A pyrolysis gasoline fraction selective hydrogenation catalyst and a method for preparing the same

Abstract

The application provides a pyrolysis gasoline fraction selective hydrogenation catalyst, which comprises alumina with a bimodal pore distribution structure and an active component; the active component comprises Pd, Pt, Ce, W, Ni and Cu, the content of Pd is 0.2wt%-0.5wt% based on 100% of the mass of the catalyst, the content of Pt is 0.02wt%-0.15wt%, the content of Ce is 0.5wt%-4.0wt%, the content of W is 0.2wt%-2.5wt%, the content of Ni is 0.5wt%-5.0wt%, and the content of Cu is 0.5wt%-3.0wt%; Ni-Cu is loaded by a microemulsion method, Pd, Pt, Ce and W are loaded by a solution method, and Pt and Ce are loaded simultaneously. After the catalyst is regenerated for 5 times, the activity and selectivity of the catalyst do not change obviously, and the catalyst still has excellent hydrogenation activity and anti-coking performance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of hydrogenation catalysts, and particularly relates to a cracking gasoline fraction selective hydrogenation catalyst and a preparation method thereof. BACKGROUND

[0002] Cracking gasoline is an important by-product of the ethylene industry, accounting for 50wt% to 80wt% of the ethylene production capacity, and is an important raw material for producing aromatic hydrocarbons after two-stage hydrogenation. The first-stage selective hydrogenation mainly removes diene hydrocarbons prone to polymerization and gelation, and the second-stage hydrogenation removes mono-olefins and other impurities. The hydrogenation catalyst technology is a key technology for the aromatic extraction process. Currently, the first-stage selective hydrogenation of cracking gasoline in the industry mainly uses Pd / Al2O3 or Ni / Al2O3 system catalysts.

[0003] In recent years, under the background of rapid expansion of ethylene production capacity and enterprises' quality improvement and efficiency enhancement, the cracking gasoline hydrogenation technology is facing new challenges: ① The upstream ethylene device tends to be large-scale, and the cracking raw material tends to be diversified, resulting in an increase in the load of the downstream cracking gasoline device, a complex and variable composition of the raw material, and an increase in the impurity content; ② Enterprises require the catalyst to be stably operated for more than 4 years for quality improvement and efficiency enhancement. Therefore, higher requirements are put forward for the hydrogenation activity, selectivity, impurity resistance, and operation stability of the cracking gasoline catalyst.

[0004] In view of the above problems, the existing technology has improved the Pd / Al2O3 or Ni / Al2O3 system catalyst, such as Chinese patent document 200810114744.0, which discloses an unsaturated hydrocarbon selective hydrogenation catalyst and a preparation method thereof. The catalyst uses alumina as the carrier and contains the following components based on the total weight of the catalyst: palladium as the active component, the content of palladium is 0.1% to 1.0%, the content of rare earth metals is 0.1% to 6.0%, the content of alkaline earth metals is 0.1% to 4.0%, and in addition, it can also contain fluorine, the content of fluorine is 0 to 3.0%, and the balance is the alumina carrier. The catalyst is suitable for the first-stage selective hydrogenation process of full-range cracking gasoline, and is also suitable for the selective hydrogenation process of unsaturated hydrocarbons in other distillate oils. The catalyst improves the impurity resistance and coking resistance of the catalyst by adding rare earth metals, alkaline earth metals, and fluorine, but the selectivity of the catalyst is not ideal.

[0005] US patent document US4484015A discloses a composition and a method, the composition contains palladium and silver, and the amount of palladium and silver is sufficient to selectively hydrogenate certain unsaturated hydrocarbons to lower unsaturated hydrocarbons (such as alkyne or diene); the composition also includes a certain alkali metal-containing compound, such as potassium fluoride. However, the activity of the catalyst needs to be further improved.

[0006] Chinese patent document 200810119385.8 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, the main active component is Ni, the auxiliary active component is selected from at least one of Mo, La, Ag, Bi, Cu, Nd, Cs, Ce, W and Zr, the main active component and the auxiliary active component both exist in an amorphous state, the average particle size is <10 nm, the carrier is a non-oxidizing porous material; and the catalyst is prepared by a microemulsion method and is used in an acetylene selective hydrogenation removal alkyne reaction, but the selectivity of the catalyst needs to be further improved.

[0007] Chinese patent document 201110234140.1 discloses a hydrogenation catalyst comprising an alumina-titania composite carrier and metal palladium and metal molybdenum or metal tungsten supported on the composite carrier; the weight ratio of alumina to titania in the composite carrier is 3:1-6:1; the content of metal palladium is 0.2-0.4% based on the weight of the catalyst; and the weight ratio of metal palladium to metal molybdenum or to metal tungsten is 1:0.8-2, the catalyst is used for hydrogenation of C5 petroleum resin.

[0008] The catalysts prepared by the above methods all use catalysts with a single pore size distribution, in the process of fixed bed reaction, affected by internal diffusion, the selectivity of the catalysts is poor. The carrier with a bimodal pore distribution can ensure high activity of the catalysts, and the existence of large pores can reduce the influence of internal diffusion and improve the selectivity of the catalysts.

[0009] As Chinese patent document 201310114077.7 discloses a hydrogenation catalyst, the active component in the catalyst is Pd, Ag and Ni, wherein Pd and Ag are supported by a water solution impregnation method, and Ni is supported by a W / O microemulsion impregnation method. After the method is used, Pd / Ag and Ni are located in pores with different pore sizes, the green oil generated in the reaction is saturated hydrogenated in large pores, and the amount of catalyst coking is reduced. But the reduction temperature of Ni often reaches about 500℃, and the Pd atoms in the reduced state are extremely easy to aggregate at the temperature, so that the activity of the catalyst is greatly reduced, and the amount of active component needs to be greatly increased to compensate for the activity loss, but this will cause the selectivity to decrease.

[0010] The Chinese patent document 202010815254.4 discloses a selective hydrogenation catalyst, the carrier is alumina or mainly alumina, and has a bimodal pore distribution structure, the content of Pd is 0.15-0.50wt% based on 100% of the mass of the catalyst, the mass ratio of Pd to W is 1-5:1, the content of Ni is 0.5-5wt%, and the mass ratio of Cu to Ni is 0.1-1:1; wherein Ni and Cu are loaded in the form of microemulsion and distributed in the macropores of the carrier; W is loaded by solution method; and Pd is loaded by both solution method and microemulsion method. When the catalyst is used for selective hydrogenation of a pyrolysis gasoline fraction, it has good hydrogenation activity, excellent selectivity, and high coking resistance. However, in order to reduce the reduction temperature of the Ni active center, copper and a small amount of palladium are added by emulsion method. Since palladium is loaded twice, the content of palladium in the catalyst is higher than that of commonly used catalysts, and can be up to 50% higher, which greatly increases the cost of the catalyst.

[0011] Therefore, it is of great significance to find a Pd catalyst with good olefin hydrogenation activity, selectivity, coking resistance, and regeneration performance for rapid expansion of ethylene production capacity and quality improvement and efficiency increase of enterprises. SUMMARY

[0012] The purpose of the present application is to provide a pyrolysis gasoline fraction selective hydrogenation catalyst and a preparation method thereof, which has good olefin hydrogenation activity, selectivity, coking resistance, and regeneration performance when used in the selective hydrogenation process of a pyrolysis gasoline fraction.

[0013] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0014] A pyrolysis gasoline fraction selective hydrogenation catalyst, comprising a carrier and an active component, the carrier comprises alumina, the alumina has a bimodal pore distribution structure, the specific surface area is 60-150m 2 / g, wherein the small holes have a diameter of 10-60 nm and the large holes have a diameter of 100-500 nm; the active components include Pd, Pt, Ce, W, Ni and Cu, wherein the content of Pd is 0.2wt%-0.5wt%, preferably 0.25wt%-0.45wt%, the content of Pt is 0.02wt%-0.15wt%, preferably 0.05wt%-0.10wt%, the content of Ce is 0.5wt%-4.0wt%, preferably 1.0wt%-3.0wt%, the content of W is 0.2wt%-2.5wt%, preferably 0.6wt%-2.0wt%, the content of Ni is 0.5wt%-5.0wt%, preferably 1.5wt%-3.5wt%, and the content of Cu is 0.5wt%-3.0wt%, preferably 1.0wt%-2.5wt%, based on 100% of the mass of the catalyst; Ni-Cu is loaded by a microemulsion method, Pd, Pt, Ce and W are loaded by a solution method, and Pt and Ce are loaded simultaneously.

