A selective hydrogenation catalyst for C2 fraction alkynes

Abstract

This invention provides a selective hydrogenation catalyst for C2 distillate alkynes. The catalyst is supported on alumina or primarily alumina and has a bimodal pore structure. The active components of the catalyst contain at least Pd, Ni, Cu, Ce, and Pt, with the following content (based on 100% weight of the support): Pd 0.02-0.04%, Ni 1-5%, Cu 0.2-1%, Ce 0.1-0.5%, and Pt 0.001-0.01%. Ni and Cu are primarily loaded in the macropores via a microemulsion method, while Pd is primarily loaded in the micropores via a solution method. The catalyst provided by this invention has a low palladium loading, is simple to prepare, exhibits good anti-coking properties, has a long service life, maintains good hydrogenation activity and excellent selectivity for a considerable period, and also possesses good regeneration performance.

Description

Technical Field

[0001] This invention relates to a selective hydrogenation catalyst for C2 fraction alkynes, and more particularly to a selective hydrogenation catalyst for a post-C2 hydrogenation process. Background Technology

[0002] Ethylene obtained from petroleum hydrocarbon steam cracking contains 0.5%–2.3% acetylene by mass. During polymerization, the acetylene in ethylene reduces the activity of the polymerization catalyst and affects the physical properties of the polymer; therefore, it must be removed. Currently, selective hydrogenation is commonly used industrially to remove acetylene from ethylene, primarily employing noble metal catalysts such as Pd, Pt, and Au. To ensure that the ethylene produced by acetylene hydrogenation and the original ethylene in the feedstock do not undergo further hydrogenation to ethane, thus preventing ethylene loss, a high hydrogenation selectivity of the catalyst is essential to achieve good economic benefits.

[0003] The terms "post-hydrogenation" and "pre-hydrogenation" refer to the position of the acetylene hydrogenation reactor relative to the demethanizer. Pre-hydrogenation refers to the reactor being located before the demethanizer, while post-hydrogenation refers to the reactor being located after the demethanizer. The advantages of post-hydrogenation are more controllable processes, less prone to temperature runaway, and easier operation. However, it is more complex and requires separate hydrogen preparation. In post-hydrogenation of C2, due to the low hydrogen content in the feedstock, acetylene is prone to hydrogenation dimerization, producing a C4 fraction. This C4 fraction further polymerizes to form oligomers with a wider molecular weight range, commonly known as "green oil." This green oil adsorbs onto the catalyst surface and further forms coke, blocking catalyst pores and preventing reactants from diffusing to the active sites, thus reducing catalyst activity.

[0004] Noble metal catalysts exhibit high activity, but they are prone to generating green oil during use, leading to coking and deactivation, which affects catalyst stability and lifespan. CN200810119385.8 discloses a non-noble metal supported selective hydrogenation catalyst, its preparation method, and its application. The catalyst includes a support and a main active component and a co-active component supported on that support. The main active component is Ni, and the co-active component is selected from at least one of Mo, La, Ag, Bi, Cu, Nd, Cs, Ce, Zn, and Zr. Both the main active component and the co-active component exist in amorphous form with an average particle size <10 nm. The support is a non-oxidizing porous material. The catalyst is prepared using a microemulsion method.

[0005] US4404124 describes a selective hydrogenation catalyst with a shell distribution of active components prepared via a stepwise impregnation method. This catalyst can be applied to the selective hydrogenation of C2 fractions to eliminate acetylene from ethylene. US5587348 describes a high-performance C2 hydrogenation catalyst prepared using alumina as a support, with the addition of silver and palladium co-catalysts, and the addition of fluorine chemically bonded to alkali metals. This catalyst exhibits characteristics such as reduced green oil formation, improved ethylene selectivity (i.e., selectivity in forming the intermediate product ethylene during hydrogenation), and reduced formation of oxygen-containing compounds.

[0006] CN1736589A reports a Pd / γ-Al2O3 selective hydrogenation catalyst prepared by a complete adsorption impregnation method, but the catalyst generates a large amount of green oil during use. CN200810114744.0 invents a selective hydrogenation catalyst for unsaturated hydrocarbons and its preparation method. This catalyst uses alumina as a support and palladium as the active component. The catalyst's resistance to impurities and coking is improved by adding rare earth and alkaline earth metals and fluorine, but its selectivity is not ideal.

[0007] The catalysts prepared by the above methods all use catalysts with a single pore size distribution. In fixed-bed reactions, the selectivity of the catalyst is poor due to the influence of internal diffusion. Supports with a bimodal pore distribution can improve catalyst selectivity while ensuring high catalyst activity. The presence of large pores can reduce the influence of internal diffusion. ZL971187339 discloses a hydrogenation catalyst with a honeycomb support, which is a large-pore support and effectively improves the catalyst selectivity. CN1129606A discloses a hydrocarbon conversion catalyst, whose support catalyst includes alumina, nickel oxide, iron oxide, etc. This catalyst includes two types of pores: one to improve the catalytic reaction surface and the other to facilitate diffusion. CN101433842A provides a hydrogenation catalyst characterized by a bimodal pore distribution. The most probable radius of the small pores is 2-50 nm, and the most probable radius of the large pores is 100-500 nm. Due to the bimodal pore distribution, the catalyst has both good hydrogenation activity and good selectivity, resulting in a large increase in ethylene production.

[0008] In the C2 hydrogenation reaction, the formation of green oil and coking of the catalyst are important factors affecting catalyst lifespan. The catalyst's activity, selectivity, and lifespan constitute its overall performance. While the methods listed above offer good pathways to improve catalyst activity and selectivity, they do not solve the problem of catalyst coking, or they address the issues of green oil formation and coking but not selectivity. Although macroporous supports can improve selectivity, the larger molecules generated by polymerization and chain growth reactions can easily accumulate in the macropores of the support, causing catalyst coking and deactivation, thus affecting catalyst lifespan.

[0009] ZL201310114077.7 discloses a hydrogenation catalyst with a bimodal pore distribution. The active components in the catalyst are Pd, Ag, and Ni, wherein Pd and Ag are located in the micropores and Ni is located in the macropores.

[0010] ZL201310114079.6 discloses a catalyst using a bimodal pore distribution catalyst support. A W / O type microemulsion with a particle size larger than the micropore size of the support is prepared. The microemulsion contains a nickel metal salt. Because the kinetic volume of the microemulsion is larger than the micropore size, the microemulsion particles can only enter the macropores of the support. Using a solution method to load Pd and Ag, the capillary effect in the micropores is stronger, and most of the Pd and Ag enter the micropores of the support. Therefore, Ni is mainly located in the macropores, while Pd and Ag are mainly located in the micropores.

[0011] CN201910988249.0 discloses a C2 hydrogenation catalyst with a bimodal pore distribution on the catalyst support. A W / O type microemulsion with particle size larger than the pore size of the support is prepared. The microemulsion contains metal salts of nickel, copper, and palladium. Because the kinetic volume of the microemulsion is larger than the pore size, the microemulsion particles can only enter the macropores of the support. Some of the palladium is supported by a solution method and is mainly distributed in the micropores of the support.

[0012] The catalyst prepared by this method allows the selective hydrogenation reaction to mainly occur in the micropores, while the green oil generated by the reaction enters the macropores and undergoes saturated hydrogenation at the Ni-Cu active centers, thus reducing the amount of coking on the catalyst.

[0013] However, the reduction temperature of Ni often reaches around 500℃. After adding Cu, the reduction temperature can be reduced to around 350℃. But at this temperature, the reduced Pd atoms are very easy to aggregate, which greatly reduces the catalyst activity. It is necessary to increase the amount of active component by a large margin to compensate for the loss of activity, but this will cause a decrease in selectivity.

[0014] To lower the reduction temperature of the Ni-Cu active center, a small amount of palladium was loaded using an emulsion method. Because palladium is loaded twice, the palladium content in the catalyst is therefore higher than that of commonly used catalysts, by up to 50%, which significantly increases the catalyst cost. Summary of the Invention

[0015] To address the aforementioned technical problems, the present invention aims to provide a selective hydrogenation catalyst for alkynes. This catalyst has a low loading of the noble metal component palladium, a simple preparation process, good anti-coking properties, a long service life, and can maintain good hydrogenation activity and excellent selectivity for a considerable period of time, while also exhibiting good regeneration performance.

[0016] To achieve the above objectives, the present invention provides a selective hydrogenation catalyst for C2 fraction alkynes, wherein the catalyst support is alumina or mainly alumina, and has a bimodal pore distribution structure;

[0017] The catalyst has a specific surface area of ​​20-50 m². 2 / g, the pore size of the micropores is 15-50nm, and the pore size of the macropores is 60-500nm;

[0018] The active components of the catalyst contain at least Pd, Ni, Cu, Ce, and Pt. Based on the weight of the support (100%), the content of Pd is 0.02-0.04%, the content of Ni is 1-5%, the content of Cu is 0.2-1%, the content of Ce is 0.1-0.5%, and the content of Pt is 0.001-0.01%.

