An acetylene selective hydrogenation catalyst for carbon di- fraction and a preparation method thereof

Abstract

The application provides a kind of acetylene selective hydrogenation catalyst of carbon fraction and preparation method.The catalyst carrier is alumina or mainly alumina, with bimodal pore distribution structure, the active component of the catalyst at least contains Pd, Ni, Cu, Ce, Pt;Among them, Ni, Cu mainly load in macropore by microemulsion method, Pd mainly load in the small pore of catalyst by solution method, Pt, Ce load on Pd after loading and calcining by solution method;With the weight of carrier as 100%, the active component content in the catalyst is: Pd 0.065-0.08%, Ni 1-5%, Cu 2-5%, Ce 0.1-0.5%, Pt 0.001-0.01%.The catalyst provided by the application has less palladium loading, simple preparation, good anti-coking performance, can maintain good hydrogenation activity and excellent selectivity for a long time, and has good regeneration performance.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of acetylene selective hydrogenation catalyst of carbon fraction and preparation method, in particular to a kind of selective hydrogenation catalyst and preparation method of CO involved carbon two post hydrogenation process. BACKGROUND

[0002] Ethylene obtained by steam cracking of petroleum hydrocarbon contains 0.5%-2.3% of acetylene by 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 catalyst used is mainly 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 hydrogenate to form ethane, causing the loss of ethylene, the high hydrogenation selectivity of the catalyst must be ensured to obtain good economic benefits.

[0003] Carbon two post hydrogenation refers to that the hydrogenation raw material is carbon two fraction, and hydrogen is introduced by metering, which is generally methane hydrogen and the like, and the content of pure hydrogen is more than 88%. In some devices, reforming hydrogen is used as hydrogen, and the content of pure hydrogen can reach more than 99%. In some devices, the hydrogen separated from the methane column is not subjected to methanation treatment, and the hydrogen contains CO, and the content of CO can reach 0.15%. Since CO and acetylene form competitive adsorption on the surface of the catalyst, the hydrogenation reaction rate of acetylene is reduced, but the selectivity of the reaction is improved.

[0004] In the carbon two post hydrogenation reaction, the amount of hydrogen is generally introduced by multiplying the content of acetylene by a fixed hydrogen / acetylene. Generally, the highest value of the first stage is not more than 1.4. Since the content of hydrogen in the hydrogenation material is small, the hydrogenation dimerization reaction of acetylene is easy to occur, and carbon four fraction is generated. The carbon four fraction is further polymerized to form low molecular weight oligomers, commonly known as "green oil". The green oil is adsorbed on the surface of the catalyst and further forms coke, which 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.

[0005] The mechanism of acetylene hydrogenation is that first, one acetylene molecule combines with one hydrogen atom to form an ethenyl group. The next step of the reaction has two competitive paths: (1) the ethenyl group combines with a hydrogen atom to form ethylene; and (2) two ethenyl groups couple to form butadiene. If the hydrogen is less, the reaction of path (2) is easy to occur, and butadiene is formed. Butadiene can further undergo a series of polymerization reactions to form green oil, and further form coke.

[0006] If the hydrogen is too much, it will also promote the hydrogenation reaction of the ethylene generated by path (1), causing the loss of ethylene, so the amount of hydrogen must be in a reasonable range in order to reduce the generation of green oil and not cause excessive loss of ethylene.

[0007] The noble metal catalyst has high activity, but is easy to generate green oil during use, causing the catalyst to be coked and deactivated, affecting the stability and service life of the catalyst. Patent CN200810119385.8 discloses a non-noble metal supported selective hydrogenation catalyst and its preparation method and application, which comprises a carrier and a main active component and an auxiliary active component supported on the carrier, wherein the main active component is Ni, and the auxiliary active component is selected from at least one of Mo, La, Ag, Bi, Cu, Nd, Cs, Ce, Zn and Zr, the main active component and the auxiliary active component both exist in an amorphous state with an average particle size of <10 nm, the carrier is a porous material without oxidation, and the catalyst is prepared by a microemulsion method.

[0008] 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 adding a silver and palladium interaction catalyst and fluorine chemically bonded with an alkali metal to an alumina carrier. The catalyst has the characteristics of reducing the generation of green oil, improving the selectivity of ethylene, and reducing the amount of oxygen-containing compounds.

[0009] Patent CN1736589 discloses a Pd / γ-Al2O3 selective hydrogenation catalyst prepared by a complete adsorption impregnation method, which generates a large amount of green oil during use. Patent CN200810114744.0 discloses an unsaturated hydrocarbon selective hydrogenation catalyst and its preparation method. The catalyst uses alumina as a carrier and palladium as an active component, and adds rare earth and alkaline earth metals and fluorine to improve the anti-impurity and anti-coking performance of the catalyst, but the selectivity of the catalyst is not ideal.

[0010] 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 catalyst and reduce the influence of internal diffusion and improve the selectivity of the catalyst. 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. CN1129606 discloses a hydrocarbon conversion catalyst, and the carrier catalyst includes alumina, nickel oxide, iron oxide, etc. The catalyst includes two kinds of pores, one of which is used to increase the surface of the catalytic reaction, and the other is conducive to diffusion. The hydrogenation catalyst provided in patent CN101433842 has the characteristics of bimodal pore distribution, and the most probable radius of the small pores is 2-50 nm, and the most probable radius of the large pores is 100-500 nm. Due to the bimodal pore distribution of the catalyst, the catalyst has good hydrogenation activity and good selectivity, and the ethylene increment is large.

[0011] 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.

[0012] ZL201310114077.7 discloses a hydrogenation catalyst, and the catalyst carrier 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.

[0013] ZL201310114079.6 discloses a catalyst, and the catalyst carrier used 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 is loaded by a solution method, and the siphon effect of the small pores is stronger, so most of the Pd enters the small pores of the carrier, and thus Ni is mainly located in the large pores and Pd is mainly located in the small pores.

[0014] 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. 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. Part of the palladium is loaded by a solution method and mainly distributed in the small pores of the carrier.

[0015] The catalyst prepared by this method makes the selective hydrogenation reaction mainly occur 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, thereby reducing the amount of catalyst coking.

[0016] However, the reduction temperature of Ni is usually about 500℃, and after adding Cu, the reduction temperature can be reduced to about 350℃, but the Pd atoms in the reduced state at this temperature are still prone to aggregation, which greatly reduces the activity of the catalyst. Therefore, the amount of active components needs to be increased substantially to compensate for the loss of activity, but this will also cause a decrease in selectivity.

[0017] To reduce the reduction temperature of the Ni-Cu active center, a small amount of palladium is loaded outside the Ni-Cu active center by the emulsion method. Since the palladium is loaded twice, the content of palladium in the catalyst is higher than that of the commonly used catalyst, which can be up to 50%, causing a significant increase in the cost of the catalyst.

[0018] If the hydrogenation raw material contains CO, the hydrogenation process will have a hydroformylation reaction to generate aldehydes, ketones, acids, etc. These fractions are more easily adsorbed on the alumina carrier, which will accelerate the process of green oil coking. However, in the above disclosed catalyst, the main active component is Pd, and the hydrogenation of by-products is mainly by Ni. These components do not have the function of carbonyl hydrogenation, that is, they cannot effectively reduce the coking rate of the carbon dihydrogen catalyst with CO participation. SUMMARY

[0019] To solve the above technical problems, the purpose of the present application is to provide an acetylene selective hydrogenation catalyst, which has a low loading amount of palladium as a noble metal component, a simple preparation process, good anti-coking performance, and can maintain good hydrogenation activity and excellent selectivity for a long time, and has good regeneration performance.

[0020] To achieve the above purpose, the present application provides a carbon dihydrogen fraction acetylene selective hydrogenation catalyst, wherein the carrier of the catalyst is alumina or mainly alumina and has a bimodal pore distribution structure.

[0021] The active components of the catalyst at least contain Pd, Ni, Cu, Ce and Pt.

[0022] In the catalyst, Ni and Cu are loaded by microemulsion method and mainly loaded in the macropore; Pd is loaded by solution method and mainly loaded in the small pore of the catalyst; Pt and Ce are loaded by solution method and loaded after Pd is loaded and calcined.

[0023] The content of Pd in the catalyst is 0.065-0.08%, the content of Ni is 1-5%, the content of Cu is 2-5%, the content of Ce is 0.1-0.5% and the content of Pt is 0.001-0.01% based on the weight of the carrier being 100%.

