Hydrogenation catalyst as well as preparation method and application thereof

Abstract

The invention discloses a hydrogenation catalyst, which comprises an alumina-zirconia composite carrier, and a main active metal and an auxiliary active metal loaded on the composite carrier, the main active metal comprises at least one of nickel or cobalt, and the content of the main active metal is 30-60 wt% in terms of metal element and in terms of the total weight of the catalyst; the auxiliary active metal is at least one of molybdenum or tungsten, and the content of the auxiliary active metal is 1-10wt% in terms of metal elements and on the basis of the total weight of the catalyst; the content of the aluminum oxide-zirconium oxide composite carrier is 30-70wt% based on the total weight of the catalyst in terms of oxide; the total acid amount of the catalyst is detected to be 0.2-0.8 mmol / g through NH3-TPD, and more than 80% of the total acid amount is strong acid. The invention further discloses a preparation method and application of the hydrogenation catalyst. The hydrogenation catalyst has high acid strength and acid density, more strong acids can promote unsaturated bonds of raw materials to form carbocations at low temperature, and the low-temperature hydrogenation performance of the catalyst can be better improved.

Description

Technical Field

[0001] The present invention relates to a hydrogenation catalyst, a preparation method of the hydrogenation catalyst, and an application of the hydrogenation catalyst. Background Art

[0002] Heavy alkylbenzene is a by-product in the process of synthesizing alkylbenzene. It contains various components such as monoalkylbenzene, dialkylbenzene, diphenylalkane, polyalkylbenzene, polybenzane, etc. Therefore, it has good low-temperature fluidity, strong anti-wear performance, and good additive induction performance, and is an ideal component of lubricating oil. At present, it has been widely used in many fields such as electrical oil, turbine oil, refrigeration oil, low-temperature lubricating oil, spindle oil, internal combustion engine lubricating oil, compressor lubricating oil, etc. The heavy alkylbenzene sulfonate prepared by sulfonating and neutralizing heavy alkylbenzene is also widely used in lubricating oil additives, corrosion inhibitors, foaming agents, emulsifiers, and oil displacement agents in tertiary oil recovery. However, due to the relatively high content of unsaturated hydrocarbons such as polyolefins, indene, and naphthalene in heavy alkylbenzene, and the presence of trace amounts of peroxyacids, the product has a relatively dark color and unstable product performance, which is restricted to a certain extent in application and needs to be refined.

[0003] At present, the main methods for refining heavy alkylbenzene are adsorption refining (activated clay, activated carbon, diatomite, etc.) and hydrogenation refining. Adsorption refining can improve the color of heavy alkylbenzene, but it cannot completely remove unstable components, and the refining effect is not good, and the loss is also large. At present, the main methods for hydrogenation refining of heavy alkylbenzene are autoclave hydrogenation with Raney Ni catalyst and fixed-bed hydrogenation refining with Pd / Al2O3 as the catalyst. Autoclave hydrogenation has cumbersome operation and high cost. The preparation and use of Raney Ni catalyst are more troublesome, and it will spontaneously ignite when exposed to air, with a relatively high risk. The Pd / Al2O3 catalyst is a noble metal catalyst with high cost. In addition, due to its high active temperature, it only has ideal activity at 160°C, which causes partial aromatic hydrocarbon hydrogenation saturation and certain influence on selectivity.

[0004] The fixed-bed continuous hydrogenation process is simple to operate and is the most ideal hydrogenation refining process for heavy alkylbenzene hydrogenation refining. The hydrogenation catalyst applied to the heavy alkylbenzene hydrogenation refining process needs to have a certain number of macropores to facilitate the entry of heavy alkylbenzene into the interior of the catalyst. At the same time, the heavy alkylbenzene hydrogenation catalyst is also required to have high low-temperature hydrogenation activity to avoid the saturation of the benzene ring of heavy alkylbenzene in the high-temperature refining reaction. Therefore, it is required that the content of strong acid on the carrier is relatively high, and the content of active metal is relatively high, such as more than 20%. At present, the main synthesis methods of macroporous alumina carriers on the market include hydrothermal synthesis method, pore-expanding agent method, template method, sol-gel method, etc., and macroporous alumina carriers with high specific surface area, high pore volume, average pore diameter reaching 15 - 80 nm, and even the macropore (pore diameter > 50 nm) distribution can reach 10 - 20% of the total pore volume can also be produced. However, this part of the carriers generally has medium-strength acid as the main component, and the content of strong acid is relatively low. At the same time, a large amount of active metal needs to be loaded on the carrier to have hydrogenation activity, and the main methods for loading the active metal include precipitation method and impregnation method. For the preparation of the catalyst, the size of the metal grains produced by the precipitation method varies according to the precipitation process, but the average particle size is mostly between 15 - 40 nm; similarly, the size of the metal grains of the impregnation method also varies according to the process, but the average particle size mostly concentrates between 5 - 30 nm. When using the above-mentioned macroporous alumina carrier to prepare the hydrogenation catalyst, during the catalyst preparation process, a large number of metal grains will enter the pores, inevitably blocking the small pores of the carrier, turning the macropores into mesopores or even small pores, affecting the diffusion of the raw materials, resulting in a decrease in the reaction efficiency of the catalyst, and also increasing the carbon deposition rate of the catalyst and shortening the catalyst life.