[0019] Ni and Cu are mainly supported in macropores, while Pd is mainly supported in micropores of the catalyst.

[0020] The Ni and Cu are loaded using a microemulsion method, while the Pd is loaded using a solution method.

[0021] In the catalyst of the present invention, the Ce content is 0.1-0.5% based on 100% of the support weight. At this content, Ce can form a monolayer of cerium oxide or a discontinuous layer of cerium oxide molecules. The Pt content is 0.001-0.01%, existing in the form of single atoms and mainly supported on cerium oxide.

[0022] According to a specific embodiment of the present invention, preferably, the catalyst further contains Ag, which can form an alloy with Pd to improve the selectivity of acetylene hydrogenation. The Ag content is preferably less than 0.2% based on 100% of the support weight.

[0023] According to a specific embodiment of the present invention, preferably, the content of Ag is 0.06-0.2%.

[0024] According to a specific embodiment of the present invention, preferably, the loading of Ag is carried out after the loading of Pd during the preparation process.

[0025] To position Ni and Cu within the macropores of the catalyst, they are loaded in a microemulsion. The microemulsion particle size is larger than the micropore size of the support but smaller than the maximum pore size of the macropores. The Ni-Cu metal salt, contained within the microemulsion, has difficulty entering the smaller support channels due to steric hindrance, and therefore primarily enters the macropores of the support.

[0026] According to a specific embodiment of the present invention, in the preparation of the catalyst, the supported metal precursor must be decomposed through activation. This process is a high-temperature calcination process, in which the metal salt generally decomposes into metal oxides, and the oxides form clusters, which are generally nanoscale. The active center of a typical hydrogenation reaction is composed of a reduced metal. Therefore, before application, the hydrogenation catalyst generally needs to be reduced to ensure that the active component exists in a metallic state. Due to different chemical properties, different oxides require reduction at different temperatures. However, for nanoscale metals, a temperature of around 200°C is a crucial critical temperature; above this temperature, metal particles will significantly aggregate. Therefore, reducing the aggregation of the main active component during the reduction process is of great significance for hydrogenation catalysts.

[0027] The selective hydrogenation catalyst for C2 distillate alkynes provided in this invention has a high reduction temperature for Ni and Cu, typically 350-400℃. This temperature is too high for Pd active sites, leading to significant aggregation. This invention found that adding Ce to the support moderates Pd aggregation; adding Pt further alleviates Pd agglomeration. Furthermore, this invention found that co-loading Ce and Pt significantly reduces Pd agglomeration, with the activity reduction not exceeding 20% ​​even after more than five regeneration reductions. This phenomenon may be due to the fact that Ce metal salts form Ce oxides after calcination, existing in a monolayer distribution. When Pt and Ce are co-loaded, Pt is primarily loaded on Ce oxides, suggesting the possible formation of Pt oxides. 2+ --O 2- --Ce 4+ The binding force between Pt and alumina is much stronger than that between Pt and alumina. Thus, the atoms of Pt act like "atomic fences" around the Pd particles, preventing the growth of Pd particles and thereby enhancing the resistance of Pd active centers to aggregation during high-temperature reduction.

[0028] This invention does not particularly limit the loading method of Ce and Pt, as long as Pt is highly dispersed on cerium oxide after loading. The "atomic fence" formed by Pt and Ce can prevent the growth of Pd particles. Pt and Ce are preferably loaded by solution method.

[0029] According to a specific embodiment of the present invention, preferably, the Pd is loaded using a solution method, and due to the siphon effect of the pores, the Pd is mainly loaded in the pores of the catalyst.

[0030] According to a specific embodiment of the present invention, preferably, the alumina in the support is in the θ, α or mixed crystal form; the alumina content in the catalyst support is above 80%.

[0031] According to a specific embodiment of the present invention, preferably, the carrier further contains other metal oxides, such as magnesium oxide and / or titanium oxide.

[0032] The present invention also provides a method for preparing the above-mentioned selective hydrogenation catalyst for C2 distillate alkynes, wherein Pd is loaded into the catalyst pores by solution loading, and after loading Pd, Ce and Pt are simultaneously loaded by solution loading; Ni and Cu are loaded by microemulsion loading, and the loading order of Ni and Cu can be determined according to the situation.

[0033] According to a specific embodiment of the present invention, preferably, the above preparation method includes the following specific methods:

[0034] Method 1, Ni-Cu, Pd, Ce-Pt:

[0035] Ni precursor salt and Cu precursor salt are loaded onto a support and calcined to obtain semi-finished catalyst A. Then, Pd precursor salt is loaded onto semi-finished catalyst A and calcined to obtain semi-finished catalyst B. Finally, Ce precursor salt and Pt precursor salt are loaded onto semi-finished catalyst B and calcined to obtain the catalyst.

[0036] Method 2, Pd, Ni-Cu, Ce-Pt:

[0037] A precursor salt of Pd is loaded onto a support and calcined to obtain a semi-finished catalyst C. Then, precursor salts of Ni and Cu are loaded onto the semi-finished catalyst C and calcined to obtain a semi-finished catalyst D. Finally, precursor salts of Ce and Pt are loaded onto the semi-finished catalyst D and calcined to obtain the catalyst.

[0038] Method 3, Pd, Ce-Pt, Ni-Cu:

[0039] A precursor salt of Pd is loaded onto a support and calcined to obtain a semi-finished catalyst C. Then, precursor salts of Ce and Pt are loaded onto the semi-finished catalyst C and calcined to obtain a semi-finished catalyst E. Finally, precursor salts of Ni and Cu are loaded onto the semi-finished catalyst E and calcined to obtain the catalyst.

[0040] According to a specific embodiment of the present invention, preferably, the preparation method further includes a step of impregnating Ag onto the semi-finished catalyst after loading the Pd precursor salt. When the active component of the catalyst contains Ag, the Ag loading is carried out by solution loading after Pd, and the order of Ag loading and Ce-Pt loading is not limited, for example:

[0041] In Method 1, Ag is first loaded onto the semi-finished catalyst B, and then Ce and Pt are loaded; or Ce and Pt are loaded onto the semi-finished catalyst B, and then Ag is loaded.

[0042] In Method 2, Ag is first loaded onto the semi-finished catalyst C, and then Ni and Cu are loaded; or, Ag is first loaded onto the semi-finished catalyst D, and then Ce and Pt are loaded; or, Ce and Pt are loaded onto the semi-finished catalyst D, and then Ag is loaded.

[0043] In Method 3, Ag is first loaded onto the semi-finished catalyst C, and then Ce and Pt are loaded; or, Ag is first loaded onto the semi-finished catalyst E, and then Ni and Cu are loaded; or, Ni and Cu are loaded onto the semi-finished catalyst E, and then Ag is loaded.

[0044] According to a specific embodiment of the present invention, preferably, in the above preparation method, the carrier is spherical, cylindrical, clover-shaped, four-leaf clover-shaped, etc.

[0045] According to a specific embodiment of the present invention, preferably, in the above preparation method, the precursor salts of Ni and Cu are prepared by dissolving the precursor salts of Ni and Cu in water to obtain an aqueous phase, adding an oil phase, a surfactant, and a co-surfactant, stirring thoroughly to form a microemulsion, adding the high-temperature calcined support or semi-finished catalyst D to the microemulsion for impregnation for 0.5-4 hours, filtering out the residual liquid, drying, and then calcining at 400-600°C to obtain semi-finished catalyst A or semi-finished catalyst D or the catalyst itself.

[0046] According to a specific embodiment of the present invention, preferably, when the precursor salts of Ni and Cu are loaded, the oil phase is a C6-C8 saturated alkane or cycloalkanes, more preferably cyclohexane and / or n-hexane.

[0047] According to a specific embodiment of the present invention, preferably, when the precursor salts of Ni and Cu are loaded, the surfactant is an ionic surfactant or a nonionic surfactant, more preferably a nonionic surfactant, and even more preferably polyethylene glycol octylphenyl ether (Triton X-100) and / or hexadecyltrimethylammonium bromide (CTAB).

[0048] According to a specific embodiment of the present invention, preferably, when the precursor salts of Ni and Cu are loaded, the co-surfactant is a C4-C6 alcohol, more preferably one or a combination of two or more of n-butanol, n-pentanol and n-hexanol.

[0049] According to a specific embodiment of the present invention, preferably, when loading Ni precursor salt and Cu precursor salt, the Ni precursor salt is a soluble salt of Ni, more preferably a nitrate or chloride salt or other soluble salt.

