Preparation method of selective hydrogenation catalyst for C2 distillate alkynes

Abstract

This disclosure relates to a method for preparing a catalyst for the selective hydrogenation of C2 distillate alkynes. The catalyst support is alumina or mainly alumina, and has a bimodal pore distribution structure with micropores having a diameter of 15–50 nm and macropores having a diameter of 60–500 nm. Pd is loaded into the micropores of the catalyst using a solution method. After loading Pd, Ce and Pt are simultaneously loaded using a solution method. Ni and Cu are loaded using a microemulsion method. The catalyst prepared by this method can be used for the selective hydrogenation of alkynes, exhibiting good anti-coking properties and selectivity.

Description

TECHNICAL FIELD

[0001] The present application relates to a preparation method of an acetylene selective hydrogenation catalyst, in particular to a preparation method of a carbon dioxide fraction acetylene selective hydrogenation catalyst BACKGROUND

[0002] Ethylene obtained by steam cracking of petroleum hydrocarbon contains 0.5% to 2.3% of acetylene in mass fraction. When used for polymerization, acetylene in ethylene can reduce the activity of polymerization catalyst and affect the physical properties of polymer, so it must be removed. At present, the method of selective hydrogenation is generally used to remove acetylene in ethylene, and the catalysts used mainly include Pd, Pt, Au and other noble metal catalysts. In order to ensure that the ethylene generated by acetylene hydrogenation and the original ethylene in the raw material do not continue to be hydrogenated to form ethane, causing the loss of ethylene, the high selectivity of the catalyst must be ensured, so as to obtain good economic benefits. Carbon dioxide after hydrogenation and before hydrogenation are according to the position of acetylene hydrogenation reactor relative to the demethanizer. The hydrogenation reactor is located before the demethanizer for before hydrogenation, and the hydrogenation reactor is located after the demethanizer for after hydrogenation. The advantage of after hydrogenation process is that the hydrogenation process control means is more, it is not easy to fly temperature, and the operation is convenient, but the process is more complex, and it needs to be separately matched with hydrogen. Carbon dioxide after hydrogenation process is easy to occur acetylene hydrogenation dimerization reaction due to the low hydrogen content in the hydrogenation material, to generate carbon four fraction, and the carbon four fraction is further polymerized to generate oligomers with wide molecular weight, commonly known as "green oil". The green oil is adsorbed on the surface of the catalyst, and further forms coking, blocks the pores of the catalyst, so that the reactants cannot diffuse to the surface of the active center of the catalyst, thereby causing the activity of the catalyst to decrease.

[0003] US4404124 prepared a selective hydrogenation catalyst with shell distribution of active components by a step-by-step impregnation method, which can be applied to the selective hydrogenation of carbon dioxide fraction to eliminate acetylene in ethylene. US5587348 prepared a carbon dioxide hydrogenation catalyst with excellent performance by using alumina as the carrier, adding a silver and palladium interaction auxiliary catalyst, and adding fluorine chemically bonded with alkali metal. The catalyst has the characteristics of reducing the generation of green oil, improving the selectivity of ethylene, i.e. the selectivity of forming intermediate product ethylene in the hydrogenation process, and reducing the generation amount of oxygen-containing compounds.

[0004] CN1736589A reported a Pd / γ-Al2O3 selective hydrogenation catalyst prepared by a complete adsorption impregnation method, and the catalyst generated a large amount of green oil during use. CN200810114744.0 invented an unsaturated hydrocarbon selective hydrogenation catalyst and a preparation method thereof. The catalyst uses alumina as the carrier and palladium as the active component, and adds rare earth and alkaline earth metal and fluorine to improve the anti-impurity and anti-coking performance of the catalyst, but the selectivity of the catalyst is not ideal.

[0005] The catalysts prepared by the above methods all have a single pore size distribution. In a fixed bed reaction process, the selectivity of the catalysts is poor due to internal diffusion. The carrier with a bimodal pore distribution can ensure high activity of the catalysts and reduce the influence of internal diffusion and improve the selectivity of the catalysts. ZL971187339 discloses a hydrogenation catalyst, and the carrier is a honeycomb carrier with a large pore size, which effectively improves the selectivity of the catalyst. CN1129606A discloses a hydrocarbon conversion catalyst, and the carrier catalyst includes alumina, nickel oxide, iron oxide and the like. The catalyst includes two kinds of pores, one is used to increase the surface of the catalytic reaction, and the other is conducive to diffusion. CN101433842A provides a hydrogenation catalyst, and the characteristic of the catalyst is that the catalyst has a bimodal pore distribution, the most probable radius of the small pore part is 2-50 nm, and the most probable radius of the large pore part is 100-500 nm. Due to the bimodal pore distribution of the catalyst, the catalyst has good hydrogenation activity and good selectivity, and the ethylene increment is large.

[0006] In the carbon dioxide hydrogenation reaction, the generation of green oil and the coking of the catalyst are important factors affecting the service life of the catalyst. The activity, selectivity and service life of the catalyst constitute the overall performance of the catalyst. The above listed methods or the methods for improving the activity and selectivity of the catalyst are better, but they do not solve the problem of easy coking of the catalyst. Or the problem of easy generation of green oil and coking of the catalyst is solved, but the problem of selectivity is not solved. The carrier with a large pore structure can improve the selectivity, but the large molecules generated by polymerization and chain growth reaction are also easy to accumulate in the large pores of the carrier, causing the catalyst to coke and deactivate, and affecting the service life of the catalyst.

[0007] ZL201310114077.7 discloses a hydrogenation catalyst, and the carrier of the catalyst has a bimodal pore distribution. The active components in the catalyst include Pd, Ag and Ni, wherein Pd and Ag are located in the small pores, and Ni is located in the large pores.

[0008] ZL201310114079.6 discloses a catalyst, and the carrier of the catalyst has a bimodal pore distribution. A W / O type microemulsion with a particle size larger than the small pores of the carrier is prepared, and the microemulsion contains a metal salt of nickel. Since the kinetic volume of the microemulsion is larger than the size of the small pores, the microemulsion particles can only enter the large pores of the carrier. Pd and Ag are loaded by a solution method, the siphon effect of the small pores is stronger, and most of Pd and Ag enter the small pores of the carrier, so that Ni is mainly located in the large pores, and Pd and Ag are mainly located in the small pores.

[0009] CN201910988249.0 discloses a carbon dihydrogen catalyst, the catalyst carrier is a bimodal pore distribution. By preparing a W / O type microemulsion with a particle size larger than the small pores of the carrier, the microemulsion contains metal salts of nickel, copper and palladium. Because the kinetic volume of the microemulsion is larger than the size of the small pores, the microemulsion particles can only enter the large pores of the carrier. Part of the palladium is loaded by a solution method, mainly distributed in the small pores of the carrier.

[0010] The catalyst prepared by this method makes the selective hydrogenation reaction mainly in the small pores, and the green oil generated by the reaction enters the large pores and undergoes saturated hydrogenation at the Ni-Cu active center, reducing the amount of catalyst coking.

[0011] However, the reduction temperature of Ni often reaches about 500°C, and after adding Cu, the reduction temperature can be reduced to about 350°C, but the Pd atoms in the reduced state at this temperature are prone to aggregation, causing a significant decrease in catalyst activity, which requires a significant increase in the amount of active components to compensate for the loss of activity, but this will also cause a decrease in selectivity.

[0012] Chinese patent application 201910990953.X discloses a carbon dihydrogen catalyst preparation method, the catalyst carrier is a bimodal pore distribution. By preparing a W / O type microemulsion with a particle size larger than the small pores of the carrier, the microemulsion contains metal salts of nickel, copper and palladium. Because the kinetic volume of the microemulsion is larger than the size of the small pores, the microemulsion particles can only enter the large pores of the carrier. Part of the Pd is loaded by a solution method, and due to the siphon effect of the small pores, this part of Pd is located in the small pores. In the preparation method of the catalyst, after loading Ni-Cu by microemulsion method, in order to reduce the reduction temperature of the Ni-Cu active center, part of the Pd is loaded outside the Ni-Cu active center by microemulsion method. Since palladium needs to be loaded by two different methods, and the same microemulsion as nickel-copper loading is used when loading palladium by microemulsion method, and this part of palladium does not directly contribute to the hydrogenation of acetylene, the obvious disadvantage is that the catalyst preparation process is complicated due to the use of two microemulsion methods and one solution method. SUMMARY

[0013] To at least partially solve the problems existing in the prior art, the embodiments of the present application disclose a preparation method of a carbon dihydrocarbon fraction alkyne selective hydrogenation catalyst, which has a simple preparation process, a small amount of palladium, a good anti-coking performance, a long service life, a good hydrogenation activity and excellent selectivity, and a good regeneration performance.

[0014] The embodiment of the present application relates to a preparation method of a carbon di-fraction alkyne selective hydrogenation catalyst, characterized in that the catalyst carrier is alumina or mainly alumina and has a bimodal pore distribution structure, the small pore has a pore size of 15-50 nm, and the large pore has a pore size of 60-500 nm; the loading of Ni and Cu is carried out by using a microemulsion method, the loading of Pd is carried out by using a solution method, and Ce and Pt are simultaneously loaded by using a solution method and after the loading of Pd.

[0015] In at least one embodiment, the preparation method comprises:

[0016] loading a precursor salt of Ni and a precursor salt of Cu on the carrier, drying and roasting to obtain a semi-finished catalyst A; then loading a precursor salt of Pd on the semi-finished catalyst A, drying and roasting to obtain a semi-finished catalyst B; and loading a precursor salt of Ce and a precursor salt of Pt on the semi-finished catalyst B, drying and roasting to obtain the catalyst.

[0017] In at least one embodiment, the specific surface area of the carrier is 20-50 m2 / g; the small pore has a pore size of 15-50 nm, and the large pore has a pore size of 60-500 nm.

[0018] In at least one embodiment, Ni-Cu is loaded in the form of a microemulsion, the particle size of the microemulsion is greater than the pore size of the small pores of the carrier and less than the maximum pore size of the large pores. The nickel and copper metal salts are contained in the microemulsion, and due to the space resistance, it is difficult to enter the smaller pores of the carrier, and thus mainly enters the large pores of the carrier.

[0019] In at least one embodiment, Pd, Ce and Pt are loaded by using a solution method, and due to the siphon effect, these active components mainly enter the small pores of the catalyst.

[0020] The principle of the present application is that in the process of selective hydrogenation of acetylene, the hydrogenation dimerization of alkyne inevitably occurs to generate butadiene, butene and other larger molecules. These olefins stay on the surface of the catalyst for a much longer time than the carbon di-fraction, are easy to polymerize to form larger molecules, and finally form coking.

[0021] When Ni-Cu is loaded in the large pores of the catalyst, these larger molecules enter the large pores of the catalyst, and the hydrogenation reaction occurs on the surface of the Ni-Cu active center, the double bonds of the large molecules are saturated by hydrogenation, and thus no longer polymerize, and the coking rate of the catalyst is greatly reduced.