[0005] Therefore, developing a hydrogenation catalyst with excellent low-temperature hydrogenation performance is a major difficulty in the heavy alkylbenzene refining process. Summary of the Invention

[0006] In order to obtain a hydrogenation catalyst with excellent low-temperature hydrogenation performance and improve the hydrogenation refining performance of heavy alkylbenzene, this application first proposes a hydrogenation catalyst, which includes an alumina-zirconia composite carrier and a main active metal and an auxiliary active metal supported on the composite carrier. The main active metal includes at least one of nickel or cobalt. Calculated as a metal element and based on the total weight of the hydrogenation catalyst, the content of the main active metal is 30 - 60 wt%; the auxiliary active metal is at least one of molybdenum or tungsten. Calculated as a metal element and based on the total weight of the hydrogenation catalyst, the content of the auxiliary active metal is 1 - 10 wt%; calculated as an oxide and based on the total weight of the hydrogenation catalyst, the content of the alumina-zirconia composite carrier is 30 - 70 wt%.

[0007] The total acid amount of the hydrogenation catalyst detected by NH3-TPD is 0.2 - 0.8 mmol / g, more preferably 0.2 - 0.5 mmol / g. More than 80% of the total acid amount is strong acid, and the total acid amount is further preferably more than 85%, and more preferably more than 90% is strong acid. In this application, the alumina-zirconia composite support is simply referred to as the composite support.

[0008] The hydrogenation catalyst of the application has a high acid strength and acid density. More strong acids can promote the formation of carbocations from the unsaturated bonds of the raw materials at low temperature, which is more conducive to improving the low-temperature hydrogenation performance of the hydrogenation catalyst.

[0009] The hydrogenation catalyst in this application has the following advantages:

[0010] (1) This hydrogenation catalyst has a high acid amount, more strong acid centers, a high specific surface area and small metal crystallites. These characteristics make the hydrogenation catalyst of this application have excellent low-temperature hydrogenation reaction activity;

[0011] (2) This hydrogenation catalyst has a large total pore volume and more large-pore channels, making this hydrogenation catalyst particularly suitable for the hydrogenation of macromolecular compounds such as heavy alkylbenzene;

[0012] (3) This hydrogenation catalyst has excellent low-temperature activity, enabling the hydrogenation reaction to occur at a lower temperature. It can not only hydrogenate and saturate unsaturated bonds such as double bonds, but also avoid the hydrogenation saturation of the benzene ring (the hydrogenation of the benzene ring requires a higher temperature), and avoid the ring opening of the benzene ring;

[0013] (4) Using the hydrogenation catalyst of this application for the hydrorefining of heavy alkylbenzene can hydrogenate and saturate the chromophore groups containing unsaturated bonds in the heavy alkylbenzene, greatly reducing the chromaticity of the hydrogenated product to less than 0.5, or even less than 0.1, and at the same time having excellent oxidation stability; in addition, since the benzene ring in the hydrogenated product is not hydrogenated, the hydrogenated product has excellent viscosity, ultra-low freezing point and other advantages, and is particularly suitable for use as lubricating oil base oil, refrigeration oil and other uses.

[0014] Furthermore, to facilitate the diffusion of the raw materials in the pores, increase the contact opportunity between the raw materials and the hydrogenation catalyst, improve the catalytic efficiency, and at the same time facilitate the fast inlet and outlet of the raw materials and products, reducing the carbon deposition rate. The total pore volume of this hydrogenation catalyst is 0.25 - 0.50 cm 3 / g, more preferably 0.25 - 0.35 cm 3 / g. The proportion of the pore volume with a pore diameter greater than 50 nm in the total pore volume is 10 - 40%, more preferably 10 - 20%.

[0015] Specifically, the mass ratio of zirconia to alumina in the composite support is 1:9 - 1:1, preferably 1:9 - 1:4.

[0016] Specifically, to ensure the proportion of pores in the hydrogenation catalyst, it further has at least one of the following characteristics:

[0017] The porosity of the hydrogenation catalyst is 40 - 60%, preferably 45 - 55%;

[0018] The specific surface area of the hydrogenation catalyst is 80 - 200 m 2 / g, preferably 100 - 150 m 2 / g.

[0019] Secondly, the present application also discloses a preparation method of any one of the above hydrogenation catalysts, which includes the following steps:

[0020] (1) Add an alumina precursor to an aqueous zirconium salt solution for hydrothermal reaction to obtain a carrier slurry;

[0021] (2) Add an aqueous solution of the precursors of the main active metal and the auxiliary active metal to the carrier slurry, and then add an aqueous solution of a precipitant to the carrier slurry for precipitation reaction to obtain a precipitate;

[0022] (3) After calcining and tableting the precipitate, an oxidized catalyst is obtained, and then a reduction reaction is carried out on the oxidized catalyst in the presence of hydrogen to obtain a hydrogenation catalyst.

[0023] In step (2), it is preferably to wash the filtered precipitate and dry it at 100 - 120 °C for 2 - 15 h to reduce the impurities contained in the precipitate.

[0024] In the preparation method of this hydrogenation catalyst, step (1) can achieve the modification and pore expansion of the composite carrier, so that the pore volume of the macropores (pore diameter > 50 nm) in the composite carrier reaches 30 - 40% of the total pore volume, and the pore volume of the macropores (pore diameter > 50 nm) of the finally prepared hydrogenation catalyst can also reach more than 10% of the total pore volume, which is beneficial to the diffusion of raw materials in the pores, increases the contact opportunity between the raw materials and the hydrogenation catalyst, improves the catalytic efficiency, and at the same time is beneficial to the fast inlet and outlet of raw materials and products, reducing the carbon deposition rate.

[0025] Specifically, in step (1), the zirconium salt in the aqueous zirconium salt solution can undergo hydrolysis to generate a certain acidity, and an exemplary hydrolysis equation is as follows:

[0026] ZrOCl2 + H2O → ZrOOH + +H + +2Cl - , or

[0027]

[0028] Zirconium salt aqueous solutions with a certain acidity can erode the surface of alumina and the surface of alumina pores. Under hydrothermal reaction conditions, H + is more likely to enter the pores and erode the pore surface, causing more macropores to form in the alumina. The reaction equation is as follows:

[0029] Al2O3 + 6H + → 2Al 3+ + 3H2O.