[0050] According to a specific embodiment of the present invention, preferably, when loading Ni precursor salt and Cu precursor salt, the Cu precursor salt is a soluble salt of Cu, more preferably a nitrate or chloride salt or other soluble salt.

[0051] According to a specific embodiment of the present invention, preferably, when loading Ni precursor salt and Cu precursor salt, the conditions for preparing the microemulsion are: the weight ratio of the aqueous phase to the oil phase is 2-3, the weight ratio of the surfactant to the oil phase is 0.15-0.6, and the weight ratio of the surfactant to the co-surfactant is 1-1.2; more preferably, the particle size of the formed microemulsion is larger than the maximum pore size of the micropores of the catalyst support, but smaller than the maximum pore size of the macropores of the catalyst support, for example, larger than 50 nm and smaller than 500 nm.

[0052] According to a specific embodiment of the present invention, preferably, in the above preparation method, the Pd-loaded precursor salt is prepared in the following manner:

[0053] The precursor salt of Pd is dissolved in water and the pH is adjusted to 1.5-3.0 to obtain a precursor salt solution of Pd. Then, the semi-finished catalyst A or the support is added to the precursor salt solution of Pd and impregnated for 0.5-4 hours. After drying, it is calcined at 400-600℃ to obtain semi-finished catalyst B or semi-finished catalyst C.

[0054] According to a specific embodiment of the present invention, preferably, the precursor salt of Pd is a soluble salt of Pd, more preferably a nitrate or chloride salt or other soluble salt.

[0055] According to a specific embodiment of the present invention, preferably, in the above preparation method, the Ce-loaded precursor salt and the Pt-loaded precursor salt are prepared in the following manner:

[0056] Ce precursor salt and Pt precursor salt are dissolved in water to obtain Ce-Pt impregnation solution (preferably, the amount of impregnation solution is 90-100% of the water absorption of the support). The pH is adjusted to 1-5. Semi-finished catalyst B, semi-finished catalyst D, or semi-finished catalyst C is impregnated in Ce-Pt impregnation solution. After the solution is completely absorbed, it is dried and calcined at 500-600℃ to obtain the catalyst or semi-finished catalyst E.

[0057] According to a specific embodiment of the present invention, preferably, the precursor salt of Pt is chloroplatinic acid or other soluble salt.

[0058] According to a specific embodiment of the present invention, preferably, the precursor salt of Ce is a soluble salt of Ce, more preferably a nitrate or other soluble salt.

[0059] According to a specific embodiment of the present invention, preferably, in the above preparation method, the impregnation of Ag is carried out in the following manner:

[0060] The precursor salt of Ag is dissolved in water to obtain Ag impregnation solution, the amount of which is 80-110% of the saturated water absorption capacity of the support; the semi-finished catalyst is impregnated in the Ag impregnation solution, and after the solution is completely absorbed, it is dried and calcined at 500-600℃ to obtain Ag-containing catalyst or semi-finished catalyst.

[0061] According to a specific embodiment of the present invention, preferably, the precursor salt of Ag is a soluble salt of Ag, more preferably a nitrate or chloride salt or other soluble salt.

[0062] The present invention also provides a method for selective hydrogenation of alkynes in a C2 fraction, such as selective hydrogenation of acetylene in a C2 fraction of an ethylene plant, which is carried out using the above-mentioned alkyne selective hydrogenation catalyst.

[0063] According to a specific embodiment of the present invention, during the reaction process, the selective hydrogenation reaction of acetylene occurs at the main active center composed of Pd, Ni-Cu is impregnated in the macropores of the support, and the green oil generated in the reaction undergoes saturated hydrogenation on the active center composed of Ni-Cu.

[0064] The catalyst of this invention exhibits the following characteristics for selective hydrogenation of C2 fraction alkynes: At the start of the hydrogenation reaction, due to the high hydrogenation activity of palladium, which is mainly distributed in the micropores, the selective hydrogenation of acetylene primarily occurs in the micropores. As the catalyst's operating time increases, a portion of larger molecular weight byproducts are generated on the catalyst surface. These substances, due to their larger molecular size, enter the macropores more frequently and have a longer residence time. Under the action of the nickel catalyst, they undergo double bond hydrogenation reactions to generate saturated hydrocarbons or aromatic hydrocarbons without isolated double bonds, and are less likely to generate substances with even larger molecular weights. After regeneration, the reduction still occurs at 350-400℃. Due to the combined effect of Ce and Pt, even at higher reduction temperatures, the catalyst activity does not change significantly after regeneration.

[0065] The study found that when the Ce content is high, the amount of green oil generated increases significantly, but the coking of the catalyst is not significantly accelerated.

[0066] The catalyst of this invention is used in the selective hydrogenation process of C2 fraction. It has good anti-coking properties, can maintain good hydrogenation activity and excellent selectivity for a long time, and has good regeneration performance.

[0067] The present invention addresses catalyst coking by utilizing the selective hydrogenation of acetylene and other molecules at the Pd active sites. Large molecules, such as green oil produced during the reaction, readily enter the macropores of the catalyst. The macropores of the catalyst are loaded with Ni-Cu components, which possess saturated hydrogenation capabilities. The green oil components undergo saturated hydrogenation at the Ni-Cu active sites. Because the double bonds are hydrogenated to saturation, the green oil components cannot undergo polymerization or the polymerization rate is significantly reduced. Their chain growth reaction is terminated or delayed, preventing the formation of large molecular weight fused-ring compounds. These compounds are easily carried out of the reactor by the material, thus significantly reducing the degree of coking on the catalyst surface and extending the catalyst's lifespan.

[0068] The alkyne selective hydrogenation catalyst provided by this invention has the following advantages:

[0069] 1. This invention reduces the loading of the precious metal palladium; the catalyst provided by CN201910988249.0 has a minimum palladium content of 0.035% (wt) and a maximum content of 0.07% (wt), while the catalyst of this invention achieves the same activity with a minimum palladium content of 0.02% (wt) and a maximum content of 0.04% (wt). It can be seen that the catalyst of this invention significantly reduces the precious metal content.

[0070] 2. The preparation process of the catalyst of the present invention is simple;

[0071] 3. The catalyst of the present invention can be used in the selective hydrogenation process of C2 fraction, has good anti-coking properties, can maintain good hydrogenation activity and excellent selectivity for a long time, and has good regeneration performance. Attached Figure Description

[0072] Figure 1 This is a particle size distribution diagram of the microemulsion in Example 1. Detailed Implementation

[0073] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0074] Equipment and Instruments:

[0075] The particle size distribution of Ni / Cu alloy microemulsions was analyzed using a dynamic light scattering particle size analyzer (M286572). The pore volume, specific surface area, and pore size distribution of the support were analyzed using a fully automated mercury porosimeter (McGen 9510). The contents of Pd, Ag, Ni, Cu, Ce, and Pt in the catalyst were determined using an A240FS atomic absorption spectrometer.

[0076] Reagents and raw materials:

[0077] Copper nitrate, silver nitrate, nickel nitrate, cerium nitrate, copper chloride, nickel chloride, chloroplatinic acid, palladium chloride, purchased from Shanghai Sinopharm Group;

[0078] Alumina carrier, purchased from Shandong Aluminum Group.

[0079] Example 1

[0080] This embodiment provides a catalyst, wherein:

[0081] The carrier is a commercially available bimodal spherical alumina-titanium oxide carrier with a titanium oxide content of 2% and a diameter of 3 mm. After calcination at 1140℃ for 4 hours, the bimodal pore size distribution ranges from 30-55 nm and 110-500 nm, with a water absorption rate of 50% and a specific surface area of ​​20.08 m². 2 / g.

[0082] Catalyst preparation:

[0083] (1) Weigh 3.13g of nickel nitrate and 0.89g of copper nitrate, dissolve them in 80mL of deionized water, add 40.00g of n-hexane, 20g of CATB, and 20g of n-pentanol, and stir thoroughly to form a microemulsion. The particle size of the microemulsion prepared by dynamic light scattering is 65.29nm.

[0084] 100g of the carrier was impregnated into the prepared microemulsion, shaken for 180min, the residual liquid was filtered off, dried at 80℃ for 4h, and calcined at 400℃ for 5h to obtain the semi-finished catalyst A1.

[0085] (2) Weigh 0.0333 g of palladium chloride, dissolve it in 80 mL of deionized water, adjust the pH to 3 to obtain a Pd salt solution, then impregnate the semi-finished catalyst A1 into the prepared Pd salt solution, impregnate for 120 min, dry at 130 °C for 3 hours, and calcine at 500 °C for 5 hours to obtain the semi-finished catalyst B1.

