A method for preparing a high-temperature and sulfur-resistant shift catalyst and the catalyst itself.

Abstract

This application relates to the field of catalysts, specifically disclosing a method for preparing a high-temperature and sulfur-resistant shift catalyst and the catalyst itself. The method for preparing the high-temperature and sulfur-resistant shift catalyst includes the following steps: S1, compounding pseudoboehmite and magnesium oxide to obtain a composite matrix; S2, impregnating the composite matrix in a composite solution of cobalt nitrate, ammonium molybdate, cerium nitrate, bismuth nitrate, and antimony nitrate to obtain a loaded material; S3, adding a binder to the loaded material, kneading, and then drying and sintering to obtain the finished product; the catalyst contains the following raw materials in weight percentages: cobalt oxide 2-5%, molybdenum oxide 5-8%, alumina 62-77%, magnesium oxide 10-20%, cerium oxide 2-5%, bismuth oxide 0.5-2%, and antimony oxide 0.5-1%; it simultaneously possesses the advantages of high-temperature resistance and sulfur shift resistance, ensuring high catalyst activity and good structural stability.

Description

Technical Field

[0001] This application relates to the field of catalysts, and more specifically, to a method for preparing a high-temperature and sulfur-resistant shift catalyst and the catalyst itself. Background Technology

[0002] In the petroleum processing field, such as hydrocracking and catalytic cracking, operations typically require high temperatures of 300-500℃. The operating temperature range for hydrocracking is 360-450℃. Catalysts must maintain high activity and good structural stability under these high temperature conditions to ensure that the active sites in the catalyst's pores are not easily affected, thereby avoiding sintering or permanent deactivation.

[0003] Crude oil commonly contains sulfides, which generate highly corrosive hydrogen sulfide during processing. Hydrogen sulfide can easily deactivate catalysts, and sulfides can selectively adsorb onto the active sites of catalysts, hindering the approach of reactant molecules. Combined with high-temperature conditions, this can easily clog the pore channels of the catalyst.

[0004] Therefore, developing a novel catalyst that possesses the advantages of high temperature resistance and sulfur conversion resistance, while ensuring high catalyst activity and good structural stability, is an urgent problem to be solved. Summary of the Invention

[0005] In order to prepare a novel catalyst that has the advantages of high temperature resistance and sulfur conversion resistance, and to ensure that the catalyst has high activity and good structural stability, this application provides a method for preparing a high temperature and sulfur conversion resistant catalyst and the catalyst itself.

[0006] In a first aspect, this application provides a method for preparing a high-temperature and sulfur-resistant shift catalyst, employing the following technical solution: A method for preparing a high-temperature and sulfur-resistant shift catalyst includes the following steps: S1. Boehmite and magnesium oxide are combined to obtain a composite matrix; S2. The composite matrix is ​​immersed in a composite solution of cobalt nitrate, ammonium molybdate, cerium nitrate, bismuth nitrate, and antimony nitrate to obtain the loaded material. S3. Add binder to the load material and knead, then dry and sinter to obtain the finished product.

[0007] By adopting the above technical solution, boehmite is calcined into γ-Al2O3, forming a porous framework structure with large pore volume and high specific surface area. Combined with magnesium oxide as an alkaline component, it can increase the density of alkaline sites on the support surface, effectively adsorb and neutralize acidic sulfides such as hydrogen sulfide generated in the reaction, inhibit the excessive deactivation of active metal sulfides, and the addition of magnesium oxide inhibits the phase transformation of γ-Al2O3 to α-Al2O3 at high temperature, maintains the integrity of the pore structure, and keeps the support stable at temperatures above 600℃, ensuring the high temperature resistance and sulfur conversion resistance of the finished catalyst.