[0030] Meanwhile, in the preparation method of this application, through steps (2) and (3), the hydrolyzed zirconium salt forms zirconia after precipitation and calcination, constituting a special composite support with alumina, improving the acid density (increasing the acid amount) of the composite support and improving the acid structure (increasing the proportion of strong acids).

[0031] Currently, the preparation methods of ZrO2-Al2O3 composite supports mainly include three categories: impregnation precipitation method, alkoxide sol-gel method, and co-precipitation method, each with its own advantages and disadvantages. Among them, the specific surface area, total pore volume, and pore diameter of the support prepared by the impregnation precipitation method depend on the original structural properties of alumina and decrease with the increase of zirconia loading. However, it is difficult for zirconia and alumina to intermix into the lattice with each other. Nevertheless, the interaction between zirconia and alumina is relatively stronger, promoting the formation of Zr-O-Al bonds and increasing the acid strength of the support, while the acid density is between that of zirconia and alumina; the grains of the support prepared by the co-precipitation method are relatively large, the specific surface area is relatively small, and part of zirconia and alumina intermix into the lattice and a solid solution is formed, making the acid density higher than that of both zirconia and alumina.

[0032] In the preparation method of this application, since the zirconium salt aqueous solution erodes and dissolves part of the alumina under hydrothermal reaction conditions, when adding a precipitant for precipitation, it simultaneously has the characteristics of both the impregnation precipitation method and the co-precipitation method, making the alumina-zirconia composite support obtained by the method of this application have a relatively high specific surface area, total pore volume, and macropore volume, and greatly improving the acid strength and acid density. More strong acids can promote the formation of carbocations from the unsaturated bonds of the raw materials at low temperatures, which is more conducive to the low-temperature hydrogenation performance of the hydrogenation catalyst. Through the preparation method of this application, the total acid amount of the hydrogenation catalyst can be increased by 3 - 6 times, the strong acid amount can be increased by 10 - 18 times, and the proportion of the strong acid amount in the total acid amount is more than 80%.

[0033] In addition, in step (2) of this preparation method, the introduction of the main active metal is carried out simultaneously with the precipitation of the zirconia and alumina composite support, so that the precipitation of the active metal also has the characteristics of both the impregnation precipitation method and the coprecipitation method. This makes the precipitated metal grains smaller, with a higher specific surface area, a stronger interaction between the active metal grains and the support, and the co-precipitated alumina and zirconia grains can separate them, enabling the hydrogenation catalyst to avoid the aggregation of active metal grains to the greatest extent during high-temperature calcination and reducing the loss of specific surface area.

[0034] Specifically, step (1) includes the following sub-steps:

[0035] (1.1) Add soluble zirconium salt to water and stir at 50 - 90 °C for 5 - 24 hours to obtain a zirconium salt aqueous solution with a concentration of 0.1 - 5 mol / L;

[0036] (1.2) Add the alumina precursor to the zirconium salt aqueous solution, stir evenly, and then carry out a hydrothermal reaction at 100 - 200 °C, preferably 120 - 180 °C, for 2 - 50 hours, preferably 5 - 30 hours, to obtain a support slurry.

[0037] Specifically, the alumina precursor is selected from boehmite, pseudoboehmite, macroporous alumina, or a combination thereof, preferably macroporous alumina; the zirconium salt is selected from zirconium oxychloride, zirconium oxynitrate, or a combination thereof.

[0038] Adopting the above process can effectively modify and expand the pores of the support, making the alumina form richer macropores.

[0039] Specifically, in step (2), based on the main active metal salt, the concentration of the aqueous solution of the precursor of the main active metal is 5 - 20 wt%; based on the co-active metal salt, the concentration of the aqueous solution of the precursor of the co-active metal is 1 - 20 wt%; the concentration of the precipitant aqueous solution is 5 - 20 wt%;

[0040] While maintaining the temperature of the support slurry at 50 - 80 °C, add the aqueous solution of the precursor of the main active metal to the support slurry, keep stirring, then add the aqueous solution of the precursor of the co-active metal to the support slurry, and then add the precipitant aqueous solution to form a reaction solution for reaction. When the pH value of the reaction solution reaches 7 - 9, stop adding the precipitant aqueous solution, and then keep the temperature and stand for aging for 1 - 5 h;

[0041] The precursor of the main active metal is nitrate, sulfate, hydrochloride, or a combination thereof;

[0042] The precursor of the co-active metal is ammonium heptamolybdate, ammonium tetramolybdate, ammonium tungstate, ammonium metatungstate, or a combination thereof;

[0043] The precipitant is selected from sodium carbonate, ammonium carbonate, sodium hydroxide, ammonia water, or a combination thereof.

[0044] Auxiliary active metals can be introduced through ammonium molybdate, ammonium tungstate solutions, etc., which can react with the salts of the main active metals added to the carrier slurry to form insoluble salts such as nickel molybdate, ammonium nickel molybdate, nickel tungstate or cobalt molybdate, ammonium cobalt molybdate, cobalt tungstate, etc., and precipitate on the composite carrier; the formation of these insoluble salts can compete with alumina for nickel and cobalt metals during high-temperature calcination, to a certain extent inhibiting the formation of spinel by nickel and cobalt metals with aluminum, making the metal grains highly dispersed and relatively enhancing the activity of the hydrogenation catalyst.

[0045] Specifically, to successfully complete the calcination of the precipitate and the reduction of the obtained oxidized catalyst, in step (3), when calcining the precipitate, the calcination temperature is 400 - 700 °C, and the calcination time is 2 - 6 h; when performing the reduction reaction on the green body, the reaction temperature is 450 - 500 °C, the reaction pressure is 0.5 - 2.0 Mpa, the reaction time is 15 - 20 h, and the hydrogen / solid volume ratio is (300 - 500):1.