[0086] (3) Weigh 0.0265g of chloroplatinic acid and 0.93g of cerium nitrate, dissolve them in 50mL of deionized water, adjust the pH to 3, and obtain a Pt-Ce salt solution. Then, impregnate the semi-finished catalyst B1 into the prepared Pt-Ce salt solution. After impregnation for 120min, dry at 130℃ for 3 hours and calcine at 500℃ for 5 hours to obtain the semi-finished catalyst C1.

[0087] (4) Weigh 0.318 g of silver nitrate and dissolve it in 50 mL of deionized water. Dissolve the semi-finished catalyst C1 prepared in step (3) in the prepared silver nitrate solution, shake, and after the solution is completely absorbed, dry at 100 °C for 4 hours and calcine at 550 °C for 5 hours to obtain the catalyst.

[0088] The microemulsion particle size distribution in this embodiment is as follows: Figure 1 As shown. Figure 1 The horizontal axis represents the microemulsion particle size in nm, and the vertical axis represents the distribution intensity of microemulsions with different particle sizes. This means that, with the maximum number of particles in a certain size range as 100, the relative intensity is calculated by comparing the particle size distribution in other ranges to this range. The overall particle size distribution range of the microemulsions is 43-84 nm, which is narrow, indicating that the microemulsion method used in this invention can obtain microemulsion samples with a narrow particle size distribution range. The graph shows a normal distribution, with the vast majority of microemulsion particles falling within a very narrow range of 60-70 nm, which is beneficial for loading the active components.

[0089] The catalyst prepared in Example 1, as determined by atomic absorption spectrometry, contained 0.02% Pd, 1% Ni, 0.3% Cu, 0.3% Ce, 0.01% Pt, and 0.2% Ag, based on the support mass of 100%.

[0090] Catalyst reduction:

[0091] Before use, place it in a fixed-bed reactor and reduce it at 380°C for 8 hours with a mixed gas with a molar ratio of N2:H2 = 1:1.

[0092] Comparative Example 1

[0093] This comparative example provides a catalyst in which the support and preparation conditions are the same as in Example 1, except that Ni is absent in the comparative example:

[0094] (1) Weigh 0.89 g of copper nitrate, dissolve it in 80 mL of deionized water, add 40.00 g of n-hexane, 20 g of CATB, and 20 g of n-pentanol, stir thoroughly to form a microemulsion, and determine the particle size of the prepared microemulsion by dynamic light scattering. The particle size is 65.25 nm.

[0095] 100g of the carrier was impregnated into the prepared microemulsion, shaken for 180min, the residual liquid was filtered off, dried at 80℃ for 4h, and calcined at 400℃ for 5h to obtain the semi-finished catalyst A1-1.

[0096] (2) Weigh 0.0333 g of palladium chloride, dissolve it in 80 mL of deionized water, adjust the pH to 3, then immerse the semi-finished catalyst A1-1 in the prepared Pd salt solution, immerse for 120 min, dry at 130 °C for 3 hours, and calcine at 500 °C for 5 hours to obtain the semi-finished catalyst B1-1.

[0097] (3) Weigh 0.0265g of chloroplatinic acid and 0.93g of cerium nitrate, dissolve them in 50mL of deionized water, adjust the pH to 3, then impregnate the semi-finished catalyst B1-1 into the prepared Pt salt solution, impregnate for 120min, dry at 130℃ for 3 hours, and calcine at 500℃ for 5 hours to obtain the semi-finished catalyst C1-1.

[0098] (4) Weigh 0.318 g of silver nitrate and dissolve it in 50 mL of deionized water. Dissolve the semi-finished catalyst C1-1 prepared in step (3) in the prepared silver nitrate solution, shake, and after the solution is completely absorbed, dry at 100 °C for 4 hours and calcine at 550 °C for 5 hours to obtain the catalyst.

[0099] The catalyst prepared in Comparative Example 1, as determined by atomic absorption spectrometry, contained 0.02% Pd, 0.3% Cu, 0.3% Ce, 0.01% Pt, and 0.2% Ag.

[0100] Catalyst reduction:

[0101] Before use, place it in a fixed-bed reactor and reduce it at 380°C for 8 hours with a mixed gas with a molar ratio of N2:H2 = 1:1.

[0102] Example 2

[0103] This embodiment provides a catalyst, wherein:

[0104] Catalyst support: Commercially available bimodal spherical alumina support with a diameter of 3.5 mm was used. After calcination at 1080℃ for 4 hours, the bimodal pore size distribution ranged from 13-36 nm to 75-340 nm, with a water absorption rate of 60% and a specific surface area of ​​49.75 m². 2 / g.

[0105] Catalyst preparation:

[0106] (1) Weigh 9.38 g of nickel nitrate and 0.424 g of copper chloride, dissolve them in 70 mL of deionized water, add 23.33 g of cyclohexane, 3.50 g of Triton X-100, and 3.18 g of n-butanol, stir thoroughly to form a microemulsion, and determine the particle size of the prepared microemulsion by dynamic light scattering. The particle size is 110.23 nm.

[0107] 100g of the high-temperature calcined carrier was immersed in the prepared microemulsion, shaken for 30min, the residual liquid was filtered off, washed with deionized water, dried at 60℃ for 10h, and calcined at 500℃ for 6h to obtain the semi-finished catalyst A2.

[0108] (2) Weigh 0.833 g of palladium chloride, dissolve it in 60 mL of deionized water, adjust the pH to 1.5, then immerse the semi-finished catalyst A2 in the prepared Pd salt solution, shake it, and after the solution is completely absorbed, dry it at 80 °C for 6 hours and calcine it at 400 °C for 6 hours to obtain the semi-finished catalyst B2.

[0109] (3) Weigh 0.233g of cerium nitrate and 0.0053g of chloroplatinic acid, dissolve them in 54mL of deionized water, stir evenly, adjust the pH to 1.5, add the semi-finished catalyst B2 to the prepared solution, shake to allow the solution to be completely absorbed, dry at 100℃, and calcine at 600℃ for 4 hours to obtain the semi-finished catalyst F2.

[0110] (4) Weigh 0.254 g of silver nitrate and dissolve it in 54 mL of deionized water. Dissolve the semi-finished catalyst F2 prepared in step (3) in the prepared silver nitrate solution, shake, and after the solution is completely absorbed, dry at 100 °C for 4 hours and calcine at 550 °C for 5 hours to obtain the catalyst.

[0111] The catalyst prepared in Example 2, as determined by atomic absorption spectrometry, contained 0.02% Pd, 3% Ni, 0.2% Cu, 0.1% Ce, 0.002% Pt, and 0.16% Ag.

[0112] Catalyst reduction:

[0113] Before use, place it in a fixed-bed reactor and reduce it at 400℃ for 8 hours with a mixed gas with a molar ratio of N2:H2 = 1:1.

[0114] Comparative Example 2

[0115] This comparative example provides a catalyst in which the same support as in Example 2 is used and the catalyst preparation conditions are the same as in Example 2, except that Ce is not supported.

[0116] Catalyst preparation:

[0117] (1) Weigh 9.38 g of nickel nitrate and 0.424 g of copper chloride, dissolve them in 70 mL of deionized water, add 23.33 g of cyclohexane, 3.50 g of Triton X-100 and 3.18 g of n-butanol, stir thoroughly to form a microemulsion, and determine the particle size of the prepared microemulsion by dynamic light scattering. The particle size is 109.87 nm.

[0118] 100g of the high-temperature calcined carrier was immersed in the prepared microemulsion, shaken for 30min, the residual liquid was filtered off, washed with deionized water, dried at 60℃ for 10h, and calcined at 500℃ for 6h to obtain the semi-finished catalyst A2-2.

[0119] (2) Weigh 0.833 g of palladium chloride, dissolve it in 60 mL of deionized water, adjust the pH to 1.5, then immerse the semi-finished catalyst A2-2 in the prepared Pd salt solution, shake it, and after the solution is completely absorbed, dry it at 80 °C for 6 hours and calcine it at 400 °C for 6 hours to obtain the semi-finished catalyst B2-2.

[0120] (3) Weigh 0.0053 g of chloroplatinic acid, dissolve it in 54 mL of deionized water, stir evenly, adjust the pH to 1.5, add the semi-finished catalyst B2-2 to the prepared solution, shake to allow the solution to be completely absorbed, dry at 100 °C, and calcine at 600 °C for 4 hours to obtain the semi-finished catalyst F2-2.

[0121] (4) Weigh 0.254 g of silver nitrate and dissolve it in 54 mL of deionized water. Dissolve the semi-finished catalyst F2-2 prepared in step (3) in the prepared silver nitrate solution, shake, and after the solution is completely absorbed, dry at 100 °C for 4 hours and calcine at 550 °C for 5 hours to obtain the catalyst.