[0008] The high specific surface area of ​​boehmite and magnesium oxide provides nanoscale channels for uniformly dispersed metallic active phases, enhancing the exposure rate of active sites. Loading substances such as cobalt nitrate and ammonium molybdate forms a Co-Mo-S active phase, which is the core catalytic center for hydrodesulfurization (HDS), efficiently removing organic sulfur from diesel and residual oil. Cerium nitrate, as an additive, can decompose into cerium oxide, whose reversible Ce... 3+ / Ce 4+ The cycle generates abundant oxygen vacancies, further enhancing the catalyst's activity, significantly promoting the formation of the Co-Mo-S phase, and improving the catalyst's activity and stability. The combination of bismuth and antimony ions can not only inhibit the excessive growth of cobalt and molybdenum, but also form a solid solution-like structure at high temperatures, improving resistance to sintering and enhancing the catalyst's structural stability.

[0009] A composite bonding structure is formed during the mixing process, which, combined with subsequent sintering, ensures the pore structure of the catalyst while improving its structural stability. Preferably, the pseudoboehmite is a modified pseudoboehmite, which is prepared by the following method: Boehmite powder was soaked and dispersed in nitric acid solution for 5-10 minutes, and then the boehmite powder was separated to obtain loaded boehmite. Hydroxyapatite nanowires were soaked and dispersed in citric acid solution, and the nanowires were filtered out to obtain loaded nanowires. Loaded boehmite and loaded nanowires were mixed at a mass ratio of 1:0.05-0.1 and dispersed in water. After heating, filtering, and drying, modified boehmite was obtained.

[0010] By adopting the above technical solution, the pseudoboehmite powder is treated with nitric acid solution, giving it a positive charge on the surface, while the hydroxyapatite nanowires are treated with citric acid solution, giving them a negative charge on the surface. Utilizing the principle of attraction between positive and negative charges, the flexible hydroxyapatite nanowires can easily wrap around and adhere to the surface of the pseudoboehmite, forming an entanglement effect. On the one hand, this increases the specific surface area of ​​the pseudoboehmite; on the other hand, the surface of the hydroxyapatite nanowires contains more active sites, thereby increasing the number of active sites on the catalyst. At the same time, the flexible hydroxyapatite nanowires can utilize their supporting and skeletal effects during mixing and subsequent sintering processes to ensure the structural stability of the catalyst.

[0011] Hydroxyapatite nanowires can be embedded in the intergranular spaces of γ-Al₂O₃ in catalysts, significantly hindering the migration and aggregation of Al₂O₃ grains at high temperatures (above 700℃), delaying the phase transformation to α-Al₂O₃ with a low specific surface area, maintaining the specific surface area of ​​the support, ensuring the high-temperature resistance of the catalyst, and during the heating process, the γ-Al₂O₃ formed by the dehydration of boehmite and the PO₄ on the surface of hydroxyapatite... 3- Interfacial condensation can occur, forming stable Al-OP covalent bonds, reducing the surface energy of the system, blocking the diffusion of hydrogen sulfide to the metal active sites, thereby improving the catalyst's heat resistance and sulfur conversion resistance.

[0012] Preferably, the average particle size of the pseudoboehmite powder is 20-40 μm, and the average length of the hydroxyapatite nanowires is 15-25 μm.

[0013] By adopting the above technical solution, limiting the proportion of raw materials and the difference in particle size, while ensuring high active sites, hydroxyapatite nanowires will not completely block the active sites, and can also improve heat resistance and enhance structural stability.

[0014] Preferably, the magnesium oxide is modified magnesium oxide, which is prepared by the following method: Magnesium oxide powder is plasma etched and then treated with ethanolamine solution to obtain carrier magnesium oxide. The carrier magnesium oxide is mixed with polyethylene glycol composite material at a mass ratio of 100:2-6, and then dried and sintered to obtain modified magnesium oxide.

[0015] By adopting the above technical solution, the surface active sites of magnesium oxide increase after plasma etching. Then, after treatment with ethanolamine, the amino and hydroxyl groups on the surface of ethanolamine combine with the magnesium ion sites on the surface of magnesium oxide to form a monomolecular membrane layer. This layer can effectively shield the water absorption sites of magnesium oxide, inhibit the effect of water absorption on the activity of magnesium oxide, and ensure the adsorption capacity and catalytic efficiency of the catalyst. Furthermore, by controlling the water absorption and expansion of magnesium oxide, the catalyst is less prone to pore blockage and structural damage, thereby ensuring the activity and structural stability of the catalyst.