[0024] According to a specific embodiment of the present application, preferably, the specific surface area of the catalyst is 20-40 m 2 / g, the pore size of the small pore is 20-50 nm and the pore size of the macropore is 90-500 nm.

[0025] In the catalyst of the present application, the content of Ce is 0.1-0.5% based on the weight of the carrier being 100%, at which content, Ce can form a single layer of cerium oxide or a discontinuous molecular layer of cerium oxide; the content of Pt is 0.001-0.01% and Pt exists in the form of single atom and is mainly loaded on cerium oxide.

[0026] The catalyst can also contain other components such as Ag.

[0027] In order to position Ni and Cu in the macropore of the catalyst, the Ni and Cu are loaded by microemulsion method, the particle size of the microemulsion is larger than the pore size of the small pore of the carrier and smaller than the maximum pore size of the macropore; the Ni-Cu metal salt is contained in the microemulsion and, due to the steric hindrance, it is difficult to enter the small pore of the carrier and thus mainly enters the macropore of the carrier.

[0028] According to a specific embodiment of the present application, in the preparation of the catalyst, the loaded metal precursor must be decomposed by activation, which is a high-temperature calcination process, in which process, the metal salt is generally decomposed into metal oxide and the oxide forms clusters, which are generally nanometer-sized. The active center of a general hydrogenation reaction is composed of reduced metal, thus, before use, the hydrogenation catalyst is generally first reduced to ensure that the active component exists in the form of metal; and due to the difference in chemical properties, different oxides need to be reduced at different temperatures. However, for nanometer-sized metal, a temperature of about 200°C is an important critical temperature, and above this temperature, the metal particles will significantly aggregate. Therefore, how to reduce the aggregation of the main active component during reduction is of great significance to the hydrogenation catalyst.

[0029] The reduction temperature of Ni and Cu in the carbon di- fraction alkene selective hydrogenation catalyst is high, generally 350-400℃, and this temperature is too high for Pd active center, at this temperature, the aggregation of Pd active center is obvious. The present application finds that the aggregation degree of Pd is mitigated after adding Ce in the carrier, and if Pt is added, the aggregation of Pd is also mitigated. The present application also finds that if Ce and Pt are loaded simultaneously, the aggregation of Pd is greatly reduced, and even after more than 5 times of regeneration and reduction, the activity is reduced by not more than 20%. The reason for this phenomenon is that the metal salt of Ce forms Ce oxide after calcination, and exists in the form of monolayer 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- --Ce 4+ species, and the binding force of the two is much higher than that of Pt and alumina, so that the atoms of Pt act as an "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.

[0030] The "atomic fence" formed by Pt and Ce can prevent the growth of Pd particles, and Pt and Ce are loaded by a solution method.

[0031] According to a specific embodiment of the present application, preferably, the Pd is loaded by a solution method, and due to the siphon effect of the small pores, Pd is mainly loaded in the small pores of the catalyst.

[0032] According to a specific embodiment of the present application, preferably, the crystal form of alumina in the carrier is θ, α crystal form or mixed crystal form thereof.

[0033] According to a specific embodiment of the present application, preferably, the content of alumina in the catalyst carrier is more than 80%.

[0034] According to a specific embodiment of the present application, preferably, the carrier further contains other metal oxides, such as magnesium oxide and / or titanium oxide.

[0035] The present application also provides a preparation method of the above-mentioned carbon di- fraction alkene selective hydrogenation catalyst, wherein Pd is loaded in the small pores of the catalyst by a solution method, and after loading Pd, Ce and Pt are simultaneously loaded by a solution method; the loading of Ni and Cu is carried out by a microemulsion method, and the loading sequence of Ni and Cu can be determined according to the situation.

[0036] According to a specific embodiment of the present application, preferably, the above-mentioned preparation method comprises the following specific modes:

[0037] Mode one, Ni-Cu, Pd, Ce-Pt:

[0038] loading a precursor salt of Pd on the carrier, calcining to obtain a semi-finished catalyst C, then loading a precursor salt of Ni and a precursor salt of Cu on the semi-finished catalyst C, calcining to obtain a semi-finished catalyst D, and finally loading a precursor salt of Ce and a precursor salt of Pt on the semi-finished catalyst D, calcining to obtain the catalyst;

[0039] Method two, Pd, Ni-Cu, Ce-Pt:

[0040] loading a precursor salt of Pd on the carrier, calcining to obtain a semi-finished catalyst C, then loading a precursor salt of Ni and a precursor salt of Cu on the semi-finished catalyst C, calcining to obtain a semi-finished catalyst D, and finally loading a precursor salt of Ce and a precursor salt of Pt on the semi-finished catalyst D, calcining to obtain the catalyst;

[0041] Method three, Pd, Ce-Pt, Ni-Cu:

[0042] loading a precursor salt of Pd on the carrier, calcining to obtain a semi-finished catalyst C, then loading a precursor salt of Ni and a precursor salt of Cu on the semi-finished catalyst C, calcining to obtain a semi-finished catalyst D, and finally loading a precursor salt of Ce and a precursor salt of Pt on the semi-finished catalyst D, calcining to obtain the catalyst.

[0043] According to a specific embodiment of the present application, preferably, in the above preparation method, the carrier is spherical, cylindrical, clover-shaped, four-leaf clover-shaped, etc.

[0044] According to a specific embodiment of the present application, preferably, in the above preparation method, the loading of the precursor salt of Ni and the precursor salt of Cu is performed by dissolving the precursor salt of Ni and the precursor salt of Cu in water to obtain an aqueous phase, adding an oil phase, a surfactant and a co-surfactant, fully stirring to form a microemulsion, and then adding the carrier or the semi-finished catalyst C or the semi-finished catalyst E after high-temperature calcination into the prepared microemulsion for 0.5-4 hours of impregnation, filtering out the residual liquid, drying, and then calcining at 400-600°C to obtain the semi-finished catalyst A or the semi-finished catalyst D or the catalyst.

[0045] According to a specific embodiment of the present application, preferably, when loading the precursor salt of Ni and the precursor salt of Cu, the oil phase is a C6-C8 saturated alkane or a cycloalkane, more preferably cyclohexane and / or n-hexane.

[0046] 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).

[0047] 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 a C4-C6 alcohol, and more preferably one or a combination of two or more of n-butanol, n-pentanol and n-hexanol.

[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 precursor salt of Ni is a soluble salt of Ni, and more preferably a nitrate salt or a chloride salt or other soluble salt.

[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 precursor salt of Cu is a soluble salt of Cu, and more preferably a nitrate salt or a chloride salt or other soluble salt.

[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 conditions for preparing the microemulsion are: the weight ratio of the aqueous phase to the oil phase is 2-3, the weight ratio of the surfactant to the oil phase is 0.15-0.6, and the weight ratio of the surfactant to the co-surfactant is 1-1.2; and more preferably, the particle size of the formed microemulsion is greater than the maximum pore diameter of the small pores of the catalyst carrier and less than the maximum pore diameter of the large pores of the catalyst carrier, for example, greater than 50 nm and less than 500 nm.

[0051] According to the specific embodiments of the present application, preferably, in the above preparation method, the precursor salt of Pd is loaded by the following method: dissolving the precursor salt of Pd in water, adjusting the pH to 1.5-2.5 to obtain a precursor salt of Pd solution, then adding the semi-finished catalyst A or the carrier into the precursor salt of Pd solution, and dipping and adsorbing for 0.5-4 h, followed by drying, and then calcining at 400-600 ℃ to obtain the semi-finished catalyst B or the semi-finished catalyst C.

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

[0053] According to the specific embodiment of the present application, preferably, in the above preparation method, the Ce-loaded precursor salt and the Pt precursor salt are prepared by dissolving the Ce precursor salt and the Pt precursor salt in water to obtain a Ce-Pt impregnation solution (preferably, the amount of the impregnation solution is 90-100% of the water absorption amount of the carrier), adjusting the pH to 1-3, impregnating the semi-finished catalyst B or semi-finished catalyst D or semi-finished catalyst C in the Ce-Pt impregnation solution, drying after the solution is completely absorbed, and calcining at 500-600℃ to obtain the catalyst or semi-finished catalyst E.

[0054] According to the specific embodiment of the present application, preferably, the Pt precursor salt is chloroplatinic acid or other soluble salt.