[0122] The catalyst prepared in Comparative Example 2, as determined by atomic absorption spectrometry, contained 0.02% Pd, 3% Ni, 0.2% Cu, 0.002% Pt, and 0.16% Ag.

[0123] Catalyst reduction:

[0124] Before use, place it in a fixed-bed reactor and reduce it at 400℃ for 8 hours with a mixed gas with a molar ratio of N2:H2 = 1:1.

[0125] Example 3

[0126] This embodiment provides a catalyst, wherein:

[0127] Carrier: A commercially available bimodal spherical alumina carrier with a diameter of 4 mm was used. After calcination at 1090℃ for 4 hours, the bimodal pore size distribution ranged from 20-40 nm to 120-390 nm, with a water absorption rate of 55% and a specific surface area of ​​42.3 m². 2 / g.

[0128] Catalyst preparation:

[0129] (1) Weigh 15.63g of nickel nitrate and 2.12g of copper chloride, dissolve them in 55mL of deionized water, add 28g of cyclohexane, 5.6g of Triton X-100 and 4.66g of n-butanol, stir thoroughly to form a microemulsion, and determine the particle size of the prepared microemulsion by dynamic light scattering.

[0130] 100g of the carrier was immersed in the prepared microemulsion, shaken for 30 min, the residual liquid was filtered off, washed with deionized water, dried at 100℃ for 10 h, and calcined at 500℃ for 6 h to obtain the semi-finished catalyst A3.

[0131] (2) Weigh 0.05 g of palladium chloride, dissolve it in 120 mL of deionized water, adjust the pH to 2.5, then immerse the semi-finished catalyst A3 in the prepared Pd salt solution, shake for 120 min, pour off the residual liquid, dry at 100 °C for 6 hours, and calcine at 500 °C for 4 hours to obtain the semi-finished catalyst B3.

[0132] (3) Weigh 1.16g of cerium nitrate and 0.00265g of chloroplatinic acid, dissolve them in 53mL of deionized water, stir evenly, adjust the pH to 1.0, add the semi-finished catalyst B3 to the prepared solution, shake to allow the solution to be completely absorbed, dry at 100℃, and calcine at 600℃ for 4 hours to obtain the semi-finished catalyst F3.

[0133] (4) Weigh 0.19 g of silver nitrate and dissolve it in 53 mL of deionized water. Dissolve the semi-finished catalyst F3 prepared in step (3) in the prepared silver nitrate solution, shake, and after the solution is completely absorbed, dry at 100 °C for 4 hours and calcine at 550 °C for 5 hours to obtain the catalyst.

[0134] The catalyst prepared in Example 3, as determined by atomic absorption spectrometry, contained 0.03% Pd, 5% Ni, 1% Cu, 0.5% Ce, 0.001% Pt, and 0.12% Ag.

[0135] Catalyst reduction:

[0136] Before use, place it in a fixed-bed reactor and reduce it for 8 hours at 350°C using a mixed gas with a molar ratio of N2:H2 = 1:1.

[0137] Comparative Example 3

[0138] This comparative example provides a catalyst in which the same support as in Example 3 is used and the catalyst preparation conditions are the same as in Example 3, except that Pt is not loaded in the comparative example.

[0139] (1) Weigh 15.63g of nickel nitrate and 2.12g of copper chloride, dissolve them in 55mL of deionized water, add 28g of cyclohexane, 5.6g of Triton X-100, and 4.66g of n-butanol, stir thoroughly to form a microemulsion, and determine the particle size of the prepared microemulsion by dynamic light scattering.

[0140] The carrier was immersed in the prepared microemulsion, shaken for 30 min, the residual liquid was filtered off, washed with deionized water, dried at 100℃ for 10 h, and calcined at 500℃ for 6 h to obtain the semi-finished catalyst A3-3.

[0141] (2) Weigh 0.05 g of palladium chloride, dissolve it in 120 mL of deionized water, adjust the pH to 2.5, then immerse the semi-finished catalyst A3-3 in the prepared Pd salt solution, shake for 120 min, pour off the residual liquid, dry at 100 °C for 6 hours, and calcine at 500 °C for 4 hours to obtain the semi-finished catalyst B3-3.

[0142] (3) Weigh 1.16g of cerium nitrate, dissolve it in 53mL of deionized water, stir evenly, adjust the pH to 1.0, add the semi-finished catalyst B3-3 to the prepared solution, shake to allow the solution to be completely absorbed, dry at 100℃, and calcine at 600℃ for 4 hours to obtain the semi-finished catalyst F3-3.

[0143] (4) Weigh 0.19 g of silver nitrate and dissolve it in 53 mL of deionized water. Dissolve the semi-finished catalyst F3-3 prepared in step (3) in the prepared silver nitrate solution, shake, and after the solution is completely absorbed, dry at 100 °C for 4 hours and calcine at 550 °C for 5 hours to obtain the catalyst.

[0144] The catalyst prepared in Comparative Example 3, as determined by atomic absorption spectrometry, contained 0.03% Pd, 5% Ni, 1% Cu, 0.5% Ce, and 0.12% Ag.

[0145] Catalyst reduction:

[0146] Before use, place it in a fixed-bed reactor and reduce it at 350°C for 8 hours with a mixed gas with a molar ratio of N2:H2 = 1:1.

[0147] Example 4

[0148] This embodiment provides a catalyst, wherein:

[0149] Carrier: Commercially available bimodal spherical alumina with a diameter of 3 mm was used. After calcination at 1070℃ for 4 hours, the bimodal pore size distribution ranged from 15-35 nm to 60-200 nm, with a water absorption rate of 65% and a specific surface area of ​​50.14 m². 2 / g.

[0150] Catalyst preparation:

[0151] (1) Weigh 6.25g of nickel nitrate and 1.48g of copper nitrate, dissolve them in 65mL of deionized water, add 30.00g of n-hexane, 18.00g of Triton X-100 and 16.50g of n-hexanol, stir thoroughly to form a microemulsion, and determine the particle size of the prepared microemulsion by dynamic light scattering. The particle size is 65.12nm.

[0152] 100g of carrier was impregnated into the prepared microemulsion, shaken for 180min, the residual liquid was filtered off, dried at 70℃ for 6 hours, and calcined at 500℃ for 4h, which was called semi-finished catalyst A4.

[0153] (2) Weigh 0.69 g of cerium nitrate and 0.0135 g of chloroplatinic acid, dissolve them in 65 mL of deionized water, stir evenly, adjust the pH to 2.5, add the semi-finished catalyst A4 to the prepared solution, shake to allow the solution to be completely absorbed, dry at 100 °C, and calcine at 600 °C for 4 hours to obtain the semi-finished catalyst B4.

[0154] (3) Weigh 0.067 g of palladium chloride, dissolve it in 100 mL of deionized water, adjust the pH to 2.2, then immerse the semi-finished catalyst B4 in the prepared Pd salt solution, immerse for 120 min, dry at 130 °C for 3 hours, and calcine at 550 °C for 4 hours to obtain the semi-finished catalyst F4.

[0155] (4) Weigh 0.316 g of silver nitrate and dissolve it in 59 mL of deionized water. Dissolve the semi-finished catalyst F4 in the prepared silver-containing silver nitrate solution, shake, and after the solution is completely absorbed, dry at 100 °C for 4 hours and calcine at 500 °C for 4 hours to obtain the catalyst.

[0156] The catalyst 4 prepared in Example 4, as determined by atomic absorption spectrometry, contained 0.04% Pd, 2% Ni, 0.5% Cu, 0.3% Ce, 0.005% Pt, and 0.2% Ag.

[0157] Catalyst reduction:

[0158] Before use, place it in a fixed-bed reactor and reduce it at 360°C for 8 hours with a mixed gas with a molar ratio of N2:H2 = 1:1.

[0159] Comparative Example 4

[0160] This comparative example provides a catalyst in which the same support as in Example 4 is used and the catalyst preparation conditions are the same as in Example 4, except that Cu is not loaded in the comparative example.

[0161] Catalyst preparation:

[0162] (1) Weigh 6.25 g of nickel nitrate, dissolve it in 65 mL of deionized water, add 30.00 g of n-hexane, 18.00 g of Triton X-100, and 16.50 g of n-hexanol, stir thoroughly to form a microemulsion, and determine the particle size of the prepared microemulsion by dynamic light scattering.

[0163] 100g of carrier was impregnated into the prepared microemulsion, shaken for 180min, the residual liquid was filtered off, dried at 70℃ for 6 hours, and calcined at 500℃ for 4h, which is called semi-finished catalyst A4-4.