[0016] In conjunction with the subsequent mixing of the polyethylene glycol (PEG) composite, the PEG composite comes into contact with the surface of the magnesium oxide (MgO) particles, forming a steric hindrance layer. During sintering, this layer inhibits direct contact between particles, effectively controlling grain growth and further improving the catalyst's heat resistance and stability. Furthermore, the PEG composite is combined with ethanolamine, both of which can thermally decompose to maintain a high specific surface area. The ethanolamine layer shields some of the magnesium ion active sites, reducing the strong adsorption rate of hydrogen sulfide. Simultaneously, the alkalinity of MgO can neutralize acidic sulfides, forming reversibly adsorbed MgS, preventing permanent deactivation. Therefore, the catalyst possesses both good heat resistance and good sulfur conversion resistance, extending its service life.

[0017] Preferably, the polyethylene glycol composite material is prepared from a polyethylene glycol ethanol solution and magnesium oxide nanosheets in a mass ratio of 1:0.1-0.18.

[0018] By adopting the above technical solution, magnesium oxide nanosheets have a higher specific surface area and more active sites. Under the condition of polyethylene glycol ethanol solution, magnesium oxide nanosheets do not easily adsorb water. After being combined with the surface of magnesium oxide powder, a composite network structure of magnesium oxide particles and magnesium oxide nanosheets is formed, thereby further improving the activity and catalytic effect of magnesium oxide and enhancing the catalytic effect of the catalyst.

[0019] Preferably, the magnesium oxide powder has an average particle size of 10-30 μm, and the magnesium oxide nanosheets have an average particle size of 80-200 nm.

[0020] By adopting the above technical solution, magnesium oxide nanosheets are attached to the surface of micron-sized particles, preferentially exposing high surface energy crystal planes, increasing oxygen vacancy density and the number of basic sites, thereby improving the activity of the catalyst. Furthermore, the nanosheet layer acts as a rigid "skeleton" to wrap the matrix particles, physically preventing direct contact between adjacent MgO grains, inhibiting grain boundary migration, and ensuring structural stability. The oxygen vacancies on the surface of the nanosheets preferentially adsorb hydrogen sulfide, forming reversible Mg-S bonds, thus preventing permanent sulfidation of active sites.

[0021] Preferably, in step S2, the composite matrix is ​​first immersed and dispersed in cobalt nitrate, cerium nitrate, and antimony nitrate, and then ammonium molybdate is added for immersion and dispersion to complete the impregnation treatment, thereby obtaining the loaded material.

[0022] By employing the above technical solution, pre-impregnation with cobalt nitrate allows cobalt ions to preferentially bind to hydroxyl groups and acidic sites on the support surface, forming highly dispersed mononuclear or oligomer structures. During subsequent calcination, Ce... 3+ / Ce 4+ and Sb 5+As a structural aid, it can effectively stabilize the γ-Al2O3 lattice, inhibit the collapse of the support pore structure, and hinder the migration and aggregation of Co3O4 particles at high temperatures (above 500℃) by forming Co-O-Ce or Co-O-Sb interfacial bonds, thereby improving the high-temperature resistance of the catalyst. Ammonium molybdate can be deposited more uniformly around the dispersed cobalt sites in subsequent impregnation, which is conducive to the formation of a highly active Co-Mo-S phase (Type II) after sulfidation. This phase has a better edge active site density and a lower sulfidation energy barrier, which significantly improves the hydrodesulfurization activity. In combination with cerium, it adsorbs and removes surface sulfur substances, delaying the impact on active sites. In combination with antimony, it reduces the adsorption strength of S atoms at the edge of MoS2, reduces sulfur coverage, and maintains the openness of active sites, thus giving the catalyst the advantage of high resistance to sulfur conversion.

[0023] Preferably, the adhesive is a polyvinyl alcohol solution.

[0024] By adopting the above technical solution, polyvinyl alcohol has a certain binding effect. After mixing, as the sintering temperature increases, polyvinyl alcohol will not affect the catalyst system structure, thus ensuring the catalyst's activity and structural stability.