[0022] During the catalyst preparation process, the active component needs to be activated after being loaded, and the activation is a high-temperature calcination process. In this process, the metal salt is generally decomposed into metal oxide, and the oxide will form clusters, which are generally nanometer-sized. For hydrogenation reaction, the hydrogenation catalyst needs to be reduced before being applied, so as to ensure that the active component exists in the metallic state, and the catalyst has hydrogenation activity. Different oxides need to be reduced at different temperatures due to different chemical properties. However, for nanometer-sized metals, 200℃ is an important critical temperature, and the metal particles will be significantly aggregated when the temperature exceeds this temperature. Therefore, reducing the reduction temperature and reducing the aggregation of the active component is undoubtedly very important to prolong the service life of the catalyst. However, the reduction temperature of the Ni-Cu active center is above 350℃, which is obviously much higher than the critical temperature of 200℃.

[0023] If other noble metals with better hydrogen trapping ability are covered on the Ni-Cu active center, the reduction temperature can be reduced, but the cost of the catalyst will undoubtedly be greatly increased.

[0024] The present inventors have found that the aggregation of Pd can be alleviated by adding 0.1-0.5% of Ce to the catalyst. The aggregation of Pd can be alleviated by adding 0.001-0.01% of Pt to the catalyst.

[0025] The present inventors have also found that the aggregation of Pd can be greatly alleviated by simultaneously loading the above-mentioned amounts of Ce and Pt using a solution method after Pd is loaded and high-temperature calcined; even after 5 times of regeneration, the activity of the catalyst is reduced by not more than 20%.

[0026] The reason may be that the metal salt of Ce will form Ce oxide after calcination, which exists in the form of single-layer distribution. When Pt is co-loaded with Ce, Pt is mainly loaded on the oxide of Ce, and it is speculated that Pt 2+--O 2----Ce4+ species may be formed, and the binding force of the two is much higher than that of Pt and alumina. In this way, the atoms of Pt act as a "atomic fence" outside the Pd particles, preventing the growth of Pd particles, thereby playing a role in improving the resistance of Pd active center to aggregation during high-temperature reduction.

[0027] The present inventors have found that, in order to achieve the effect of loading Pt on the oxide of Ce, it is best that, during the loading process, the Ce exists in the form of cation in the solution of the precursor salt of Ce; and the Pt exists in the form of anionic complex in the precursor salt of Pt. For example, [PtCl4] 2- , and so on. In this way, during the co-loading process, the solution forms Ce 3+ -[PtCl4] 2 --NO3 -Thus, the ion pair, Pt and Ce, is naturally supported together. During the calcination process after the supporting, Ce is oxidized to CeO2, which is easily formed as a monolayer on the alumina due to the strong interaction between CeO2 and alumina, and Pt is located on the CeO2 to form a highly dispersed state.

[0028] In the preparation method of the present application, the content of Ce is 0.1-0.5% based on 100% of the weight of the carrier. At this content, Ce can form a monolayer of CeO2 or a discontinuous molecular layer of CeO2. The content of Pt is 0.001-0.01%, which exists in the form of a single atom and is mainly supported on the CeO2.

[0029] The active component of the catalyst also contains at least Pd, Ni and Cu. The content of Pd is 0.02-0.04% based on 100% of the weight of the carrier, the content of Ni is 1-5%, and the content of Cu is 0.2-1%.

[0030] According to a specific embodiment of the present application, the catalyst preferably further contains Ag, which can form an alloy with Pd to improve the selectivity of acetylene hydrogenation. The content of Ag is preferably less than 0.2% based on 100% of the weight of the carrier.

[0031] According to a specific embodiment of the present application, the content of Ag is preferably 0.06-0.2%.

[0032] According to a specific embodiment of the present application, the loading of Ag is preferably carried out after the loading of Pd during the preparation process.

[0033] The present application does not particularly limit the method for loading Ni-Cu, as long as Ni-Cu is loaded in the macropores of the catalyst. In order to position Ni and Cu in the macropores of the catalyst, the Ni and Cu are preferably loaded in the form of a microemulsion, the particle size of which is greater than the pore size of the small pores of the carrier and less than the maximum pore size of the macropores. The Ni-Cu metal salt is contained in the microemulsion, which is difficult to enter the small pores of the carrier due to steric hindrance and thus mainly enters the macropores of the carrier.

[0034] The present application does not particularly limit the method for loading Ce and Pt, as long as Pt is highly dispersed on CeO2 after loading. The "atomic fence" formed by Pt and Ce can prevent the growth of Pd particles. Pt and Ce are preferably loaded by a solution method and are mainly located in the small pores of the catalyst.

[0035] According to a specific embodiment of the present application, the Pd is preferably loaded by a solution method. Due to the siphon effect of the small pores, Pd is mainly loaded in the small pores of the catalyst.

[0036] According to the specific embodiment of the present application, preferably, the crystal form of the alumina in the carrier is θ, α crystal form or a mixed crystal form thereof; the alumina in the catalyst carrier is more than 80%.

[0037] According to the specific embodiment of the present application, preferably, the carrier further contains other metal oxides, such as magnesium oxide and / or titanium oxide.

[0038] The preferred catalyst preparation method of the present application can be carried out in the following steps:

[0039] The precursor salt of Pd is loaded on the carrier, and a semi-finished catalyst A is obtained by calcination; then the precursor salt of Ce and the precursor salt of Pt are loaded on the semi-finished catalyst A, and a semi-finished catalyst B is obtained by calcination; finally, the precursor salt of Ni and the precursor salt of Cu are loaded on the semi-finished catalyst E, and a semi-finished catalyst C is obtained by calcination; Ag is loaded on the catalyst C, and the catalyst is obtained by calcination.

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

[0041] According to the specific embodiment of the present application, preferably, in the above preparation method, the carrier is spherical, cylindrical, trilobal, tetralobal, etc.

[0042] The more specific implementation process of the present application is:

[0043] (1) The precursor salts of Ni and Cu are dissolved in water, and an oil phase, a surfactant and a co-surfactant are added, and the mixture is fully stirred to form a microemulsion. The conditions for preparing the microemulsion provided in the present application are: the weight ratio of the water phase to the oil phase is 2-3, the weight ratio of the surfactant to the oil phase is 0.15-0.6, the weight ratio of the surfactant to the co-surfactant is 1-1.2, and the particle size of the formed microemulsion is greater than 50 nm and less than 500 nm. The carrier is added to the prepared microemulsion and impregnated for 0.5-4 hours, and then the residual liquid is filtered out. After drying, calcination is carried out at 400-600°C to obtain a semi-finished catalyst A.

[0044] (2) The precursor salt of Pd is dissolved in water, and the pH is adjusted to 1.5-3.0, preferably 1.5-2.5. The semi-finished catalyst A is added to the Pd salt solution, and impregnated and adsorbed for 0.5-4 hours. After drying, calcination is carried out at 300-550°C, and the preferred temperature is 420-520°C, to obtain a semi-finished catalyst B.

[0045] (3) Dissolve the precursor salt of Pt and Ce in deionized water, adjust the pH to 1.0-5.0, preferably 1.0-3.0, then add the semi-finished catalyst B to the prepared solution, dry and calcine at 400-600°C to obtain the semi-finished catalyst C.

[0046] (4) Dissolve the precursor salt of Ag in deionized water, then immerse the semi-finished catalyst C prepared in the above step into the Ag salt solution, dry and calcine at 400-600°C to obtain the desired catalyst.

[0047] According to the specific embodiments of the present application, steps (1) and (2) can be interchanged, step (3) is after step (2), and step (4) is after step (2).

[0048] According to the specific embodiments of the present application, preferably, when loading the precursor salt of Ni and the precursor salt of Cu, the oil phase is C6-C8 saturated alkane or cycloalkane, more preferably cyclohexane and / or n-hexane.

[0049] According to the specific embodiments of the present application, preferably, when loading the precursor salt of Ni and the precursor salt of Cu, the surfactant is an ionic surfactant or a non-ionic surfactant, more preferably a non-ionic surfactant, and further preferably polyethylene glycol octylphenyl ether (Triton X-100) and / or hexadecyl trimethyl ammonium bromide (CTAB).

[0050] According to the specific embodiments of the present application, preferably, when loading the precursor salt of Ni and the precursor salt of Cu, the co-surfactant is C4-C6 alcohol, more preferably n-butanol and / or n-pentanol.

[0051] According to the specific embodiments of the present application, preferably, when loading the precursor salt of Ni and the precursor salt of Cu, the precursor salt of Ni is a soluble salt of Ni, more preferably nitrate or chloride salt or other soluble salt.

[0052] According to the specific embodiments of the present application, preferably, when loading the precursor salt of Ni and the precursor salt of Cu, the precursor salt of Cu is a soluble salt of Cu, more preferably nitrate or chloride salt or other soluble salt.

[0053] According to the specific embodiments of the present application, preferably, the precursor salt of Pt is chloroplatinic acid or other soluble salt.

[0054] According to the specific embodiments of the present application, preferably, the precursor salt of Ce is a soluble salt of Ce, more preferably nitrate or other soluble salt.

[0055] According to the specific embodiment of the present application, preferably, in the above preparation method, the impregnation of Ag is carried out by the following way:

[0056] The precursor salt of Ag is dissolved in water to obtain an Ag impregnation solution, and the amount of the Ag impregnation solution is 80-110% of the saturated water absorption amount of the carrier; the semi-finished catalyst is impregnated in the Ag impregnation solution, and after the solution is completely absorbed, the semi-finished catalyst is dried and calcined at 400-600℃ to obtain the Ag-containing catalyst or semi-finished catalyst.

[0057] According to the specific embodiment of the present application, preferably, the precursor salt of Ag is a soluble salt of Ag, and more preferably, is nitrate or chloride salt or other soluble salt.

[0058] According to the specific embodiment of the present application, during the reaction, the selective hydrogenation of acetylene occurs in the main active center composed of Pd, and the Ni-Cu is impregnated in the large pores of the carrier, and the green oil generated in the reaction is saturated hydrogenated on the active center composed of Ni-Cu.

[0059] The selective hydrogenation of acetylene using the catalyst of the present application has the following characteristics: at the beginning of the hydrogenation reaction, due to the high hydrogenation activity of Pd and the main distribution of Pd in the small pores, the selective hydrogenation of acetylene mainly occurs in the small pores; with the extension of the running time of the catalyst, a part of the by-products with large molecular weight are generated on the surface of the catalyst, and these substances enter the large pores due to the large molecular size and long residence time, and are hydrogenated by the nickel catalyst to generate saturated hydrocarbons or aromatic hydrocarbons without isolated double bonds, and it is not easy to generate substances with larger molecular weight; after the air calcination regeneration of the catalyst, the reduction is still carried out at 350-400℃, and due to the joint action of Ce and Pt, even if the reduction temperature is high, the activity of the regenerated catalyst does not change obviously.

