Bimetal hydrofining catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of hydrofining, and discloses a bimetallic hydrofining catalyst as well as a preparation method and application thereof. The bimetallic hydrofining catalyst contains an alumina carrier, platinum oxide and cobalt oxide, the platinum oxide and the cobalt oxide serve as active components, the content of the alumina carrier is 80-98 wt%, the content of the active components is 2-20 wt%, the mass ratio of the platinum oxide to the cobalt oxide is 1: (3-400), and the alumina carrier is in bimodal pore distribution within the range of 2 nm-10 nm and 20 nm-50 nm. The bimetallic hydrofining catalyst provided by the invention provides sufficient active sites, optimizes diffusion performance, and has the advantages of good active metal dispersibility, high hydrogenation reaction activity, small noble metal loading amount, low manufacturing cost and excellent catalytic performance.

Description

Technical Field

[0001] This invention relates to the field of hydrorefining technology, specifically to a bimetallic hydrorefining catalyst, its preparation method, and its application. Background Technology

[0002] In recent years, with the rapid development of the aviation and automotive industries and the increasing demands for energy conservation and environmental protection, mineral oils, limited by their raw materials and production processes, struggle to meet the lubrication requirements under certain harsh conditions. Meanwhile, the market share of high-grade environmentally friendly lubricants is gradually increasing. Therefore, the synthesis and application of PAO (polyalphaolefin) type lubricating oil base oils are crucial to meeting increasingly stringent usage requirements. PAO lubricating oil base oils possess advantages such as good viscosity-temperature properties, low pour point, high flash point, good low-temperature fluidity, good thermal stability, good oxidation stability, and no potential toxicity. They can adapt to extreme working conditions, ensuring the safe and stable operation of equipment components in more demanding environments. Furthermore, PAO is virtually sulfur-free, produces little carbon deposits, is biodegradable, and causes minimal environmental pollution after decomposition, making it an environmentally friendly lubricant.

[0003] High-quality PAO lubricating oil base oil synthesized from coal-derived indirectly liquefied and stabilized heavy oil is sulfur-free and nitrogen-free. It employs a pre-hydrogenation and subsequent separation process: α-olefins synthesized by Fischer-Tropsch undergo oligomerization to obtain a crude polymer product, which is then hydrogenated and separated to obtain the target fraction product—refined PAO lubricating oil base oil. Catalyst selectivity and stability have always been research hotspots in the hydrogenation field. Besides unsaturated olefins, the crude polymer product contains a certain amount of oxygen-containing organic compounds such as alcohols and aldehydes, as well as oxygen-containing substances such as water and acids generated during hydrogenation. These oxygen-containing compounds place certain demands on the thermal stability, strength, and activity of the catalyst. Therefore, the developed hydrogenation refining catalyst for the process of preparing PAO lubricating oil base oil from Fischer-Tropsch synthetic oil must consider not only the catalyst's hydrogenation activity but also its stability and tolerance to oxygen-containing organic compounds. Such catalyst preparation technologies have rarely been reported or disclosed in previous technologies.

[0004] There are many types of catalysts for the hydrorefining of lubricating oils. Their active hydrogenation components include noble metals such as platinum and palladium, and non-noble metals such as nickel, molybdenum, and cobalt. Foreign lubricating oil refining catalysts mainly use Ni-Mo metal components and alumina supports, but there are also noble metal catalysts, such as ICR-403 and ICR-407 developed by Chevron. In catalytic hydrogenation reactions, transition metals, especially noble metals, have strong dissociation and hydrogen absorption capabilities and excellent catalytic hydrogenation activity. When metal particles are highly dispersed on a catalyst support, the HH covalent bonds of hydrogen molecules adsorbed on the catalyst surface can be efficiently broken, forming active hydrogen atoms; simultaneously, the π bonds in the adsorbed olefins are also weakened, reducing the activation energy required for the hydrogenation reaction and thus increasing the reaction rate. Platinum is an active component in hydrogenation, dehydrogenation, tail gas purification, and petroleum catalytic reforming catalysis, but its high price, high cost, and limited production volume restrict its further development. Supported platinum catalysts exhibit high activity, shorten reaction time, and provide a high degree of hydrogenation under milder conditions during hydrogenation. However, the precious metal platinum suffers from problems such as easy agglomeration and uneven dispersion on the support, as well as the large amount of platinum required, low utilization rate, and high manufacturing cost. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of uneven platinum dispersion on the support in existing hydrogenation catalysts, weak resistance to carbon deposition and water erosion, large platinum dosage, low platinum utilization, high manufacturing cost, and mismatch between the specific surface area and pore structure of the support and the molecular size of polyalphaolefins. This invention provides a bimetallic hydrorefining catalyst, its preparation method, and its application. This bimetallic hydrorefining catalyst uses a support with a specific bimodal pore distribution, providing sufficient active sites while optimizing diffusion performance to meet the hydrogenation reaction of macromolecular polyalphaolefin synthetic oils. It ensures the dispersion of active components and the diffusion of hydrogenation reactants and products, thereby guaranteeing good hydrogenation performance. Simultaneously, by loading platinum and cobalt bimetallic elements, the dispersion state and interaction of the metal active components are improved, increasing the dispersion and utilization efficiency of the active components on the support surface, further enhancing the catalyst activity, optimizing the loading of precious metals, and thus reducing catalyst cost. This bimetallic hydrorefining catalyst exhibits good thermal stability and resistance to carbon deposition and water erosion.