[0025] Preferably, the drying temperature is 100-130℃ and the sintering temperature is 500-600℃.

[0026] By adopting the above technical solutions, the drying temperature and sintering temperature are limited, ensuring the activity and structural stability of the finished catalyst.

[0027] Secondly, this application provides a high-temperature and sulfur-resistant shift catalyst, which adopts the following technical solution: A high-temperature and sulfur-resistant conversion catalyst comprises the following raw materials in weight percentage: 2-5% cobalt oxide, 5-8% molybdenum oxide, 62-77% aluminum oxide, 10-20% magnesium oxide, 2-5% cerium oxide, 0.5-2% bismuth oxide, and 0.5-1% antimony oxide.

[0028] By adopting the above technical solution, the prepared catalyst has the advantages of high temperature resistance and sulfur conversion resistance, ensuring that the catalyst has high activity and good structural stability, and extending the service life of the catalyst.

[0029] In summary, this application has the following beneficial effects: 1. Pseudoboehmite is calcined to transform into γ-Al2O3, forming a porous framework structure with large pore volume and high specific surface area. Combined with magnesium oxide as an alkaline component, it can increase the density of alkaline sites on the support surface, effectively adsorb and neutralize acidic sulfides such as hydrogen sulfide generated in the reaction, inhibit the excessive deactivation of active metal sulfides, and the addition of magnesium oxide inhibits the phase transformation of γ-Al2O3 to α-Al2O3 at high temperature, maintains the integrity of the pore structure, and keeps the support stable at temperatures above 600℃, ensuring the high temperature resistance and sulfur conversion resistance of the finished catalyst.

[0030] 2. The high specific surface area of ​​boehmite and magnesium oxide provides nanoscale channels for uniformly dispersed metallic active phases, enhancing the exposure rate of active sites. This allows for the loading of substances such as cobalt nitrate and ammonium molybdate, forming a Co-Mo-S active phase, which is the core catalytic center for hydrodesulfurization (HDS), efficiently removing organic sulfur from diesel and residual oil. Cerium nitrate, as an additive, can decompose into cerium oxide, and its reversible Ce... 3+ / Ce 4+ The cycle generates abundant oxygen vacancies, further enhancing the catalyst's activity, significantly promoting the formation of the Co-Mo-S phase, and improving the catalyst's activity and stability. The combination of bismuth and antimony ions can not only inhibit the excessive growth of cobalt and molybdenum, but also form a solid solution-like structure at high temperatures, improving resistance to sintering and enhancing the catalyst's structural stability. Detailed Implementation

[0031] The present application will be further described in detail below with reference to the embodiments.

[0032] All of the following ingredients are commercially available.

[0033] Preparation example of modified pseudoboehmite Preparation Example 1: Modified pseudoboehmite was prepared by the following method: 1 kg of boehmite powder was soaked and dispersed in 10 kg of 5% nitric acid solution for 8 min at a stirring speed of 1000 r / min. The average particle size of the boehmite powder was 30 μm. The boehmite powder was then separated to obtain loaded boehmite. 100 g of hydroxyapatite nanowires were soaked and dispersed in 5 kg of 5% citric acid solution at a stirring speed of 1000 r / min. The average length of the hydroxyapatite nanowires was 20 μm. The hydroxyapatite nanowires were separated by filtration to obtain loaded nanowires. 1 kg of loaded boehmite and 0.08 kg of loaded nanowires were ultrasonically dispersed in 20 kg of water at a frequency of 20 kHz at 70 °C for 20 min. After the heating process, the mixture was filtered and separated, and then air-dried to obtain modified boehmite with an average particle size of less than 80 μm.

