°C for 2 hours, cooled to 40°C, and purged with helium for 60 minutes. CO pulse titration was performed: 2% CO-He was titrated using a loop injection method, pulsed to adsorption, and detected using a TCD detector. Specific results are shown in Table 2 below.

[0122] Table 2. Metal dispersion (Ni) of the catalysts in the examples and the comparative catalysts.

[0123] catalyst Metal dispersion (Ni) C1 16.3％ C3 15.1％ C5 14.9％ C7 15.4％ D1 12.8％ D2 11.9％ D3 11.6％ D4 12.1％

[0124] As can be seen from the results in Table 2, the C4-tetrylene selective hydrogenation catalyst prepared by the present invention has a more excellent metal dispersion.

[0125] Example 9

[0126] Catalytic performance of the catalyst:

[0127] Raw material source: The C4 fraction rich in alkynes was taken from Lanzhou Petrochemical Ethylene Plant, containing 10-25 wt% vinyl acetylene (hereinafter referred to as VA) and 10-25 wt% butadiene;

[0128] Composition of raw materials and products: The composition of industrial-grade cracked C4 was determined by SH / T 1141 analysis.

[0129]

[0130]

[0131] Catalyst evaluation conditions: The catalyst was reduced at 420℃ for 8 hours under a hydrogen atmosphere using an isothermal bubbling bed reactor. The reaction temperature was 40℃, the reaction pressure was 1.0 MPa, the H2 / VA molar ratio was 2.5, and the liquid hourly space velocity was 5–10 h⁻¹. -1 The catalyst loading volume is 50 ml, and the C4 acetylene is diluted with raffinate C4.

[0132] Reaction process flow: C4 acetylene is metered through a metering tube and then pumped to the reaction pressure using a plunger pump. After preheating, it is mixed with hydrogen gas at a constant pressure and enters the catalyst bed from the bottom of the reactor. The reaction products are cooled and then enter a gas-liquid separator for separation. The separated H2 is depressurized and metered by a wet flow meter before being vented. The liquid is discharged into a product storage tank. The content of vinyl acetylene and butadiene is analyzed by Varian 3800 gas chromatography.

[0133] The specific evaluation conditions and results of the catalysts in the examples and comparative examples are shown in Table 3.

[0134] Table 3 Evaluation conditions and results for the examples and comparative examples

[0135]

[0136] As can be seen from the results in Table 3, compared with Comparative Example 1, Comparative Example 2, Comparative Example 5, and Comparative Example 3, and Comparative Example 7, the catalyst prepared by the present invention using alumina supported by a leaf-like aggregate structure has advantages such as high VA conversion rate and good butadiene selectivity.

[0137] Of course, the present invention may have other embodiments and variations. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and variations according to the present invention, but these corresponding changes and variations should all fall within the protection scope of the claims of the present invention.

Claims

1. A selective hydrogenation catalyst for C4-acetylenes, characterized in that, The alumina support has a leaf-like aggregate structure and, based on 100% of the total catalyst weight, contains 8–25 wt% nickel oxide, 0.05–5 wt% silver oxide, 0–1.5 wt% copper oxide, 0.1–4 wt% alkali metal and / or alkaline earth metal oxides, 0–3 wt% cerium oxide and / or lanthanum oxide, with the balance being alumina support; the specific surface area of ​​the catalyst is 60–160 m² / g. 2 / g, with a pore volume of 0.35–0.65 ml / g; the alumina carrier is prepared by hydrothermal synthesis. The alumina support was prepared by the following method: Step (1): Add the compound that can decompose into NH3 and CO2 in the subsequent hydrothermal treatment in step (2) to the inorganic aluminum salt aqueous solution, and stir until completely dissolved to form a mixed solution; Step (2): CO2 gas at a pressure of 0.1-2 MPa is introduced into the mixed solution, followed by hydrothermal treatment. The obtained product is filtered to separate solid and liquid. The obtained solid is washed, dried and calcined to obtain alumina carrier with a leaf-like aggregate structure.