[0046] Furthermore, the present application also discloses the use of any of the above hydrogenation catalysts in the hydrorefining of heavy alkylbenzene, and the heavy alkylbenzene is benzene substituted with C 10 -C 38 alkyl groups and contains unsaturated hydrocarbons. The unsaturated hydrocarbons include polyolefins, indene, naphthalene, or a combination thereof.

[0047] Specifically, during the hydrorefining of heavy alkylbenzene, the reaction temperature is 80 - 120 °C; the reaction pressure is 0.5 - 4 Mpa, preferably 1 - 2 Mpa; the weight hourly space velocity of the raw material is 0.1 - 1 h -1 , preferably 0.3 - 0.5 h -1 ; the hydrogen / liquid volume ratio is 100 - 500 Nm 3 / m 3 , preferably 200 - 300 Nm 3 / m 3 .

[0048] In some specific embodiments, the hydrorefining method of heavy alkylbenzene in the present application adopts a continuous hydrogenation process in a fixed-bed reactor. In this hydrorefining, due to the excellent low-temperature activity of the hydrogenation catalyst, the hydrogenation reaction can occur at a lower temperature, which can not only hydrogenate and saturate unsaturated bonds such as double bonds, but also avoid the hydrogenation saturation of the benzene ring (hydrogenation of the benzene ring requires a higher temperature), and avoid the ring opening of the benzene ring.

[0049] During the hydrorefining process, the chromophoric groups containing unsaturated bonds in heavy alkylbenzene are hydrogenated and saturated, greatly reducing the chromaticity of the hydrogenated product to less than 0.5, or even less than 0.1, while having excellent oxidation stability. In addition, since the benzene rings in the hydrogenated product are not hydrogenated, the hydrogenated product has excellent viscosity, ultra-low freezing point and other advantages, and is particularly suitable for use as lubricating oil base oil, refrigeration oil and other applications.

[0050] This heavy alkylbenzene hydrorefining process can adopt low-temperature hydrogenation and fixed-bed continuous hydrogenation processes, with mild reaction conditions, short process flow, low investment, simple operation, no pollution generated during the reaction process, and high product yield. Brief Description of the Drawings

[0051] Figure 1 It is a flow chart of the heavy alkylbenzene hydrorefining process of this application.

[0052] Figure 2 It is a pore size distribution diagram of the macroporous alumina raw material used in the examples.

[0053] Figure 3 It is an NH3-TPD spectrum diagram of the macroporous alumina raw material used in the examples.

[0054] Figure 4 It is a pore size distribution diagram of the modified alumina support obtained in the examples.

[0055] Figure 5 It is an NH3-TPD spectrum diagram of the modified alumina support obtained in the examples.

[0056] Figure 6 It is a pore size distribution diagram of the hydrogenation catalyst obtained in Example 1.

[0057] Figure 7 It is an NH3-TPD spectrum diagram of the hydrogenation catalyst obtained in Example 1.

[0058] Figure 8 It is a pore size distribution diagram of the hydrogenation catalyst obtained in Comparative Example 1.

[0059] Figure 9 It is an NH3-TPD spectrum diagram of the hydrogenation catalyst obtained in Comparative Example 1. Detailed Embodiments

[0060] The raw materials used in the following examples and comparative examples are all commercially available raw materials, and the specific properties of the main raw materials are as follows:

[0061] Macroporous alumina, industrial grade, the characterization data is shown in Table 1, the pore size distribution diagram is shown in Figure 2 and the NH3-TPD diagram is shown in Figure 3; Zirconium oxychloride, industrial grade; nickel nitrate hexahydrate, nickel chloride hexahydrate, sulfuric acid hexahydrate, cobalt nitrate hexahydrate, ammonium metatungstate, ammonium heptamolybdate, sodium carbonate, analytical pure; heavy alkylbenzene, industrial grade; hydrogen, industrial grade.

[0062] The analytical methods used in the following examples and comparative examples are as follows:

[0063] The specific surface area, total pore volume, macropore volume, and porosity of the support and hydrogenation catalyst were analyzed by mercury intrusion method;

[0064] The acid amount and acid distribution of the support and hydrogenation catalyst were analyzed by NH3-TPD method. The total acid amount of the hydrogenation catalyst or support was calculated as the total molar amount of the NH3 desorption peaks measured at a temperature of 100°C - 800°C, and the strong acid amount was calculated as the molar amount of the NH3 desorption peaks measured at a temperature above 450°C;

[0065] The bromine index of the heavy alkylbenzene raw material and product was analyzed by microcoulometry;

[0066] The aromatics in the heavy alkylbenzene raw material and product were analyzed by liquid chromatography; and

[0067] The chromaticity of the heavy alkylbenzene raw material and product was analyzed by GB / T 6540 Method for the Determination of Color of Petroleum Products.

[0068] Preparation of modified alumina support:

[0069] Dissolve zirconium oxychloride in water to prepare a zirconium oxychloride solution with a concentration of 1 mol / L, stir at 60°C for 12 hours to obtain a zirconium salt aqueous solution; take macroporous alumina according to the weight ratio of alumina to zirconia of 9:1, add it to the zirconium salt aqueous solution, stir evenly, transfer it to a high-pressure reaction kettle with a polytetrafluoroethylene inner lining, carry out hydrothermal reaction at 150°C for 18 hours, take it out after cooling to prepare a support slurry.