[0055] According to the specific embodiment of the present application, preferably, the Ce precursor salt is a soluble salt of Ce, and more preferably, is nitrate or other soluble salt.

[0056] The present application also provides a method for selective hydrogenation of acetylene in carbon dioxide fraction with CO, for example, selective hydrogenation of acetylene in carbon dioxide fraction of ethylene plant, which is carried out by using the acetylene selective hydrogenation catalyst described above.

[0057] According to the specific embodiment of the present application, in the reaction process, the selective hydrogenation reaction 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.

[0058] The selective hydrogenation of acetylene in carbon dioxide fraction by 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 palladium and the main distribution in small pores, the selective hydrogenation reaction of acetylene mainly occurs in 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, which enter the large pores due to the large molecular size and long residence time, and are hydrogenated to saturated hydrocarbons or aromatic hydrocarbons without isolated double bonds under the action of nickel catalyst; the hydrogenation of carbonyl group forms alcohol, and it is not easy to generate substances with larger molecular weight. After regeneration of the catalyst, the reduction is still at 350-400℃, and due to the joint action of Ce and Pt, the activity of the regenerated catalyst does not change significantly even if the reduction temperature is higher.

[0059] The present application researches and finds that when the content of Ce is high, the amount of green oil generated increases significantly, but the coking of the catalyst does not accelerate significantly.

[0060] The present application researches and finds that increasing the content of Cu loaded in the emulsion reduces the generation of green oil, and reduces the coking rate of the catalyst. The reason for reducing the generation of green oil after increasing the content of Cu is that Cu itself has the function of hydrogenation of carbonyl group. Although Ni-Cu is loaded at the same time, the reduction temperature of Cu itself is low, and the half melting point of Cu is also significantly lower than that of Ni. In the reduction process, Cu itself can form a separate Cu active center by agglomeration, can hydrogenate the carbonyl group formed by the hydrogenation of aldehyde, form alcohol, and reduce the possibility of further polymerization of aldehyde to form larger molecules or acid, and acid has the strongest effect of deactivating the catalyst.

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

[0062] The idea of the present application to solve the coking of the catalyst is:

[0063] The selective hydrogenation reaction of acetylene occurs in the main active center composed of Pd, and the green oil and other large molecules produced in the reaction are easy to enter the large pores of the catalyst. In the large pores of the catalyst, Ni-Cu components are loaded, and Ni-Cu has the function of saturated hydrogenation. The green oil components will undergo saturated hydrogenation reaction in the Ni-Cu active center. Since the double bond is saturated by hydrogenation, the green oil components cannot undergo polymerization reaction or the polymerization reaction rate is greatly reduced, the chain growth reaction is terminated or delayed, and large molecular weight condensed ring compounds cannot be formed, which are easy to be carried out of the reactor by the material, so the coking degree of the surface of the catalyst is greatly reduced, and the service life of the catalyst is prolonged.

[0064] The acetylene selective hydrogenation catalyst provided by the present application has the following advantages:

[0065] 1. The loading amount of noble metal palladium is reduced. Since noble metal palladium does not need to be loaded in the large pores, the loading amount of noble metal is reduced.

[0066] 2. The step of loading noble metal palladium by emulsion method is changed to loading Ce and Pt by solution method. Since the solution preparation process is simpler than the preparation of microemulsion, the catalyst preparation process is simplified.

[0067] 3. The catalyst of the present application can be used in the selective hydrogenation process of carbon fraction, has good anti-coking performance, can maintain good hydrogenation activity and excellent selectivity for a long time, and has good regeneration performance. BRIEF DESCRIPTION OF DRAWINGS

[0068] Figure 1 It is the microemulsion particle size distribution graph of Example 1; DETAILED DESCRIPTION

[0069] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present application, the technical solutions of the present application are described in detail as follows, but cannot be understood as limiting the implementable scope of the present application.

[0070] Apparatus and instruments:

[0071] Dynamic light scattering particle size analyzer, the particle size distribution of the microemulsion of the Ni / Cu alloy was analyzed on a M286572 dynamic light scattering analyzer; full-automatic mercury injection apparatus, the pore volume, specific surface area and pore size distribution of the carrier were analyzed on a 9510 type mercury injection apparatus of American Micromeritics Company; the contents of Pd, Ag, Ni, Cu, Ce and Pt in the catalyst were determined on an A240FS atomic absorption spectrometer.

[0072] Reagents and raw materials:

[0073] The analytically pure nickel nitrate, copper nitrate, palladium chloride, chloroplatinic acid and silver nitrate were purchased from Shanghai Reagent Corporation;

[0074] Alumina was purchased from Shandong Aluminum Industry Group.

[0075] Example 1

[0076] The present embodiment provides a catalyst, wherein:

[0077] Catalyst carrier: commercially available bimodal pore distribution spherical alumina carrier with a diameter of 3.5 mm. After being calcined at 1065 ℃ for 4 h, the bimodal pore size distribution ranges from 20-38 nm and 80-340 nm, the water absorption rate is 50%, and the specific surface area is 40.21 m 2 / g.

[0078] Catalyst preparation:

[0079] (1) 3.11 g of nickel nitrate and 4.23 g of copper chloride were weighed, dissolved in 60 mL of deionized water, 26.5 g of cyclohexane was added, 14.2 g of Triton X-100 was added, 12.7 g of n-butanol was added, and the mixture was fully stirred to form a microemulsion. The particle size of the prepared microemulsion was determined by dynamic light scattering to be 110.23 nm;

[0080] 100 g of the high-temperature calcined carrier was immersed in the prepared microemulsion, shaken for 30 min, and the remaining liquid was filtered and washed with deionized water. Drying was carried out at 60 ℃ for 10 hours, and calcination was carried out at 500 ℃ for 6 h to obtain semi-finished catalyst A1;

[0081] (2) 0.133 g of palladium chloride was weighed, dissolved in 60 mL of deionized water, and the pH was adjusted to 1.5. The semi-finished catalyst A1 was immersed in the prepared Pd salt solution, shaken, and dried at 80 ℃ for 6 hours after the solution was completely absorbed. Calcination was carried out at 400 ℃ for 6 hours to obtain semi-finished catalyst B1.

[0082] (3) Weigh 0.31 g of cerium nitrate and 0.0042 g of chloroplatinic acid, dissolve them in 50 mL of deionized water, stir evenly, adjust the pH to 1.5, add the semi-finished catalyst B1 to the prepared solution, shake to allow the solution to be completely absorbed, dry at 100 °C, and calcine at 600 °C for 4 hours to obtain the catalyst.

[0083] The particle size distribution of the microemulsion obtained in step (1) of this embodiment is as follows: Figure 1 As shown. Figure 1 The horizontal axis represents the microemulsion particle size in nm, and the vertical axis represents the distribution intensity of microemulsions with different particle sizes. This means that, with the maximum number of particles in a certain size range as 100, the relative intensity is calculated by comparing the particle size distribution in other ranges to this range. The overall particle size distribution range of the microemulsion is 90-130 nm, a narrow range, indicating that the microemulsion preparation method used in this invention can obtain microemulsion samples with a narrow particle size distribution range. The graph shows a normal distribution, with the vast majority of microemulsion particles falling within a very narrow range of 110-120 nm, which is beneficial for the loading of active components.

[0084] The catalyst prepared by atomic absorption spectrometry showed that, in Example 1, the content of Pd was 0.08%, Ni was 1%, Cu was 2%, Ce was 0.1%, and Pt was 0.002%.

[0085] Catalyst reduction:

[0086] Before use, place it in a fixed-bed reactor and reduce it for 8 hours at 400°C using a mixed gas with a molar ratio of N2:H2 = 1:1.

[0087] Comparative Example 1

[0088] This comparative example provides a catalyst in which the same support as in Example 1 is used, and the catalyst preparation conditions are the same as in Example 1, except that Ce is not supported:

[0089] (1) Weigh 3.11g of nickel nitrate and 4.23g of copper chloride, dissolve them in 60mL of deionized water, add 26.5g of cyclohexane, 14.2g of Triton X-100 and 12.7g of n-butanol, stir thoroughly to form a microemulsion, and determine the particle size of the prepared microemulsion by dynamic light scattering.