[0006] To achieve the above objectives, the first aspect of the present invention provides a bimetallic hydrorefining catalyst comprising an alumina support and platinum oxide and cobalt oxide as active components, wherein the alumina support comprises 80-98% by weight, the active components comprise 2-20% by weight, and the mass ratio of platinum oxide to cobalt oxide is 1:(3-400), and the alumina support exhibits a bimodal pore distribution in the ranges of 2nm-10nm and 20nm-50nm.

[0007] Preferably, in the alumina carrier, the pore volume ratio of pores with a pore size of 2nm to 10nm is 10% to 50%, and the pore volume ratio of pores with a pore size of 20nm to 50nm is 50% to 80%.

[0008] Preferably, the alumina support has an average pore size of 8–25 nm.

[0009] Preferably, the pore volume of the alumina carrier is 0.5 cm³. 3 / g or more, preferably 0.5-0.8cm 3 / g.

[0010] Preferably, the specific surface area of ​​the alumina carrier is 130 m². 2 / g or more, preferably 150-240m 2 / g.

[0011] Preferably, the alumina support is a γ-Al2O3 support.

[0012] A second aspect of the present invention provides a method for preparing the above-mentioned bimetallic hydrorefining catalyst, the method comprising the following steps:

[0013] (1) Alumina, pore-forming agent and adhesive are mixed and kneaded, then extruded into strips, and then subjected to first drying and first calcination in sequence to obtain catalyst support;

[0014] (2) The catalyst support is impregnated in an impregnation solution containing platinum salt and cobalt salt, followed by a second drying and a second calcination to obtain a bimetallic hydrogenation refining catalyst.

[0015] The alumina has a dry basis content of 68-72%; the alumina has a colloidal index of 85-99.8%; and the colloidal solvent is at least one of nitric acid aqueous solution, citric acid aqueous solution, and phosphoric acid aqueous solution.

[0016] Preferably, in step (1), the pore-forming agent is at least one of guar gum powder, methylcellulose, hydroxymethylcellulose, dry starch and glycerol.

[0017] Preferably, the mass ratio of the alumina to the pore-forming agent is (35-45):1.

[0018] Preferably, in step (1), the concentration of the adhesive solvent is 1 to 10 wt%.

[0019] Preferably, in step (1), the mass ratio of the alumina to the water in the adhesive solvent is (0.8 to 1.5): 1.

[0020] Preferably, in step (1), the kneading conditions include: a kneading speed of 30-60 rpm and a kneading time of 20-50 min;

[0021] Preferably, in step (1), the conditions for extruding the strip include: a speed of 20 to 50 rpm and a time of 10 to 30 min;

[0022] Preferably, in step (1), the conditions for the first drying include: a temperature of 100 to 200°C and a time of 0.5 to 20 hours.

[0023] Preferably, in step (1), the conditions for the first calcination include: a temperature of 300 to 600°C and a time of 0.5 to 24 hours.

[0024] Preferably, in step (2), the platinum salt is at least one of chloroplatinic acid hexahydrate, platinum nitrate, and hexaammineplatinum.

[0025] Preferably, in step (2), the cobalt salt is at least one of cobalt nitrate, cobalt sulfate, and cobalt chloride.

[0026] Preferably, in step (2), the impregnation solution also contains a competing adsorbent.

[0027] Preferably, in step (2), the competing adsorbent is at least one of nitric acid, hydrochloric acid, sulfuric acid, acetic acid and citric acid.

[0028] Preferably, in step (2), the concentration of the competing adsorbent in the impregnation solution is 0.02 to 0.5 wt%.

[0029] Preferably, in step (2), the conditions for the second drying include: a temperature of 100-150°C and a time of 0.5-12 hours.

[0030] Preferably, in step (2), the second roasting process includes: first heating to 300-400°C, holding at that temperature for 1.5-3 hours, then heating to 450-600°C and roasting for 3.5-6 hours.

[0031] The third aspect of the present invention provides the application of the above-described bimetallic hydrogenation refining catalyst in the hydrogenation of poly-α-olefins.

[0032] Compared with the prior art, the present invention has the following technical effects:

[0033] (1) This invention achieves uniform dispersion of metal active components on the surface of the support by loading platinum and cobalt bimetallic elements, improves the dispersion state and interaction of metal active components, improves the utilization efficiency of active components, and further improves the activity of the catalyst.

[0034] (2) By adding cobalt while loading platinum, the present invention can form a composite metal oxide structure on the catalyst surface, generating an unbalanced valence state and an asymmetric structure, which improves the catalyst's thermal stability, resistance to carbon deposition and water erosion; by optimizing the loading amount of precious metal, the problem of large amount of platinum used for loading a single precious metal, low platinum utilization rate and high manufacturing cost is solved.

[0035] (3) The present invention selects a carrier with a specific dual-pore distribution structure, regulates the specific surface area and pore structure of the carrier, provides sufficient active sites, and optimizes the diffusion performance of reactants and products. Detailed Implementation

[0036] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0037] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0038] The bimetallic hydrorefining catalyst of this invention contains an alumina support and platinum oxide and cobalt oxide as active components. The alumina support comprises 80–98% by weight, the active components comprise 2–20% by weight, and the mass ratio of platinum oxide to cobalt oxide is 1:(3–400). The alumina support exhibits a bimodal pore distribution in the ranges of 2 nm–10 nm and 20 nm–50 nm. The bimetallic hydrorefining catalyst of this invention provides sufficient active sites while optimizing diffusion performance, exhibits good dispersion of the active metal, high hydrogenation reaction activity, low noble metal loading, and low manufacturing cost.