[0060] The present application researches and finds that when the content of Ce is high, the amount of green oil generated is obviously increased, but the coking of the catalyst is not obviously accelerated.

[0061] The catalyst of the present application has good anti-coking performance when used in the selective hydrogenation process of carbon fraction, and can maintain good hydrogenation activity and excellent selectivity for a long time, and has good regeneration performance.

[0062] The acetylene selective hydrogenation catalyst provided by the present application at least has the following advantages:

[0063] 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.

[0064] 2. The microemulsion loading process is more complex than the solution loading process, especially the drying process after microemulsion loading, which needs to be carried out at lower temperatures, extending the catalyst production cycle. Furthermore, the stability of the microemulsion itself is affected by temperature and other environmental factors, limiting its stable storage time. These factors undoubtedly increase the difficulty of microemulsion loading. Therefore, replacing a microemulsion loading process with a solution loading process would undoubtedly shorten the catalyst production cycle and simplify the production process. Attached Figure Description

[0065] Figure 1 : Particle size distribution diagram of the microemulsion in Example 1.

[0066] The horizontal axis of the graph represents the microemulsion particle size in nm, and the vertical axis represents the distribution intensity of microemulsions with different particle sizes.

[0067] from Figure 1 In the microemulsion, the particle size distribution range is mainly 50-60 nm, which is narrow. This indicates that the microemulsion preparation method used in this invention can obtain microemulsion samples with a narrow particle size distribution range, which is beneficial for the loading of active components. Detailed Implementation

[0068] The C2 fraction alkyne selective hydrogenation catalyst referred to in this invention includes the support. Unless otherwise specified, all parts used in the embodiments of this application are parts by weight.

[0069] Equipment: Dynamic light scattering particle size analyzer (M286572) was used to analyze the particle size distribution of Ni / Cu alloy microemulsions; fully automated mercury porosimetry (MMP) was used to analyze the pore volume, specific surface area, and pore size distribution of the support. The contents of Pd, Ag, Ni, Cu, Ce, and Pt in the catalyst were determined using an A240FS atomic absorption spectrometer.

[0070] Raw materials: Nickel nitrate 3.13g, copper nitrate 0.89g, palladium chloride, chloroplatinic acid, silver nitrate (analytical grade, Shanghai Guoyao Group Co., Ltd.); alumina (Shandong Aluminum Group Co., Ltd.).

[0071] Example 1

[0072] Support: The commercially available bimodal pore size distribution spherical alumina support with a diameter of 3 mm was used. After calcination at 1110 °C for 4 h, the bimodal pore size distribution ranges from 20 to 40 nm and 120 to 400 nm, the water absorption is 60%, and the specific surface area is 40.21 m2 / g. 100 g of the support was weighed.

[0073] Catalyst preparation:

[0074] (1) 2.21 g of nickel chloride and 1.48 g of copper nitrate were weighed and dissolved in 70 mL of deionized water, 26.92 g of cyclohexane was added, 16.16 g of Triton X-100 was added, 16.16 g of n-hexanol was added, and the mixture was stirred to form a microemulsion. The 100 g of high-temperature calcined support was immersed in the prepared microemulsion, shaken for 90 min, the remaining liquid was filtered out, dried at 100 °C for 5 hours, and calcined at 400 °C for 5 hours, and the semi-finished catalyst A was obtained.

[0075] (2) 0.0337 g of palladium chloride was weighed and dissolved in 100 mL of deionized water, the pH was adjusted to 1.5, and the semi-finished catalyst A was immersed in the prepared Pd salt solution. After 60 min of immersion, the semi-finished catalyst B was obtained by drying at 120 °C for 5 hours and calcining at 300 °C for 2 hours.

[0076] (3) 0.528 g of cerium chloride and 0.021 g of chloroplatinic acid were weighed and dissolved in 60 mL of deionized water, the pH was adjusted to 1.0, and the semi-finished catalyst B was immersed in the prepared solution. After the solution was completely absorbed, the desired catalyst was obtained by drying at 120 °C for 5 hours and calcining at 600 °C for 5 hours.

[0077] The particle size of the prepared microemulsion emulsion was measured by dynamic light scattering to be 54.58 nm.

[0078] The prepared catalyst was measured by atomic absorption spectrometry, and the Pd content was 0.02%, the Ni content was 1%, the Cu content was 0.5%, the Pt content was 0.01%, and the Ce content was 0.3%.

[0079] Reduction of the catalyst:

[0080] Before use, it was placed in a fixed bed reaction device and reduced at 350 °C for 8 h using a mixed gas with a molar ratio of N2:H2=1:1.

[0081] The support and preparation conditions of Comparative Example 1 were the same as those of Example 1, except that no nickel was loaded.

[0082] (1) Take 1.48 g of copper nitrate, dissolve in 70 mL of deionized water, add 26.92 g of cyclohexane, 16.16 g of Triton X-100, and 16.16 g of n-hexanol, and stir thoroughly to form a microemulsion. Dip 100 g of the high-temperature calcined carrier into the prepared microemulsion, shake for 90 min, filter out the remaining liquid, dry at 100°C for 5 hours, and calcine at 400°C for 5 hours to obtain a semi-finished catalyst A1.

[0083] (2) Take 0.0337 g of palladium chloride, dissolve in 100 mL of deionized water, adjust the pH to 1.5, and then dip the semi-finished catalyst A1 into the prepared Pd salt solution. After 60 min of immersion, dry at 120°C for 5 hours, and calcine at 300°C for 2 hours to obtain a semi-finished catalyst B1.

[0084] (3) Take 0.528 g of cerium chloride and 0.021 g of chloroplatinic acid, dissolve in 60 mL of deionized water, and adjust the pH to 1.0. Then dip the obtained semi-finished catalyst B1 into the prepared solution. After the solution is completely absorbed, dry at 120°C for 5 hours, and calcine at 600°C for 5 hours to obtain the desired catalyst.

[0085] The particle size of the prepared microemulsion emulsion is 54.27 nm, as determined by dynamic light scattering.

[0086] The prepared catalyst has a Pd content of 0.02%, a Cu content of 0.5%, a Pt content of 0.01%, and a Ce content of 0.3%, as determined by atomic absorption spectrometry.

[0087] Reduction of the catalyst:

[0088] Before use, place it in a fixed bed reaction device and reduce it at a temperature of 350°C for 8 hours using a mixed gas with a molar ratio of N2:H2 = 1:1.

[0089] Example 2

[0090] Catalyst carrier: A commercially available bimodal pore distribution spherical alumina carrier with a diameter of 4 mm is used. After calcination at 1090°C for 4 hours, the bimodal pore size distribution ranges from 15 to 38 nm and 80 to 350 nm, the water absorption rate is 65%, and the specific surface area is 49.61 m2 / g. Take 100 g of the carrier.

[0091] Catalyst preparation:

[0092] (1) Take 9.34 g of nickel nitrate, 0.423 g of copper chloride, dissolve in 65 mL of deionized water, add 21.67 g of n-hexane, add 8.66 g of CABT, add 7.21 g of n-butanol, stir thoroughly to form a microemulsion, dip the weighed 100 g of high-temperature calcined carrier into the prepared microemulsion, shake for 30 min, filter out the residual liquid, and wash with deionized water. Dry at 60°C for 10 hours, calcine at 500°C for 4 hours, and call it semi-finished catalyst C.

[0093] (2) Take 0.0866 g of palladium nitrate, dissolve in 110 mL of deionized water, adjust the pH to 2.5, and then dip the semi-finished catalyst C into the prepared Pd salt solution, and soak for 30 min, then dry at 100°C for 6 hours, and calcine at 550°C for 4 hours to obtain semi-finished catalyst D.

[0094] (3) Take 0.93 g of cerium nitrate and 0.011 g of chloroplatinic acid, dissolve in 59 mL of deionized water, and adjust the pH to 3.0. Then dip the semi-finished catalyst D into the prepared solution, and after the solution is completely absorbed, dry at 120°C for 5 hours, and calcine at 500°C for 6 hours to obtain semi-finished catalyst E.

[0095] (4) Take 0.0433 g of silver nitrate, dissolve in 65 mL of deionized water, and then dip the semi-finished catalyst E into the prepared solution, and after the solution is completely absorbed, dry at 120°C for 5 hours, and calcine at 500°C for 4 hours to obtain the desired catalyst.

[0096] The particle size of the prepared microemulsion emulsion is 60.04 nm, measured by dynamic light scattering.

[0097] The prepared catalyst is measured by atomic absorption spectrometry, and the content of Pd is 0.04%, the content of Ni is 3%, the content of Cu is 0.2%, the content of Pt is 0.005%, the content of Ce is 0.3%, and the content of Ag is 0.2%.

[0098] Reduction of the catalyst:

[0099] Before use, place it in a fixed bed reaction device, and reduce it at a temperature of 350°C for 8 hours with a mixed gas of molar ratio N2:H2=1:1.

[0100] Comparative Example 2

[0101] The same carrier as in Example 2 is used, and the catalyst preparation conditions are the same as in Example 2, except that Cu is not loaded.

[0102] Catalyst preparation:

[0103] (1) Take 9.34 g of nickel nitrate, dissolve in 65 mL of deionized water, add 21.67 g of n-hexane, add 8.66 g of CABT, and add 7.21 g of n-butanol, and stir thoroughly to form a microemulsion. Take 100 g of the high-temperature calcined carrier and immerse it in the prepared microemulsion, shake for 30 min, filter out the remaining liquid, and wash with deionized water. Dry at 60°C for 10 hours, and calcine at 500°C for 4 hours to obtain a semi-finished catalyst C1.

[0104] (2) Take 0.0866 g of palladium nitrate, dissolve in 110 mL of deionized water, adjust the pH to 2.5, and then immerse the semi-finished catalyst C1 into the prepared Pd salt solution. After 30 min of immersion, dry at 100°C for 6 hours, and calcine at 550°C for 4 hours to obtain a semi-finished catalyst D1.

[0105] (3) Take 0.93 g of cerium nitrate and 0.011 g of chloroplatinic acid, dissolve in 59 mL of deionized water, and adjust the pH to 3.0. Then immerse the semi-finished catalyst D1 into the prepared solution. After the solution is completely absorbed, dry at 120°C for 5 hours, and calcine at 500°C for 6 hours to obtain a semi-finished catalyst E1.

[0106] (4) Take 0.0433 g of silver nitrate, dissolve in 65 mL of deionized water, and then immerse the semi-finished catalyst E1 into the prepared solution. After the solution is completely absorbed, dry at 120°C for 5 hours, and calcine at 500°C for 4 hours to obtain the desired catalyst.

[0107] The particle size of the prepared microemulsion emulsion is 60.12 nm, as determined by dynamic light scattering.