[0090] 100g of the high-temperature calcined support was immersed in the prepared microemulsion, shaken for 30 min, the residual liquid was filtered off, and the mixture was washed with deionized water. It was then dried at 60℃ for 10 h and calcined at 500℃ for 6 h to obtain the semi-finished catalyst A1-1.

[0091] (2) Take 0.133 g of palladium chloride, dissolve in 60 mL of deionized water, adjust the pH to 1.5, then immerse the semi-finished catalyst A1-1 into the prepared Pd salt solution, shake, and after the solution is completely absorbed, dry at 80°C for 6 hours, and calcine at 400°C for 6 hours to obtain the semi-finished catalyst B1-1;

[0092] (3) Take 0.0042 g of chloroplatinic acid, dissolve in 50 mL of deionized water, stir until uniform, then adjust the pH to 1.0, add the semi-finished catalyst B1-1 into the prepared solution, shake to make the solution completely absorbed, dry at 100°C, and calcine at 600°C for 4 hours to obtain the catalyst.

[0093] The prepared catalyst is determined by atomic absorption spectrometry, and the content of Pd in Comparative Example 1 is 0.08%, the content of Ni is 1%, the content of Cu is 2%, and the content of Pt is 0.002%.

[0094] Reduction of the catalyst:

[0095] 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.

[0096] Example 2

[0097] This example provides a catalyst, wherein:

[0098] Support: A commercially available bimodal pore distribution spherical alumina-titania support is used, the content of titania is 2%, and the diameter is 3mm. After calcination at 1140°C for 4h, the bimodal pore size distribution ranges from 30-50nm and 110-500nm, the water absorption rate is 45%, and the specific surface area is 20.08m 2 / g.

[0099] Catalyst preparation:

[0100] (1) Take 15.56 g of nickel nitrate and 14.76 g of copper nitrate, dissolve in 65 mL of deionized water, add 30.00 g of n-hexane, 17.5 g of CATB, and 17 g of n-pentanol, and fully stir to form a microemulsion. Dynamic light scattering determines that the particle size of the prepared microemulsion is 65.29nm;

[0101] Immerse 100 g of high-temperature calcined support into the prepared microemulsion, shake for 180 min, filter out the remaining liquid, dry at 80°C for 4 hours, and calcine at 400°C for 5h to obtain the semi-finished catalyst A2;

[0102] (2) 0.109 g of palladium chloride was weighed and dissolved in 80 mL of deionized water, and the pH was adjusted to 2.5. The semi-finished catalyst A2 was then immersed in the prepared Pd salt solution, and after 120 min of immersion, it was dried at 130°C for 3 hours and calcined at 500°C for 5 hours to obtain the semi-finished catalyst B2;

[0103] (3) 0.00216 g of platinic chloride and 0.93 g of cerium nitrate were weighed and dissolved in 45 mL of deionized water, and the pH was adjusted to 3.0. The semi-finished catalyst B2 was then immersed in the prepared Pt salt solution, and after 120 min of immersion, it was dried at 130°C for 3 hours and calcined at 500°C for 5 hours to obtain the catalyst.

[0104] The prepared catalyst was determined by atomic absorption spectrometry, and the Pd content was 0.065%, the Ni content was 5%, the Cu content was 5%, the Ce content was 0.5%, and the Pt content was 0.001% in Example 2.

[0105] Reduction of the catalyst:

[0106] Before use, it was placed in a fixed bed reaction device and reduced for 8 h at a temperature of 380°C using a mixed gas with a molar ratio of N2:H2 = 1:1.

[0107] Comparative Example 2

[0108] This comparative example provides a catalyst, wherein the carrier and the preparation conditions are the same as those of Example 2, and the difference is that there is no Ni in Comparative Example 2:

[0109] (1) 14.76 g of copper nitrate was weighed and dissolved in 65 mL of deionized water, 30.00 g of n-hexane was added, 17.5 g of CATB was added, and 17 g of n-pentanol was added. Stir well to form a microemulsion. The particle size of the prepared microemulsion was determined by dynamic light scattering to be 65.29 nm;

[0110] 100 g of the high-temperature calcined carrier was immersed in the prepared microemulsion, shaken for 180 min, and the remaining liquid was filtered out. It was dried at 80°C for 4 hours and calcined at 400°C for 5 hours to obtain the semi-finished catalyst A2-1;

[0111] (2) 0.109 g of palladium chloride was weighed and dissolved in 80 mL of deionized water, and the pH was adjusted to 2.5. The semi-finished catalyst A2-1 was then immersed in the prepared Pd salt solution, and after 120 min of immersion, it was dried at 130°C for 3 hours and calcined at 500°C for 5 hours to obtain the semi-finished catalyst B2-1;

[0112] (3) take chloroplatinic acid 0.00216g, take cerium nitrate 0.93g, dissolve in 45mL deionized water, adjust pH to 3.0, then immerse the semi-finished catalyst B2-1 into the prepared Pt salt solution, after 120min of immersion, dry at 130℃ for 3 hours, and calcine at 500℃ for 5 hours to obtain the catalyst.

[0113] The prepared catalyst is determined by atomic absorption spectrometry, and in the comparative example 2, the Pd content is 0.065%, the Cu content is 5%, the Ce content is 0.5%, and the Pt content is 0.001%.

[0114] Reduction of the catalyst:

[0115] Before use, place in a fixed bed reaction device, reduce for 8h at 400℃ using a mixed gas with a molar ratio of N2:H2=1:1.

[0116] Example 3

[0117] The present embodiment provides a catalyst, wherein:

[0118] Support: commercially available bimodal pore distribution spherical alumina support with a diameter of 4mm. After calcination at 1120℃ for 4h, the bimodal pore size distribution ranges from 20-40nm and 120-390nm, the water absorption rate is 55%, and the specific surface area is 30.45m 2 / g.

[0119] Catalyst preparation:

[0120] (1) take nickel nitrate 9.34g, copper chloride 8.85g, dissolve in 55mL deionized water, add cyclohexane 19.6g, add Triton X-100 4.9g, add n-butanol 4.2g, and fully stir to form a microemulsion. The particle size of the prepared microemulsion is 350.48nm determined by dynamic light scattering;

[0121] Immerse 100g of high-temperature calcined support into the prepared microemulsion, shake for 30min, filter out the residual liquid, and wash with deionized water. Dry at 100℃ for 10 hours, and calcine at 500℃ for 6h to obtain the semi-finished catalyst A3;

[0122] (2) take palladium chloride 0.116g, dissolve in 120mL deionized water, adjust pH to 2.0, then immerse the semi-finished catalyst A3 into the prepared Pd salt solution, shake for 120min, then pour off the residual liquid, dry at 100℃ for 6 hours, and calcine at 500℃ for 4 hours to obtain the semi-finished catalyst B3;

[0123] (3) Take cerium nitrate 1.16 g, chloroplatinic acid 0.0108 g, dissolve in 53 mL of deionized water, after stirring uniformly, adjust the pH to 1.6, add the semi-finished catalyst B3 into the prepared solution, shake to make the solution completely absorbed, dry at 100°C, 600 calcine for 4 hours to obtain the catalyst.

[0124] The content of Pd is 0.07%, the content of Ni is 3%, the content of Cu is 3%, the content of Ce is 0.3%, and the content of Pt is 0.005% in the prepared catalyst, example 3, by atomic absorption spectrometry.

[0125] Reduction of the catalyst:

[0126] Before use, place it in a fixed bed reaction device, use mixed gas with a molar ratio of N2:H2=1:1, reduce at 350°C for 8h.

[0127] Comparative example 3

[0128] This comparative example provides a catalyst, wherein the same carrier as example 3 is used, and the catalyst preparation conditions are the same as example 3, the difference is that there is no Pt loaded in the comparative example:

[0129] (1) Take nickel nitrate 9.34 g, copper chloride 8.85 g, dissolve in 55 mL of deionized water, add cyclohexane 19.6 g, add Triton X-100 4.9 g, add n-butanol 4.2 g, stir thoroughly to form a microemulsion, and the particle size of the prepared microemulsion is 350.48 nm measured by dynamic light scattering;

[0130] Immerse 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 100°C for 10 hours, and calcine at 500°C for 6h to obtain the semi-finished catalyst A3-1;

[0131] (2) Take palladium chloride 0.116 g, dissolve in 120 mL of deionized water, adjust the pH to 2.0, then immerse the semi-finished catalyst A3-1 into the prepared Pd salt solution, shake for 120 min, then pour off the residual liquid, dry at 100°C for 6 hours, and calcine at 500°C for 4 hours to obtain the semi-finished catalyst B3-1;

[0132] (3) Take cerium nitrate 1.16 g, dissolve in 53 mL of deionized water, stir uniformly, adjust the pH to 1.6, add the semi-finished catalyst B3-1 into the prepared solution, shake to make the solution completely absorbed, dry at 100°C, 600 calcine for 4 hours to obtain the catalyst.