[0015] In the cracking gasoline fraction selective hydrogenation catalyst provided by the present application, the content of Ce is limited to 0.5wt%-4.0wt%, 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 limited to 0.02wt%-0.15wt%, so that Pt exists in the form of a single atom and is mainly loaded on cerium oxide.

[0016] Optionally, in the cracking gasoline fraction selective hydrogenation catalyst provided by the present application, the carrier further contains other metal oxides in addition to alumina, such as lithium oxide, titanium oxide, etc. The content of the alumina in the carrier is recommended to be 80wt%-100wt%, based on 100% of the mass of the carrier.

[0017] Optionally, in the cracking gasoline fraction selective hydrogenation catalyst provided by the present application, the shape of the carrier is not specifically limited, and can be any one of a sphere, a cylinder, a trilobal shape and a quadrilobal shape, etc.

[0018] For hydrogenation reaction, the hydrogenation catalyst needs to be reduced before being applied in the catalyst, to ensure that the active component exists in the metallic state, so that the catalyst has hydrogenation activity. Because in the preparation process of the catalyst, activation 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 nanosized. Different oxides need to be reduced at different temperatures due to their different chemical properties, but for nanosized metals, a temperature of about 200 DEG 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 the reduction process, and further avoid the decrease of the utilization rate of the active component due to the aggregation of the active component, and the decrease of the hydrogenation activity of the catalyst, is of great significance to the hydrogenation catalyst.

[0019] The idea of the present application to solve the easy aggregation of the active component in the catalyst at high temperature and the anti-coking of the catalyst is:

[0020] The selective hydrogenation reaction of diene in the raw material occurs in the main active center composed of Pd and W, and the produced macromolecules such as gum 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 a saturated hydrogenation function, and the macromolecular compound components will occur saturated hydrogenation reaction in the Ni-Cu active center. Because the double bond is hydrogenated and saturated, the macromolecular components such as gum cannot occur polymerization reaction or the polymerization reaction rate is greatly reduced, the chain growth reaction is terminated or delayed, and cannot form giant molecular weight condensed ring compounds, and is easy to be carried out of the reactor by the material, so that the coking degree of the surface of the catalyst is greatly reduced, and the operation life of the catalyst is prolonged.

[0021] The method for controlling the positioning of Ni-Cu in the large pores of the catalyst in the present application is that Ni-Cu is loaded in the form of 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. The Ni-Cu metal salt is contained in the microemulsion, and due to the space resistance, it is difficult to enter the small pore channel of the carrier, and therefore mainly enters the large pores of the carrier. The loading of Pd is carried out by using solution method, and due to the siphon effect of the small pores, Pd is mainly loaded in the small pores of the catalyst.

[0022] But because the reduction temperature of Ni-Cu is high, generally 350-400℃, but at this temperature, the aggregation of Pd active center is obvious. The inventor has found that after adding Ce in the carrier, the aggregation degree of Pd is mitigated; if Pt is added, the aggregation of Pd is also mitigated. The inventor has also found that if Ce and Pt are loaded simultaneously, even after 5 times of calcination, the dispersion degree of the active component is still reduced by not more than 20%. The reason is that the metal salt of Ce forms the oxide of Ce after calcination, which exists in the form of monolayer distribution. When Pt is loaded with Ce, Pt is mainly loaded on the oxide of Ce, and it is speculated that Pt-Ce 2+ --O 2- --Ce 4+ species, and the binding force is much higher than that of Pt and alumina, so that the atoms of Pt are like a "atomic fence" outside the Pd particles, preventing the growth of Pd particles, thereby playing a role in improving the high-temperature resistance of Pd active center to aggregation. In order to make the "atomic fence" formed by Pt and Ce prevent the growth of Pd particles, Pt and Ce are also loaded by the solution method, so that they are mainly located in the small pores of the catalyst.

[0023] The synergistic effect between W and Pd can improve the selectivity of diene hydrogenation. W is loaded by the solution method, and the loading of W is after the loading of Pd.

[0024] Therefore, the present application provides a preparation method of the above-mentioned selective hydrogenation catalyst for pyrolysis gasoline fraction, Pd, Ce, Pt and W are all loaded by the solution method; Ce and Pt are loaded simultaneously, and the solution method for loading Ce-Pt and W is after the solution method for loading Pd; Ni-Cu is loaded by the microemulsion method, and the step of loading Ni-Cu by the microemulsion method is not limited;

[0025] The process of loading Ni-Cu by the microemulsion method includes the following steps: dissolving the precursor salt of Ni and the precursor salt of Cu in water to obtain an aqueous phase, then mixing the aqueous phase with an oil phase, a surfactant and a co-surfactant, and the mass ratio of the aqueous phase to the oil phase is 2-3, the mass ratio of the surfactant to the oil phase is 0.15-0.6, and the mass ratio of the surfactant to the co-surfactant is 1.0-1.2; and then stirring to form a microemulsion of Ni-Cu with a particle size of greater than 60 nm and less than 500 nm, so as to control the particle size of the microemulsion to be greater than the pore size of the small pores of the carrier and less than the pore size of the large pores of the carrier.

[0026] Optionally, in the preparation method of the selective hydrogenation catalyst for pyrolysis gasoline fraction, the solution method is used to load Ce-Pt and W in sequence after loading Pd by the solution method; or the solution method is used to load W and Ce-Pt in sequence after loading Pd by the solution method.

[0027] Optionally, the present application provides a preparation method of the pyrolysis gasoline fraction selective hydrogenation catalyst, wherein the microemulsion method is used to load Ni-Cu before the solution method is used to load Pd.

[0028] Optionally, the present application provides a preparation method of the pyrolysis gasoline fraction selective hydrogenation catalyst, wherein the microemulsion method is used to load Ni-Cu before the solution method is used to load Pd.

[0029] Specifically, the present application recommends that the oil phase is C6-C8 saturated alkane or cycloalkane, preferably cyclohexane or n-hexane; the surfactant is ionic surfactant and / or non-ionic surfactant, preferably non-ionic surfactant, more preferably polyethylene glycol octylphenyl ether (Triton X-100) or cetyltrimethylammonium bromide (CTAB); and the co-surfactant is organic alcohol, preferably C4-C6 alcohol, more preferably n-butanol and / or n-pentanol.

[0030] To prevent Ni from entering small pores and covering the loaded Pd, it is preferred that the solution method is used to load Pd after the microemulsion method is used to load Ni-Cu. Preferably, the preparation method of the pyrolysis gasoline fraction selective hydrogenation catalyst recommended by the present application specifically comprises the following steps:

[0031] Loading Ni-Cu: after the carrier is impregnated in the microemulsion of Ni-Cu, the remaining liquid is filtered out, and then the first semi-finished catalyst is obtained by drying and calcination;

[0032] Loading Pd: the precursor salt of Pd is dissolved in water, the pH is adjusted to 2.0-2.5 by sodium carbonate, and then the first semi-finished catalyst is impregnated and adsorbed, and then the second semi-finished catalyst is obtained by drying and calcination;

[0033] Loading Ce-Pt: the precursor salt of Ce and the precursor compound of Pt are dissolved in deionized water to obtain a solution containing Ce and Pt, the pH is adjusted to 2-2.5 by sodium carbonate, and then the second semi-finished catalyst is saturatedly impregnated, and then the third semi-finished catalyst is obtained by drying and calcination after the saturated impregnation is completed;

[0034] Loading W: the precursor salt of W is dissolved in deionized water to obtain a solution containing W, and then the third semi-finished catalyst is saturatedly impregnated, and then the pyrolysis gasoline fraction selective hydrogenation catalyst is obtained by drying and calcination after the saturated impregnation is completed.