[0108] The prepared catalyst has a Pd content of 0.04%, a Ni content of 3%, a Pt content of 0.005%, a Ce content of 0.3%, and an Ag content of 0.2%, as determined by atomic absorption spectrometry.

[0109] Example 3

[0110] Carrier: A commercially available bimodal pore distribution spherical alumina carrier with a diameter of 4 mm is used. After calcination at 1120°C for 4 hours, the bimodal pore size distribution ranges from 25 to 50 nm and 95 to 500 nm, the water absorption rate is 48.5%, and the specific surface area is 20.14 m2 / g. Take 100 g of the carrier.

[0111] Catalyst preparation:

[0112] (1) Take 6.63 g of nickel chloride, 0.3388 g of copper nitrate, dissolve in 46 mL of deionized water, add 26 g of n-hexane, add CATB 4.956 g, add n-butanol 4.96 g, stir thoroughly to form a microemulsion, immerse the weighed 100 g of high-temperature calcined carrier into the prepared microemulsion, shake for 240 min, filter out the residual liquid, dry at 120°C for 1 hour, calcine at 600°C for 6h, and call it semi-finished catalyst F.

[0113] (2) Take 0.05 g of palladium chloride, dissolve in 90 mL of deionized water, adjust the pH to 2, then immerse the semi-finished catalyst F into the prepared Pd salt solution, immerse for 90 min, dry at 120°C for 4 hours, and calcine at 520°C for 6 hours to obtain semi-finished catalyst G.

[0114] (3) Take 0.216 g of silver nitrate, dissolve in 43.7 mL of deionized water, dissolve the semi-finished catalyst G prepared in step (2) into the prepared silver-containing silver nitrate solution, shake, and after the solution is completely absorbed, dry at 150°C for 2 hours, and calcine at 550°C for 5 hours to obtain semi-finished catalyst H.

[0115] (4) Take 1.55 g of cerium nitrate, 0.0021 g of chloroplatinic acid, dissolve in 48.5 mL of deionized water, adjust the pH to 5.0, then immerse the semi-finished catalyst I into the prepared solution, after the solution is completely absorbed, dry at 120°C for 5 hours, and calcine at 400°C for 4 hours to obtain the desired catalyst.

[0116] The particle size of the prepared microemulsion emulsion is 399.56 nm measured by dynamic light scattering.

[0117] The prepared catalyst is measured by atomic absorption spectrometry, and the Pd content is 0.03%, the Ni content is 3%, the Cu content is 1%, the Pt content is 0.001%, and the Ce content is 0.5%, and the Ag content is 0.1%.

[0118] Reduction of the catalyst:

[0119] Before use, place it in a fixed bed reaction device, reduce it with pure hydrogen at a temperature of 560°C for 8h.

[0120] Comparative Example 3

[0121] The same carrier as in Example 3 is used, and the catalyst preparation conditions are the same as in Example 3, except that no Pt is loaded

[0122] (1) Take 6.63 g of nickel chloride, 0.3388 g of copper nitrate, dissolve in 46 mL of deionized water, add 26 g of n-hexane, add 4.956 g of CATB, add 4.96 g of n-butanol, stir thoroughly to form a microemulsion, immerse the weighed 100 g of high-temperature calcined carrier into the prepared microemulsion, shake for 240 min, filter out the residual liquid, dry at 120°C for 1 hour, calcine at 600°C for 6 hours, and call it semi-finished catalyst F1.

[0123] (2) Take 0.05 g of palladium chloride, dissolve in 90 mL of deionized water, adjust the pH to 2, and then immerse the semi-finished catalyst F1 into the prepared Pd salt solution, immerse for 90 min, dry at 120°C for 4 hours, and calcine at 520°C for 6 hours to obtain semi-finished catalyst G1.

[0124] (3) Take 0.216 g of silver nitrate, dissolve in 43.7 mL of deionized water, and then immerse the semi-finished catalyst G1 prepared in step (2) into the prepared silver-containing silver nitrate solution, shake, and after the solution is completely absorbed, dry at 150°C for 2 hours, and calcine at 550°C for 5 hours to obtain semi-finished catalyst H1.

[0125] (4) Take 1.55 g of cerium nitrate, dissolve in 48.5 mL of deionized water, adjust the pH to 5.0, and then immerse the semi-finished catalyst H1 into the prepared solution, and after the solution is completely absorbed, dry at 120°C for 5 hours, and calcine at 400°C for 4 hours to obtain the desired catalyst.

[0126] The particle size of the prepared microemulsion emulsion is 399.63 nm measured by dynamic light scattering.

[0127] The prepared catalyst is measured by atomic absorption spectrometry, and the Pd content is 0.03%, the Ni content is 3%, the Cu content is 1%, the Ce content is 0.5%, and the Ag content is 0.1%.

[0128] Reduction of the catalyst:

[0129] Before use, place it in a fixed bed reaction device, reduce it with pure hydrogen at a temperature of 560°C for 8 hours.

[0130] Example 4

[0131] Carrier: A commercially available bimodal pore size distribution spherical alumina-titania carrier with a titania content of 20% and a diameter of 3 mm is used. After calcination at 1120°C for 4 hours, the bimodal pore size distribution ranges from 23 to 47 nm and 90 to 450 nm, the water absorption rate is 60%, and the specific surface area is 30.47 m2 / g. Take 100 g of the carrier.

[0132] Catalyst preparation:

[0133] (1) Take 8.84 g of nickel chloride, 1.18 g of copper nitrate, dissolve in 70 mL of deionized water, add 35 g of n-hexane, add 21 g of Triton X-100, add 21 g of n-pentanol, and stir thoroughly to form a microemulsion. Dip 100 g of high-temperature calcined carrier into the prepared microemulsion, shake for 180 min, filter out the remaining liquid, dry at 80°C for 4 hours, and calcine at 550°C for 5 hours to obtain a semi-finished catalyst J.

[0134] (2) Take 0.058 g of palladium chloride, dissolve in 80 mL of deionized water, adjust the pH to 2, and then dip the semi-finished catalyst J into the prepared Pd salt solution. After 120 min of immersion, dry at 130°C for 3 hours and calcine at 420°C for 4 hours to obtain a semi-finished catalyst K.

[0135] (3) Take 0.628 g of cerium chloride and 0.0147 g of chloroplatinic acid, dissolve in 57 mL of deionized water, and adjust the pH to 1.3. Then dip the semi-finished catalyst K into the prepared solution. After the solution is completely absorbed, dry at 120°C for 5 hours and calcine at 420°C for 4 hours to obtain a semi-finished catalyst M.

[0136] Take 0.13 g of silver nitrate, dissolve in 43.7 mL of deionized water, and dissolve the semi-finished catalyst M prepared in step (3) in the prepared silver-containing silver nitrate solution. Shake until the solution is completely absorbed, dry at 150°C for 2 hours, and calcine at 600°C for 6 hours to obtain the desired catalyst.

[0137] The particle size of the prepared microemulsion emulsion is 50.14 nm as determined by dynamic light scattering.

[0138] The prepared catalyst has a Pd content of 0.035%, a Ni content of 4%, a Cu content of 0.4%, a Pt content of 0.007%, a Ce content of 0.3%, and an Ag content of 0.06% as determined by atomic absorption spectrometry.

[0139] Reduction of the catalyst:

[0140] Before use, place it in a fixed bed reaction device and reduce it for 8 h at a temperature of 380°C using a mixed gas with a molar ratio of N2:H2 = 1:1.

[0141] Comparative Example 4

[0142] (1) Take 8.84 g of nickel chloride, 1.18 g of copper nitrate, dissolve in 70 mL of deionized water, add 35 g of n-hexane, add 21 g of Triton X-100, add 21 g of n-pentanol, and stir thoroughly to form a microemulsion. Dip 100 g of high-temperature calcined carrier into the prepared microemulsion, shake for 180 min, filter out the remaining liquid, dry at 80°C for 4 hours, and calcine at 550°C for 5 hours to obtain a semi-finished catalyst J.

[0143] (2) Take 0.058 g of palladium chloride, dissolve in 80 mL of deionized water, adjust the pH to 2, and then dip the semi-finished catalyst J into the prepared Pd salt solution. After 120 min of immersion, dry at 130°C for 3 hours and calcine at 420°C for 4 hours to obtain a semi-finished catalyst K.

[0144] (3) Take 0.628 g of cerium chloride and 0.0147 g of chloroplatinic acid, dissolve in 57 mL of deionized water, and adjust the pH to 1.3. Then dip the semi-finished catalyst K into the prepared solution. After the solution is completely absorbed, dry at 120°C for 5 hours and calcine at 420°C for 4 hours to obtain a semi-finished catalyst M.

[0145] Take 0.13 g of silver nitrate, dissolve in 43.7 mL of deionized water, and then dissolve the semi-finished catalyst M prepared in step (3) into the prepared silver-containing silver nitrate solution. Shake until the solution is completely absorbed, dry at 150°C for 2 hours, and calcine at 600°C for 6 hours to obtain the desired catalyst.

[0146] The particle size of the prepared microemulsion emulsion is 50.26 nm as measured by dynamic light scattering.

[0147] The prepared catalyst has a Pd content of 0.035%, a Ni content of 4%, a Cu content of 0.4%, a Pt content of 0.007%, and an Ag content of 0.06% as measured by atomic absorption spectrometry.

[0148] Reduction of the catalyst:

[0149] Before use, place it in a fixed bed reaction device and reduce it for 8 h at a temperature of 380°C using a mixed gas with a molar ratio of N2:H2 = 1:1.

[0150] Example 5

[0151] Carrier: A commercially available bimodal pore distribution spherical alumina-magnesia carrier with a magnesium oxide content of 3% and a diameter of 3 mm is used. After calcination at 1000°C for 4 h, the bimodal pore size distribution ranges from 23 to 47 nm and 80 to 380 nm, the water absorption rate is 60%, and the specific surface area is 43.5 m2 / g. Take 100 g of the carrier.

[0152] Catalyst preparation:

[0153] (1) Take 15.56 g of nickel nitrate, 1.77 g of copper nitrate, dissolve in 80 mL of deionized water, add 40.00 g of cyclohexane, add 18.00 g of Triton X-100, add 16.50 g of n-pentanol, and stir thoroughly to form a microemulsion. Immerse the prepared carrier 100 g into the prepared microemulsion, shake for 180 min, filter out the remaining liquid, dry at 70°C for 6 hours, and calcine at 500°C for 5h, and call it semi-finished catalyst N.

[0154] (2) Take 0.042 g of palladium chloride, dissolve in 80 mL of deionized water, adjust the pH to 3.0, and then immerse the semi-finished catalyst N into the prepared Pd salt solution. After immersing for 120 min, dry at 130°C for 3 hours, and calcine at 500°C for 5h to obtain semi-finished catalyst O.