[0070] Dissolve sodium carbonate in water to prepare an aqueous solution with a concentration of 15 wt%, slowly drop it into the support slurry, carry out precipitation reaction at 50°C, when the pH value of the reaction solution reaches 8, the precipitation ends, then let it stand and age for 4 h to obtain a suspension; filter and wash the suspension, dry it at 110°C for 8 h, and calcine it at 500°C for 4 h to obtain a modified alumina support, and this modified alumina support is the alumina-zirconia composite support.

[0071] The characterization data of the modified alumina support are shown in Table 1, and the pore size distribution diagram is shown in Figure 4 and the NH3-TPD diagram is shown in Figure 5 .

[0072] Example 1

[0073] Dissolve zirconium oxychloride in water to prepare a zirconium oxychloride solution with a concentration of 1 mol / L, stir at 60 °C for 12 hours to obtain an aqueous zirconium salt solution; take macroporous alumina according to the weight ratio of alumina to zirconia of 9:1, add it to the aqueous zirconium salt solution, stir evenly, transfer it to a high-pressure reactor with a polytetrafluoroethylene lining, carry out hydrothermal reaction at 150 °C for 18 hours, take it out after cooling to prepare a carrier slurry.

[0074] Adjust the temperature of the carrier slurry to 50 °C and keep it. According to 50 wt% of nickel metal in the total weight of the hydrogenation catalyst, dissolve nickel nitrate hexahydrate in water to prepare a nickel nitrate solution with a concentration of 20 wt%, and add the nickel nitrate solution to the carrier slurry; according to 5 wt% of molybdenum metal in the total weight of the hydrogenation catalyst, dissolve ammonium heptamolybdate in water to prepare an ammonium heptamolybdate solution with a concentration of 5 wt%, and drop it into the carrier slurry.

[0075] Keep the temperature of the carrier slurry, slowly drop the aqueous sodium carbonate solution with a concentration of 15 wt% into the carrier slurry to form a reaction solution, carry out precipitation reaction at 50 °C, when the pH value of the reaction solution reaches 8, the precipitation ends, keep the temperature of the reaction solution, and carry out static aging for 4 h to obtain a suspension.

[0076] Filter and wash the suspension, dry it at 110 °C for 8 h, then calcine it at 500 °C for 4 h, and press it into tablets to obtain an oxidized catalyst; the oxidized catalyst is reduced at 480 °C, hydrogen pressure of 0.5 Mpa, and hydrogen-to-solid volume ratio of 500:1 for 18 h to obtain the hydrogenation catalyst EC-1.

[0077] The hydrogenation catalyst EC-1 contains 50 wt% nickel, 5 wt% molybdenum, 40.5 wt% alumina, and 4.5 wt% zirconia.

[0078] The characterization data of the hydrogenation catalyst EC-1 are shown in Table 1, and the pore size distribution diagram is shown in Figure 6 , and the NH3-TPD diagram is shown in Figure 7 .

[0079] Comparative Example 1

[0080] According to 50 wt% of nickel metal in the total weight of the hydrogenation catalyst, dissolve nickel nitrate hexahydrate in water to prepare a nickel nitrate solution with a concentration of 20 wt%. According to 45 wt% of alumina in the total weight of the hydrogenation catalyst, take macroporous alumina and add it to the nickel nitrate solution to prepare a slurry.

[0081] Adjust the temperature of the slurry to 50 °C and keep it. According to 5 wt% of molybdenum metal in the total weight of the hydrogenation catalyst, dissolve ammonium heptamolybdate in water to prepare an ammonium heptamolybdate solution with a concentration of 5 wt%, and drop it into the slurry.

[0082] Maintain the temperature of the slurry, slowly drop an aqueous sodium carbonate solution with a concentration of 15 wt% into the slurry, carry out a precipitation reaction at 50 °C, and when the pH value of the reaction solution reaches 8, the precipitation ends. Maintain the temperature of the reaction solution and carry out static aging for 4 h to obtain a suspension.

[0083] Filter and wash the suspension, dry it at 110 °C for 8 h, then calcine it at 500 °C for 4 h, and press it into tablets to obtain an oxidized catalyst; the oxidized catalyst is reduced at a temperature of 480 °C, a hydrogen pressure of 0.5 Mpa, and a hydrogen-to-solid volume ratio of 500:1 for 18 h to obtain a comparative hydrogenation catalyst PC-1.

[0084] The comparative hydrogenation catalyst PC-1 contains 50 wt% nickel, 5 wt% molybdenum, and 45 wt% alumina.

[0085] The characterization data of the comparative hydrogenation catalyst PC-1 are shown in Table 1, and the pore size distribution diagram is shown in Figure 8 , and the NH3-TPD diagram is shown in Figure 9 .

[0086] Example 2

[0087] Dissolve zirconium oxychloride in water to make a zirconium oxychloride solution with a concentration of 3 mol / L, stir it at 50 °C for 24 hours to obtain an aqueous zirconium salt solution; take macroporous alumina according to the weight ratio of alumina to zirconia of 5:1, add it to the aqueous zirconium salt solution, stir evenly, transfer it to a high-pressure reaction kettle with a polytetrafluoroethylene inner lining, and carry out a hydrothermal reaction at 180 °C for 6 hours. After cooling, take it out to make a support slurry.

[0088] Adjust the temperature of the support slurry to 80 °C and maintain it. According to the total weight of the hydrogenation catalyst, take nickel chloride hexahydrate and dissolve it in water to make a nickel chloride solution with a concentration of 10 wt%. Add the nickel chloride solution to the support slurry. According to the total weight of the hydrogenation catalyst, take ammonium heptamolybdate and dissolve it in water to make an ammonium heptamolybdate solution with a concentration of 10 wt%, and drop it into the support slurry.

[0089] Maintain the temperature of the support slurry, slowly drop an aqueous ammonium carbonate solution with a concentration of 20 wt% into the support slurry to form a reaction solution, carry out a precipitation reaction at 80 °C, and when the pH value of the reaction solution reaches 7, the precipitation ends, and then carry out static aging for 3 h to obtain a suspension.