[0039] In the bimetallic hydrorefining catalyst of the present invention, the content of the alumina support can be 80-98% by weight, preferably 80-95% by weight; the content of the active component can be 2-20% by weight, preferably 5-20% by weight. The mass ratio of platinum oxide to cobalt oxide can be 1:(3-400), preferably 1:(6-210). The cobalt oxide can be cobalt tetroxide.

[0040] In the bimetallic hydrorefining catalyst of the present invention, the pore volume ratio of the alumina support having a pore size of 2 nm to 10 nm can be 10% to 50%, preferably 17% to 48%; the pore volume ratio of the pore size having a pore size of 20 nm to 50 nm can be 50% to 80%, preferably 50% to 78%. The support with a specific bimodal pore distribution provides sufficient active sites while optimizing diffusion performance.

[0041] In the bimetallic hydrorefining catalyst of the present invention, the average pore size of the alumina support can be 8–25 nm, preferably 10–20 nm. The pore volume of the alumina support can be 0.5 cm³. 3 / g or more, preferably 0.56-0.76cm 3 / g. The specific surface area of ​​the alumina support can be 130m². 2 / g or more, preferably 156-234m 2 / g. The alumina support can be at least one of γ-Al2O3, β-Al2O3 and α-Al2O3, preferably γ-Al2O3 support.

[0042] In some embodiments, the bimetallic hydrorefining catalyst of the present invention contains an alumina support and platinum oxide and cobalt oxide as active components. The alumina support comprises 80-98% by weight, the active components comprise 2-20% by weight, and the mass ratio of platinum oxide to cobalt oxide is 1:(3-400). The alumina support exhibits a bimodal pore distribution in the ranges of 2nm-10nm and 20nm-50nm. In the alumina support, the pore volume percentage of pores with a diameter of 2nm-10nm is 10-50%, and the pore volume percentage of pores with a diameter of 20nm-50nm is 50-80%. The average pore size of the alumina support is 8-25nm, and the pore volume is 0.5cm³. 3 / g or more, with a specific surface area of ​​130m² 2 / g or more, wherein the alumina support is a γ-Al2O3 support.

[0043] The present invention also provides a method for preparing the above-mentioned bimetallic hydrorefining catalyst, the method comprising the following steps:

[0044] (1) Alumina, pore-forming agent and adhesive are mixed and kneaded, then extruded into strips, and then subjected to first drying and first calcination in sequence to obtain catalyst support;

[0045] (2) The catalyst support is impregnated in an impregnation solution containing platinum salt and cobalt salt, followed by a second drying and a second calcination to obtain a bimetallic hydrogenation refining catalyst.

[0046] The alumina has a dry basis content of 68-72%; the alumina has a colloidal index of 85-99.8%; and the colloidal solvent is at least one of nitric acid aqueous solution, citric acid aqueous solution, and phosphoric acid aqueous solution.

[0047] According to the method described in this invention, a support with a specific bimodal pore distribution is selected to provide sufficient active sites while optimizing diffusion performance to meet the hydrogenation reaction of macromolecular polyα-olefin synthetic oils. This ensures the dispersion of active components and the diffusion of hydrogenation reactants and products, thereby guaranteeing the catalyst's excellent hydrogenation performance. Simultaneously, by loading platinum and cobalt bimetallic elements, the dispersion state and interaction of the metal active components are improved, increasing the dispersion and utilization efficiency of the active components on the support surface, further enhancing the catalyst's activity, optimizing the loading of precious metals, and thus reducing catalyst costs. This bimetallic hydrogenation catalyst exhibits good thermal stability, resistance to carbon deposition, and resistance to water erosion.

[0048] In the method described in this invention, the alumina can be at least one of γ-Al₂O₃, β-Al₂O₃, and α-Al₂O₃, preferably γ-Al₂O₃. The dry basis weight of the alumina can be 68-72%. The colloidal index of the alumina can be 85-99.8%, preferably 99-99.8%. The purity of the alumina can be greater than 98 wt%, preferably 98.5-99.99 wt%. The pore volume (BET) of the alumina can be 0.5-1.2 cm⁻¹. 3 / g, preferably 0.5~0.9cm 3 / g; specific surface area can be 150~450m² 2 / g, preferably 150-350mg / g 2 / g. By selecting appropriate alumina and colloidal solvent, and controlling the dry basis and colloidal index of the raw materials, a bimodal pore distribution of the catalyst support can be achieved in the ranges of 2nm–10nm and 20nm–50nm.

[0049] In the method described in this invention, in step (1), the pore-forming agent can be at least one of guar gum powder, methylcellulose, hydroxymethylcellulose, dry starch, and glycerol, preferably guar gum powder. The mass ratio of the alumina to the pore-forming agent can be (35-45):1, preferably (40-45):1.

[0050] In the method described in this invention, in step (1), the adhesive solvent can be at least one of nitric acid aqueous solution, citric acid aqueous solution, and phosphoric acid aqueous solution, preferably nitric acid aqueous solution. The concentration of the adhesive solvent can be 1-10 wt%, preferably 1-1.5 wt%. The mass ratio of the alumina to the water in the adhesive solvent can be (0.8-1.5):1, preferably (0.8-1.2):1.

[0051] In the method described in this invention, the specific process of mixing alumina, pore-forming agent and adhesive in step (1) includes: mixing alumina and pore-forming agent, adding adhesive at a stirring rate of 30-60 rpm, mixing and kneading at 20-35°C for 20-50 min.