[0035] Preferably, the preparation method of the pyrolysis gasoline fraction selective hydrogenation catalyst recommended by the present application specifically comprises the following steps:

[0036] Loading Ni-Cu: after the carrier is impregnated in the microemulsion of the Ni-Cu, the residual liquid is filtered out, dried and calcined to obtain a first semi-finished catalyst;

[0037] Loading Pd: after the first semi-finished catalyst is impregnated and adsorbed by dissolving the precursor salt of Pd in water, adjusting the pH to 2.0-2.5 with sodium carbonate and then adding the first semi-finished catalyst, the first semi-finished catalyst is dried and calcined to obtain a second semi-finished catalyst;

[0038] Loading W: after the second semi-finished catalyst is saturatedly impregnated by dissolving the precursor salt of W in deionized water to obtain a W-containing solution and then adding the second semi-finished catalyst, the second semi-finished catalyst is dried and calcined after the saturated impregnation is completed to obtain a third semi-finished catalyst;

[0039] Loading Ce-Pt: after the third semi-finished catalyst is saturatedly impregnated by dissolving the precursor salt of Ce and the precursor compound of Pt in deionized water to obtain a Ce- and Pt-containing solution, adjusting the pH to 2-2.5 with sodium carbonate and then adding the third semi-finished catalyst, the third semi-finished catalyst is dried and calcined after the saturated impregnation is completed to obtain the cracking gasoline fraction selective hydrogenation catalyst.

[0040] Optionally, the application further provides a preparation method of the cracking gasoline fraction selective hydrogenation catalyst, which specifically comprises the following steps:

[0041] Loading Pd: after the carrier is impregnated by dissolving the precursor salt of Pd in water and adjusting the pH to 2.0-2.5, the first semi-finished catalyst is obtained by drying and calcining;

[0042] Loading W: after the first semi-finished catalyst is saturatedly impregnated by dissolving the precursor salt of W in deionized water to obtain a W-containing solution, the second semi-finished catalyst is obtained by drying and calcining after the saturated impregnation is completed;

[0043] Loading Ce-Pt: after the second semi-finished catalyst is saturatedly impregnated by dissolving the precursor salt of Ce and the precursor compound of Pt in deionized water to obtain a Ce- and Pt-containing solution, adjusting the pH to 2-2.5 and then adding the second semi-finished catalyst, the third semi-finished catalyst is obtained by drying and calcining after the saturated impregnation is completed;

[0044] Loading Ni-Cu: after the third semi-finished catalyst is impregnated in the microemulsion of the Ni-Cu, the residual liquid is filtered out, dried and calcined to obtain the cracking gasoline fraction selective hydrogenation catalyst.

[0045] Optionally, the application further provides a preparation method of the cracking gasoline fraction selective hydrogenation catalyst, which specifically comprises the following steps:

[0046] Pd loading: the precursor salt of Pd is dissolved in water, the pH is adjusted to 2.0-2.5, then the carrier is added for impregnation adsorption, and then dried and calcined to obtain the first semi-finished product catalyst;

[0047] Ce-Pt loading: the precursor salt of Ce and the precursor compound of Pt are dissolved in deionized water to obtain a solution containing Ce and Pt, the pH is adjusted to 2-2.5, then the first semi-finished product catalyst is added for saturated impregnation, and then dried and calcined to obtain the second semi-finished product catalyst;

[0048] Ni-Cu loading: after the second semi-finished product catalyst is impregnated in the Ni-Cu microemulsion, the residual liquid is filtered out, dried and calcined to obtain the third semi-finished product catalyst;

[0049] W loading: the precursor salt of W is dissolved in deionized water to obtain a solution containing W, then the third semi-finished product catalyst is added for saturated impregnation, and then dried and calcined to obtain the pyrolysis gasoline fraction selective hydrogenation catalyst.

[0050] Optionally, in the preparation method of the pyrolysis gasoline fraction selective hydrogenation catalyst, the impregnation time and calcination parameters in each loading step are not specifically limited and can be conventional in the industry. In the preparation method of the pyrolysis gasoline fraction selective hydrogenation catalyst recommended by the present application, in the step of loading Ni-Cu, the impregnation time is 0.5-4 h, and the calcination temperature is 300-600°C, and the calcination time is 3-6 h;

[0051] In the step of loading Pd, the impregnation time is 0.5-4 h, the calcination temperature is 400-550°C, and the calcination time is 3-6 h;

[0052] In the step of loading Ce-Pt, the impregnation time is 0.5-4 h, the calcination temperature is 500-600°C, and the calcination time is 3-6 h;

[0053] In the step of loading W, the impregnation adsorption time is 0.5-4 h, the calcination temperature is 400-550°C, and the calcination time is 3-6 h.

[0054] Optionally, in the preparation method of the selective hydrogenation catalyst for pyrolysis gasoline fraction, the precursor salt of Pd, Ce, Ni, Cu and W is a soluble salt, which can be nitrate, chloride or other soluble salt. For example, the precursor salt of Pd can be selected from any one of soluble Pd salts such as palladium chloride and palladium nitrate; the precursor salt of Ni can be selected from any one of soluble Ni salts such as nickel acetate and nickel nitrate; the precursor salt of Cu can be selected from any one of soluble Cu salts such as copper nitrate and copper chloride; the precursor salt of W can be selected from any one of soluble W salts such as ammonium metatungstate and ammonium tungstate; and the precursor salt of Ce can be selected from any one of soluble Ce salts such as cerium nitrate. The precursor compound of Pt can be selected from any one of soluble inorganic Pt compounds such as chloroplatinic acid and platinum trichloride.

[0055] Optionally, the reduction temperature of the selective hydrogenation catalyst for pyrolysis gasoline fraction before being put into hydrogenation reaction is 350-400℃.

[0056] The selective hydrogenation catalyst for pyrolysis gasoline fraction or the selective hydrogenation catalyst for pyrolysis gasoline fraction prepared by the preparation method has the following characteristics: at the beginning of hydrogenation reaction, due to the high hydrogenation activity of Pd and the main distribution of Pd in small pores, the selective hydrogenation reaction of diene mainly occurs in small pores. With the extension of the running time of the catalyst, a part of by-products with large molecular weight are generated on the surface of the catalyst. These substances with large molecular size enter the large pores more and stay for a long time, and under the action of the Ni catalyst, the double bond hydrogenation reaction occurs to generate saturated hydrocarbons or aromatic hydrocarbons without isolated double bond, 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 after regeneration for about 5 times, the activity and selectivity of the catalyst do not change obviously.

[0057] The present application has the following advantages:

[0058] 1. The pyrolysis gasoline fraction selective hydrogenation catalyst provided by the present application has excellent hydrogenation activity, selectivity, coking resistance and regeneration performance. In the catalyst system of the present application, the carrier has a bimodal pore distribution structure, Pd and W are loaded by a solution method, the siphon effect of the small pores causes Pd and W to be mainly loaded in the small pores of the catalyst, and the selective hydrogenation reaction of dienes in the hydrogenation raw material occurs in the main active center composed of Pd and W; the synergistic effect between Pd and W can improve the hydrogenation activity and selectivity of dienes. Ni-Cu is loaded in the form of a microemulsion, the particle size of the microemulsion is between the pore size of the small pores of the carrier and the maximum pore size of the large pores, and the space resistance causes the microemulsion to be difficult to enter the small pores of the carrier, so that Ni-Cu is mainly loaded in the large pores of the carrier. Ni-Cu has a saturation hydrogenation function, and the macromolecules such as gum generated in the reaction can easily enter the large pores of the catalyst to occur saturation hydrogenation reaction and be carried out of the reactor by the material, thereby being beneficial to reducing the coking on the surface of the catalyst. The "atomic fence" formed by Pt and Ce loaded in the small pore structure plays a role in isolating and dispersing Pd particles, can prevent the growth of Pd particles, and improve the dispersion degree of the active center Pd and the high-temperature agglomeration resistance.

[0059] 2. After the pyrolysis gasoline fraction selective hydrogenation catalyst provided by the present application is regenerated, the reduction is still at 350-400℃, and the activity and selectivity of the regenerated catalyst do not change obviously: after the catalyst is regenerated for about 5 times, the activity and selectivity do not change obviously, and the catalyst still has excellent hydrogenation activity and coking resistance. DETAILED DESCRIPTION

[0060] The present application will be described in detail below by examples. It is necessary to point out here that the following examples are only used to further illustrate the present application and cannot be understood as limiting the protection scope of the present application, and those skilled in the art can make some non-essential improvements and adjustments to the present application according to the above content of the present application.

[0061] The specific experimental steps or conditions are not specified in the examples, and can be performed according to the conventional experimental steps described in the literature in the art or the operation or conditions. The reagents or instruments used are not specified by the manufacturer, and are all conventional reagent products that can be obtained by purchase.