[0090] Filter and wash the suspension, dry it at 115 °C for 2 h, then calcine it at 400 °C for 6 h, and press it into tablets to obtain an oxidized catalyst; the oxidized catalyst is reduced at a temperature of 450 °C, a hydrogen pressure of 2 Mpa, and a hydrogen-to-solid volume ratio of 300:1 for 15 h to obtain a hydrogenation catalyst EC-2.

[0091] The hydrogenation catalyst EC-2 contains 30 wt% nickel, 10 wt% molybdenum, 50 wt% alumina, and 10 wt% zirconia.

[0092] The characterization data of the hydrogenation catalyst EC-2 are shown in Table 1.

[0093] Example 3

[0094] Zirconium oxychloride was dissolved in water to prepare a zirconium oxychloride solution with a concentration of 2 mol / L, and stirred at 90 °C for 6 hours to obtain an aqueous zirconium salt solution; macroporous alumina was taken according to the weight ratio of alumina to zirconia of 5.33:1, added to the aqueous zirconium salt solution, stirred evenly, transferred to a high-pressure reactor with a polytetrafluoroethylene lining, and hydrothermally reacted at 120 °C for 30 hours. After cooling, it was taken out to prepare a carrier slurry.

[0095] The temperature of the carrier slurry was adjusted to 70 °C and maintained. According to 60 wt% of the total weight of the hydrogenation catalyst for cobalt metal, cobalt nitrate hexahydrate was dissolved in water to prepare a cobalt nitrate solution with a concentration of 16 wt%, and the cobalt nitrate solution was added to the carrier slurry. According to 2 wt% of the total weight of the hydrogenation catalyst for molybdenum metal, ammonium heptamolybdate was dissolved in water to prepare a 20 wt% ammonium heptamolybdate solution, and it was dropped into the carrier slurry.

[0096] Maintaining the temperature of the carrier slurry, an aqueous sodium carbonate solution with a concentration of 5 wt% was slowly dropped into the carrier slurry to form a reaction solution, and a precipitation reaction was carried out at 70 °C. When the pH value of the reaction solution reached 9, the precipitation ended, and then it was left standing for aging for 5 h to obtain a suspension.

[0097] The suspension was filtered, washed, dried at 120 °C for 2 h, then calcined at 700 °C for 2 h, and tableted to obtain an oxidized catalyst; the oxidized catalyst was reduced at a temperature of 500 °C, a hydrogen pressure of 0.5 Mpa, and a hydrogen-to-solid volume ratio of 450:1 for 20 h to obtain the hydrogenation catalyst EC-3.

[0098] The hydrogenation catalyst EC-3 contains 60 wt% cobalt, 2 wt% molybdenum, 32 wt% alumina, and 6 wt% zirconia.

[0099] The characterization data of the hydrogenation catalyst EC-3 are shown in Table 1.

[0100] Example 4

[0101] Zirconium oxychloride was dissolved in water to prepare a zirconium oxychloride solution with a concentration of 0.5 mol / L, and stirred at 70 °C for 15 hours to obtain an aqueous zirconium salt solution; macroporous alumina was taken according to the weight ratio of alumina to zirconia of 4:1, added to the aqueous zirconium salt solution, stirred evenly, transferred to a high-pressure reactor with a polytetrafluoroethylene lining, and hydrothermally reacted at 170 °C for 15 hours. After cooling, it was taken out to prepare a carrier slurry.

[0102] Adjust the temperature of the carrier slurry to 60 °C and maintain it. Calculate based on cobalt metal accounting for 40 wt% of the total weight of the hydrogenation catalyst. Dissolve cobalt nitrate hexahydrate in water to prepare a cobalt nitrate solution with a concentration of 5 wt%. Add the cobalt nitrate solution to the carrier slurry. Calculate based on tungsten metal accounting for 8 wt% of the total weight of the hydrogenation catalyst. Dissolve ammonium metatungstate in water to prepare an ammonium metatungstate solution with a concentration of 1 wt%, and drop it into the carrier slurry.

[0103] Maintain the temperature of the carrier slurry. Slowly drop an aqueous ammonium carbonate solution with a concentration of 10 wt% into the carrier slurry to form a reaction solution. Conduct a precipitation reaction at 60 °C. When the pH value of the reaction solution reaches 7.5, the precipitation ends, and then let it stand and age for 2 h to obtain a suspension.

[0104] Filter and wash the suspension, dry it at 100 °C for 15 h, then calcine it at 600 °C for 4 h, and press it into shape to obtain an oxidized catalyst; the oxidized catalyst is reduced at a temperature of 460 °C, a hydrogen pressure of 1 Mpa, and a hydrogen-to-solid volume ratio of 400:1 for 17 h to obtain the hydrogenation catalyst EC-4.

[0105] The hydrogenation catalyst EC-4 contains 40 wt% cobalt, 8 wt% tungsten, 41.6 wt% alumina, and 10.4 wt% zirconia.

[0106] The characterization data of the hydrogenation catalyst EC-4 are shown in Table 1.

[0107] Example 5

[0108] Dissolve zirconium oxychloride in water to prepare a zirconium oxychloride solution with a concentration of 4 mol / L. Stir at 80 °C for 16 hours to obtain an aqueous zirconium salt solution; take macroporous alumina according to the weight ratio of alumina to zirconia of 5.75:1, add it to the aqueous zirconium salt solution, stir evenly, transfer it to a high-pressure reaction kettle with a polytetrafluoroethylene lining, conduct a hydrothermal reaction at 140 °C for 13 hours, take it out after cooling, and prepare a carrier slurry.