[0052] In the method described in this invention, in step (1), the extrusion conditions include: a speed of 20–50 rpm, preferably 30–40 rpm; and a time of 10–30 min, preferably 15–25 min. The first drying conditions include: a temperature of 100–200 °C, preferably 120–150 °C; and a time of 0.5–20 h, preferably 2–4 h. The first calcination conditions include: a temperature of 300–600 °C, preferably 500–550 °C; and a time of 0.5–24 h, preferably 2–4 h. By limiting the mixing and extrusion rates and the drying and calcination temperatures, a bimodal pore distribution is achieved in the catalyst support within the ranges of 2 nm–10 nm and 20 nm–50 nm.

[0053] In the method described in this invention, in step (2), the platinum salt can be at least one of chloroplatinic acid hexahydrate, platinum nitrate, and hexaammineplatinum, preferably chloroplatinic acid hexahydrate. The cobalt salt can be at least one of cobalt nitrate, cobalt sulfate, and cobalt chloride, preferably cobalt nitrate. The solvent of the impregnation solution can be water and / or ethanol, preferably water. The ratio of the catalyst support to the purified solution can be 50g:(25-80)mL, preferably 50g:(25-40)mL. In the impregnation solution, the concentration of the platinum salt can be 0.001-0.05g / mL, preferably 0.05-0.02g / mL; the concentration of the cobalt salt can be 0.003-1.1g / mL, preferably 0.5-0.9g / mL.

[0054] In the method described in this invention, in step (2), the impregnation solution may further contain a competing adsorbent. The competing adsorbent may be at least one selected from nitric acid, hydrochloric acid, sulfuric acid, acetic acid, and citric acid, preferably nitric acid. In step (2), the concentration of the competing adsorbent in the impregnation solution may be 0.02–0.5 wt%, preferably 0.05–0.2 wt%. The impregnation conditions include: a temperature of 60–85°C, preferably 65–80°C; and a time of 12–24 h, preferably 12–18 h.

[0055] In some embodiments, the method may further include preparing the impregnation solution by mixing a platinum salt, a cobalt salt, and water to obtain the impregnation solution. In other embodiments, the method may further include preparing the impregnation solution by mixing a platinum salt, a cobalt salt, a competing adsorbent, and water to obtain the impregnation solution. In still other embodiments, the method may further include preparing the impregnation solution by mixing chloroplatinic acid hexahydrate, cobalt nitrate, nitric acid, and water to obtain the impregnation solution.

[0056] In the method described in this invention, in step (2), the conditions for the second drying include: a temperature of 100–150°C, preferably 120–150°C; and a time of 0.5–12 h, preferably 2–4 h. The second calcination process may include: first heating to 300–400°C, holding at that temperature for 1.5–3 h, then heating to 450–600°C, and calcining for 3.5–6 h.

[0057] In the method described in this invention, the method may further include: reducing the bimetallic hydrorefining catalyst obtained in step (2) under a hydrogen atmosphere. The conditions for reduction under a hydrogen atmosphere include: a hydrogen partial pressure of 2–6 MPa, preferably 3–4 MPa; a temperature of 250–500 °C, preferably 280–320 °C; and a time of 1–48 h, preferably 4–8 h. In this document, the hydrogen partial pressure is gauge pressure.

[0058] In some embodiments, the method for refining the bimetallic hydrogenation catalyst according to the present invention includes the following steps:

[0059] (1) Mix alumina and pore-forming agent, add adhesive solvent at a stirring rate of 30-60 rpm, mix and knead at 20-35℃ for 20-50 min, then extrude into strips at a rate of 20-50 rpm for 10-30 min, and then perform a first drying at 100-200℃ for 0.5-20 h and a first calcination at 300-600℃ for 0.5-24 h to obtain catalyst support;

[0060] (2) The catalyst support is impregnated in an impregnation solution containing platinum salt, cobalt salt and competitive adsorbent at 60-85°C for 12-24h, then dried at 100-150°C for 0.5-12h, then heated to 300-400°C and held for 1.5-3h, then heated to 450-600°C and calcined for 3.5-6h to obtain a bimetallic hydrogenation refining catalyst;

[0061] (3) The bimetallic hydrogenation refining catalyst is reduced in a hydrogen atmosphere at a hydrogen partial pressure of 2-6 MPa and a temperature of 250-500 °C for 1-48 h.

[0062] The alumina has a dry basis content of 68-72%; its colloidal index is 85-99.8%; it is at least one of γ-Al₂O₃, β-Al₂O₃, and α-Al₂O₃; and its pore volume (BET) is 0.7-1.2 cm⁻¹. 3 / g, specific surface area of ​​200-450m² 2 / g; the pore-forming agent is at least one of guar gum powder, methylcellulose, hydroxymethylcellulose, dry starch, and glycerol; the mass ratio of alumina to the pore-forming agent is (35-45):1; the colloidal solvent is at least one of nitric acid aqueous solution, citric acid aqueous solution, and phosphoric acid aqueous solution; the concentration of the colloidal solvent is 1-10 wt%; the mass ratio of alumina to water in the colloidal solvent is (0.8-1.5):1; the platinum salt is at least one of chloroplatinic acid hexahydrate, platinum nitrate, and hexaammineplatinum; the cobalt salt is nitrate The catalyst carrier is selected from at least one of cobalt sulfate, cobalt chloride, and cobalt sulfate; the ratio of the catalyst carrier to the impregnation solution is 50 g:(25-80) mL, preferably 50 g:(25-40) mL; in the impregnation solution, the concentration of the platinum salt is 0.001-0.05 g / mL, and the concentration of the cobalt salt is 0.003-1.10 g / mL; the competitive adsorbent is selected from at least one of nitric acid, hydrochloric acid, sulfuric acid, acetic acid, and citric acid; the concentration of the competitive adsorbent in the impregnation solution is 0.02-0.5 wt%.