[0164] (2) Weigh 0.69 g of cerium nitrate and 0.0135 g of chloroplatinic acid, dissolve them in 65 mL of deionized water, stir evenly, adjust the pH to 2.5, add the semi-finished catalyst A4-4 to the prepared solution, shake to allow the solution to be completely absorbed, dry at 100 °C, and calcine at 600 °C for 4 hours to obtain the semi-finished catalyst B4-4.

[0165] (3) Weigh 0.067 g of palladium chloride, dissolve it in 100 mL of deionized water, adjust the pH to 2.2, then impregnate the semi-finished catalyst B4-4 into the prepared Pd salt solution, impregnate for 120 min, dry at 130 °C for 3 hours, and calcine at 550 °C for 4 hours to obtain the semi-finished catalyst F4-4.

[0166] (4) Weigh 0.316 g of silver nitrate and dissolve it in 59 mL of deionized water. Dissolve the semi-finished catalyst F4-4 in the prepared silver-containing silver nitrate solution, shake, and after the solution is completely absorbed, dry at 100 °C for 4 hours and calcine at 500 °C for 4 hours to obtain the catalyst.

[0167] The catalyst prepared in Comparative Example 4, as determined by atomic absorption spectrometry, contained 0.04% Pd, 2% Ni, 0.3% Ce, 0.005% Pt, and 0.2% Ag.

[0168] Catalyst reduction:

[0169] Before use, place it in a fixed-bed reactor and reduce it at 360°C for 8 hours with a mixed gas with a molar ratio of N2:H2 = 1:1.

[0170] Example 5

[0171] This embodiment provides a catalyst, wherein:

[0172] The carrier is a commercially available spherical substrate with a bimodal pore distribution, comprising 97% alumina and 3% titanium oxide, with a diameter of 3 mm. After calcination at 1120℃ for 4 hours, the bimodal pore size distribution ranges from 23-47 nm and 80-380 nm, with a water absorption rate of 55% and a specific surface area of ​​30.2 m². 2 / g.

[0173] Catalyst preparation:

[0174] (1) Weigh 12.5g of nickel nitrate and 0.847g of copper chloride, dissolve them in 84.4mL of deionized water, add 28.123g of n-hexane, 4.5g of Triton X-100, and 3.75g of n-hexanol, stir thoroughly to form a microemulsion, and determine the particle size of the prepared microemulsion by dynamic light scattering.

[0175] 100g of the high-temperature calcined carrier was impregnated into the prepared microemulsion, shaken for 180min, the residual liquid was filtered off, dried at 90℃ for 6 hours, and calcined at 600℃ for 4h, which is called semi-finished catalyst A5.

[0176] (2) Weigh 0.05 g of palladium chloride, dissolve it in 90 mL of deionized water, adjust the pH to 2.0, then immerse the semi-finished catalyst A5 in the prepared Pd salt solution, immerse for 120 min, pour off the residual liquid, dry at 130 °C for 3 hours, and calcine at 500 °C for 4 hours to obtain the semi-finished catalyst B5.

[0177] (3) Weigh 0.22g of silver nitrate and dissolve it in 54mL of deionized water. Dissolve the semi-finished catalyst B5 prepared in step (2) in the prepared silver-containing silver nitrate solution, shake, and after the solution is completely absorbed, dry at 100℃ for 4 hours and calcine at 400℃ for 6 hours to obtain semi-finished catalyst G5.

[0178] (4) Weigh 0.465 g of cerium nitrate and 0.0081 g of chloroplatinic acid, dissolve them in 54 mL of deionized water, stir evenly, adjust the pH to 3.0, add the semi-finished catalyst G5 to the prepared solution, shake to allow the solution to be completely absorbed, dry at 100 °C, and calcine at 600 °C for 6 h to obtain the catalyst.

[0179] The total Pd content of the catalyst prepared in Example 5 was determined by atomic absorption spectrometry to be 0.03%, Ni content 4%, Cu content 0.4%, Ce content 0.2%, Pt content 0.003%, and Ag content 0.14%.

[0180] Catalyst reduction:

[0181] Before use, place it in a fixed-bed reactor and reduce it at 350°C for 8 hours with a mixed gas with a molar ratio of N2:H2 = 1:1.

[0182] Comparative Example 5

[0183] This comparative example provides a catalyst in which the catalyst preparation conditions are the same as in Example 5, except that the pore size distribution of the catalyst support is unimodal.

[0184] (1) Weigh 12.5g of nickel nitrate and 0.847g of copper chloride, dissolve them in 84.4mL of deionized water, add 28.123g of n-hexane, 4.5g of Triton X-100, and 3.75g of n-hexanol, stir thoroughly to form a microemulsion, and determine the particle size of the prepared microemulsion by dynamic light scattering.

[0185] 100g of the high-temperature calcined carrier was impregnated into the prepared microemulsion, shaken for 180min, the residual liquid was filtered off, dried at 90℃ for 6 hours, and calcined at 600℃ for 4h, which is called semi-finished catalyst A5-5.

[0186] (2) Weigh 0.05 g of palladium chloride, dissolve it in 90 mL of deionized water, adjust the pH to 2.0, then immerse the semi-finished catalyst A5-5 in the prepared Pd salt solution, immerse for 120 min, pour off the residual liquid, dry at 130 °C for 3 hours, and calcine at 500 °C for 4 hours to obtain the semi-finished catalyst B5-5.

[0187] (3) Weigh 0.22g of silver nitrate and dissolve it in 54mL of deionized water. Dissolve the semi-finished catalyst B5-5 prepared in step (2) in the prepared silver-containing silver nitrate solution, shake, and after the solution is completely absorbed, dry at 100℃ for 4 hours and calcine at 400℃ for 6 hours to obtain semi-finished catalyst G5-5.

[0188] (4) Weigh 0.465 g of cerium nitrate and 0.0081 g of chloroplatinic acid, dissolve them in 54 mL of deionized water, stir evenly, adjust the pH to 3.0, add the semi-finished catalyst G5-5 to the prepared solution, shake to allow the solution to be completely absorbed, dry at 100 °C, and calcine at 600 °C for 6 h to obtain the catalyst.

[0189] According to atomic absorption spectrometry, the total Pd content of the catalyst prepared in Comparative Example 5 was 0.03%, the Ni content was 4%, the Cu content was 0.4%, the Ce content was 0.2%, the Pt content was 0.003%, and the Ag content was 0.14%.

[0190] Catalyst reduction:

[0191] Before use, place it in a fixed-bed reactor and reduce it at 350°C for 8 hours with a mixed gas with a molar ratio of N2:H2 = 1:1.

[0192] Example 6

[0193] This embodiment provides a catalyst, wherein:

[0194] Carrier: A commercially available bimodal spherical carrier with a pore size distribution, containing 97% alumina and 3% titanium oxide, with a diameter of 3 mm, was used. After calcination at 1090℃ for 4 hours, the bimodal pore size distribution ranged from 20-40 nm to 90-280 nm, with a water absorption rate of 60% and a specific surface area of ​​49.56 m². 2 / g.

[0195] Catalyst preparation:

[0196] (1) Weigh 9.38g of nickel nitrate and 0.526g of copper chloride, dissolve them in 70mL of deionized water, add 25g of cyclohexane, 5g of CATB, and 4.76g of n-hexanol, stir thoroughly to form a microemulsion, and determine the particle size of the microemulsion prepared in step (1) by dynamic light scattering.

[0197] 100g of the high-temperature calcined carrier was immersed in the prepared microemulsion, shaken for 90min, the residual liquid was filtered off, dried at 80℃ for 5h, and calcined at 600℃ for 4h, which was called semi-finished catalyst A6.

[0198] (2) Weigh 0.0583 g of palladium chloride, dissolve it in 100 mL of deionized water, adjust the pH to 1.8, then immerse the semi-finished catalyst A6 in the prepared Pd salt solution, immerse for 60 min, dry at 100 °C for 5 hours, and calcine at 400 °C for 6 hours to obtain the semi-finished catalyst B6.

[0199] (3) Weigh 0.316 g of silver nitrate and dissolve it in 57 mL of deionized water. Dissolve the semi-finished catalyst B6 in the prepared silver nitrate solution, shake, and after the solution is completely absorbed, dry at 140 °C for 2 hours and calcine at 400 °C for 6 hours to obtain the semi-finished catalyst G6.

[0200] (4) Weigh 0.58 g of cerium nitrate and 0.0081 g of chloroplatinic acid, dissolve them in 55 mL of deionized water, stir evenly, adjust the pH to 3.0, add the semi-finished catalyst G6 to the prepared solution, shake to allow the solution to be completely absorbed, dry at 100 °C, and calcine at 600 °C for 6 h to obtain the catalyst.

[0201] The catalyst prepared in Example 6, as determined by atomic absorption spectrometry, contained 0.035% Pd, 3% Ni, 0.25% Cu, 0.25% Ce, 0.003% Pt, and 0.20% Ag.