[0062] The technical scheme of the present application is applicable to any existing pyrolysis gasoline fraction, and for the convenience of comparison, the pyrolysis gasoline in each of the following examples and comparative examples is used to perform experiments on the pyrolysis gasoline fraction of the same batch in the ethylene plant of Lanzhou Petrochemical.

[0063] Evaluation method:

[0064] The particle size distribution of the Ni-Cu microemulsion is tested by a dynamic light scattering particle size analyzer.

[0065] The content of each component in the catalyst is analyzed and detected by using the national standards "General Method for Atomic Absorption Spectrometry" GB / T 15337 and "General Method for Flame Atomic Absorption Spectrometry of Chemical Reagents" GB 19723;

[0066] The specific surface area and pore size of the catalyst and the carrier are determined according to the standard GB / T 21650;

[0067] The metal dispersion is determined by using the hydrogen-oxygen titration method in a Micromeritics Autochem 2920 chemisorption instrument.

[0068] The diene value of the oil product is determined by using the UOP 326-2008 method;

[0069] The bromine value of the oil product is determined by using the SH / T 0236-92 standard;

[0070] The water content of the oil product is determined by using the GB / T 11133-89 standard;

[0071] The sulfur content of the oil product is determined by using a WK-2B microcoulomb instrument;

[0072] The carbon content on the surface of the catalyst is determined by using an elemental analyzer.

[0073] The application is further illustrated below through specific examples, but it is not considered that the application is limited to this.

[0074] Example 1

[0075] The catalyst carrier is a commercially available bimodal pore distribution spherical alumina carrier, which is calcined at 1020°C, has a bimodal pore size distribution range of 15-60 nm and 150-400 nm, and has a specific surface area of 120 m 2 / g. 100 g of the carrier is weighed.

[0076] Preparation of the catalyst:

[0077] (1) Nickel nitrate and copper nitrate are weighed and dissolved in 70 g of deionized water, 35 g of cyclohexane is added, 15 g of CTAB is added, 13 g of n-pentanol is added, and the mixture is fully stirred to form a microemulsion. 100 g of the high-temperature calcined carrier is immersed in the prepared microemulsion, shaken for 60 min, the remaining liquid is filtered out, dried at 100°C for 4 h, and calcined at 300°C for 6 h to obtain a semi-finished catalyst A1;

[0078] (2) PdCl2 is weighed and prepared into an active component impregnation solution, and the pH is adjusted to 2.0 with Na2CO3. The semi-finished catalyst A1 is immersed in the prepared Pd active component solution, and after 60 min of immersion, it is dried at 120°C for 3 h and calcined at 400°C for 6 h to obtain a semi-finished catalyst B1;

[0079] (3) Take chloroplatinic acid, cerium nitrate to prepare active component impregnation solution, adjust pH to 2.0 with sodium carbonate, immerse semi-finished catalyst B1 into the prepared solution, dry at 120°C for 3h after impregnation for 120min, calcine at 500°C for 5h to obtain semi-finished catalyst C1;

[0080] (4) Take ammonium tungstate and dissolve in deionized water, immerse semi-finished catalyst C1 in the prepared solution, dry at 100°C for 4h after impregnation for 180min, calcine at 550°C for 5h to obtain the desired catalyst D1.

[0081] The particle size of the prepared microemulsion is 90nm by dynamic light scattering method.

[0082] Reduction of the catalyst:

[0083] Before use, place in a fixed bed reaction device, reduce at 350°C under hydrogen atmosphere for 8h.

[0084] Comparative Example 1

[0085] Use the same carrier as in Example 1, the catalyst preparation conditions and reduction conditions are the same as in Example 1, the difference is that Ce is not loaded during catalyst preparation. The specific catalyst preparation steps in this comparative example 1 are as follows:

[0086] (1) Take nickel nitrate, copper nitrate and dissolve in 70g deionized water, add cyclohexane 35g, add CTAB 15g, add n-pentanol 13g, stir thoroughly to form a microemulsion, immerse the 100g high-temperature calcined carrier into the prepared microemulsion, shake for 60min, filter out the residual liquid, dry at 100°C for 4h, calcine at 300°C for 6h to obtain semi-finished catalyst DA1;

[0087] (2) Take palladium chloride and prepare active component impregnation solution, adjust pH to 2.0 with sodium carbonate, immerse semi-finished catalyst DA1 into the prepared Pd salt solution, dry at 120°C for 3h after impregnation for 60min, calcine at 400°C for 6h to obtain semi-finished catalyst DB1;

[0088] (3) Take chloroplatinic acid and prepare active component impregnation solution, adjust pH to 2.0 with sodium carbonate, immerse semi-finished catalyst DB1 into the prepared solution, dry at 120°C for 3h after impregnation for 120min, calcine at 500°C for 5h to obtain semi-finished catalyst DC1;

[0089] (4) Take ammonium tungstate and dissolve in deionized water, immerse semi-finished catalyst DC1 in the prepared solution, dry at 100°C for 4h after impregnation for 180min, calcine at 550°C for 5h to obtain the desired catalyst DD1.

[0090] The particle size of the prepared microemulsion emulsion was 90 nm, which was measured by dynamic light scattering.

[0091] Comparative Example 2

[0092] The same carrier as in Example 1 was used, and the catalyst preparation conditions and reduction conditions were the same as in Example 1, except that Pt was not loaded during catalyst preparation. The specific catalyst preparation steps in this Comparative Example 2 are as follows:

[0093] (1) Nickel nitrate and copper nitrate were weighed and dissolved in 70 g of deionized water, 35 g of cyclohexane was added, 15 g of CTAB was added, and 13 g of n-pentanol was added. Stir well to form a microemulsion. 100 g of high-temperature calcined carrier was immersed in the prepared microemulsion, shaken for 60 min, and the remaining liquid was filtered out. Dry at 100°C for 4 h, and calcine at 300°C for 6 h. The resulting product is called semi-finished catalyst DA11.

[0094] (2) PdCl2 was weighed and prepared into an active component impregnation solution. The pH was adjusted to 2.0 with Na2CO3. The semi-finished catalyst DA11 was immersed in the prepared Pd active component solution, and after 60 min of immersion, it was dried at 120°C for 3 h and calcined at 400°C for 6 h to obtain semi-finished catalyst DB11.

[0095] (3) Ce(NO3)3 was weighed and prepared into an active component impregnation solution. The pH was adjusted to 2.0 with Na2CO3. The semi-finished catalyst DB11 was immersed in the prepared solution, and after 120 min of immersion, it was dried at 120°C for 3 h and calcined at 500°C for 5 h to obtain semi-finished catalyst DC11.

[0096] (4) Ammonium tungstate was dissolved in deionized water, and the semi-finished catalyst DC11 was dissolved in the prepared solution. After 180 min of immersion, it was dried at 100°C for 4 h and calcined at 550°C for 5 h to obtain the desired catalyst DD11.

[0097] The particle size of the prepared microemulsion emulsion was 90 nm, which was measured by dynamic light scattering.

[0098] Example 2

[0099] Catalyst carrier: A commercially available bimodal pore distribution clover-shaped alumina-titania carrier with a mass content of 10 wt% of titania was used. The carrier was calcined at 1000°C, and the bimodal pore size distribution range was 10-40 nm and 200-500 nm. The specific surface area was 110 m 2 / g. 100 g of the carrier was weighed.

[0100] Catalyst preparation:

[0101] (1) Take palladium chloride to prepare active component impregnation solution, adjust pH to 2.3 with sodium carbonate, immerse 100 g of high-temperature calcined carrier weighed in the prepared Pd active component solution, dry at 100 ℃ for 5 h after impregnation for 240 min, calcine at 500 ℃ for 4 h, and obtain semi-finished catalyst A2;

[0102] (2) Dissolve ammonium tungstate in deionized water, immerse the semi-finished catalyst A2 in the prepared solution, dry at 100 ℃ for 4 h after impregnation for 120 min, and calcine at 550 ℃ for 3 h to obtain semi-finished catalyst B2;

[0103] (3) Take cerium nitrate and chloroplatinic acid to prepare active component impregnation solution, adjust pH to 2.2 with sodium carbonate, add the semi-finished catalyst B2 to the prepared solution, dry at 100 ℃ after impregnation for 180 min, and calcine at 580 ℃ for 6 h to obtain semi-finished catalyst C2;

[0104] (4) Dissolve nickel nitrate and copper nitrate in 65 g of deionized water, add 22 g of cyclohexane, 11 g of Triton X-100, and 11 g of n-hexanol, fully stir to form a microemulsion, immerse the prepared semi-finished catalyst C2 in the prepared microemulsion, shake for 200 min, filter out the residual liquid, dry at 100 ℃ for 4 h, and calcine at 500 ℃ for 4 h to obtain the desired catalyst D2.