[0133] The content of Pd was 0.07%, the content of Ni was 3%, the content of Cu was 3%, and the content of Ce was 0.3% in the prepared catalyst, Comparative Example 3, as determined by atomic absorption spectrometry.

[0134] Reduction of the catalyst:

[0135] Before use, it was placed in a fixed bed reaction device and reduced at 350°C for 8h using a mixed gas with a molar ratio of N2:H2=1:1.

[0136] Example 4

[0137] The present example provides a catalyst, wherein:

[0138] Support: commercially available bimodal pore size distribution spherical alumina with a diameter of 3mm was used. After calcination at 1090°C for 4h, the bimodal pore size distribution range was 20-35nm and 60-200nm, the water absorption rate was 65%, and the specific surface area was 40.14m 2 / g.

[0139] Preparation of the catalyst:

[0140] (1) 2.21g of nickel chloride and 5.90g of copper nitrate were weighed and dissolved in 60mL of deionized water, 26g of n-hexane, 14g of Triton X-100, and 14g of n-hexanol were added, and the mixture was stirred to form a microemulsion. The particle size of the prepared microemulsion was 65.12nm as determined by dynamic light scattering;

[0141] 100g of the high-temperature calcined support was immersed in the prepared microemulsion and shaken for 180min, the remaining liquid was filtered out, dried at 70°C for 6h, and calcined at 500°C for 4h to obtain semi-finished catalyst A4;

[0142] (2) 0.16g of palladium nitrate was weighed and dissolved in 100mL of deionized water, the pH was adjusted to 2.2, and then the semi-finished catalyst A4 was immersed in the prepared Pd salt solution. After immersion for 120min, it was dried at 130°C for 3h and calcined at 550°C for 4h to obtain semi-finished catalyst B4;

[0143] (3) 1.55g of cerium nitrate and 0.011g of chloroplatinic acid were weighed and dissolved in 65mL of deionized water. After stirring uniformly, the pH was adjusted to 2.5, and the semi-finished catalyst B4 was added to the prepared solution. After shaking to absorb the solution, it was dried at 100°C and calcined at 600°C for 4h to obtain the catalyst.

[0144] The content of Pd was 0.075%, the content of Ni was 1%, the content of Cu was 2%, the content of Ce was 0.5%, and the content of Pt was 0.005% in the prepared catalyst, Example 4, as determined by atomic absorption spectrometry.

[0145] Reduction of the catalyst:

[0146] Before use, place in a fixed bed reaction device, using a mixed gas of molar ratio N2:H2=1:1, reduction treatment at 360°C temperature for 8h.

[0147] Comparative Example 4

[0148] This comparative example provides a catalyst, wherein the same carrier as in Example 4 is used, and the catalyst preparation conditions are the same as in Example 4, the difference being that no Cu is loaded in the comparative example.

[0149] Catalyst preparation:

[0150] (1) Take 2.21 g of nickel chloride, dissolve in 60 mL of deionized water, add 26 g of n-hexane, add 14 g of Triton X-100, and add 14 g of n-hexanol, stir well to form a microemulsion, and the particle size of the prepared microemulsion is 65.12 nm measured by dynamic light scattering;

[0151] Immerse 100 g of the high-temperature calcined carrier 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 4h to obtain a semi-finished catalyst A4-1;

[0152] (2) Take 0.16 g of palladium nitrate, dissolve in 100 mL of deionized water, adjust the pH to 2.2, and then immerse the semi-finished catalyst A4-1 into the prepared Pd salt solution, immerse for 120 min, dry at 130°C for 3 hours, and calcine at 550°C for 4 hours to obtain a semi-finished catalyst B4-1;

[0153] (3) Take 1.55 g of cerium nitrate and 0.011 g of chloroplatinic acid, dissolve in 65 mL of deionized water, stir uniformly, adjust the pH to 2.5, and then add the semi-finished catalyst B4-1 into the prepared solution, shake to absorb the solution, dry at 100°C, and calcine at 600°C for 4 hours to obtain the catalyst.

[0154] The prepared catalyst is determined by atomic absorption spectrometry, and in Comparative Example 4, the content of Pd is 0.075%, the content of Ni is 1%, the content of Ce is 0.5%, and the content of Pt is 0.005%.

[0155] Reduction of the catalyst:

[0156] Before use, place in a fixed bed reaction device, using a mixed gas of molar ratio N2:H2=1:1, reduction treatment at 360°C temperature for 8h.

[0157] Example 5

[0158] This example provides a catalyst, wherein:

[0159] Support: Commercially available bimodal pore size distribution spherical alumina with 97% alumina and 3% titania, 3 mm in diameter. After calcination at 1120°C for 4 h, the bimodal pore size distribution ranges from 23-47 nm and 80-380 nm, water absorption is 55%, and the specific surface area is 30.2 m 2 / g.

[0160] Catalyst preparation:

[0161] (1) 9.34 g of nickel nitrate and 7.38 g of copper nitrate were weighed and dissolved in 70 mL of deionized water, 35 g of n-hexane, 21 g of Triton X-100, and 21 g of n-hexanol were added, and the mixture was stirred to form a microemulsion. The particle size of the prepared microemulsion was determined by dynamic light scattering to be 50.3 nm;

[0162] 100 g of the high-temperature calcined support was immersed in the prepared microemulsion and shaken for 180 min. The residual liquid was filtered out, dried at 90°C for 6 hours, and calcined at 600°C for 4 h to obtain semi-finished catalyst A5;

[0163] (2) 0.113 g of palladium chloride was weighed and dissolved in 90 mL of deionized water, and the pH was adjusted to 2.0. The semi-finished catalyst A5 was then immersed in the prepared Pd salt solution, and after 120 min of immersion, the residual liquid was poured out. The catalyst was dried at 130°C for 3 hours and calcined at 500°C for 4 hours to obtain semi-finished catalyst B5;

[0164] (3) 0.465 g of cerium nitrate and 0.0081 g of chloroplatinic acid were weighed and dissolved in 50 mL of deionized water. After stirring and adjusting the pH to 3.0, the semi-finished catalyst B5 was added to the prepared solution. After shaking to ensure complete absorption of the solution, the catalyst was dried at 100°C and calcined at 600°C for 6 h to obtain the catalyst.

[0165] The total Pd content of the prepared catalyst was determined by atomic absorption spectrometry to be 0.068%, the Ni content was 3%, the Cu content was 2.5%, the Ce content was 0.2%, and the Pt content was 0.002%.

[0166] Reduction of the catalyst:

[0167] Before use, the catalyst was placed in a fixed bed reaction device and reduced for 8 h at 350°C using a mixed gas with a molar ratio of N2:H2=1:1.

[0168] Comparative Example 5

[0169] This comparative example provides a catalyst, wherein the catalyst preparation conditions are the same as those of Example 5, except that the order of steps (2) and (3) is reversed:

[0170] (1) Take 9.34 g of nickel nitrate, 7.38 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-hexanol, stir well to form a microemulsion, and measure the particle size of the prepared microemulsion by dynamic light scattering. The particle size is 50.3 nm;

[0171] The high-temperature calcined 100 g of the carrier is immersed in the prepared microemulsion, shaken for 180 min, filtered to remove the residual liquid, dried at 90°C for 6 hours, and calcined at 600°C for 4 hours to obtain a semi-finished catalyst A5-1.

[0172] (2) Take 0.465 g of cerium nitrate and 0.0081 g of chloroplatinic acid, dissolve in 50 mL of deionized water, stir uniformly, adjust the pH to 3.0, and then add the semi-finished catalyst A5-1 to the prepared solution. Shake to make the solution fully absorbed, dry at 100°C, and calcine at 600°C for 6 hours to obtain a semi-finished catalyst B5-1.