[0202] Catalyst reduction:

[0203] Before use, place it in a fixed-bed reactor and reduce it at 350°C for 8 hours with a mixed gas with a molar ratio of N2:H2 = 1:1.

[0204] Comparative Example 6

[0205] This comparative example provides a catalyst in which the support and preparation steps are the same as those in Example 6, except that the Cu content is 0.1%.

[0206] Catalyst preparation:

[0207] (1) Weigh 9.38g of nickel nitrate and 0.21g of copper chloride, dissolve them in 70mL of deionized water, add 25g of cyclohexane, 5g of CATB, and 4.76g of n-hexanol, stir thoroughly to form a microemulsion, and determine the particle size of the microemulsion prepared in step (1) by dynamic light scattering.

[0208] 100g of the high-temperature calcined carrier was impregnated into the prepared microemulsion, shaken for 90min, the residual liquid was filtered off, dried at 80℃ for 5 hours, and calcined at 600℃ for 4h, which is called semi-finished catalyst A6-6.

[0209] (2) Weigh 0.0583 g of palladium chloride, dissolve it in 100 mL of deionized water, adjust the pH to 1.8, then immerse the semi-finished catalyst A6-6 in the prepared Pd salt solution, immerse for 60 min, dry at 100 °C for 5 hours, and calcine at 400 °C for 6 hours to obtain the semi-finished catalyst B6-6.

[0210] (3) Weigh 0.316 g of silver nitrate and dissolve it in 57 mL of deionized water. Dissolve the semi-finished catalyst B6-6 in the prepared silver-containing silver nitrate solution, shake, and after the solution is completely absorbed, dry at 140 °C for 2 hours and calcine at 400 °C for 6 hours to obtain the semi-finished catalyst G6-6.

[0211] (4) Weigh 0.58 g of cerium nitrate and 0.0081 g of chloroplatinic acid, dissolve them in 55 mL of deionized water, stir evenly, adjust the pH to 3.0, add the semi-finished catalyst G6-6 to the prepared solution, shake to allow the solution to be completely absorbed, dry at 100 °C, and calcine at 600 °C for 6 h to obtain the catalyst.

[0212] The catalyst prepared in Comparative Example 6, as determined by atomic absorption spectrometry, contained 0.035% Pd, 3% Ni, 0.1% Cu, 0.25% Ce, 0.003% Pt, and 0.20% Ag.

[0213] Catalyst reduction:

[0214] Before use, place it in a fixed-bed reactor and reduce it at 350°C for 8 hours with a mixed gas with a molar ratio of N2:H2 = 1:1.

[0215] Example 7

[0216] This embodiment provides a catalyst, wherein:

[0217] Catalyst preparation:

[0218] A commercially available bimodal spherical alumina carrier with a diameter of 4 mm was weighed. After calcination at 1350℃ for 4 hours, the pore size distribution ranges were 30-50 nm and 100-480 nm, respectively, with a water absorption rate of 50% and a specific surface area of ​​22 m². 2 / g.

[0219] (1) Weigh 3.13g of anhydrous nickel nitrate and 1.82g of copper nitrate and dissolve them in 65mL of water. Add 32.5g of cyclohexane, 13g of Triton X-100 and 10.8g of n-butanol and stir thoroughly to form a microemulsion. The particle size of the microemulsion prepared in step (1) was determined to be 390.25nm by dynamic light scattering method.

[0220] 100g of the carrier was added to the prepared microemulsion and impregnated for 4 hours. The remaining liquid was filtered off, dried at 60°C for 10 hours, and calcined at 600°C for 4 hours to obtain the semi-finished catalyst A7.

[0221] (2) Dissolve 0.033g of palladium chloride in 120mL of deionized water, adjust the pH to 2.4, then add the semi-finished catalyst A7 to the salt solution of Pd, impregnate and adsorb for 1 hour, pour off the remaining liquid, dry at 120℃ for 2 hours, and calcine at 600℃ for 4 hours to obtain the semi-finished catalyst B7.

[0222] (3) Weigh 0.93g of cerium nitrate and 0.027g of chloroplatinic acid, dissolve them in 48mL of deionized water, stir evenly, adjust the pH to 2.0, add the semi-finished catalyst B7 to the prepared solution, shake to allow the solution to be completely absorbed, dry at 100℃, and calcine at 600℃ for 6h to obtain the semi-finished catalyst F7.

[0223] (4) Take 48 mL of deionized water, add 0.095 g of silver nitrate to dissolve it completely, immerse the semi-finished catalyst F7 in the prepared solution, shake until the solution is completely absorbed, dry at 120 °C for 2 hours, and calcine at 600 °C for 4 hours to obtain the catalyst.

[0224] The contents of the catalyst prepared in Example 7 were determined by atomic absorption spectrometry to be: Pd content 0.02%, Ni content 1%, Cu content 0.6%, Ce content 0.4%, Pt content 0.01%, and Ag content 0.06%.

[0225] Catalyst reduction:

[0226] Before use, place it in a fixed-bed reactor and reduce it with hydrogen at 380°C for 8 hours with a reduction space velocity of 100 h⁻¹. -1 .

[0227] Comparative Example 7

[0228] This comparative example provides a catalyst in which the same support as in Example 7 is used. The preparation conditions of Comparative Example 7 are the same as those of Example 7, except that the order of steps (2) and (3) is reversed.

[0229] Catalyst preparation:

[0230] (1) Weigh 3.13g of anhydrous nickel nitrate and 1.82g of copper nitrate and dissolve them in 65mL of water. Add 32.5g of cyclohexane, 13g of Triton X-100 and 10.8g of n-butanol and stir thoroughly to form a microemulsion. The particle size of the microemulsion prepared in step (1) was determined to be 390.31nm by dynamic light scattering method.

[0231] 100g of the carrier was added to the prepared microemulsion and impregnated for 4 hours. The remaining liquid was filtered off, dried at 60°C for 10 hours, and calcined at 600°C for 4 hours to obtain the semi-finished catalyst A7-7.

[0232] (2) Weigh 0.93g of cerium nitrate and 0.027g of chloroplatinic acid, dissolve them in 48mL of deionized water, stir evenly, adjust the pH to 2.0, add the semi-finished catalyst A7-7 to the prepared solution, shake to allow the solution to be completely absorbed, dry at 100℃, and calcine at 600℃ for 6h to obtain the semi-finished catalyst B7-7.

[0233] (3) Dissolve 0.033g of palladium chloride salt in 120mL of deionized water, adjust the pH to 2.4, then add the semi-finished catalyst B7-7 into the salt solution of Pd, impregnate and adsorb for 1 hour, then descalcine the remaining liquid, dry at 120℃ for 2 hours, and calcine at 600℃ for 4 hours to obtain the semi-finished catalyst F7-7.

[0234] (4) Take 48 mL of deionized water, add 0.095 g of silver nitrate to dissolve it completely, immerse the semi-finished catalyst F7-7 in the prepared solution, shake until the solution is completely absorbed, dry at 120 °C for 2 hours, and calcine at 600 °C for 4 hours to obtain the catalyst.

[0235] The contents of the catalyst prepared in Comparative Example 7 were determined by atomic absorption spectrometry to be: Pd content 0.02%, Ni content 1%, Cu content 0.6%, Ce content 0.4%, Pt content 0.01%, and Ag content 0.06%.

[0236] Catalyst reduction:

[0237] Before use, place it in a fixed-bed reactor and reduce it with hydrogen at 380°C for 8 hours with a reduction space velocity of 100 h⁻¹. -1 .

[0238] Example 8

[0239] This embodiment provides a catalyst, wherein:

[0240] The carrier is a commercially available spherical substrate with a bimodal pore distribution, comprising 80% alumina and 20% magnesium oxide, with a diameter of 3 mm. After calcination at 1100℃ for 4 hours, the bimodal pore size distribution ranges from 20-43 nm and 60-320 nm, with a water absorption rate of 57% and a specific surface area of ​​35.2 m². 2 / g.

[0241] Catalyst preparation:

[0242] (1) Weigh 6.25g of nickel nitrate and 0.847g of copper chloride, dissolve them in 70mL of deionized water, add 25g of cyclohexane, 5.2g of CATB, and 4.8g of n-hexanol, stir thoroughly to form a microemulsion, and determine the particle size of the microemulsion prepared in step (1) by dynamic light scattering.

[0243] 100g of the high-temperature calcined carrier was impregnated into the prepared microemulsion, shaken for 200min, the residual liquid was filtered off, dried at 90℃ for 6 hours, and calcined at 500℃ for 4h, which is called semi-finished catalyst A8.