[0105] The particle size of the prepared microemulsion is 150 nm measured by dynamic light scattering method.

[0106] Reduction of the catalyst:

[0107] Before use, place in a fixed bed reaction device, reduce at a hydrogen atmosphere and a temperature of 370 ℃ for 7 h.

[0108] Comparative Example 3

[0109] Use the same carrier as in Example 2, and in the preparation process of the catalyst in this comparative example, Ce and Pt are loaded respectively, and the catalyst reduction conditions are the same as in Example 2. The preparation steps of the catalyst in Comparative Example 3 are as follows:

[0110] Catalyst preparation:

[0111] (1) Take palladium chloride to prepare active component impregnation solution, adjust pH to 2.3 with sodium carbonate, immerse 100 g of high-temperature calcined carrier weighed in the prepared Pd active component solution, dry at 100 ℃ for 5 h after impregnation for 240 min, calcine at 500 ℃ for 4 h, and obtain semi-finished catalyst DA2;

[0112] (2) Take tungsten acid ammonium to dissolve in deionized water, dip the semi-finished catalyst DA2 into the prepared solution, after 120 min of immersion, dry at 100°C for 4h, and calcine at 550°C for 3h to obtain semi-finished catalyst DB2;

[0113] (3) Take cerium nitrate to prepare an active component impregnation solution, adjust the pH to 2.2 with sodium carbonate, and then add the semi-finished catalyst DB2 into the prepared solution, after 180 min of immersion, dry at 100°C, and calcine at 580°C for 6h to obtain semi-finished catalyst DC2;

[0114] (4) Take chloroplatinic acid to prepare an active component impregnation solution, adjust the pH to 2.2 with sodium carbonate, and then add the semi-finished catalyst DC2 into the prepared solution, after 180 min of immersion, dry at 100°C, and calcine at 580°C for 6h to obtain semi-finished catalyst DD2;

[0115] (5) Take nickel nitrate and copper nitrate to dissolve in 65g of deionized water, add 22g of cyclohexane, 11g of Triton X-100, and 11g of n-hexanol, and fully stir to form a microemulsion, then dip the prepared semi-finished catalyst DD2 into the prepared microemulsion, shake for 200 min, filter out the residual liquid, dry at 100°C for 4h, and calcine at 500°C for 4h to obtain the desired catalyst DE2.

[0116] The particle size of the prepared microemulsion is 150nm as determined by dynamic light scattering method.

[0117] Comparative Example 4

[0118] The same carrier as in Example 2 is used, and in this comparative example, Pt and Ce are loaded before Pd in the catalyst preparation process, and the catalyst reduction conditions are the same as in Example 2. The preparation steps of the catalyst in Comparative Example 4 are as follows:

[0119] Catalyst preparation:

[0120] (1) Take cerium nitrate and chloroplatinic acid to prepare an active component impregnation solution, adjust the pH to 2.2 with sodium carbonate, and then add 100g of the high-temperature calcined carrier to the prepared solution, after 180 min of immersion, dry at 100°C, and calcine at 580°C for 6h to obtain semi-finished catalyst DA21;

[0121] (2) Take palladium chloride to prepare an active component impregnation solution, adjust the pH to 2.3 with sodium carbonate, and then dip the semi-finished catalyst DA21 into the prepared Pd active component solution, after 240 min of immersion, dry at 100°C for 5h, and calcine at 500°C for 4h to obtain semi-finished catalyst DB21;

[0122] (3) Weigh ammonium tungstate into deionized water, immerse the semi-finished catalyst DB21 into the prepared solution, dry at 100°C for 4h after 120min of immersion, and calcine at 550°C for 3h to obtain the semi-finished catalyst DC21;

[0123] (4) Weigh nickel nitrate and copper nitrate into 65g of deionized water, add cyclohexane 22, add Triton X-100 11g, add n-hexanol 11g, and fully stir to form a microemulsion. Immerse the prepared semi-finished catalyst DC21 into the prepared microemulsion, shake for 200min, filter out the residual liquid, dry at 100°C for 4h, and calcine at 500°C for 4h to obtain the desired catalyst DD21.

[0124] The particle size of the prepared microemulsion is 150nm as determined by dynamic light scattering method.

[0125] Comparative Example 5

[0126] The same carrier as in Example 2 is used, and in this comparative example, W is loaded before Pd in the catalyst preparation process, and the catalyst reduction conditions are the same as in Example 2. The preparation steps of the catalyst in Comparative Example 5 are as follows:

[0127] Catalyst preparation:

[0128] (1) Weigh ammonium tungstate into deionized water, immerse the semi-finished catalyst DB21 into the prepared solution, dry at 100°C for 4h after 120min of immersion, and calcine at 550°C for 3h to obtain the semi-finished catalyst DC21;

[0129] (2) Weigh palladium chloride to prepare an active component immersion solution, adjust the pH to 2.3 with sodium carbonate, immerse the semi-finished catalyst DA22 into the prepared Pd active component solution, dry at 100°C for 5h after 240min of immersion, and calcine at 500°C for 4h to obtain the semi-finished catalyst DB22;

[0130] (3) Weigh cerium nitrate and chloroplatinic acid to prepare an active component immersion solution, adjust the pH to 2.2 with sodium carbonate, immerse the semi-finished catalyst DB22 into the prepared solution, dry at 100°C after 180min of immersion, and calcine at 580°C for 6h to obtain the semi-finished catalyst DC22;

[0131] (4) Weigh nickel nitrate and copper nitrate into 65g of deionized water, add cyclohexane 22, add Triton X-100 11g, add n-hexanol 11g, and fully stir to form a microemulsion. Immerse the prepared semi-finished catalyst DC22 into the prepared microemulsion, shake for 200min, filter out the residual liquid, dry at 100°C for 4h, and calcine at 500°C for 4h to obtain the desired catalyst DD22.

[0132] The particle size of the prepared microemulsion was 150 nm by dynamic light scattering method.

[0133] Example 3

[0134] Catalyst carrier: a commercially available bimodal pore distribution cylindrical alumina carrier was used, which was calcined at 1010°C, and had a bimodal pore size distribution ranging from 10-60 nm and 150-500 nm, and a specific surface area of 90 m 2 / g. 100 g of the carrier was weighed.

[0135] Catalyst preparation:

[0136] (1) Nickel acetate and copper chloride were weighed and dissolved in 70 g of deionized water, 28 g of cyclohexane was added, 5 g of Triton X-100 was added, and 5 g of n-butanol was added, and the mixture was stirred to form a microemulsion. 100 g of the high-temperature calcined carrier was immersed in the prepared microemulsion, shaken for 100 min, the remaining liquid was filtered out, dried at 80°C for 5 h, and calcined at 450°C for 5 h to obtain semi-finished catalyst A3;

[0137] (2) PdCl2 was weighed and prepared into an active component impregnation solution, and the pH was adjusted to 2.1 with Na2CO3. The semi-finished catalyst A3 was immersed in the prepared Pd active component solution, and after 180 min of immersion, it was dried at 100°C for 5 h and calcined at 420°C for 6 h to obtain semi-finished catalyst B3;

[0138] (3) Ammonium metatungstate was dissolved in deionized water, and the semi-finished catalyst B3 was immersed in the prepared solution. After 200 min of immersion, it was dried at 140°C for 2 h and calcined at 520°C for 6 h to obtain semi-finished catalyst C3;

[0139] (4) Ce(NO3)3 and PtCl3 were weighed and prepared into an active component impregnation solution, and the pH was adjusted to 2.5. The semi-finished catalyst C3 was added to the prepared solution, and after 60 min of immersion, it was dried at 100°C for 4 h and calcined at 510°C for 6 h to obtain the desired catalyst D3.

[0140] The particle size of the prepared microemulsion was 130 nm by dynamic light scattering method.

[0141] Reduction of the catalyst:

[0142] Before use, it was placed in a fixed bed reaction device and reduced at a temperature of 400°C in a hydrogen atmosphere for 8 h.