[0063] In other embodiments, the method for bimetallic hydrogenation catalysts of the present invention includes the following steps:

[0064] (1) Mix γ-Al2O3 and guar gum powder, add nitric acid aqueous solution at a stirring rate of 30-60 rpm, mix and knead at 20-35℃ for 20-50 min, then extrude into strips at a rate of 20-50 for 10-30 min, and then perform a first drying at 100-200℃ for 0.5-20 h and a first calcination at 300-600℃ for 0.5-24 h to obtain a catalyst support;

[0065] (2) The catalyst support is impregnated in an impregnation solution containing chloroplatinic acid hexahydrate, cobalt nitrate and nitric acid at 60-85°C for 12-24 hours, then dried at 100-150°C for 0.5-12 hours, then heated to 300-400°C and held for 1.5-3 hours, then heated to 450-600°C and calcined for 3.5-6 hours to obtain a bimetallic hydrogenation refining catalyst;

[0066] (3) The bimetallic hydrogenation refining catalyst is reduced in a hydrogen atmosphere at a hydrogen partial pressure of 2-6 MPa and a temperature of 250-500°C for 1-48 hours;

[0067] The γ-Al₂O₃ has a dry basis content of 68-72%; its solubility index is 85-99.8%; and its pore volume (BET) is 0.5-1.2 cm³. 3 / g, specific surface area of ​​150-450m² 2 / g; the mass ratio of γ-Al2O3 to guar gum powder is (35-45):1; the concentration of the nitric acid aqueous solution is 1-10wt%; the mass ratio of water in the γ-Al2O3 and the nitric acid aqueous solution is (0.8-1.5):1; the volume ratio of the catalyst support to the impregnation solution is 50g:(25-80)mL, preferably 50g:(25-40)mL; in the impregnation solution, the concentration of chloroplatinic acid hexahydrate is 0.001-0.05g / mL, the concentration of cobalt nitrate is 0.003-1.10g / mL; the concentration of nitric acid in the impregnation solution is 0.02-0.5wt%.

[0068] This invention also provides the application of the above-mentioned bimetallic hydrorefining catalyst in the hydrogenation of polyalphaolefins. According to the application described in this invention, the bimetallic hydrorefining catalyst exhibits excellent effects in reducing unsaturated olefins and oxygen-containing compounds in the feedstock during the hydrogenation of polyalphaolefins, significantly reducing the bromine value of the hydrogenation product and improving product quality.

[0069] The following examples further illustrate the bimetallic hydrogenation refining catalyst, its preparation method, and its applications according to the present invention. These examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following examples.

[0070] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.

[0071] Example 1

[0072] (1) 262.5g of γ-Al2O3 (specific surface area of ​​350m²) was added. 2 / g, pore volume 0.9cm³ 3 The catalyst support was obtained by mixing 6.0 g of guar gum powder (with an average pore size of 10.29 nm, a dry basis of 70%, and a colloidal index of 99.5%) with 6.0 g of guar gum powder, then adding 218 g of nitric acid aqueous solution (concentration of 1.0 wt%) at a stirring rate of 40 rpm and mixing and kneading at 25 °C for 40 min, extruding at a rate of 30 rpm for 20 min, and then drying at 150 °C for 2 h and calcining at 500 °C for 2 h.

[0073] (2) Prepare 100 mL of impregnation solution (in the impregnation solution, the concentration of chloroplatinic acid hexahydrate is 0.023 g / mL, the concentration of cobalt nitrate is 0.205 g / mL, and the concentration of nitric acid is 0.05 wt%), impregnate 50 g of the catalyst support in 42 mL of the impregnation solution at 60 °C for 12 h, then dry at 150 °C for 2 h, then heat to 350 °C and hold for 2 h, then heat to 500 °C and calcine for 4 h to obtain the bimetallic hydrogenation refining catalyst;

[0074] (3) The bimetallic hydrogenation refining catalyst was reduced for 6 hours in a hydrogen atmosphere at a hydrogen partial pressure of 3 MPa and a temperature of 300 °C to obtain a bimetallic hydrogenation refining activated catalyst.

[0075] Example 2

[0076] (1) 280.9g of γ-Al2O3 (specific surface area of ​​350m²) was added. 2 / g, pore volume 0.9cm³ 3 The catalyst support was obtained by mixing 7.2g of guar gum powder with 7g of guar gum powder (average pore size 10.29nm, dry basis 70%, colloidal index 99.5%), and then adding 315g of nitric acid aqueous solution (concentration 1.0wt%) at a stirring rate of 30rpm. The mixture was kneaded at 25℃ for 30min, extruded at a rate of 30rpm for 30min, and then dried at 150℃ for 4h and calcined at 550℃ for 4h.

[0077] (2) Prepare 100 mL of impregnation solution (in the impregnation solution, the concentration of chloroplatinic acid hexahydrate is 0.015 g / mL, the concentration of cobalt nitrate is 0.312 g / mL, and the concentration of nitric acid is 0.08 wt%), impregnate 50 g of the catalyst support in 40 mL of the impregnation solution at 60 °C for 24 h, then dry at 150 °C for 2 h, then heat to 350 °C and hold for 2 h, then heat to 550 °C and calcine for 4 h to obtain the bimetallic hydrogenation refining catalyst;

[0078] (3) The bimetallic hydrogenation refining catalyst was reduced for 6 hours in a hydrogen atmosphere at a hydrogen partial pressure of 4 MPa and a temperature of 300 °C to obtain a bimetallic hydrogenation refining activated catalyst.