[0244] (2) Weigh 0.047 g of palladium chloride, dissolve it in 90 mL of deionized water, adjust the pH to 2.0, then immerse the semi-finished catalyst A8 in the prepared Pd salt solution, immerse for 120 min, pour off the residual liquid, dry at 130 °C for 3 hours, and calcine at 500 °C for 4 hours to obtain the semi-finished catalyst B8.

[0245] (3) Weigh 0.93g of cerium nitrate and 0.0081g of chloroplatinic acid, dissolve them in 57mL of deionized water, stir evenly, adjust the pH to 3.0, add the semi-finished catalyst B8 to the prepared solution, shake to allow the solution to be completely absorbed, dry at 100℃, and calcine at 600℃ for 6h to obtain the catalyst.

[0246] The total Pd content of the catalyst prepared in Example 8 was determined by atomic absorption spectrometry to be 0.028%, Ni content 2%, Cu content 0.4%, Ce content 0.4%, and Pt content 0.003%.

[0247] Catalyst reduction:

[0248] Before use, place it in a fixed-bed reactor and reduce it at 350°C for 8 hours with a mixed gas with a molar ratio of N2:H2 = 1:1.

[0249] Comparative Example 8

[0250] This comparative example provides a catalyst in which the catalyst preparation steps are the same as in Example 8, except that the conditions in step 2 are different.

[0251] The carrier is a commercially available spherical substrate with a bimodal pore distribution, comprising 80% alumina and 20% magnesium oxide, with a diameter of 3 mm. After calcination at 1100℃ for 4 hours, the bimodal pore size distribution ranges from 20-43 nm and 60-320 nm, with a water absorption rate of 57% and a specific surface area of ​​35.2 m². 2 / g.

[0252] Catalyst preparation:

[0253] (1) Weigh 6.25g of nickel nitrate and 0.847g of copper chloride, dissolve them in 70mL of deionized water, add 25g of cyclohexane, 5.2g of CATB, and 4.8g of n-hexanol, stir thoroughly to form a microemulsion, and determine the particle size of the microemulsion prepared in step (1) by dynamic light scattering.

[0254] 100g of the high-temperature calcined carrier was impregnated into the prepared microemulsion, shaken for 200min, the residual liquid was filtered off, dried at 90℃ for 6 hours, and calcined at 500℃ for 4h, which is called semi-finished catalyst A8-1.

[0255] (2) Weigh 0.047 g of palladium chloride, dissolve it in 90 mL of deionized water, adjust the pH to 1.0, then immerse the semi-finished catalyst A8-1 in the prepared Pd salt solution, immerse for 120 min, pour off the residual liquid, dry at 130 °C for 3 hours, and calcine at 500 °C for 4 hours to obtain the semi-finished catalyst B8-1.

[0256] (3) Weigh 0.93g of cerium nitrate and 0.0081g of chloroplatinic acid, dissolve them in 57mL of deionized water, stir evenly, adjust the pH to 3.0, add the semi-finished catalyst B8-1 to the prepared solution, shake to allow the solution to be completely absorbed, dry at 100℃, and calcine at 600℃ for 6h to obtain the catalyst.

[0257] According to atomic absorption spectrometry, the total Pd content in the catalyst prepared in Comparative Example 8 was 0.028%, the Ni content was 2%, the Cu content was 0.4%, the Ce content was 0.4%, and the Pt content was 0.003%.

[0258] Performance testing of catalysts applied to post-hydrogenation reactions of C2

[0259] The catalyst was loaded at a rate of 150 mL in a fixed-bed single-stage reactor, with 50 mL of packing material. The reactant space velocity was 5000 h / h, the operating pressure was 1.8 MPa, the hydrogen-to-acetylene ratio was 1.5, and the reactor inlet temperature was 40 °C. The composition of the reactants is shown in Table 1. The catalyst evaluation results are shown in Table 2.

[0260] Table 1 Composition of reactants

[0261] reactants <![CDATA[C2H2]]> <![CDATA[C2H4]]> <![CDATA[C2H6]]> <![CDATA[C3-C4]]> Content (v / v%) 1.5 86 12 <![CDATA[3×10 -3 ]]>

[0262] Acetylene conversion rate (%) = (Acetylene content at reactor inlet - Acetylene content at reactor outlet) / Acetylene content at reactor inlet;

[0263] Ethylene selectivity = 2 - (Hydrogen content at reactor inlet - Acetylene content at reactor outlet) / (Acetylene content at reactor inlet - Acetylene content at reactor outlet)

[0264] Activity reduction rate (%) = (Initial acetylene conversion rate - Acetylene conversion rate after regeneration or 1000 hours) / Initial acetylene conversion rate

[0265] Table 2 Catalyst Evaluation Results

[0266]

[0267] As can be seen from Table 2, compared with Example 1, the catalyst of Comparative Example 1 has no Ni, the green oil generated during selective hydrogenation cannot be saturated with hydrogen, the catalyst cokes quickly, and the conversion rate after 1000 hours is 32.67% lower than that of Example 1. However, after 5 regenerations, the activity of the catalysts in both the examples and the comparative examples is not significantly different from that in the first cycle.

[0268] The catalyst in Comparative Example 2, which was not loaded with Ce, showed an activity 25.3% lower than that of the catalyst in Example 2 after five regenerations.

[0269] The catalyst in Comparative Example 3 was not loaded with Pt, and after regeneration 5 times, its activity was 31% lower than that of the catalyst in Example 3.

[0270] The catalyst in Comparative Example 4 was not loaded with Cu, and the catalyst could not be completely reduced at 360°C. Most of the green oil generated during the selective hydrogenation process could not be saturated with hydrogen, so coking was faster. After 1000 hours, the acetylene conversion rate was 26.9% lower than that in Example 4.

[0271] The support used in Comparative Example 5 has a unimodal pore distribution, and Ni-Cu can only be located on the outer surface of the catalyst. Therefore, it has good initial activity, but it does not have the effect of hydrogen saturation of by-products, so coking is very fast.

[0272] In Comparative Example 6, the Cu content was too low, which resulted in the Ni / Cu active centers not being completely reduced at 350°C. Only some of the active centers had the ability to saturate hydrogenate the hydrogenation byproducts. After 1000 hours, the catalyst performance was significantly lower than that of Example 6.

[0273] In Comparative Example 7, Ce-Pt was loaded before Pd. During the activation process after Pd loading, Ce-Pt formed an atomic "fence" that blocked Pd atoms, resulting in a smaller particle size of the Pd active centers and a significantly lower initial activity than in Example 7. However, after 5 regenerations, its activity showed little change compared to the first cycle.

[0274] In Comparative Example 8, due to the high impregnation acidity, the distribution of the active component Pd was not close to the outer surface of the catalyst, resulting in low catalyst activity selectivity.

[0275] The Pd content of Example 8 is similar to that of Example 5. However, Example 8 is not loaded with Ag. Compared with Example 5, the activity selectivity of Example 8 is slightly lower.

Claims

1. A selective hydrogenation catalyst for C2 distillate alkynes, wherein, The catalyst support is alumina or the alumina content in the catalyst support is above 80%, and it has a bimodal pore distribution structure; The catalyst has a specific surface area of ​​20-50 m². 2 / g, the pore size of the micropores is 15-50nm, and the pore size of the macropores is 60-500nm; The active components of the catalyst contain at least Pd, Ni, Cu, Ce, Pt, and Ag. Based on the weight of the support (100%), the content of Pd is 0.02-0.04%, the content of Ni is 1-5%, the content of Cu is 0.2-1%, the content of Ce is 0.1-0.5%, the content of Pt is 0.001-0.01%, and the content of Ag is less than 0.2%. Ni and Cu are mainly supported in macropores, while Pd is mainly supported in micropores of the catalyst. In this process, Ni and Cu are loaded using a microemulsion method, where the particle size of the microemulsion is larger than the pore size of the carrier but smaller than the maximum pore size of the macropores; Pd is loaded using a solution method, and Ag is loaded using a solution method; after loading Pd, Ce and Pt are simultaneously loaded using a solution method.

2. The catalyst according to claim 1, wherein, The content of Pd is 0.03-0.04%, the content of Ni is 2-5%, the content of Cu is 0.25-0.5%, the content of Ce is 0.1-0.3%, and the content of Pt is 0.003-0.01%.

3. The catalyst according to claim 1, wherein, The content of Ag is 0.06-0.2%.

4. The catalyst according to claim 1, wherein, During the preparation process, the loading of Ag is carried out after the loading of Pd.

5. The catalyst according to claim 1, wherein, The alumina in the carrier has a θ, α, or a mixture thereof crystal form.

6. The catalyst according to claim 1, wherein, The carrier also contains other metal oxides.

7. The catalyst according to claim 1, wherein, The carrier also contains magnesium oxide and / or titanium oxide.

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