[0143] Comparative Example 6

[0144] The same carrier as in Example 3 was used, and in the present comparative example, the Pt and Ce in Example 3 were simultaneously loaded to replace the Mo and Ce simultaneously loaded in the catalyst preparation process, and the catalyst reduction conditions were the same as in Example 3. The preparation steps of the catalyst in Comparative Example 6 are as follows:

[0145] Catalyst preparation:

[0146] (1) Nickel acetate and copper chloride were weighed and dissolved in 70 g of deionized water, 28 g of cyclohexane was added, 5 g of Triton X-100 was added, and 5 g of n-butanol was added, and the mixture was stirred to form a microemulsion. 100 g of high-temperature calcined carrier was immersed in the prepared microemulsion, shaken for 100 min, the remaining liquid was filtered out, dried at 80°C for 5 h, and calcined at 450°C for 5 h to obtain a semi-finished catalyst DA3;

[0147] (2) PdCl2 was weighed and prepared into an active component impregnation solution, and the pH was adjusted to 2.1 with Na2CO3. The semi-finished catalyst DA3 was immersed in the prepared Pd active component solution, and after 180 min of immersion, it was dried at 100°C for 5 h and calcined at 420°C for 6 h to obtain a semi-finished catalyst DB3;

[0148] (3) Ammonium metatungstate was weighed and dissolved in deionized water, and the semi-finished catalyst DB3 was immersed in the prepared solution. After 200 min of immersion, it was dried at 140°C for 2 h and calcined at 520°C for 6 h to obtain a semi-finished catalyst DC3;

[0149] (4) Cerium nitrate and ammonium heptamolybdate were weighed and prepared into an active component impregnation solution, and the pH was adjusted to 2.5. The semi-finished catalyst DC3 was added to the prepared solution, and after 60 min of immersion, it was dried at 100°C for 4 h and calcined at 510°C for 6 h to obtain the desired catalyst DD3.

[0150] The particle size of the prepared microemulsion emulsion was 130 nm as determined by dynamic light scattering.

[0151] Example 4

[0152] Catalyst carrier: A commercially available bimodal pore distribution spherical alumina carrier was used, which was calcined at 960°C, and the bimodal pore size distribution range was 10-50 nm and 100-450 nm, and the specific surface area was 105 m 2 / g. 100 g of the carrier was weighed.

[0153] Catalyst preparation:

[0154] (1) Pd(NO3)2 was weighed and prepared into active component impregnation solution, and the pH was adjusted to 2.2 with Na2CO3. 100 g of the high-temperature calcined carrier was immersed in the prepared Pd active component solution, and after 30 min of immersion, it was dried at 100°C for 5 h and calcined at 450°C for 6 h to obtain semi-finished catalyst A4;

[0155] (2) Ce(NO3)3 and H2PtCl6 were weighed and prepared into active component impregnation solution, and the pH was adjusted to 2.3 with Na2CO3. The semi-finished catalyst A4 was added to the prepared solution, and after 90 min of immersion, it was dried at 100°C for 5 h and calcined at 550°C for 4.5 h to obtain semi-finished catalyst B4;

[0156] (3) Ni(NO3)2 and Cu(NO3)2 were dissolved in 75 g of deionized water, 30 g of cyclohexane was added, 4.5 g of Triton X-100 was added, and 4.0 g of n-butanol was added. After stirring, a microemulsion was formed. The prepared semi-finished catalyst B4 was immersed in the prepared microemulsion, shaken for 30 min, and the remaining liquid was filtered out. After drying at 100°C for 4 h and calcining at 400°C for 5 h, semi-finished catalyst C4 was obtained.

[0157] (4) Ammonium metatungstate was weighed and dissolved in deionized water. The semi-finished catalyst C4 was immersed in the prepared solution, and after 240 min of immersion, it was dried at 100°C for 4 h and calcined at 450°C for 4 h to obtain the desired catalyst D4.

[0158] The particle size of the prepared microemulsion was 140 nm as determined by dynamic light scattering.

[0159] Reduction of the catalyst:

[0160] Before use, it was placed in a fixed bed reaction device and reduced at a temperature of 380°C for 9 h in a hydrogen atmosphere.

[0161] Comparative Example 7

[0162] The same carrier as in Example 4 was used, and in this comparative example, Ni and Cu were loaded using the solution method during catalyst preparation. The catalyst reduction conditions were the same as in Example 4. The specific catalyst preparation steps in Comparative Example 7 are as follows:

[0163] Catalyst preparation:

[0164] (1) Pd(NO3)2 was weighed and prepared into active component impregnation solution, and the pH was adjusted to 2.2 with Na2CO3. 100 g of the high-temperature calcined carrier was immersed in the prepared Pd active component solution, and after 30 min of immersion, it was dried at 100°C for 5 h and calcined at 450°C for 6 h to obtain semi-finished catalyst DA4;

[0165] (2) Take cerium nitrate, chloroplatinic acid to prepare active component impregnation solution, adjust pH to 2.3 with sodium carbonate, add semi-finished catalyst DA4 into the prepared solution, impregnate for 90 min, dry at 100°C for 5 h, and calcine at 550°C for 4.5 h to obtain semi-finished catalyst DB4;

[0166] (3) Take nickel nitrate and copper nitrate to prepare active component impregnation solution, impregnate the prepared semi-finished catalyst DB4 into the prepared solution, impregnate for 180 min, dry at 100°C for 4 h, and calcine at 400°C for 5 h to obtain semi-finished catalyst DC4;

[0167] (4) Take ammonium metatungstate and dissolve in deionized water, impregnate the semi-finished catalyst DC4 into the prepared solution, impregnate for 240 min, dry at 100°C for 4 h, and calcine at 450°C for 4 h to obtain the desired catalyst DD4.

[0168] Comparative Example 8

[0169] The same carrier as in Example 4 is used, and the catalyst reduction conditions in the comparative example are the same as in Example 4, the only difference being that in the preparation of catalyst DD41 in Comparative Example 8, the amount of nickel nitrate added is different, and theoretically the content of Ni in the catalyst prepared in Comparative Example 8 is less than 0.5 wt%.

[0170] Comparative Example 9

[0171] The same carrier as in Example 4 is used, and the catalyst reduction conditions in the comparative example are the same as in Example 4, the only difference being that in the preparation of catalyst DD41 in Comparative Example 8, the amount of copper nitrate added is different, and theoretically the content of Cu in the catalyst prepared in Comparative Example 8 is greater than 3.0 wt%.

[0172] Example 5

[0173] Catalyst carrier: commercially available bimodal pore distribution clover-shaped alumina carrier, calcined at 1030°C, bimodal pore size distribution range of 10-60 nm and 200-500 nm, specific surface area of 73 m 2 / g. Take 100 g of the carrier.

[0174] Catalyst preparation:

[0175] (1) Take nickel acetate and copper nitrate and dissolve in 80 g of deionized water, add 35 g of n-hexane, add 21 g of Triton X-100, and add 20 g of n-hexanol, and stir to form a microemulsion, impregnate the 100 g of high-temperature calcined carrier into the prepared microemulsion, shake for 150 min, filter out the remaining liquid, dry at 100°C for 4 h, and calcine at 500°C for 4 h to obtain semi-finished catalyst A5;

[0176] (2) The palladium chloride was weighed and prepared into an active component impregnation solution, the pH was adjusted to 2.5 with sodium carbonate, and then the semi-finished catalyst A5 was impregnated into the prepared Pd salt solution. After impregnation for 200 min, drying was carried out at 120°C for 3h, and calcination was carried out at 550°C for 3h to obtain the semi-finished catalyst B5.

[0177] (3) The chloroplatinic acid and cerium nitrate were weighed and prepared into an active component impregnation solution, the pH was adjusted to 2.1 with sodium carbonate, and then the semi-finished catalyst B5 was impregnated into the prepared solution. After impregnation for 200 min, drying was carried out at 120°C for 3h, and calcination was carried out at 600°C for 3h to obtain the semi-finished catalyst C5.

[0178] (4) The ammonium metatungstate was weighed and dissolved in deionized water, and then the semi-finished catalyst C5 was dissolved in the prepared ammonium metatungstate solution. After impregnation for 60 min, drying was carried out at 100°C for 4h, and calcination was carried out at 400°C for 6h to obtain the desired catalyst D5.

[0179] The particle size of the prepared microemulsion was 120 nm as determined by dynamic light scattering method.

[0180] Reduction of the catalyst:

[0181] Before use, it was placed in a fixed bed reaction device and reduced at a hydrogen atmosphere and a temperature of 360°C for 10h.