[0079] Example 3

[0080] (1) 280.9g of γ-Al2O3 (specific surface area of ​​420m²) was added. 2 / g, pore volume 0.8cm³ 3The catalyst support was obtained by mixing 7.2g of guar gum powder with 7g of average pore size 7.62nm, dry basis weight 68%, and colloidal index 99.0%. Then, 235g of nitric acid aqueous solution (concentration 1.5wt%) was added at a stirring rate of 30rpm and mixed and kneaded at 25℃ for 30min. The mixture was then extruded at a rate of 30rpm for 30min, and then dried at 150℃ for 4h and calcined at 550℃ for 4h.

[0081] (2) Prepare 100 mL of impregnation solution (in the impregnation solution, the concentration of chloroplatinic acid hexahydrate is 0.004 g / mL, the concentration of cobalt nitrate is 0.893 g / mL, and the concentration of nitric acid is 0.1 wt%), impregnate 50 g of the catalyst support in 37 mL of the impregnation solution at 65 °C for 20 h, then dry at 150 °C for 2 h, then heat to 350 °C and hold for 2 h, then heat to 550 °C and calcine for 4 h to obtain the bimetallic hydrogenation refining catalyst;

[0082] (3) The bimetallic hydrogenation refining catalyst was reduced for 6 hours in a hydrogen atmosphere at a hydrogen partial pressure of 4 MPa and a temperature of 300 °C to obtain a bimetallic hydrogenation refining activated catalyst.

[0083] Example 4

[0084] (1) 280.9g of γ-Al2O3 (specific surface area of ​​420m²) was added. 2 / g, pore volume 0.8cm³ 3 The catalyst support was obtained by mixing 7.2g of guar gum powder with 7g of average pore size 7.62nm, dry basis 68%, and colloidal index 99.0%. Then, 235g of nitric acid aqueous solution (concentration 1.5wt%) was added at a stirring rate of 40rpm and mixed and kneaded at 25℃ for 20min. The mixture was then extruded at a rate of 30rpm for 20min, and then dried at 120℃ for 4h and calcined at 550℃ for 4h.

[0085] (2) Prepare 100 mL of impregnation solution (in the impregnation solution, the concentration of chloroplatinic acid hexahydrate is 0.007 g / mL, the concentration of cobalt nitrate is 0.930 g / mL, and the concentration of citric acid is 0.1 wt%), impregnate 50 g of the catalyst support in 35 mL of the impregnation solution at 65 °C for 20 h, then dry at 120 °C for 4 h, then heat to 350 °C and hold for 2 h, then heat to 500 °C and calcine for 6 h to obtain the bimetallic hydrogenation refining catalyst;

[0086] (3) The bimetallic hydrogenation refining catalyst was reduced for 8 hours in a hydrogen atmosphere at a hydrogen partial pressure of 3 MPa and a temperature of 280 °C to obtain a bimetallic hydrogenation refining activated catalyst.

[0087] Example 5

[0088] (1) 262.5g of γ-Al2O3 (specific surface area of ​​350m²) was added. 2 / g, pore volume 0.9cm³ 3 The catalyst support was obtained by mixing 6.0 g of guar gum powder (with an average pore size of 10.29 nm, a dry basis of 70%, and a colloidal index of 99.5%) with 6.0 g of guar gum powder, then adding 218 g of nitric acid aqueous solution (concentration of 1.5 wt%) at a stirring rate of 30 rpm and mixing and kneading at 25 °C for 25 min, extruding at a rate of 40 rpm for 20 min, and then drying at 120 °C for 4 h and calcining at 550 °C for 4 h.

[0089] (2) Prepare 100 mL of impregnation solution (in the impregnation solution, the concentration of chloroplatinic acid hexahydrate is 0.003 g / mL, the concentration of cobalt nitrate is 1.00 g / mL, and the concentration of acetic acid is 0.15 wt%), impregnate 50 g of the catalyst support in 42 mL of the impregnation solution at 65 °C for 20 h, then dry at 120 °C for 4 h, then heat to 350 °C and hold for 4 h, then heat to 500 °C and calcine for 4 h to obtain the bimetallic hydrogenation refining catalyst;

[0090] (3) The bimetallic hydrogenation refining catalyst was reduced for 4 hours in a hydrogen atmosphere at a hydrogen partial pressure of 4 MPa and a temperature of 320 °C to obtain a bimetallic hydrogenation refining activated catalyst.

[0091] Example 6

[0092] (1) 262.5g of γ-Al2O3 (specific surface area of ​​380m²) was added. 2 / g, pore volume is 0.85cm³ 3 The catalyst support was obtained by mixing 7.5 g of methylcellulose with an average pore size of 8.95 nm, a dry basis of 72%, and a colloidal index of 99.8%. Then, 331 g of citric acid aqueous solution (concentration of 1.5 wt%) was added at a stirring rate of 30 rpm and mixed and kneaded at 25 °C for 50 min. The mixture was then extruded at a rate of 20 rpm for 30 min and then dried at 100 °C for 20 h and calcined at 300 °C for 24 h.

[0093] (2) Prepare 100 mL of impregnation solution (in the impregnation solution, the concentration of platinum nitrate is 0.001 g / mL, the concentration of cobalt sulfate is 1.06 g / mL, and the concentration of hydrochloric acid is 0.5 wt%), impregnate 50 g of the catalyst support in 40 mL of the impregnation solution at 70 °C for 20 h, then dry at 100 °C for 12 h, then heat to 300 °C and hold for 4 h, then heat to 450 °C and calcine for 6 h to obtain the bimetallic hydrogenation refining catalyst;

[0094] (3) The bimetallic hydrogenation refining catalyst was reduced for 48 hours in a hydrogen atmosphere at a hydrogen partial pressure of 2 MPa and a temperature of 450 °C to obtain a bimetallic hydrogenation refining activated catalyst.