[0173] (3) Take 0.113 g of palladium chloride, dissolve in 90 mL of deionized water, adjust the pH to 2.0, and then immerse the semi-finished catalyst B5-1 in the prepared Pd salt solution. After immersing for 120 min, pour off the residual liquid, dry at 130°C for 3 hours, and calcine at 500°C for 4 hours to obtain the catalyst.

[0174] The prepared catalyst is determined by atomic absorption spectrometry. In the comparative example 5, the total content of Pd is 0.068%, the content of Ni is 3%, the content of Cu is 2.5%, the content of Ce is 0.2%, and the content of Pt is 0.002%.

[0175] Reduction of the catalyst:

[0176] 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.

[0177] Example 6

[0178] This example provides a catalyst, wherein:

[0179] Carrier: A commercially available bimodal pore size distribution spherical carrier is used, with 97% alumina and 3% titanium oxide, and a diameter of 3 mm. After calcination at 1113°C for 4 hours, the bimodal pore size distribution ranges from 30-45 nm and 150-380 nm, the water absorption rate is 60%, and the specific surface area is 25.38 m 2 / g.

[0180] Catalyst preparation:

[0181] (1) Take 0.125 g of palladium chloride, dissolve in 100 mL of deionized water, adjust the pH to 1.8, then immerse the calcined carrier 100 g into the prepared Pd salt solution, immerse for 60 min, dry at 100°C for 5 hours, calcine at 400°C for 6 hours, to obtain semi-finished catalyst A6;

[0182] (2) Take 6.63 g of nickel chloride and 11.8 g of copper nitrate, dissolve in 50 mL of deionized water, add 20 g of cyclohexane, 8 g of CATB, and 7 g of n-hexanol, stir thoroughly to form a microemulsion, and measure the particle size of the prepared microemulsion by dynamic light scattering. The particle size is 200 nm;

[0183] Immerse the semi-finished catalyst A6 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 to obtain semi-finished catalyst B6;

[0184] (3) Take 0.31 g of cerium nitrate and 0.011 g of chloroplatinic acid, dissolve in 55 mL of deionized water, stir uniformly, adjust the pH to 2.6, add the semi-finished catalyst B6 into the prepared solution, shake until the solution is fully absorbed, dry at 100°C, and calcine at 600°C for 6 hours to obtain the catalyst.

[0185] The prepared catalyst is measured by atomic absorption spectrometry. In Example 6, the Pd content is 0.075%, the Ni content is 3%, the Cu content is 4%, the Ce content is 0.1%, and the Pt content is 0.005%.

[0186] Reduction of the catalyst:

[0187] 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.

[0188] Comparative Example 6

[0189] This comparative example provides a catalyst, wherein the carrier of Comparative Example 6 is the same as that of Example 6, and the preparation steps are the same, except that the particle size of the microemulsion of Comparative Example 6 is smaller than the maximum pore size of the small pores.

[0190] Catalyst preparation:

[0191] (1) Take 0.125 g of palladium chloride, dissolve in 100 mL of deionized water, adjust the pH to 1.8, then immerse the calcined carrier 100 g into the prepared Pd salt solution, immerse for 60 min, dry at 100°C for 5 hours, calcine at 400°C for 6 hours, to obtain semi-finished catalyst A6-1;

[0192] (2) Take 6.63 g of nickel chloride, 11.8 g of copper nitrate, dissolve in 50 mL of deionized water, add 33 g of cyclohexane, 30 g of CATB, and 27 g of n-hexanol, stir thoroughly to form a microemulsion, and measure the particle size of the prepared microemulsion by dynamic light scattering. The particle size is 30 nm;

[0193] Immerse the semi-finished catalyst A6-1 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 4h to obtain the semi-finished catalyst B6-1;

[0194] (3) Take 0.31 g of cerium nitrate and 0.011 g of chloroplatinic acid, dissolve in 55 mL of deionized water, stir uniformly, adjust the pH to 2.6, add the semi-finished catalyst B6-1 to the prepared solution, shake to absorb the solution, dry at 100°C, and calcine at 600°C for 6h to obtain the catalyst.

[0195] Determine the content of Pd, Ni, Cu, Ce, and Pt in the prepared catalyst by atomic absorption spectrometry. In the comparative example 6, the content of Pd is 0.075%, the content of Ni is 3%, the content of Cu is 4%, the content of Ce is 0.1%, and the content of Pt is 0.005%.

[0196] Reduction of the catalyst:

[0197] 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.

[0198] Example 7

[0199] This example provides a catalyst, wherein:

[0200] Catalyst preparation:

[0201] Take a commercially available bimodal pore size distribution spherical alumina carrier with a diameter of 4 mm. After calcination at 1150°C for 4h, the pore size distribution ranges are 30-50 nm and 260-500 nm, respectively, the water absorption rate is 50%, and the specific surface area is 19.95 m 2 / g.

[0202] (1) Take 0.13 g of palladium chloride salt and dissolve in 120 mL of deionized water, adjust the pH to 1.9, then add 100 g of the calcined carrier to the Pd salt solution, immerse and adsorb for 1 hour, then pour out the remaining liquid, dry at 120°C for 2 hours, and calcine at 600°C for 4h to obtain the semi-finished catalyst A7;

[0203] (2) Weigh 6.22 g of anhydrous nickel nitrate and 4.66 g of copper chloride into 60 mL of water, add 20 g of cyclohexane, 3 g of Triton X-100, and 2.5 g of n-butanol, and stir thoroughly to form a microemulsion. The particle size of the prepared microemulsion is 499.62 nm as determined by dynamic light scattering method;

[0204] The obtained semi-finished catalyst A7 is added to the prepared microemulsion and immersed for 4 hours, then the remaining liquid is filtered out, dried at 60°C for 10 hours, and calcined at 600°C for 4 hours to obtain semi-finished catalyst B7;

[0205] (3) Weigh 1.24 g of cerium nitrate and 0.0147 g of chloroplatinic acid into 48 mL of deionized water, stir until uniform, then adjust the pH to 2.0. Add the semi-finished catalyst B7 to the prepared solution, shake to ensure complete absorption of the solution, then dry at 100°C, and calcine at 600°C for 6 hours to obtain the catalyst.

[0206] The atomic absorption spectrometry is used to determine the elemental content, and the catalyst prepared in Example 7 has a Pd content of 0.078%, a Ni content of 2%, a Cu content of 2.2%, a Ce content of 0.4%, and a Pt content of 0.007%.

[0207] Reduction of the catalyst:

[0208] Reduction gas: hydrogen, reduction space velocity: 100 h -1 , temperature 380°C, for 8 hours.

[0209] Comparative Example 7

[0210] This comparative example provides a catalyst, wherein the same carrier as in Example 7 is used, and Comparative Example 7 is prepared under the same conditions as Example 7, except that Pd and Pt are simultaneously loaded, and Ce is loaded afterwards:

[0211] (1) Weigh 0.13 g of palladium chloride and 0.0147 g of chloroplatinic acid into 120 mL of deionized water, adjust the pH to 2.0, then add the calcined carrier 100 g into the Pd salt solution, immerse and adsorb for 1 hour, then pour out the remaining liquid, dry at 120°C for 2 hours, and calcine at 600°C for 4 hours to obtain semi-finished catalyst A7-1;

[0212] (2) Weigh 6.22 g of anhydrous nickel nitrate and 4.66 g of copper chloride into 60 mL of water, add 20 g of cyclohexane, 3 g of Triton X-100, and 2.5 g of n-butanol, and stir thoroughly to form a microemulsion. The particle size of the prepared microemulsion is 499.62 nm as determined by dynamic light scattering method;

[0213] The obtained semi-finished catalyst A7-1 was added to the prepared microemulsion and impregnated for 4 hours, then the residual liquid was filtered and removed, dried at 60°C for 10 hours, and calcined at 600°C for 4 hours to obtain the semi-finished catalyst B7-1.

[0214] (3) 1.24 g of cerium nitrate was weighed out and dissolved in 48 mL of deionized water, and after uniform stirring, the pH was adjusted to 2.0. The semi-finished catalyst B7-1 was added to the prepared solution, shaken to make the solution completely absorbed, dried at 100°C, and calcined at 600°C for 6 hours to obtain the catalyst.

[0215] The atomic absorption spectrometry was used to determine the element content, and the catalyst prepared in the comparative example 7 had a Pd content of 0.078%, a Ni content of 2%, a Cu content of 2.2%, a Ce content of 0.4%, and a Pt content of 0.007%.