[0155] (3) Take 0.25 g of silver nitrate, dissolve in 58 mL of deionized water, and dissolve the semi-finished catalyst O of step (2) in the prepared silver-containing silver nitrate solution. Shake until the solution is completely absorbed, dry at 100°C for 4 hours, and calcine at 550°C for 5h to obtain semi-finished catalyst P.

[0156] (4) Take 0.62 g of cerium nitrate and 0.0084 g of chloroplatinic acid, dissolve in 57 mL of deionized water, and adjust the pH to 1.5. Then immerse the semi-finished catalyst P into the prepared solution. After the solution is completely absorbed, dry at 120°C for 5 hours, and calcine at 500°C for 4 hours to obtain the required catalyst.

[0157] The particle size of the prepared microemulsion emulsion is 65.08 nm, as determined by dynamic light scattering.

[0158] The prepared catalyst has a Pd content of 0.025%, a Ni content of 5%, a Cu content of 0.6%, a Pt content of 0.004%, a Ce content of 0.2%, and an Ag content of 0.16%, as determined by atomic absorption spectrometry.

[0159] Reduction of the catalyst:

[0160] Before use, place it in a fixed bed reaction device and reduce it at a temperature of 350°C for 8h using a mixed gas with a molar ratio of N2:H2=1:1.

[0161] Comparative Example 5

[0162] The catalyst preparation conditions are the same as in Example 5, except that the catalyst reduction temperature is 500°C.

[0163] (1) Take 15.56 g of nickel nitrate, 1.77 g of copper nitrate, dissolve in 80 mL of deionized water, add 40.00 g of cyclohexane, add 18.00 g of Triton X-100, add 16.50 g of n-pentanol, and stir thoroughly to form a microemulsion. Immerse the prepared carrier 100 g into the prepared microemulsion, shake for 180 min, filter out the remaining liquid, dry at 70°C for 6 hours, and calcine at 500°C for 5h, and call it semi-finished catalyst N.

[0164] (2) Take 0.042 g of palladium chloride, dissolve in 80 mL of deionized water, adjust the pH to 3.0, and then immerse the semi-finished catalyst N into the prepared Pd salt solution. After immersing for 120 min, dry at 130°C for 3 hours, and calcine at 500°C for 5h to obtain semi-finished catalyst O.

[0165] (3) Take 0.25 g of silver nitrate, dissolve in 58 mL of deionized water, and then immerse the semi-finished catalyst O of step (2) into the prepared silver-containing silver nitrate solution. After shaking until the solution is completely absorbed, dry at 100°C for 4 hours, and calcine at 550°C for 5h to obtain semi-finished catalyst P.

[0166] (4) Take 0.62 g of cerium nitrate and 0.0084 g of chloroplatinic acid, dissolve in 57 mL of deionized water, and adjust the pH to 1.5. Then immerse the semi-finished catalyst P into the prepared solution. After the solution is completely absorbed, dry at 120°C for 5 hours, and calcine at 500°C for 4h to obtain the required catalyst.

[0167] The particle size of the prepared microemulsion emulsion is 65.09 nm, as determined by dynamic light scattering.

[0168] The Pd content of the prepared catalyst is 0.025%, the Ni content is 5%, the Cu content is 0.6%, the Pt content is 0.004%, the Ce content is 0.2%, and the Ag content is 0.16%, as determined by atomic absorption spectrometry.

[0169] Reduction of the catalyst:

[0170] Before use, place it in a fixed bed reaction device and reduce it at a temperature of 500°C for 8h using a mixed gas with a molar ratio of N2:H2=1:1.

[0171] Example 6

[0172] Carrier: A commercially available bimodal pore distribution spherical alumina-magnesia carrier with a magnesium oxide content of 10% and a diameter of 3 mm is used. After calcination at 1000°C for 4h, the bimodal pore size distribution ranges from 23 to 47 nm and 80 to 380 nm, the water absorption is 55%, and the specific surface area is 46.7 m2 / g. Take 100 g of the carrier.

[0173] Catalyst preparation:

[0174] (1) Take 3.74 g of nickel nitrate, 0.59 g of copper nitrate, dissolve in 80 mL of deionized water, add 40.00 g of n-hexane, add 18.00 g of Triton X-100, add 16.50 g of n-hexanol, stir well to form a microemulsion, immerse the prepared carrier 100 g into the prepared microemulsion, shake for 180 min, filter out the remaining liquid, dry at 70°C for 6 hours, calcine at 600°C for 4.5h, and call it semi-finished catalyst Q.

[0175] (2) Take 0.037 g of palladium chloride, dissolve in 80 mL of deionized water, adjust the pH to 1.5, then immerse the semi-finished catalyst Q into the prepared Pd salt solution, immerse for 120 min, dry at 130°C for 3 hours, and calcine at 460°C for 3 hours to obtain semi-finished catalyst R.

[0176] (3) Take 0.189 g of silver nitrate, dissolve in 55 mL of deionized water, dissolve the semi-finished catalyst R prepared in step (2) 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 550°C for 6 hours to obtain semi-finished catalyst S.

[0177] (4) Take 0.46 g of cerium nitrate, 0.0021 g of chloroplatinic acid, dissolve in 53 mL of deionized water, adjust the pH to 1.8, then immerse the semi-finished catalyst S into the prepared solution, after the solution is completely absorbed, dry at 120°C for 5 hours, and calcine at 400°C for 4 hours to obtain the required catalyst.

[0178] The particle size of the prepared microemulsion emulsion is 65.17 nm measured by dynamic light scattering.

[0179] The total Pd content of the prepared catalyst is 0.022%, the Ni content is 1.2%, the Cu content is 0.2%, the Pt content is 0.001%, the Ce content is 0.15%, and the Ag content is 0.12% measured by atomic absorption spectrometry.

[0180] Reduction of the catalyst:

[0181] Before use, place it in a fixed bed reaction device, use a mixed gas with a molar ratio of N2:H2=1:1, reduce at a temperature of 400°C for 8h.

[0182] Comparative Example 6

[0183] The catalyst preparation conditions are the same as in Example 6, except that the catalyst reduction temperature is 200°C.

[0184] (1) Take 3.74 g of nickel nitrate, 0.59 g of copper nitrate, dissolve in 80 mL of deionized water, add 40.00 g of n-hexane, add 18.00 g of Triton X-100, add 16.50 g of n-hexanol, stir thoroughly to form a microemulsion, immerse the prepared carrier 100 g into the prepared microemulsion, shake for 180 min, filter out the remaining liquid, dry at 70°C for 6 hours, calcine at 600°C for 4.5 h, and call it semi-finished catalyst Q1.

[0185] (2) Take 0.037 g of palladium chloride, dissolve in 80 mL of deionized water, adjust the pH to 1.5, and then immerse the semi-finished catalyst Q1 into the prepared Pd salt solution, immerse for 120 min, dry at 130°C for 3 hours, and calcine at 460°C for 3 hours to obtain semi-finished catalyst R1.

[0186] (3) Take 0.189 g of silver nitrate, dissolve in 55 mL of deionized water, and then immerse the semi-finished catalyst R1 prepared in step (2) into 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 550°C for 6 hours to obtain semi-finished catalyst S1.

[0187] (4) Take 0.46 g of cerium nitrate and 0.0021 g of chloroplatinic acid, dissolve in 53 mL of deionized water, adjust the pH to 1.8, and then immerse the semi-finished catalyst S1 into the prepared solution, and after the solution is completely absorbed, dry at 120°C for 5 hours, and calcine at 400°C for 4 hours to obtain the required catalyst.

[0188] The total Pd content of the prepared catalyst is 0.022%, the Ni content is 1.2%, the Cu content is 0.2%, the Pt content is 0.001%, the Ce content is 0.15%, and the Ag content is 0.12%, as determined by atomic absorption spectrometry.

[0189] The particle size of the prepared microemulsion emulsion is 65.24 nm, as determined by dynamic light scattering.

[0190] Reduction of the catalyst:

[0191] Before use, place it in a fixed bed reaction device, use a mixed gas with a molar ratio of N2:H2=1:1, reduce at a temperature of 200°C for 8 h.

[0192] Example 7

[0193] Carrier: A commercially available bimodal pore distribution spherical alumina carrier with a diameter of 3 mm is used. After calcination at 1150°C for 4 h, the bimodal pore size distribution ranges from 35 to 50 nm and 120 to 500 nm, the water absorption rate is 45%, and the specific surface area is 19.84 m 2 / g. Take 100 g of the carrier.

[0194] Catalyst preparation:

[0195] (1) Take 12.45 g of nickel nitrate, 0.847 g of copper chloride, dissolve in 69 mL of deionized water, add 23 g of n-pentane, add 3.45 g of CATB, add 2.88 g of n-octanol, and fully stir to form a microemulsion. Dip 100 g of the high-temperature calcined carrier weighed into the prepared microemulsion, shake for 90 min, filter out the remaining liquid, dry at 80°C for 5 hours, and calcine at 600°C for 4 hours, and call the semi-finished catalyst T.

[0196] (2) Take 0.042 g of palladium chloride, dissolve in 100 mL of deionized water, adjust the pH to 2.3, and then dip the semi-finished catalyst T prepared in step (2) into the prepared Pd salt solution. After 60 min of immersion, dry at 100°C for 5 hours, and calcine at 500°C for 4 hours to obtain the semi-finished catalyst U.

[0197] (3) Take 0.283 g of silver nitrate, dissolve in 40.5 mL of deionized water, and dissolve the semi-finished catalyst U prepared in step (2) into the prepared silver-containing silver nitrate solution. Shake until the solution is completely absorbed, dry at 100°C for 4 hours, and calcine at 600°C for 6 hours to obtain the semi-finished catalyst V.

[0198] (4) Take 1.55 g of cerium nitrate and 0.01 g of chloroplatinic acid, dissolve in 42.7 mL of deionized water, and adjust the pH to 1.3. Then dip the semi-finished catalyst V into the prepared solution. After the solution is completely absorbed, dry at 120°C for 5 hours, and calcine at 400°C for 6 hours to obtain the desired catalyst.

[0199] The particle size of the microemulsion emulsion prepared in step (1) was measured by dynamic light scattering to be 498.5 nm.

[0200] The prepared catalyst was measured by atomic absorption spectrometry to have a Pd content of 0.025%, a Ni content of 4%, a Cu content of 0.4%, a Pt content of 0.005%, a Ce content of 0.5%, and an Ag content of 0.18%.

[0201] Reduction of the catalyst:

[0202] Before use, place in a fixed bed reaction device and reduce for 8 h at a temperature of 360°C using a mixed gas with a molar ratio of N2:H2 = 1:1.

[0203] Comparative Example 7

[0204] The carrier of Comparative Example 7 is the same as that of Example 7, and the preparation conditions are the same, except that the order of steps (2) and (4) is reversed.