[0109] Adjust the temperature of the carrier slurry to 65 °C and maintain it. Calculate based on nickel metal accounting for 45 wt% of the total weight of the hydrogenation catalyst. Dissolve nickel sulfate hexahydrate in water to prepare a nickel sulfate solution with a concentration of 8 wt%. Add the nickel sulfate solution to the carrier slurry. Calculate based on tungsten metal accounting for 1 wt% of the total weight of the hydrogenation catalyst. Dissolve ammonium metatungstate in water to prepare an ammonium metatungstate solution with a concentration of 15 wt%, and drop it into the carrier slurry.

[0110] Maintain the temperature of the carrier slurry, and slowly drop an aqueous ammonia solution with a concentration of 8 wt% into the carrier slurry to form a reaction solution. Carry out a precipitation reaction at 65 °C. When the pH value of the reaction solution reaches 8.5, the precipitation ends, and then let it stand and age for 1 h to obtain a suspension.

[0111] Filter and wash the suspension, dry it at 105 °C for 10 h, then calcine it at 550 °C for 3 h, and press it into tablets to obtain an oxidized catalyst; the oxidized catalyst is reduced at a temperature of 470 °C, a hydrogen pressure of 1.5 Mpa, and a hydrogen-to-solid volume ratio of 350:1 for 16 h to obtain a hydrogenation catalyst EC-5.

[0112] The hydrogenation catalyst EC-5 contains 45 wt% nickel, 1 wt% tungsten, 46 wt% alumina, and 8 wt% zirconia.

[0113] The characterization data of the hydrogenation catalyst EC-5 are shown in Table 1.

[0114] Table 1 Characterization results of the carrier and the hydrogenation catalyst

[0115]

[0116] It can be seen from Table 1 that compared with the commercially available macroporous alumina raw material, the specific surface area of the modified alumina carrier modified with zirconia has decreased to a certain extent, but its total pore volume and porosity have increased to a certain extent, indicating that the macropores in the modified alumina carrier have increased significantly. The data shows that the increase in the proportion of macropores in the modified alumina carrier is more than 70%, and the total acid amount has been greatly increased.

[0117] The following describes the specific application of the hydrogenation catalyst in this application in the hydrorefining of alkylbenzene.

[0118] In this application, a fixed-bed reactor continuous hydrorefining process is adopted. Please refer to Figure 1 , and the general process of its hydrorefining industry is as follows: The raw material containing heavy alkylbenzene is mixed with hydrogen and then enters the raw material-product heat exchanger for heat exchange, and then is heated to a certain temperature by a reaction heating furnace. Subsequently, it enters the reactor filled with the hydrogenation catalyst of this application. After the hydrogenation reaction, it is heat-exchanged through the raw material-product heat exchanger and then enters the high-pressure separator. Hydrogen exits from the top of the high-pressure separator, is mixed with fresh hydrogen, and then is recycled through a recycle compressor; the liquid product is discharged from the bottom of the high-pressure separator after pressure relief and enters the stripping tower. After stripping with nitrogen, the product exits the unit from the bottom of the stripping tower. The gas phase at the top of the stripping tower enters the condenser, the waste liquid is discharged from the bottom of the condenser, and the non-condensable waste gas is discharged from the top of the condenser for harmless treatment. In the following application examples and application comparative examples, this hydrorefining process is adopted and will not be elaborated.

[0119] Application Example 1

[0120] The hydrogenation catalyst EC-1 obtained in Example 1 was loaded into a fixed bed reactor for heavy alkylbenzene hydrogenation refining reaction. Hydrogen was passed through once, and the feeding method was top-in and bottom-out. The reaction conditions were temperature 90°C, pressure 1.0 MPa, weight space velocity 0.5 h -1 The volume ratio of hydrogen to liquid is 300. The reaction results are shown in Table 2.

[0121] Application Comparative Example 1

[0122] Except that the hydrogenation catalyst used was the comparative hydrogenation catalyst PC-1 obtained in Comparative Example 1, the other conditions were the same as those in Application Example 1. The reaction results are shown in Table 2.

[0123] Application Comparative Example 2

[0124] The hydrogenation catalyst PC-1 obtained in Comparative Example 1 was loaded into a fixed bed reactor for heavy alkylbenzene hydrogenation refining reaction. Hydrogen was passed through once, and the feeding method was top-in and bottom-out. The reaction conditions were temperature 150°C, pressure 1.0 MPa, weight space velocity 0.5 h -1 The volume ratio of hydrogen to liquid is 300. The reaction results are shown in Table 2.

[0125] Application Example 2

[0126] The hydrogenation catalyst EC-2 obtained in Example 2 was loaded into a fixed bed reactor for heavy alkylbenzene hydrogenation refining reaction. Hydrogen was passed through once, and the feeding method was top-in and bottom-out. The reaction conditions were temperature 100°C, pressure 1.0 MPa, weight space velocity 0.3 h -1 The volume ratio of hydrogen to liquid is 300. The reaction results are shown in Table 2.

[0127] Application Example 3

[0128] The hydrogenation catalyst EC-3 obtained in Example 3 was loaded into a fixed bed reactor for heavy alkylbenzene hydrogenation refining reaction. Hydrogen was passed through once, and the feeding method was top-in and bottom-out. The reaction conditions were temperature 100°C, pressure 1.5 MPa, weight space velocity 0.4 h -1 The volume ratio of hydrogen to liquid is 200. The reaction results are shown in Table 2.

[0129] Application Example 4

[0130] The hydrogenation catalyst EC-4 obtained in Example 4 was loaded into a fixed bed reactor for heavy alkylbenzene hydrogenation refining reaction. Hydrogen was passed through once, and the feeding method was top-in and bottom-out. The reaction conditions were temperature 120°C, pressure 2.0 MPa, weight space velocity 0.3 h -1 The volume ratio of hydrogen to liquid is 300. The reaction results are shown in Table 2.