[0216] Reduction of the catalyst:

[0217] Reduction gas: hydrogen, reduction space velocity: 100 h -1 , temperature 380°C, for 8 hours.

[0218] Example 8

[0219] This example provides a catalyst, wherein:

[0220] Support: commercially available bimodal pore size distribution spherical alumina support with a diameter of 4 mm. After calcination at 1170°C for 4 hours, the pore size distribution ranges were 35-50 nm and 350-500 nm, respectively, the water absorption rate was 48%, and the specific surface area was 19.95 m 2 / g.

[0221] Catalyst preparation:

[0222] (1) 0.16 g of palladium nitrate was weighed out and dissolved in 100 mL of deionized water, and the pH was adjusted to 2.2. The calcined support 100 g was impregnated into the prepared Pd salt solution, shaken for 120 min, then the residual liquid was poured out, dried at 100°C for 6 hours, and calcined at 520°C for 4 hours to obtain the semi-finished catalyst A8.

[0223] (2) 0.62 g of cerium nitrate and 0.0215 g of chloroplatinic acid were weighed out and dissolved in 48 mL of deionized water, and after uniform stirring, the pH was adjusted to 1.6. The semi-finished catalyst A8 was added to the prepared solution, shaken to make the solution completely absorbed, dried at 100°C, and calcined at 550°C for 4 hours to obtain the semi-finished catalyst B8.

[0224] (3) Take 4.42 g of nickel chloride, 5.9 g of copper nitrate, dissolve in 60 mL of deionized water, add 20 g of cyclohexane, add 4 g of Triton X-100, add 4 g of n-butanol, stir thoroughly to form a microemulsion, and measure the particle size of the prepared microemulsion by dynamic light scattering. The particle size is 450.48 nm;

[0225] The obtained semi-finished catalyst B8 is added to the prepared microemulsion for impregnation for 4 hours, the residual liquid is filtered out, dried at 80°C for 5 hours, and calcined at 550°C for 4 hours to obtain a semi-finished catalyst C8;

[0226] (4) Take 0.158 g of silver nitrate, dissolve in 48 mL of deionized water, and immerse the semi-finished catalyst C8 in the prepared silver nitrate solution. After the solution is completely absorbed, dry at 100°C, and calcine at 500°C for 4 hours to obtain the desired catalyst.

[0227] The prepared catalyst is measured by atomic absorption spectrometry. In Example 3, the content of Pd is 0.075%, the content of Ni is 2%, the content of Cu is 2%, the content of Ce is 0.2%, the content of Pt is 0.01%, and the content of Ag is 0.10%.

[0228] Reduction of the catalyst:

[0229] Before use, place it in a fixed bed reaction device, and use a mixed gas with a molar ratio of N2:H2 = 1:1 at 350°C for reduction treatment for 8h.

[0230] Comparative Example 8

[0231] This comparative example provides a catalyst, wherein the same carrier as in Example 8 is used, and Comparative Example 8 is prepared in the same steps as Example 8, except that the oil phase and surfactant used in step (3) are less, and the particle size of the microemulsion is larger than the maximum pore size of the carrier macropore.

[0232] (1) Take 0.16 g of palladium nitrate, dissolve in 100 mL of deionized water, and adjust the pH to 2.2. Immerse the calcined carrier 100 g into the prepared Pd salt solution, shake for 120 min, then pour off the residual liquid, dry at 100°C for 6 hours, and calcine at 520°C for 4 hours to obtain a semi-finished catalyst A8-1;

[0233] (2) Take 0.62 g of cerium nitrate and 0.0215 g of chloroplatinic acid, dissolve in 48 mL of deionized water, and stir uniformly. Adjust the pH to 1.6, add the semi-finished catalyst A8-1 to the prepared solution, shake until the solution is completely absorbed, dry at 100°C, and calcine at 550°C for 4 hours to obtain a semi-finished catalyst B8-1;

[0234] (3) Take 8.84 g of nickel chloride, 5.9 g of copper nitrate, dissolve in 60 mL of deionized water, add 15 g of cyclohexane, add 3 g of Triton X-100, add 3 g of n-butanol, stir thoroughly to form a microemulsion, and measure the particle size of the prepared microemulsion by dynamic light scattering. The particle size of the prepared microemulsion is 580.48 nm;

[0235] The obtained semi-finished catalyst B8-1 is added to the prepared microemulsion for impregnation for 4 hours, the residual liquid is filtered out, dried at 80°C for 5 hours, and calcined at 550°C for 4 hours to obtain the semi-finished catalyst C8-1;

[0236] (4) Take 0.158 g of silver nitrate, dissolve in 48 ml of deionized water, and immerse the semi-finished catalyst C8-1 in the prepared silver nitrate solution. After the solution is completely absorbed, dry at 100°C, and calcine at 500 for 4 hours to obtain the desired catalyst.

[0237] The prepared catalyst is determined by atomic absorption spectrometry. In Example 3, the content of Pd is 0.075%, the content of Ni is 0.8%, the content of Cu is 0.8%, the content of Ce is 0.2%, the content of Pt is 0.01%, and the content of Ag is 0.10%.

[0238] Reduction of the catalyst:

[0239] 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 350°C for 8h.

[0240] Implementation effect:

[0241] The catalyst loading is 100 mL, the reaction material space velocity is 4000 / h, the operating pressure is 1.8 MPa, the hydrogen / acetylene ratio is 1.5, and the reactor inlet temperature is 70°C.

[0242] Reaction material:

[0243] The composition of the crude hydrogen is: CO content is 1 v / v%, hydrogen content is 50 v / v%, and methane is 49 v / v%.

[0244] Reactor inlet material composition:

[0245] Hydrogen 2.47 v / v%, methane 2.42 v / v%, acetylene 1 v / v%, ethylene 80.75 v / v%, ethane 13.07 v / v%, carbon three 0.28 v / v%, CO 480 ppm.

[0246] Acetylene conversion rate (%) = (reactor inlet acetylene content - reactor outlet acetylene content) / reactor inlet acetylene content;

[0247] Ethylene selectivity = 2 - (hydrogen content at the inlet of the reactor - acetylene content at the outlet of the reactor) / (acetylene content at the inlet of the reactor - acetylene content at the outlet of the reactor);

[0248] Activity reduction rate = (initial acetylene conversion rate - acetylene conversion rate after regeneration or 1000 hours) / initial acetylene conversion rate.

[0249] The results of the catalyst evaluation are shown in Table 1.

[0250] Table 1 Catalyst evaluation results

[0251]

[0252]

[0253] As can be seen from Table 1, in Comparative Example 1, the other components are the same as in Example 1, and the preparation conditions are also the same, but no Ce is loaded. When reduced at 400°C, the Pd has a small amount of agglomeration, and the initial activity and selectivity are slightly lower than those of Example 1, and the amount of carbon four produced is also slightly higher than that of Example 1. After 5 regenerations, the activity decreases much more than that of Example 1.

[0254] The other components of Comparative Example 2 are the same as those of Example 2, and the catalyst preparation conditions are also the same. The difference is that no Ni is loaded. In the initial stage of operation, the initial activity and selectivity of Comparative Example 2 are the same as those of Example 2, but there is a significant difference after 1000 hours. The reason is that there is no Ni in the catalyst, and there is no function of saturating the hydrogenation by-products, so the coking rate of the catalyst is significantly faster, and the performance of the catalyst decreases faster.

[0255] Compared with Example 3, the catalyst preparation conditions of Comparative Example 3 are also the same, and the other components are also the same, but no Pt is loaded. When reduced at 350°C, the Pd has a small amount of agglomeration, and the initial activity and selectivity are slightly lower than those of Example 3, and the amount of carbon four produced is also slightly higher than that of Example 1. After 5 regenerations, the activity decreases much more than that of Example 3.

[0256] In Comparative Example 4, the catalyst preparation conditions are the same as those of Example 4, and the active component content is the same. The difference is that no Cu is loaded. In the initial stage of operation, the initial activity and selectivity of Comparative Example 4 are the same as those of Example 4, but there is a significant difference after 1000 hours. The reason is that there is no Cu in the catalyst, and the active center of Ni in the large pore cannot be effectively reduced at 360°C, and also, the unsaturated bonds in the hydrogenation by-products molecules cannot be hydrogenated, leading to rapid coking of the catalyst and faster performance decline.