[0205] (1) Weigh 12.45 g of nickel nitrate, 0.847 g of copper chloride, dissolve in 69 mL of deionized water, add 23 g of n-pentane, add 3.45 g of CATB, add 2.88 g of n-octanol, and fully stir to form a microemulsion. Immerse the weighed 100 g of high-temperature calcined carrier into the prepared microemulsion, shake for 90 min, filter out the remaining liquid, dry at 80°C for 5 hours, and calcine at 600°C for 4 hours, and call the semi-finished catalyst T1.

[0206] (2) Weigh 1.55 g of cerium nitrate and 0.01 g of chloroplatinic acid, dissolve in 42.7 mL of deionized water, adjust the pH to 1.3, and immerse the semi-finished catalyst T1 into the prepared solution. After the solution is completely absorbed, dry at 120°C for 5 hours, and calcine at 400°C for 6 hours to obtain the semi-finished catalyst U1.

[0207] (3) Weigh 0.283 g of silver nitrate, dissolve in 40.5 mL of deionized water, and dissolve the semi-finished catalyst U1 prepared in step (2) into 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 600°C for 6 hours to obtain the semi-finished catalyst V1.

[0208] (4) Weigh 0.042 g of palladium chloride, dissolve in 100 mL of deionized water, and adjust the pH to 2.3. Then immerse the semi-finished catalyst V1 into the prepared Pd salt solution, immerse for 60 min, dry at 100°C for 5 hours, and calcine at 500°C for 4 hours to obtain the required catalyst.

[0209] The particle size of the microemulsion emulsion prepared in step (1) is 499.2 nm, as determined by dynamic light scattering.

[0210] The prepared catalyst has a Pd content of 0.025%, a Ni content of 4%, a Cu content of 0.4%, a Pt content of 0.005%, a Ce content of 0.5%, and an Ag content of 0.18%, as determined by atomic absorption spectrometry.

[0211] Reduction of the catalyst:

[0212] Before use, place in a fixed bed reaction device, reduce for 8 h at a temperature of 360°C using a mixed gas with a molar ratio of N2:H2=1:1.

[0213] Example 8

[0214] Catalyst preparation:

[0215] Weigh a commercially available bimodal pore distribution spherical carrier, which contains 97% alumina and 3% titanium oxide, and has a diameter of 4 mm. After calcination at 1120°C for 4 h, the pore size distribution ranges are 25-45 nm and 90-460 nm, respectively, the water absorption rate is 48%, and the specific surface area is 32.54 m2 / g, the carrier 100 g was weighed.

[0216] (1) 14.75 g of anhydrous nickel nitrate, 1.48 g of copper nitrate were weighed, dissolved in 71.5 g of water, 27.5 g of n-hexane, 17.16 g of CTAB, 15.5 g of n-pentanol were added, and stirred thoroughly to form a microemulsion. The calcined carrier was immersed in the prepared microemulsion for 4 hours, the residual liquid was filtered out, and washed with deionized water until neutral. Dried at 60°C for 10 hours, calcined at 500°C for 4 hours to obtain the semi-finished catalyst W.

[0217] (2) 0.047 g of palladium chloride salt was weighed and dissolved in 120 mL of deionized water, the pH was adjusted to 1.7, and the semi-finished catalyst W was added to the Pd salt solution, immersed and adsorbed for 1 hour, dried at 120°C for 2 hours, and calcined at 480°C for 2 hours to obtain the desired semi-finished catalyst X.

[0218] (3) 0.704 g of cerium nitrate, 0.0042 g of chloroplatinic acid were weighed and dissolved in 46 mL of deionized water, the pH was adjusted to 1.3, and the semi-finished catalyst X was immersed in the prepared solution. After the solution was completely absorbed, it was dried at 120°C for 5 hours, calcined at 400°C for 6 hours, 50 mL of deionized water was added, 0.33 g of silver nitrate was added to completely dissolve it, the pH was adjusted to 3, and the semi-finished catalyst W was immersed in the prepared solution, shaken for 15 min, dried at 120°C for 2 hours, and calcined at 500°C for 4 hours to obtain the semi-finished catalyst Y.

[0219] (4) 0.157 g of silver nitrate was weighed and dissolved in 43.2 mL of deionized water, and the semi-finished catalyst Y prepared in step (3) was dissolved in the prepared silver-containing silver nitrate solution. Shake, dry at 100°C for 4 hours, and calcine at 550°C for 4 hours to obtain the desired catalyst.

[0220] The particle size of the microemulsion emulsion prepared in step (1) was measured by dynamic light scattering to be 390.38 nm.

[0221] The prepared catalyst was determined by atomic absorption spectrometry, and the Pd content was 0.022%, the Ni content was 5%, the Cu content was 0.5%, the Pt content was 0.002%, the Ce content was 0.4%, and the Ag content was 0.10%.

[0222] Reduction of the catalyst:

[0223] Reduction gas: hydrogen, reduction space velocity: 100 h-1, temperature: 350°C, and holding time: 8 h.

[0224] Comparative Example 8

[0225] Catalyst preparation:

[0226] Comparative Example 8 was prepared using the same support as Example 8, the same steps as Example 8, except that the Pd was not calcined, and the loading continued with Pt, Ce

[0227] Catalyst preparation:

[0228] (1) Weigh 14.75 g of anhydrous nickel nitrate, 1.48 g of copper nitrate, dissolve in 71.5 g of water, add 27.5 g of n-hexane, 17.16 g of CTAB, 15.5 g of n-pentanol, and stir well to form a microemulsion. The calcined support is immersed in the prepared microemulsion for 4 hours, then the remaining liquid is filtered out and washed with deionized water until neutral. Dry at 60°C for 10 hours, and calcine at 500°C for 4 hours to obtain the semi-finished catalyst W1.

[0229] (2) Weigh 0.047 g of palladium chloride salt and dissolve in 120 mL of deionized water, adjust the pH to 1.7, then add the semi-finished catalyst W1 to the Pd salt solution, immerse and adsorb for 1 hour, then dry at 120°C for 2 hours to obtain the desired semi-finished catalyst X1.

[0230] (3) Weigh 0.704 g of cerium nitrate, 0.0042 g of chloroplatinic acid and dissolve in 46 mL of deionized water, adjust the pH to 1.3, then immerse the semi-finished catalyst X1 into the prepared solution, after the solution is completely absorbed, dry at 120°C for 5 hours, calcine at 400°C for 6 hours, take 50 mL of deionized water, add 0.33 g of silver nitrate to completely dissolve it, adjust the pH to 3, immerse the semi-finished catalyst W in the prepared solution, shake for 15 min, dry at 120°C for 2 hours, calcine at 500°C for 4 hours to obtain the semi-finished catalyst Y1.

[0231] (4) Weigh 0.157 g of silver nitrate and dissolve in 43.2 mL of deionized water, dissolve the semi-finished catalyst Y prepared in step (3) in the prepared silver-containing silver nitrate solution, shake, after the solution is completely absorbed, dry at 100°C for 4 hours, calcine at 550°C for 4 hours to obtain the desired catalyst.

[0232] The particle size of the microemulsion emulsion prepared in step (1) is 390.45 nm, as determined by dynamic light scattering.

[0233] The prepared catalyst was determined by atomic absorption spectrometry, with a Pd content of 0.022%, a Ni content of 5%, a Cu content of 0.5%, a Pt content of 0.002%, a Ce content of 0.4%, and an Ag content of 0.10%.

[0234] Reduction of the catalyst:

[0235] Reduction gas: hydrogen, reduction space velocity: 100 h -1 , temperature 350°C, for 8 h.

[0236] Example 9

[0237] Catalyst preparation: The carrier uses a commercially available bimodal pore size distribution spherical alumina carrier with a diameter of 3 mm. After calcination at 1120℃ for 4h, the bimodal pore size distribution ranges from 30-50nm and 100-500nm, the water absorption rate is 62%, and the specific surface area is 20.34m2 / g. 100g of the carrier is weighed.

[0238] (1) Weigh 8.84g of nickel chloride, 1.18g of copper nitrate, 71.5g of water, add 27.5g of n-hexane, 17.16g of CTAB, and 15.5g of n-pentanol, and stir well to form a microemulsion. The weighed 100g of high-temperature calcined carrier is immersed in the prepared microemulsion, shaken for 90min, the remaining liquid is filtered out, dried at 120℃ for 2 hours, and calcined at 500℃ for 4h to obtain the semi-finished catalyst α.

[0239] (2) Weigh 0.042g of palladium chloride, dissolve in 100mL of deionized water, adjust the pH to 2.3, and then immerse the semi-finished catalyst α into the prepared Pd salt solution. After 60min of immersion, dry at 100℃ for 5 hours, and calcine at 500℃ for 4 hours to obtain the semi-finished catalyst β.

[0240] (3) Weigh 0.283g of silver nitrate, dissolve in 55.8mL of deionized water, and dissolve the semi-finished catalyst β prepared in step (2) into the prepared silver-containing silver nitrate solution. Shake until the solution is completely absorbed, dry at 140℃ for 2 hours, and calcine at 500℃ for 5 hours to obtain the semi-finished catalyst γ.

[0241] (4) Weigh 1.55g of cerium nitrate and 0.011g of chloroplatinic acid, dissolve in 59mL of deionized water, and adjust the pH to 3.0. Then immerse the semi-finished catalyst γ into the prepared solution. After the solution is completely absorbed, dry at 120℃ for 5 hours, and calcine at 400℃ for 4 hours to obtain the desired catalyst.

[0242] The particle size of the microemulsion prepared in (1) is 100.23nm, as determined by dynamic light scattering.

[0243] The prepared catalyst has a Pd content of 0.025%, a Ni content of 4%, a Cu content of 0.4%, a Pt content of 0.005%, a Ce content of 0.5%, and an Ag content of 0.18%, as determined by atomic absorption spectrometry.

[0244] Reduction of the catalyst:

[0245] Reduction gas: hydrogen, reduction space velocity: 100h -1 , temperature 370℃, for 4h.

[0246] The catalyst support of Comparative Example 9 is the same as that of Example 9, and the conditions are also the same, except that Ag is loaded first and then Pd is loaded.

[0247] Catalyst preparation:

[0248] The support is a commercially available bimodal pore distribution spherical alumina support with a diameter of 3 mm. After calcination at 1120°C for 4 h, the bimodal pore size distribution ranges from 30 to 50 nm and 100 to 500 nm, the water absorption is 62%, and the specific surface area is 20 m 2 / g. 100 g of the support is weighed.

[0249] (1) 8.84 g of nickel chloride, 1.18 g of copper nitrate, 71.5 g of water, 27.5 g of n-hexane, 17.16 g of CTAB, and 15.5 g of n-pentanol are weighed into a beaker, and the mixture is stirred to form a microemulsion. 100 g of the high-temperature calcined support is immersed in the prepared microemulsion, shaken for 90 min, and the remaining liquid is filtered out. The resulting product is dried at 120°C for 2 h and calcined at 500°C for 4 h to obtain a semi-finished catalyst a1.