[0182] Comparative Example 10

[0183] The catalyst preparation conditions and reduction conditions were the same as in Example 5, except that the pore size distribution of the alumina carrier used in the preparation process of the catalyst DD5 in this comparative example was unimodal. The properties of the catalyst carrier used in this comparative example are as follows:

[0184] A commercially available bimodal pore distribution clover-shaped alumina carrier was used, which was calcined at 1000°C, and the pore size distribution range was 5-100 nm, and the specific surface area was 80 m 2 / g. 100 g of the carrier was weighed.

[0185] Comparative Example 11

[0186] The same carrier as in Example 5 was used, and the catalyst preparation process and catalyst reduction conditions in this comparative example were the same as in Example 5, except that the amounts of chloroplatinic acid and cerium nitrate added in the preparation process of the catalyst DD51 in this comparative example 11 were different. In theory, the Pt content in the catalyst prepared in this comparative example 11 was greater than 0.15wt%, and the Ce content was less than 0.5%.

[0187] Example 6

[0188] Catalyst support: A commercially available bimodal pore distribution clover shape alumina-lithia support with 2wt% of lithium oxide content was used, which was calcined at 950°C, and had a bimodal pore size distribution ranging from 10-30nm and 100-300nm, and a specific surface area of 140m 2 / g. 100g of the support was weighed.

[0189] Catalyst preparation:

[0190] (1) Nickel nitrate and copper chloride were weighed and dissolved in 60g of deionized water, 22g of cyclohexane was added, 8.0g of CTAB was added, and 8.0g of n-pentanol was added, and the mixture was stirred to form a microemulsion. 100g of the high-temperature calcined support was immersed in the prepared microemulsion, shaken for 240 minutes, the remaining liquid was filtered out, dried at 100°C for 4 hours, and calcined at 600°C for 3 hours to obtain semi-finished catalyst A6;

[0191] (2) Palladium nitrate was weighed and prepared into an active component impregnation solution, and sodium carbonate was used to adjust the pH to 2.4. The semi-finished catalyst A6 was immersed in the prepared Pd active component solution, and after 100 minutes of immersion, it was dried at 120°C for 3 hours and calcined at 500°C for 5 hours to obtain semi-finished catalyst B6;

[0192] (3) Chloroplatinic acid and cerium nitrate were weighed and prepared into an active component impregnation solution, and sodium carbonate was used to adjust the pH to 2.4. The semi-finished catalyst B6 was immersed in the prepared solution, and after 240 minutes of immersion, it was dried at 120°C for 3 hours and calcined at 550°C for 4 hours to obtain semi-finished catalyst C6;

[0193] (4) Ammonium tungstate was dissolved in deionized water, and the semi-finished catalyst C6 was immersed in the prepared solution. After 90 minutes of immersion, it was dried at 100°C for 4 hours and calcined at 500°C for 4 hours to obtain the desired catalyst D6.

[0194] The particle size of the prepared microemulsion was measured by dynamic light scattering method to be 145nm.

[0195] Reduction of the catalyst:

[0196] Before use, it was placed in a fixed bed reaction device and reduced at a temperature of 390°C for 8 hours in a hydrogen atmosphere.

[0197] Comparative Example 12

[0198] The catalyst preparation conditions and reduction conditions were the same as in Example 6, except that the pore size distribution of the alumina support used was different. In the catalyst DD6 of this comparative example 12, the pore size distribution of the alumina support used was 2-30nm and 100-300nm.

[0199] The catalyst support used in the specific present comparative example: a commercially available bimodal pore distribution clover-shaped alumina-lithium oxide support with a lithium oxide mass content of 2wt%, which was calcined at 940°C, had a bimodal pore diameter distribution ranging from 2-30nm and 100-300nm, and a specific surface area of 145m 2 / g. 100g of the support was weighed.

[0200] Comparative Example 13

[0201] Using the same support as in Example 6, the catalyst preparation method in the present comparative example was similar to that in Example 6, with the only difference being that the amount of surfactant used in the Ni-Cu microemulsion loading was different, and the surfactant / oil phase in Example 6 was replaced with 0.9 during the preparation process, and the catalyst reduction conditions were the same as in Example 6. The specific catalyst preparation steps in the present comparative example are as follows:

[0202] Catalyst preparation:

[0203] (1) Nickel nitrate, copper chloride were weighed and dissolved in 60g of deionized water, 22g of cyclohexane was added, 19.8g of CTAB was added, and 19.8g of n-pentanol was added, and the mixture was stirred to form a microemulsion. 100g of the high-temperature calcined support was immersed in the prepared microemulsion, shaken for 240min, the remaining liquid was filtered out, dried at 100°C for 4h, and calcined at 600°C for 3h to obtain a semi-finished catalyst DA61;

[0204] (2) Palladium nitrate was weighed and prepared into an active component impregnation solution, and sodium carbonate was used to adjust the pH to 2.4. The semi-finished catalyst DA61 was immersed in the prepared Pd active component solution, and after 100min of immersion, it was dried at 120°C for 3h and calcined at 500°C for 5h to obtain a semi-finished catalyst DB61;

[0205] (3) Chloroplatinic acid and cerium nitrate were weighed and prepared into an active component impregnation solution, and sodium carbonate was used to adjust the pH to 2.4. The semi-finished catalyst DB61 was immersed in the prepared solution, and after 240min of immersion, it was dried at 120°C for 3h and calcined at 550°C for 4h to obtain a semi-finished catalyst DC61;

[0206] (4) Ammonium tungstate was weighed and dissolved in deionized water, and the semi-finished catalyst DC61 was immersed in the prepared solution. After 90min of immersion, it was dried at 100°C for 4h and calcined at 500°C for 4h to obtain the desired catalyst DD61.

[0207] The particle size of the prepared microemulsion was measured by dynamic light scattering method to be 43nm.

[0208] After detection, the content of each component and the metal dispersion degree of the catalyst prepared in each example and comparative example are shown in Table 1.

[0209] Table 1 Catalyst composition of examples and comparative examples

[0210]

[0211] The catalysts prepared in each example and comparative example were used for the hydrogenation reaction of the pyrolysis gasoline fraction, and the specific hydrogenation reaction conditions were as follows:

[0212] The catalysts were evaluated in an adiabatic fixed-bed hydrogenation reaction device, and the catalyst loading amount was 100 mL.

[0213] The pyrolysis gasoline C5-C9 fraction was used, and the reaction process conditions were as follows: reactor inlet temperature 45°C, reaction pressure 2.8 MPa, fresh material volume space velocity 2.0 h -1 , hydrogen / oil volume ratio 200:1, and feedstock / product dilution ratio 1:3 (mass ratio).

[0214] The properties of the pyrolysis gasoline C5-C9 fraction are shown in Table 2, and the hydrogenation evaluation results are shown in Table 3.

[0215] Table 2 Properties of pyrolysis gasoline fraction feedstock

[0216]

[0217] Table 3 500h running results of catalysts of examples and comparative examples

[0218]

[0219]

[0220] In the above table, the calculation formula of the diene hydrogenation selectivity is as follows:

[0221]

[0222] From the data in the above table, it can be seen that, with the pyrolysis gasoline fraction as the raw material, under the same process conditions, the hydrogenation product of the catalyst provided by the present application has a lower diene value, the catalyst has good diene hydrogenation activity, and also has excellent diene hydrogenation selectivity; after 500h running, the carbon content accumulated on the surface of the catalyst is maintained at a low level, and the catalyst has high anti-coking performance. Compared with the comparative example catalyst, the catalyst of the present application has more excellent diene hydrogenation activity, selectivity and anti-coking performance, and can greatly improve the hydrogenation activity and running period of the hydrogenation catalyst.

[0223] In order to investigate the regeneration performance of the catalyst, the catalyst was regenerated by air coke-burning treatment outside the device after running for a period of time, and the regeneration temperature was 500°C.

[0224] The first regeneration treatment was performed on the above catalysts after running for 500h, and the regenerated catalysts were used for pyrolysis gasoline hydrogenation, and the hydrogenation reaction process conditions were the same as above. The performance evaluation results of the first regenerated catalysts after running for 500h are shown in Table 4.