2. The selective hydrogenation catalyst for C4-acetylenes according to claim 1, characterized in that, In step (2), the hydrothermal treatment is carried out in an autoclave.

3. The selective hydrogenation catalyst for C4-acetylenes according to claim 1, characterized in that, In step (2), the hydrothermal treatment is carried out in a hydrothermal reactor.

4. The selective hydrogenation catalyst for C4-acetylenes according to claim 1, characterized in that, In step (1), the compound that can decompose into CO2 and NH3 in subsequent hydrothermal treatment is one or more selected from ammonium carbonate, ammonium bicarbonate, urea and ammonium oxalate; in step (1), the molar ratio of aluminum ions of the inorganic aluminum salt to the compound is 0.1 to 4; in step (1), the inorganic aluminum salt is one or more selected from aluminum sulfate, aluminum nitrate and aluminum chloride.

5. The selective hydrogenation catalyst for C4-acetylenes according to claim 1, characterized in that, In step (1), the molar ratio of aluminum ions in the inorganic aluminum salt to the compound is 0.5 to 3.

6. The selective hydrogenation catalyst for C4-acetylenes according to claim 1, characterized in that, In step (2), the hydrothermal temperature of the hydrothermal treatment is 100-300℃, and the hydrothermal treatment time is 2-48h; the drying temperature is 80-120℃, and the drying time is 2-10h; the calcination time is 3-10h, and the calcination temperature is 700-1000℃.

7. The selective hydrogenation catalyst for C4-acetylenes according to claim 1, characterized in that, Based on the total weight of the catalyst (100%), it contains 10–19 wt% nickel oxide, 0.1–1.5 wt% silver oxide, 0.3–0.8 wt% copper oxide, 0.1–4 wt% alkali metal and / or alkaline earth metal oxides, 0.1–1.5 wt% cerium oxide and / or lanthanum oxide, with the balance being the support.

8. The selective hydrogenation catalyst for C4-acetylenes according to claim 1, characterized in that, The nickel, silver, and copper are added in the form of soluble salts. The soluble salt of nickel is selected from at least one of nickel nitrate, nickel acetate, nickel chloride, and nickel sulfate. The soluble salt of silver is silver nitrate, and the soluble salt of copper is copper nitrate.

9. The selective hydrogenation catalyst for C4-acetylenes according to claim 1, characterized in that, The catalyst may also contain alkali metals and / or alkaline earth metals, in oxide form, at a content of 0.3 to 2 wt%; the alkali metals and / or alkaline earth metals are at least one of Li, Na, K, Ca, Mg, Sr, and Be.

10. The selective hydrogenation catalyst for C4-acetylenes according to claim 9, characterized in that, The alkali metal and / or alkaline earth metal is one or two of Li, K, and Mg.

11. The selective hydrogenation catalyst for C4-acetylenes according to claim 1, characterized in that, Before use, the catalyst is reduced with hydrogen at 250–450°C for 6–24 hours.

12. A method for preparing a selective hydrogenation catalyst for C4-acetylenes according to any one of claims 1-11, characterized in that, Includes the following steps: A selective hydrogenation catalyst for C4-acetylenes is obtained by impregnating a soluble salt solution containing nickel, silver, and copper onto an alumina support in one or more steps, followed by drying and calcination at 300–450°C for 3–8 hours. The alumina support has a leaf-like aggregate structure and is prepared by the following method: Step (1): Add the compound that can decompose into NH3 and CO2 in the subsequent hydrothermal treatment in step (2) to the inorganic aluminum salt aqueous solution, and stir until completely dissolved to form a mixed solution; Step (2): CO2 gas at a pressure of 0.1-2 MPa is introduced into the mixed solution, and then hydrothermal treatment is performed. The obtained product is filtered to separate solid and liquid. The obtained solid is washed, dried and calcined to obtain alumina with a leaf-like aggregate structure.

Images