[0131] Application Example 5

[0132] The hydrogenation catalyst EC-5 obtained in Example 5 was loaded into a fixed bed reactor for heavy alkylbenzene hydrogenation refining reaction. Hydrogen was passed through once, and the feeding method was top-in and bottom-out. The reaction conditions were temperature 110°C, pressure 1.0 MPa, weight space velocity 0.5 h -1 The volume ratio of hydrogen to liquid is 300. The reaction results are shown in Table 2.

[0133] Table 2 Reaction results of application examples and comparative examples

[0134]

[0135]

[0136] It can be seen from Table 2 that the hydrogenation catalyst prepared by the present application can complete the refined hydrogenation of alkylbenzene at low temperature, improve the product quality of alkylbenzene, greatly reduce the chromaticity and bromine index of the product, and avoid the loss of aromatics.

Claims

1. A hydrogenation catalyst, characterized in that, It includes an alumina-zirconia composite support and a main active metal and an auxiliary active metal supported on the composite support. The main active metal contains at least one of nickel or cobalt. Calculated as a metal element and based on the total weight of the hydrogenation catalyst, the content of the main active metal is 30-60 wt%. The auxiliary active metal is at least one of molybdenum or tungsten. Calculated as a metal element and based on the total weight of the hydrogenation catalyst, the content of the auxiliary active metal is 1-10 wt%. Calculated as an oxide and based on the total weight of the hydrogenation catalyst, the content of the alumina-zirconia composite support is 30-70 wt%. The total acid amount of the hydrogenation catalyst detected by NH3-TPD is 0.2-0.8 mmol / g, and more than 80% of the total acid amount is strong acid.

2. The hydrogenation catalyst according to claim 1, wherein The total pore volume of the hydrogenation catalyst is 0.25 - 0.50 cm 3 / g, and the proportion of the pore volume with a pore diameter greater than 50 nm in the total pore volume is 10 - 40%.

3. The hydrogenation catalyst according to claim 1, wherein The mass ratio of zirconia to alumina in the composite support is 1:9-1:

1.

4. The hydrogenation catalyst according to claim 1, wherein It also has at least one of the following characteristics: The porosity of the hydrogenation catalyst is 40-60%. The specific surface area of the hydrogenation catalyst is 80 - 200 m 2 / g.

5. The preparation method of the hydrogenation catalyst according to any one of claims 1-4, characterized in that, It includes the following steps: (1) Adding an alumina precursor to an aqueous zirconium salt solution for hydrothermal reaction to obtain a support slurry; (2) Adding an aqueous solution of the precursors of the main active metal and the auxiliary active metal to the support slurry, and then adding an aqueous solution of a precipitant to the support slurry for precipitation reaction to obtain a precipitate; (3) After calcining and tableting the precipitate to obtain an oxidized catalyst, and then performing a reduction reaction on the oxidized catalyst in the presence of hydrogen to obtain a hydrogenation catalyst.

6. The preparation method according to claim 5, characterized in that, Step (1) includes the following sub-steps: (1.1) Adding a soluble zirconium salt to water and stirring at 50-90 °C for 5-24 hours to obtain an aqueous zirconium salt solution with a concentration of 0.1-5 mol / L; (1.2) Adding the alumina precursor to the aqueous zirconium salt solution, stirring evenly, and then performing hydrothermal reaction at 100-200 °C for 2-50 hours to obtain a support slurry.

7. According to the preparation method described in claim 5, characterized in that In step (2), calculated as the main active metal salt, the concentration of the aqueous solution of the precursor of the main active metal is 5-20 wt%; calculated as the auxiliary active metal salt, the concentration of the aqueous solution of the precursor of the auxiliary active metal is 1-20 wt%; the concentration of the aqueous solution of the precipitant is 5-20 wt%; Keeping the temperature of the support slurry at 50-80 °C, adding the aqueous solution of the precursor of the main active metal to the support slurry, keeping stirring, then adding the aqueous solution of the precursor of the auxiliary active metal to the support slurry, and then adding the aqueous solution of the precipitant to form a reaction solution for reaction. When the pH value of the reaction solution reaches 7-9, stop adding the aqueous solution of the precipitant, and then keep the temperature and stand for aging for 1-5 h; The precursor of the main active metal is nitrate, sulfate, hydrochloride, or a combination thereof; The precursor of the auxiliary active metal is ammonium heptamolybdate, ammonium tetramolybdate, ammonium tungstate, ammonium metatungstate, or a combination thereof; The precipitant is selected from sodium carbonate, ammonium carbonate, sodium hydroxide, ammonia water, or a combination thereof.

8. According to the preparation method described in claim 5, characterized in that In step (3), when calcining the precipitate, the calcination temperature is 400 - 700 °C and the calcination time is 2 - 6 h; when performing the reduction reaction on the green body, the reaction temperature is 450 - 500 °C, the reaction pressure is 0.5 - 2.0 Mpa, the reaction time is 15 - 20 h, and the hydrogen / solid volume ratio is (300 - 500):

1.

9. Use of the hydrogenation catalyst according to any one of claims 1-4 in the hydrorefining of heavy alkylbenzene, wherein the heavy alkylbenzene is a benzene substituted with C 10 -C 38 alkyl groups and contains unsaturated hydrocarbons in the heavy alkylbenzene.

10. The application according to claim 5, wherein During the hydrorefining of heavy alkylbenzene, the reaction temperature is 80 - 120 °C; the reaction pressure is 0.5 - 4 Mpa; the weight hourly space velocity of the raw material is 0.1 - 1 h -1 ; the hydrogen / liquid volume ratio is 100 - 500 Nm 3 / m 3 .

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