[0095] Example 7

[0096] (1) 262.5g of γ-Al2O3 (specific surface area of ​​380m²) was added. 2 / g, pore volume is 0.85cm³ 3 The catalyst support was obtained by mixing 5.8 g of dry starch with 8.95 nm average pore size, 72% dry basis and 99.8% colloidal index, and 194 g of phosphoric acid aqueous solution (10 wt%) was added at a stirring rate of 60 rpm and mixed and kneaded at 25 °C for 20 min. The mixture was then extruded at a rate of 50 rpm for 10 min and then dried at 200 °C for 0.5 h and calcined at 600 °C for 0.5 h.

[0097] (2) Prepare 100 mL of impregnation solution (in the impregnation solution, the concentration of hexaammineplatinum is 0.04 g / mL, the concentration of cobalt chloride is 0.14 g / mL, and the concentration of sulfuric acid is 0.02 wt%), impregnate 50 g of the catalyst support in 40 mL of the impregnation solution at 60 °C for 20 h, then dry at 150 °C for 0.5 h, then heat to 400 °C and hold for 1.5 h, then heat to 600 °C and calcine for 3.5 h to obtain the bimetallic hydrogenation refining catalyst;

[0098] (3) The bimetallic hydrogenation refining catalyst was reduced for 48 hours in a hydrogen atmosphere at a hydrogen partial pressure of 6 MPa and a temperature of 250 °C to obtain a bimetallic hydrogenation refining activated catalyst.

[0099] Comparative Example 1

[0100] Prepared according to the method of Example 3, except that cobalt nitrate is replaced with nickel nitrate. Specifically, 100 mL of impregnation solution is prepared (in the impregnation solution, the concentration of chloroplatinic acid hexahydrate is 0.004 g / mL, the concentration of nickel nitrate is 0.95 g / mL, and the concentration of nitric acid is 0.1 wt%).

[0101] Comparative Example 2

[0102] Prepared according to the method of Example 3, except that nitric acid is not added during the preparation of the impregnation solution. Specifically, 100 mL of impregnation solution is prepared (in the impregnation solution, the concentration of chloroplatinic acid hexahydrate is 0.004 g / mL and the concentration of cobalt nitrate is 0.893 g / mL).

[0103] Comparative Example 3

[0104] Prepared according to the method of Example 3, except that chloroplatinic acid hexahydrate is replaced with palladium nitrate. Specifically, 100 mL of impregnation solution is prepared (in the impregnation solution, the concentration of palladium nitrate is 0.003 g / mL, the concentration of cobalt nitrate is 0.85 g / mL, and the concentration of nitric acid is 0.1 wt%).

[0105] Comparative Example 4

[0106] (1) γ-Al2O3 (specific surface area of ​​450 m²) 2 / g, pore volume is 0.72cm³ 3 The catalyst support was prepared by using a 100 mL impregnation solution (containing 0.006 g / mL chloroplatinic acid hexahydrate, 1.12 g / mL cobalt nitrate, and 0.1 wt%). 50 g of the catalyst support was impregnated in 30 mL of the impregnation solution at 65 °C for 1.5 h. After being left overnight, the catalyst was dried at 120 °C for 4 h. Then, the temperature was raised to 350 °C and held for 2 h. Finally, the temperature was raised to 550 °C and calcined for 4 h to obtain the bimetallic hydrogenation refining catalyst.

[0107] (2) The bimetallic hydrogenation refining catalyst was reduced for 8 hours in a hydrogen atmosphere at a hydrogen partial pressure of 3 MPa and a temperature of 280 °C to obtain a bimetallic hydrogenation refining activated catalyst.

[0108] Test case

[0109] (1) The specific surface area and pore structure (BET) of the catalyst supports prepared in Examples 1-7 and Comparative Examples 1-4 were tested. The test methods were in accordance with the national standards GB / T 19587-1997 and GB / T21650.2-2008. The measured specific surface area, pore volume and pore size distribution are recorded in Table 1.

[0110] (2) The bulk density and compressive strength of the bimetallic hydrogenation refining catalysts prepared in Examples 1-7 and Comparative Examples 1-4 were tested. The test methods were in accordance with the national standards GB / T 5162-2021 and GB / T36317-2018. The measured bulk density and compressive strength are recorded in Table 1.

[0111] (3) X-ray fluorescence spectroscopy (XRF) was performed on the bimetallic hydrogenation refining catalysts prepared in Examples 1-7 and Comparative Examples 1-4. The test method was in accordance with the national standard GB / T 30905-2014. The elemental composition was recorded in Table 2.

[0112] (4) The bimetallic hydrorefining activation catalysts prepared in Examples 1-7 and Comparative Examples 1-4 were tested for activity. Using crude PAO product synthesized from coal indirectly liquefied and stabilized heavy oil as raw material, the hydrorefining reaction was carried out in a 10 mL fixed-bed reactor under the following conditions: hydrogen-to-oil ratio of 500:1, reaction pressure of 6 MPa, and volume hourly space velocity of 0.5 h⁻¹. -1 The reaction temperature was 250℃, and the evaluation results are shown in Table 3. In this paper, the pressure is gauge pressure.