[0257] In the catalyst of Comparative Example 5, the activity and selectivity of the catalyst changed little after 1000 hours, and the activity changed little after 5 times of regeneration, but the activity was obviously lower than that of the examples. The reason might be that Ce-Pt was loaded first, which inhibited the agglomeration of Pd during activation, and the active centers of the optimum size could not be formed, and part of the active centers had no activity at 70°C, so the initial activity was not high.

[0258] The activity and selectivity of the catalyst of Comparative Example 6 were lower than those of Example 6 at the initial stage of the reaction. The reason might be that the microemulsion particle size was too small when Ni-Cu was loaded, part of the Ni-Cu was loaded in the small pores, and part of the Pd active centers were covered, which resulted in that the activity and selectivity at the initial stage were lower than those of Example 6, the activity of Ni-Cu in the large pores was insufficient, and part of the hydrogenation by-products were still coked on the catalyst, so the performance of the catalyst of Comparative Example 6 decreased more after 1000 hours.

[0259] In Comparative Example 7, Pd and Pt were loaded first, and Ce was loaded later, Pd and Pt formed an alloy structure, and the later-loaded Ce could not effectively prevent the agglomeration of the Pd and Pt active centers. The performance of the catalyst at the initial stage was lower than that of Example 7, and the performance gap became larger and larger with the increase of the number of regeneration.

[0260] In Comparative Example 8, the particle size of the prepared microemulsion was larger than the maximum pore diameter of the semi-finished catalyst C8-1, and Cu and Ni in the microemulsion could not be completely loaded on the semi-finished catalyst C8-1, the content of Cu was too low, the Cu / Ni active centers could not be fully reduced at 350°C, and thus the by-products formed in the reaction could not be saturated hydrogenated, and the acetylene conversion rate decreased obviously after 1000 hours. Due to the addition of silver, the activity of the catalyst decreased slightly, and the selectivity increased.

[0261] Example 2 and Comparative Example 4 were compared. The performance attenuation range of Example 2 was smaller after 1000 hours due to the high content of Cu. Comparative Example 4 had no Cu at all, and the performance attenuation range of Comparative Example 4 was the largest after 1000 hours.

Claims

1. An acetylene selective hydrogenation catalyst for carbon di- fraction, wherein, The alumina content in the catalyst carrier is more than 80%, and the catalyst carrier has a bimodal pore distribution structure; The active components of the catalyst at least include Pd, Ni, Cu, Ce and Pt; In the process, Ni and Cu are loaded by using a microemulsion method, mainly in the macropores; Pd is loaded by using a solution method, mainly in the micropores of the catalyst; Pt and Ce are loaded by using a solution method, after Pd is loaded and calcined; The content of Pd in the catalyst is 0.065-0.08% based on the weight of the carrier, the content of Ni is 1-5%, the content of Cu is 2-5%, the content of Ce is 0.1-0.5%, and the content of Pt is 0.001-0.01%.

2. The catalyst of claim 1, wherein, The specific surface area of the catalyst is 20-40 m2 / g, the pore diameter of the micropores is 20-50 nm, and the pore diameter of the macropores is 90-500 nm.

3. The catalyst of claim 1, wherein, The particle size of the microemulsion is greater than the pore diameter of the micropores of the carrier and less than the maximum pore diameter of the macropores.

4. The catalyst of claim 1, wherein, The crystal form of the alumina in the carrier is θ, α or a mixed crystal form thereof.

5. The catalyst of claim 1, wherein, The carrier further contains other metal oxides.

6. The catalyst of claim 1, wherein, The carrier further contains magnesium oxide and / or titanium oxide.

7. A method for preparing the acetylene selective hydrogenation catalyst for carbon fraction according to any one of claims 1-6, comprising the following steps: loading precursor salts of Ni and Cu on the carrier, calcining to obtain a semi-finished catalyst A, then loading a precursor salt of Pd on the semi-finished catalyst A, calcining to obtain a semi-finished catalyst B, and finally loading precursor salts of Ce and Pt on the semi-finished catalyst B and performing calcination treatment; Alternatively, loading a precursor salt of Pd on the carrier, calcining to obtain a semi-finished catalyst C, then loading precursor salts of Ni and Cu on the semi-finished catalyst C, calcining to obtain a semi-finished catalyst D, and finally loading precursor salts of Ce and Pt on the semi-finished catalyst D and performing calcination treatment; Alternatively, loading a precursor salt of Pd on the carrier, calcining to obtain a semi-finished catalyst C, then loading precursor salts of Ce and Pt on the semi-finished catalyst C, calcining to obtain a semi-finished catalyst E, and finally loading precursor salts of Ni and Cu on the semi-finished catalyst E and performing calcination treatment.

8. The production method according to claim 7, wherein The loading of the precursor salts of Ni and Cu is performed by the following method: dissolving the precursor salts of Ni and Cu in water to obtain an aqueous phase, adding an oil phase, a surfactant and a co-surfactant, fully stirring to form a microemulsion, immersing the carrier or the semi-finished catalyst C or the semi-finished catalyst E after high-temperature calcination in the prepared microemulsion for 0.5-4 hours, filtering out the residual liquid, drying, and then calcining at 400-600°C.

9. The production method according to claim 8, wherein The oil phase is a C6-C8 saturated alkane or a cycloalkane.

10. The production method according to claim 8, wherein The oil phase is cyclohexane and / or n-hexane.

11. The production method according to claim 8, wherein The surfactant is an ionic surfactant or a non-ionic surfactant.

12. The production method according to claim 8, wherein, The surfactant is a non-ionic surfactant.

13. The method of making according to claim 8, wherein, The surfactant is polyethylene glycol octylphenyl ether and / or hexadecyl trimethyl ammonium bromide.

14. The production method according to claim 8, wherein, The co-surfactant is C4-C6 alcohol.

15. The method of making according to claim 8, wherein, The co-surfactant is n-butanol and / or n-pentanol.

16. The method of making according to claim 8, wherein, The precursor salt of Ni is a soluble salt of Ni.

17. The method of making according to claim 8, wherein, The precursor salt of Ni is nitrate or chloride.

18. The method of making according to claim 8, wherein, The precursor salt of Cu is a soluble salt of Cu.

19. The method of making according to claim 8, wherein, The precursor salt of Cu is nitrate or chloride.

20. The method of manufacturing according to claim 8, wherein, The conditions for preparing the microemulsion 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, and the weight ratio of the surfactant to the co-surfactant is 1-1.

2.

21. The method of manufacturing according to claim 8, wherein, The particle size of the formed microemulsion is greater than the maximum pore diameter of the small pores of the catalyst carrier and less than the maximum pore diameter of the large pores of the catalyst carrier.

22. The method of manufacturing according to claim 8, wherein, The particle size of the formed microemulsion is greater than 50 nm and less than 500 nm.

23. The method of making according to claim 7 or 8, wherein, The precursor salt of Pd is loaded by the following method: The precursor salt of Pd is dissolved in water, the pH is adjusted to 1.5-2.5 to obtain a precursor salt of Pd solution, then the semi-finished catalyst A or the carrier is added to the precursor salt of Pd solution, and is immersed and adsorbed for 0.5-4 h, then is dried, and is calcined at 400-600 ℃.

24. The method of manufacturing according to claim 23, wherein, The precursor salt of Pd is a soluble salt of Pd.

25. The method of making according to claim 23, wherein, The precursor salt of Pd is nitrate or chloride of Pd.

26. The method of making according to any one of claims 7-25, wherein, The precursor salt of Ce and the precursor salt of Pt are loaded by the following method: The precursor salt of Ce and the precursor salt of Pt are dissolved in water to obtain a Ce-Pt impregnation solution, the pH is adjusted to 1-3, the semi-finished catalyst B or the semi-finished catalyst D or the semi-finished catalyst C is immersed in the Ce-Pt impregnation solution, after the solution is completely absorbed, drying is performed, and calcination is performed at 500-600 ℃.

27. The method of making according to claim 26, wherein, The amount of the impregnation solution is 90-100% of the water absorption amount of the carrier.

28. The method of making according to claim 26, wherein, The precursor salt of Pt is chloroplatinic acid.

29. The method of manufacturing according to claim 26, wherein, The precursor salt of Ce is a soluble salt of Ce.

30. The method of manufacturing according to claim 26, wherein, The precursor salt of Ce is nitrate.

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