[0225] Table 4 Performance of the first regenerated catalysts of the examples and the comparative examples

[0226]

[0227]

[0228] Table 5 Evaluation results of the examples and the comparative examples after the catalysts were regenerated for 5 times and running for 500h

[0229]

[0230]

[0231] From the experimental data in the above table, it can be seen that under the same process conditions, the catalysts of the present application exhibit more excellent regeneration performance when pyrolysis gasoline fraction is used as the raw material, and the running period of the hydrogenation catalysts can be greatly improved.

[0232] Of course, the present application can have other various embodiments, and those skilled in the art can make various corresponding changes and modifications according to the present application without departing from the spirit and essence of the present application. However, these corresponding changes and modifications should all belong to the protection scope of the claims of the present application.

Claims

1. A selective hydrotreating catalyst for cracked gasoline fractions, characterized in that, The catalyst comprises a support and active components. The support consists of alumina with a bimodal pore distribution structure and a specific surface area of ​​60–150 m² / g, wherein the pore size of the micropores is 10–60 nm and the pore size of the macropores is 100–500 nm. The active components consist of Pd, Pt, Ce, W, Ni, and Cu. Based on the mass of the catalyst (100%), the Pd content is 0.2 wt%–0.5 wt%, the Pt content is 0.02 wt%–0.15 wt%, the Ce content is 0.5 wt%–4.0 wt%, the W content is 0.2 wt%–2.5 wt%, the Ni content is 0.5 wt%–5.0 wt%, and the Cu content is 0.5 wt%–3.0 wt%. Ni-Cu is loaded using a microemulsion method, and the microemulsion particle size is controlled to distribute Ni and Cu in the macropores of the support. Pd, Pt, Ce, and W are all loaded using a solution method, mainly in the micropores of the support, with Pt and Ce being loaded simultaneously. Solution loading of Ce-Pt follows solution loading of Pd.

2. The selective hydrotreating catalyst for cracked gasoline fractions as described in claim 1, characterized in that, The Pd content is 0.25wt% to 0.45wt%.

3. The selective hydrotreating catalyst for cracked gasoline fractions as described in claim 1, characterized in that, The Pt content is 0.05wt%~0.10wt%.

4. The selective hydrotreating catalyst for cracked gasoline fractions as described in claim 1, characterized in that, The Ce content is 1.0wt% to 3.0wt%.

5. The selective hydrotreating catalyst for cracked gasoline fractions as described in claim 1, characterized in that, The W content is 0.6wt% to 2.0wt%.

6. The selective hydrotreating catalyst for cracked gasoline fractions as described in claim 1, characterized in that, The Ni content is 1.5wt% to 3.5wt%.

7. The selective hydrotreating catalyst for cracked gasoline fractions as described in claim 1, characterized in that, The Cu content is 1.0wt% to 2.5wt%.

8. A method for preparing a selective hydrogenation catalyst for cracked gasoline fractions according to any one of claims 1-7, characterized in that, Pd, Ce, Pt and W were all loaded using the solution method. Ce and Pt were loaded simultaneously, and the solution loading of Ce-Pt and W was after the solution loading of Pd. The preparation process of Ni-Cu microemulsion includes the following steps: dissolving Ni precursor salt and Cu precursor salt in water to obtain an aqueous phase; then mixing the aqueous phase with an oil phase, a surfactant, and a co-surfactant to form a Ni-Cu microemulsion; wherein the mass ratio of the aqueous phase to the oil phase is 2-3, the mass ratio of the surfactant to the oil phase is 0.15-0.6, and the mass ratio of the surfactant to the co-surfactant is 1.0-1.

2.

9. The preparation method according to claim 8, characterized in that, After loading Pd by solution method, Ce-Pt and W were loaded by solution method in sequence.

10. The preparation method according to claim 8, characterized in that, After loading Pd by solution method, W and Ce-Pt were loaded by solution method in sequence.

11. The preparation method according to claim 8, characterized in that, Ni-Cu was loaded via microemulsion before Pd was loaded via solution method.

12. The preparation method according to claim 8, characterized in that, The oil phase is a C6-C8 saturated alkane or cycloalkane; The surfactant is an ionic surfactant and / or a nonionic surfactant; the co-surfactant is an organic alcohol.

13. The preparation method according to claim 8, characterized in that, Includes the following steps: Pd loading: The precursor salt of Pd is dissolved in water, the pH is adjusted to 2.0-2.5, and then the carrier is added for impregnation and adsorption. After drying and calcination, the first semi-finished catalyst is obtained. Loading W: Dissolve the precursor salt of W in deionized water to obtain a W-containing solution, then add the first semi-finished catalyst for saturated impregnation, dry, and calcine to obtain the second semi-finished catalyst. Ce-Pt loading: Ce precursor salt and Pt precursor compound are dissolved in deionized water to obtain Ce and Pt solution. The pH is adjusted to 2-2.5, and then the second semi-finished catalyst is added for saturated impregnation, dried and calcined to obtain the third semi-finished catalyst. Ni-Cu loading: The third semi-finished catalyst is added to the Ni-Cu microemulsion for impregnation, the residual liquid is filtered off, and then dried and calcined.

14. The preparation method according to claim 8, characterized in that, Includes the following steps: Ni-Cu supported: The support is added to the Ni-Cu microemulsion for impregnation, the residue is filtered off, and the mixture is dried and calcined to obtain the fourth semi-finished catalyst. Pd loading: The precursor salt of Pd is dissolved in water, the pH is adjusted to 2.0-2.5, and then the fourth semi-finished catalyst is added for impregnation and adsorption. After drying and calcination, the fifth semi-finished catalyst is obtained. Ce-Pt loading: Ce precursor salt and Pt precursor compound are dissolved in deionized water to obtain Ce and Pt solution. The pH is adjusted to 2-2.5, and then the fifth semi-finished catalyst is added for saturated impregnation, dried and calcined to obtain the sixth semi-finished catalyst. Loading W: Dissolve the precursor salt of W in deionized water to obtain a W-containing solution, then add the sixth semi-finished catalyst for saturated impregnation, drying, and calcination.

15. The preparation method according to claim 8, characterized in that, Includes the following steps: Ni-Cu supported: The support is added to the Ni-Cu microemulsion for impregnation, the residual liquid is filtered off, and the mixture is dried and calcined to obtain the fourth semi-finished catalyst. Pd loading: The precursor salt of Pd is dissolved in water, the pH is adjusted to 2.0-2.5, and then the fourth semi-finished catalyst is added for impregnation and adsorption. After drying and calcination, the fifth semi-finished catalyst is obtained. Loading W: Dissolve the precursor salt of W in deionized water to obtain a W-containing solution, then add the fifth semi-finished catalyst for saturated impregnation, dry, and calcine to obtain the seventh semi-finished catalyst; Ce-Pt loading: Ce precursor salt and Pt precursor compound are dissolved in deionized water to obtain Ce and Pt solution. The pH is adjusted to 2-2.5, and then the seventh semi-finished catalyst is added for saturated impregnation, drying, and calcination.

16. The preparation method according to claim 8, characterized in that, Includes the following steps: Pd loading: The precursor salt of Pd is dissolved in water, the pH is adjusted to 2.0-2.5, and then the carrier is added for impregnation and adsorption. After drying and calcination, the first semi-finished catalyst is obtained. Ce-Pt loading: Ce precursor salt and Pt precursor compound are dissolved in deionized water to obtain Ce and Pt solution. The pH is adjusted to 2-2.5, and then the first semi-finished catalyst is added for saturated impregnation, dried and calcined to obtain the eighth semi-finished catalyst. Ni-Cu supported catalyst: The eighth semi-finished catalyst is added to the Ni-Cu microemulsion for impregnation, the residue is filtered off, dried and calcined to obtain the ninth semi-finished catalyst; Loading W: Dissolve the precursor salt of W in deionized water to obtain a W-containing solution, then add the ninth semi-finished catalyst for saturated impregnation, drying, and calcination.

17. The preparation method according to claim 12, characterized in that, The oil phase is cyclohexane or n-hexane.

18. The preparation method according to claim 12, characterized in that, The surfactant is a nonionic surfactant.

19. The preparation method according to claim 18, characterized in that, The nonionic surfactant is polyethylene glycol octylphenyl ether or hexadecyltrimethylammonium bromide.

20. The preparation method according to claim 12, characterized in that, The co-surfactant is a C4-C6 organic alcohol.

21. The preparation method according to claim 20, characterized in that, The co-surfactant is n-butanol and / or n-pentanol.

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