[0113] Table 1

[0114]

[0115] Table 2

[0116]

[0117] Table 3

[0118]

[0119] As can be seen from the results in Table 1, the bimetallic hydrogenation catalyst of the present invention uses a support with a specific bimodal pore distribution, which can satisfy the hydrogenation reaction of PAO monomer molecules. The large pores also allow large hydrocarbon molecules to diffuse and undergo hydrogenation reactions inside, thus improving the catalytic hydrogenation efficiency and activity. The compressive strength data of the bimetallic hydrogenation refining catalyst show that the catalyst has high compressive strength, good thermal stability, and high resistance to carbon deposition and water erosion.

[0120] As can be seen from the results in Table 2, the bimetallic hydrogenation refining catalyst of the present invention has a low noble metal loading. The bimetallic catalyst improves the dispersion state and interaction of the active metal components, as well as the dispersion and utilization efficiency of the active components on the support surface, thereby optimizing the catalyst performance while reducing costs.

[0121] As can be seen from the results in Table 3, the examples using the bimetallic hydrorefining catalyst described in this invention have high catalytic activity, excellent effect in reducing unsaturated olefins and oxygen-containing compounds in the feedstock, can significantly reduce the bromine value of the hydrogenation product, increase the kinematic viscosity and viscosity index of PAO base oil, and improve the oxidation stability of PAO hydrogenation product oil, enabling it to meet the technical specifications of different grades of PAO base oil.

[0122] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A bimetallic hydrogenation refining catalyst, characterized in that, The bimetallic hydrorefining catalyst contains an alumina support and platinum oxide and cobalt oxide as active components. The alumina support has a content of 80-98% by weight, the active components have a content of 2-20% by weight, and the mass ratio of platinum oxide to cobalt oxide is 1:(3-400). The alumina support exhibits a bimodal pore distribution in the ranges of 2nm-10nm and 20nm-50nm.

2. The bimetallic hydrorefining catalyst according to claim 1, characterized in that, In the alumina carrier, the volume of pores with a pore size of 2 nm to 10 nm accounts for 10 to 50%, and the volume of pores with a pore size of 20 nm to 50 nm accounts for 50 to 80%. Preferably, the alumina support has an average pore size of 8–25 nm.

3. The bimetallic hydrorefining catalyst according to claim 1 or 2, characterized in that, The pore volume of the alumina carrier is 0.5 cm³. 3 / g or more, preferably 0.5-0.8cm 3 / g; and / or The specific surface area of ​​the alumina carrier is 130 m². 2 / g or more, preferably 150-240mg 2 / g.

4. The bimetallic hydrorefining catalyst according to any one of claims 1-3, characterized in that, The alumina support is a γ-Al2O3 support.

5. A method for preparing the bimetallic hydrorefining catalyst according to any one of claims 1-4, characterized in that, The method includes the following steps: (1) Alumina, pore-forming agent and adhesive are mixed and kneaded, then extruded into strips, and then subjected to first drying and first calcination in sequence to obtain catalyst support; (2) The catalyst support is impregnated in an impregnation solution containing platinum salt and cobalt salt, followed by a second drying and a second calcination to obtain a bimetallic hydrogenation refining catalyst. The alumina has a dry basis of 68-72%; The alumina has a colloidal index of 85–99.8%; The colloidal solvent is at least one of nitric acid aqueous solution, citric acid aqueous solution and phosphoric acid aqueous solution.

6. The method according to claim 5, characterized in that, In step (1), the pore-forming agent is at least one of guar gum powder, methylcellulose, hydroxymethylcellulose, dry starch, and glycerin; Preferably, the mass ratio of the alumina to the pore-forming agent is (35-45):

1.

7. The method according to claim 5 or 6, characterized in that, In step (1), the concentration of the adhesive solvent is 1 to 10 wt%. Preferably, in step (1), the mass ratio of the alumina to the water in the adhesive solvent is (0.8 to 1.5):

1.

8. The method according to any one of claims 5-7, characterized in that, In step (1), the kneading conditions include: a kneading speed of 30-60 rpm and a kneading time of 20-50 min; And / or, the conditions for the extrusion strip include: a speed of 20 to 50 rpm; and a time of 10 to 30 min; And / or, in step (1), the conditions for the first drying include: a temperature of 100-200°C and a time of 0.5-20h; And / or, in step (1), the conditions for the first calcination include: a temperature of 300 to 600°C and a time of 0.5 to 24 hours.

9. The method according to any one of claims 5-8, characterized in that, In step (2), the platinum salt is at least one of chloroplatinic acid hexahydrate, platinum nitrate, and hexaammineplatinum; And / or, in step (2), the cobalt salt is at least one of cobalt nitrate, cobalt sulfate and cobalt chloride.

10. The method according to any one of claims 5-9, characterized in that, In step (2), the impregnation solution also contains a competing adsorbent; Preferably, in step (2), the competing adsorbent is at least one selected from nitric acid, hydrochloric acid, sulfuric acid, acetic acid, and citric acid; Preferably, in step (2), the concentration of the competing adsorbent in the impregnation solution is 0.02 to 0.5 wt%.

11. The method according to any one of claims 5-10, characterized in that, In step (2), the conditions for the second drying include: a temperature of 100-150°C and a time of 0.5-12 hours; And / or, in step (2), the second roasting process includes: first heating to 300-400°C, holding at that temperature for 1.5-3 hours, then heating to 450-600°C and roasting for 3.5-6 hours.

12. The application of the bimetallic hydrogenation refining catalyst according to any one of claims 1-4 in the hydrogenation of poly-α-olefins.

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