[0250] (2) 0.283 g of silver nitrate is weighed into 55.8 mL of deionized water, and the semi-finished catalyst a1 prepared in step (1) is dissolved in the prepared silver-containing solution. After shaking, the solution is dried at 140°C for 2 h and calcined at 500°C for 5 h to obtain a semi-finished catalyst β1.

[0251] (3) 0.042 g of palladium chloride is weighed into 100 mL of deionized water, and the pH is adjusted to 2.3. The semi-finished catalyst β1 is then immersed in the prepared Pd salt solution, and after 60 min of immersion, the resulting product is dried at 100°C for 5 h and calcined at 500°C for 4 h to obtain a semi-finished catalyst γ1.

[0252] (4) 1.55 g of cerium nitrate and 0.011 g of chloroplatinic acid are weighed into 59 mL of deionized water, and the pH is adjusted to 3.0. The semi-finished catalyst γ1 is then immersed in the prepared solution, and after the solution is completely absorbed, the resulting product is dried at 120°C for 5 h and calcined at 400°C for 4 h to obtain the desired catalyst.

[0253] The particle size of the microemulsion prepared in (1) is 100.31 nm, as determined by dynamic light scattering.

[0254] The prepared catalyst is measured by atomic absorption spectrometry, and the Pd content is 0.025%, the Ni content is 4%, the Cu content is 0.4%, the Pt content is 0.005%, and the Ce content is 0.5%, and the Ag content is 0.18%.

[0255] Reduction of the catalyst:

[0256] Reducing gas: hydrogen, reducing space velocity: 100 h -1 , temperature 370℃, holding for 4h.

[0257] Example 10

[0258] Support: a commercially available bimodal pore size distribution spherical alumina support with a diameter of 3mm. After calcination at 1100℃ for 4h, the bimodal pore size distribution ranges from 30-45nm and 300-450nm, the water absorption is 62%, and the specific surface area is 49.87m 2 / g. 100g of the support was weighed.

[0259] Catalyst preparation:

[0260] (1) 6.63g of nickel chloride and 0.59g of copper nitrate were weighed and dissolved in 70mL of deionized water, 35g of n-hexane was added, 21g of CATB was added, and n-pentanol was added, and a microemulsion was formed by stirring. 100g of the high-temperature calcined support was immersed in the prepared microemulsion, shaken for 90min, the remaining liquid was filtered out, dried at 80℃ for 5h, and calcined at 550℃ for 4h, and the semi-finished catalyst δ was obtained.

[0261] (2) 0.05g of palladium chloride was weighed and dissolved in 100mL of deionized water, and the pH was adjusted to 1.8. The semi-finished catalyst δ was immersed in the prepared Pd salt solution, and after 60min of immersion, it was dried at 100℃ for 5h and calcined at 420℃ for 2h to obtain the semi-finished catalyst ε.

[0262] (3) 0.28g of silver nitrate was weighed and dissolved in 55.8mL of deionized water. The semi-finished catalyst ε prepared in step (2) was dissolved in the prepared silver-containing silver nitrate solution, shaken, and after the solution was completely absorbed, it was dried at 140℃ for 2h and calcined at 500℃ for 4h to obtain the semi-finished catalyst ζ.

[0263] (4) 1.24g of cerium nitrate and 0.0063g of chloroplatinic acid were weighed and dissolved in 62mL of deionized water, and the pH was adjusted to 3.0. The semi-finished catalyst ζ was immersed in the prepared solution, and after the solution was completely absorbed, it was dried at 120℃ for 5h and calcined at 400℃ for 5h to obtain the desired catalyst.

[0264] The particle size of the microemulsion prepared in step (1) was measured by dynamic light scattering to be 50.37nm.

[0265] The prepared catalyst was measured by atomic absorption spectrometry, and the Pd content was 0.03%, the Ni content was 3%, the Cu content was 0.2%, the Pt content was 0.003%, the Ce content was 0.4%, and the Ag content was 0.018%.

[0266] Reduction of the catalyst:

[0267] Before use, place in a fixed bed reaction device, with a mixture of gases in a molar ratio of N2:H2 = 1:1, at a temperature of 400°C, reduction treatment for 8h.

[0268] Comparative Example 10

[0269] The carrier is the same as Example 10, except that in Comparative Example 10, Cu and Ni are loaded using the solution method.

[0270] Catalyst preparation:

[0271] (1) Take 6.63 g of nickel chloride and 0.59 g of copper nitrate, dissolve in 62 mL of deionized water, add the prepared carrier to the prepared salt solution, shake, and after the solution is completely absorbed, dry at 80°C for 5 hours, and calcine at 550°C for 4h, called semi-finished catalyst δ1.

[0272] (2) Take 0.05 g of palladium chloride, dissolve in 100 mL of deionized water, adjust the pH to 1.8, and then immerse the semi-finished catalyst δ1 prepared in step (2) into the prepared Pd salt solution, immerse for 60 min, dry at 100°C for 5 hours, and calcine at 420°C for 2 hours to obtain semi-finished catalyst ε1.

[0273] (3) Take 0.28 g of silver nitrate, dissolve in 55.8 mL of deionized water, and then immerse the semi-finished catalyst ε1 prepared in step (2) into 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 500°C for 4 hours to obtain semi-finished catalyst ζ1.

[0274] (4) Take 1.24 g of cerium nitrate and 0.0063 g of chloroplatinic acid, dissolve in 62 mL of deionized water, adjust the pH to 3.0, and then immerse the semi-finished catalyst ζ1 into the prepared solution, and after the solution is completely absorbed, dry at 120°C for 5 hours, and calcine at 400°C for 5 hours to obtain the desired catalyst.

[0275] The particle size of the microemulsion emulsion prepared in step (1) is 50.27 nm, as determined by dynamic light scattering.

[0276] The prepared catalyst has a Pd content of 0.03%, a Ni content of 3%, a Cu content of 0.2%, a Pt content of 0.003%, a Ce content of 0.4%, and an Ag content of 0.018%, as determined by atomic absorption spectrometry.

[0277] Reduction of the catalyst:

[0278] Before use, place in a fixed bed reaction device, with a mixture of gases in a molar ratio of N2:H2 = 1:1, at a temperature of 400°C, reduction treatment for 8h.

[0279] Example 11

[0280] Preparation of catalyst:

[0281] A commercially available bimodal pore size distribution spherical alumina support with a diameter of 4 mm was weighed. After calcination at 1090°C for 4 h, the pore size distribution ranges were 20-46 nm and 85-350 nm, respectively, the water absorption was 55%, and the specific surface area was 40 m 2 / g. 100 g of the support was weighed.

[0282] (1) 15.57 g of nickel nitrate and 1.18 g of copper nitrate were weighed and dissolved in 71.5 g of water, 25 g of n-hexane, 16.16 g of CTAB and 15.0 g of n-pentanol were added to form a microemulsion, the prepared support was added to the prepared microemulsion and immersed for 80 min, then the residual liquid was filtered out and washed with deionized water until neutral. Drying was carried out at 80°C for 6 hours, and calcination was carried out at 550°C for 4 hours to obtain a semi-finished catalyst π.

[0283] (2) 0.021 g of palladium nitrate was weighed and dissolved in 100 mL of deionized water, and the pH was adjusted to 2.1. The semi-finished catalyst π was immersed in the prepared Pd salt solution, and after 60 min of immersion, drying was carried out at 100°C for 5 hours, and calcination was carried out at 350°C for 4 hours to obtain a semi-finished catalyst ρ.

[0284] (3) 1.55 g of cerium nitrate and 0.0084 g of chloroplatinic acid were weighed and dissolved in 52 mL of deionized water, and the pH was adjusted to 2.8. The semi-finished catalyst σ was immersed in the prepared solution, and after the solution was completely absorbed, drying was carried out at 120°C for 5 hours, and calcination was carried out at 400°C for 5 hours to obtain a semi-finished catalyst ρ.

[0285] (4) 49.5 mL of deionized water was taken, 0.189 g of silver nitrate was added and dissolved completely, and the semi-finished catalyst ρ was immersed in the prepared solution and shaken for 10 min. Drying was carried out at 100°C for 4 hours, and calcination was carried out at 550°C for 4 hours to obtain the desired catalyst σ.

[0286] The particle size of the microemulsion prepared in step (1) was measured by dynamic light scattering method to be 120.62 nm.

[0287] The elemental content was determined by atomic absorption spectrometry, and the Pd content was 0.035%, the Ni content was 5%, the Cu content was 0.4%, the Pt content was 0.004%, the Ce content was 0.5%, and the Ag content was 0.12%.

[0288] Reduction of catalyst:

[0289] Reduction gas: hydrogen, reduction space velocity: 100 h -1 , temperature 350°C, for 4 h.

[0290] Comparative Example 11

[0291] The same carrier as in Example 11 was used, and the same preparation conditions as in Comparative Example 11 were used, except that in Comparative Example 11, Pt and Pd were loaded simultaneously, and Ce was loaded separately after the Pt and Pd.

[0292] Catalyst preparation:

[0293] (1) 15.57 g of nickel nitrate and 1.18 g of copper nitrate were weighed out, dissolved in 71.5 g of water, and 25 g of n-hexane, 16.16 g of CTAB, and 15.0 g of n-pentanol were added to form a microemulsion. The carrier prepared was immersed in the prepared microemulsion for 80 min, the remaining liquid was filtered out, and the catalyst was washed with deionized water until it was neutral. The catalyst was dried at 80°C for 6 hours and calcined at 550°C for 4 hours to obtain a semi-finished catalyst π.

[0294] (2) 0.021 g of palladium nitrate and 0.0084 g of chloroplatinic acid were weighed out, dissolved in 100 mL of deionized water, and the pH was adjusted to 2.1. The semi-finished catalyst π was immersed in the prepared Pd salt solution, and after 60 min of immersion, the catalyst was dried at 100°C for 5 hours and calcined at 350°C for 4 hours to obtain a semi-finished catalyst ρ.

[0295] (3) 1.55 g of cerium nitrate was weighed out, dissolved in 52 mL of deionized water, and the pH was adjusted to 2.8. The semi-finished catalyst σ was immersed in the prepared solution, and after the solution was completely absorbed, the catalyst was dried at 120°C for 5 hours and calcined at 400°C for 5 hours to obtain a semi-finished catalyst ρ.

[0296] (4) 49.5 mL of deionized water was taken, 0.189 g of silver nitrate was added to dissolve completely, and the semi-finished catalyst ρ was immersed in the prepared solution and shaken for 10 min. The catalyst was dried at 100°C for 4 hours and calcined at 550°C for 4 hours to obtain the desired catalyst σ.

[0297] The particle size of the microemulsion prepared in step (1) was measured by dynamic light scattering method to be 120.51 nm.

[0298] The elemental content was determined by atomic absorption spectrometry, and the Pd content was 0.035%, the Ni content was 5%, the Cu content was 0.4%, the Pt content was 0.004%, the Ce content was 0.5%, and the Ag content was 0.12%.

[0299] The particle size of the prepared microemulsion was measured by dynamic light scattering method to be 120 nm.

[0300] Reduction of the catalyst:

[0301] Reduction gas: hydrogen, reduction space velocity: 100 h -1 , temperature 350°C, for 4 h.

[0302] Performance of catalysts in post-hydrogenation reactions of C2

[0303] The catalyst was loaded at a rate of 50 mL in a fixed-bed single-stage reactor, with 350 mL of packing material. The reactant space velocity was 4000 h / h, the operating pressure was 2.0 MPa, the hydrogen-to-acetylene ratio was 1.4, and the reactor inlet temperature was 45 °C. The composition of the reactants is shown in Table 1.

[0304] Table 1 Composition of reactants

[0305] Reaction mass [C2H2] [C2H4] [C2H6] [C3-C4] Content (v / v %) 1.4 84 14 5*10 -3 ]]>

[0306] The catalyst evaluation results are shown in Table 2.

[0307] Table 2 Evaluation Test Results

[0308]

[0309] The comparison of the evaluation test results in Table 2 shows that:

[0310] Compared to Example 1, Comparative Example 1 did not have Ni loading; only Cu was present in the macropores. Although it also exhibited some hydrogenation activity, its saturated hydrogenation activity was significantly insufficient. While the initial acetylene conversion and selectivity were essentially the same as those of the corresponding examples, after 1000 hours, they were significantly lower than those of the examples. This indicates that the saturated hydrogenation effect of Ni on byproducts is important for improving anti-coking performance.

[0311] Compared to Example 2, the acetylene conversion rate reached 100% in the initial stage of catalyst operation. However, in Example 2, which did not have Cu loading, the difference was significant after 1000 hours, indicating that Cu loading is also important for the saturation hydrogenation of byproducts. This is because without Cu, Ni cannot be effectively reduced at 350°C, and the byproducts are not saturated with hydrogen, resulting in a larger difference after 1000 hours. However, after five regenerations, the initial conversion rates of the two catalysts were quite similar.

[0312] Comparative Example 3 and Example 3 were similar after 1000 hours, with little decrease in activity selectivity. However, Comparative Example 3 did not have Pt loading, and its performance decreased significantly after 5 regenerations.

[0313] Compared to Example 4, Comparative Example 4 did not have Ce loaded. The initial conversion rate of Comparative Example 4 was lower than that of Example 4, possibly because the higher reduction temperature had already affected the catalyst. Although both showed good activity selectivity after 1000 hours, the activity of the comparative example decreased by more than 20% after 5 regenerations, indicating that Ni-Cu is crucial for improving the catalyst's anti-coking performance, and Ce-Pt is important for improving the catalyst's regeneration performance.

[0314] Comparative Example 5 and Example 5 have the same catalyst composition, but the catalyst in Comparative Example 5 is reduced at 500°C. The initial activity and selectivity of the catalysts are obviously different, indicating that the reduction temperature does affect the performance of the catalyst. The higher the temperature, the lower the activity and selectivity.

[0315] The catalyst in Comparative Example 6 is prepared under the same conditions as Example 6, but the catalyst composition is the same. However, the performance of the catalyst after 1000 hours is significantly different. The reason may be that the Ni-Cu active center is not reduced at 200°C, and cannot play a role in the saturated hydrogenation of by-products.

[0316] In Comparative Example 7, Ce-Pt is loaded before Pd. The activity of the catalyst in the comparative example is significantly lower than that in the example. This may be due to the blocking effect of Ce-Pt on Pd, which makes it difficult for Pd to form active centers with effective activity during calcination. The catalyst shows insufficient activity, but better selectivity than the example. This shows that small particles are good, and Pd has low activity and high selectivity characteristics.

[0317] In Comparative Example 8, Pd is loaded and then Ce-Pt is loaded without calcination. Objectively, this should be the same as Comparative Example 7, that is, Ce-Pt prevents the growth of Pd particles. From the evaluation results, Comparative Examples 7 and 8 show the same trend, that is, the activity is lower than the example, and the selectivity is higher than the example. The regeneration performance is very good.

[0318] In Comparative Example 9, Ag is loaded before Pd. It can be seen that the initial selectivity of Comparative Example 9 is significantly lower than that of Example 9, indicating that the Pd-Ag alloy is formed, mainly because Ag is on the surface of the alloy, and the catalyst has better selectivity.

[0319] In Comparative Example 10, in Example 10, Ni-Cu is loaded using the solution method, which causes Ni-Cu to also enter the small pores of the catalyst, which cannot play a role in the saturated hydrogenation of by-products, but only helps the initial activity of the catalyst, but also causes the initial selectivity to decrease. The performance after 1000 hours decreases significantly. Since almost all active components are concentrated in the small pores, their regeneration performance is also not ideal, and there is a significant difference after 5 regenerations compared to Example 10.

[0320] In Comparative Example 11, Pd and Pt are loaded at the same time. Although the performance after 5 regenerations is slightly better than that without Pt loading, the performance decreases significantly after 5 regenerations without the synergistic effect of Ce-Pt.

[0321] Comparative Example 3 and Example 10 have lower calcination temperatures, and their activities are better.

[0322] Comparative Example 1 and Example 6 have Ag added, and the catalyst selectivity data is better.

Claims

1. A process for preparing a carbon di- fraction acetylene selective hydrogenation catalyst, characterized by, The active component of the catalyst contains Pd, Ni, Cu, Ce, Pt; the catalyst carrier is alumina or mainly alumina, and has a bimodal pore distribution structure, with a pore size of 15-50 nm for small pores and 60-500 nm for large pores; the alumina in the catalyst carrier is more than 80%; Ni and Cu are loaded by a microemulsion method, the particle size of the microemulsion is greater than the pore size of the small pores of the carrier and less than the maximum pore size of the large pores; Pd is loaded by a solution method, and Ce and Pt are loaded by a solution method simultaneously and after the loading of Pd; Pd, Ce and Pt are mainly loaded in the small pores of the catalyst.

2. The method of claim 1, wherein, The method comprises: loading precursor salts of Ni and Cu on the carrier, and obtaining a semi-finished catalyst A through drying and calcination; then loading a precursor salt of Pd on the semi-finished catalyst A, and obtaining a semi-finished catalyst B through drying and calcination; loading precursor salts of Ce and Pt on the semi-finished catalyst B, and obtaining the catalyst through drying and calcination.

3. The method of claim 2, wherein, Ni-Cu is loaded in the form of a microemulsion, and the particle size of the microemulsion is greater than the pore size of the small pores of the carrier and less than the maximum pore size of the large pores.

4. The method of claim 2, wherein, The content of Ce is 0.1-0.5% based on 100% of the weight of the carrier; and the content of Pt is 0.001-0.01%.

5. The method of claim 2, wherein, The content of Pd is 0.02-0.04%, the content of Ni is 1-5%, and the content of Cu is 0.2-1% based on 100% of the weight of the carrier.

6. The method of claim 2 wherein, The catalyst further contains Ag; the content of Ag is 0.2% or less based on 100% of the weight of the carrier.

7. The method of claim 6, wherein, The content of Ag is 0.06-0.2%.

8. The method of claim 6, wherein, The loading of Ag is performed after the loading of Pd.

9. The method of claim 2, wherein, The crystal form of the alumina in the carrier is θ, α or a mixed crystal form thereof; the alumina in the catalyst carrier is more than 80%.

10. The method of claim 9, wherein, The carrier further contains other metal oxides, and the other metal oxides are magnesium oxide and / or titanium oxide.

11. The method of claim 6, wherein, The method comprises: loading a precursor salt of Pd on the carrier, and obtaining a semi-finished catalyst A through calcination; then loading precursor salts of Ce and Pt on the semi-finished catalyst A, and obtaining a semi-finished catalyst B through calcination; finally loading precursor salts of Ni and Cu on the semi-finished catalyst E, and obtaining a semi-finished catalyst C through calcination; loading Ag on the catalyst A, the catalyst B or the catalyst C.

12. The method of any one of claims 1-11, wherein, The carrier is spherical, cylindrical, trilobal or quadrilobal.

13. The method of any one of claims 1-11, wherein, The method comprises: (1) dissolving precursor salts of Ni and Cu in water, adding an oil phase, a surfactant and a co-surfactant, and fully stirring to form a microemulsion; then dipping the carrier in the microemulsion for 0.5-4 hours, filtering out the remaining liquid, and calcining at 400-600°C after drying to obtain a semi-finished catalyst A; (2) dissolving a precursor salt of Pd in water, adjusting the pH to 1.5-3.0, and then dipping the semi-finished catalyst A in the Pd salt solution for 0.5-4 hours; and calcining at 300-550°C after drying to obtain a semi-finished catalyst B; (3) dissolving precursor salts of Ce and Pt in water, adjusting the pH to 1.5-3.0, and then dipping the semi-finished catalyst B in the Ce and Pt salt solution for 0.5-4 hours; and calcining at 300-550°C after drying to obtain the catalyst. (3) dissolving the precursor salt of Pt and Ce in deionized water, adjusting pH to 1.0-5.0, then adding the semi-finished catalyst B into the prepared solution, drying and calcining at 400-600 DEG C after the solution is completely absorbed, to obtain semi-finished catalyst C; (4) dissolving the precursor salt of Ag in deionized water, then immersing the semi-finished catalyst C prepared above into the salt solution of Ag, drying and calcining at 400-600 DEG C; The step (1) and the step (2) can be interchanged, the step (3) is after the step (2), and the step (4) is after the step (2).

14. The method of claim 13, wherein, When the precursor salt of Ni and the precursor salt of Cu are loaded, the oil phase is C6-C8 saturated alkane or cycloalkane.

15. The method of claim 13, wherein, When the precursor salt of Ni and the precursor salt of Cu are loaded, the surfactant is ionic surfactant or non-ionic surfactant.

16. The method of claim 13, wherein, When the precursor salt of Ni and the precursor salt of Cu are loaded, the co-surfactant is C4-C6 alcohol.

17. The method of claim 13, wherein, When the precursor salt of Ni and the precursor salt of Cu are loaded, the precursor salt of Ni is soluble salt of Ni.

18. The method of claim 13, wherein, When the precursor salt of Ni and the precursor salt of Cu are loaded, the precursor salt of Cu is soluble salt of Cu.

19. The method of claim 13, wherein, The precursor salt of Pt is chloroplatinic acid or other soluble salt; and the precursor salt of Ce is soluble salt of Ce.

20. The method of claim 13, wherein, The precursor salt of Ag is soluble salt of Ag.

21. The method of claim 13 wherein: The conditions for preparing the microemulsion provided in the application are as follows: the weight ratio of water phase / oil phase is 2-3, the weight ratio of surfactant / oil phase is 0.15-0.6, and the weight ratio of surfactant / co-surfactant is 1-1.2.

Images