[0034] Preparation Example 2: The difference between this preparation example and Preparation Example 1 is that: 1 kg of boehmite powder was soaked and dispersed in 10 kg of 5% nitric acid solution for 5 min at a stirring speed of 1000 r / min. The average particle size of the boehmite powder was 20 μm. The boehmite powder was then separated to obtain loaded boehmite. 100 g of hydroxyapatite nanowires were soaked and dispersed in 5 kg of 5% citric acid solution at a stirring speed of 1000 r / min. The average length of the hydroxyapatite nanowires was 15 μm. The hydroxyapatite nanowires were separated by filtration to obtain loaded nanowires. 1 kg of loaded boehmite and 0.05 kg of loaded nanowires were ultrasonically dispersed in 20 kg of water at a frequency of 20 kHz at 70 °C for 20 min. After the heating process, the mixture was filtered and separated, and then air-dried to obtain modified boehmite with an average particle size of less than 60 μm.

[0035] Preparation Example 3: The difference between this preparation example and Preparation Example 1 is that: 1 kg of boehmite powder was soaked and dispersed in 10 kg of 5% nitric acid solution for 10 min with a stirring speed of 1000 r / min. The average particle size of the boehmite powder was 40 μm. The boehmite powder was then separated to obtain loaded boehmite. 100 g of hydroxyapatite nanowires were soaked and dispersed in 5 kg of 5% citric acid solution with a stirring speed of 1000 r / min. The average length of the hydroxyapatite nanowires was 25 μm. The hydroxyapatite nanowires were separated by filtration to obtain loaded nanowires. 1 kg of loaded boehmite and 0.1 kg of loaded nanowires were ultrasonically dispersed in 20 kg of water at a frequency of 20 kHz at 70 °C for 20 min. After the heating process, the mixture was filtered and separated, and then air-dried to obtain modified boehmite with an average particle size of less than 100 μm.

[0036] Preparation example of modified magnesium oxide Preparation Example 4: Modified magnesium oxide was prepared using the following method: Magnesium oxide powder was plasma etched using argon gas at a etching rate of 20 nm / min for 5 min. After etching, 1 kg of magnesium oxide powder was placed in 5 kg of ethanolamine ethanol solution with a mass fraction of 2% and stirred for 10 min. The magnesium oxide powder was then separated by filtration to obtain loaded magnesium oxide. The average particle size of the magnesium oxide powder was 20 μm. Polyethylene glycol was placed in ethanol and stirred until completely dissolved. The polyethylene glycol was polyethylene glycol 1000, resulting in a 5% (w / w) polyethylene glycol ethanol solution. 0.15 kg of magnesium oxide nanosheets with an average particle size of 150 nm were added to 1 kg of the polyethylene glycol ethanol solution. The magnesium oxide nanosheets were then added and ultrasonically dispersed at 20 kHz for 10 min. After mixing evenly, the polyethylene glycol composite material was obtained. Magnesium oxide and polyethylene glycol composite were mixed at a mass ratio of 100:4, dried at 120°C for 2 hours, and then sintered at 580°C for 4 hours to obtain modified magnesium oxide with an average particle size of less than 50 μm.

[0037] Preparation Example 5: The difference between this preparation example and Preparation Example 4 is that: Magnesium oxide powder was plasma etched using argon gas at a etching rate of 20 nm / min for 5 min. After etching, 1 kg of magnesium oxide powder was placed in 5 kg of ethanolamine ethanol solution with a mass fraction of 2% and stirred for 10 min. The magnesium oxide powder was then separated by filtration to obtain loaded magnesium oxide. The average particle size of the magnesium oxide powder was 10 μm. Polyethylene glycol was placed in ethanol and stirred until completely dissolved. The polyethylene glycol was polyethylene glycol 1000, resulting in a 5% (w / w) polyethylene glycol ethanol solution. 0.1 kg of magnesium oxide nanosheets with an average particle size of 80 nm were added to 1 kg of the polyethylene glycol ethanol solution. The magnesium oxide nanosheets were then added and ultrasonically dispersed at 20 kHz for 10 min. After mixing evenly, the polyethylene glycol composite material was obtained. Magnesium oxide and polyethylene glycol composite were mixed at a mass ratio of 100:2, dried at 120°C for 2 hours, and then sintered at 580°C for 4 hours to obtain modified magnesium oxide with an average particle size of less than 30 μm.

[0038] Preparation Example 6: The difference between this preparation example and Preparation Example 4 is that: Magnesium oxide powder was subjected to plasma etching using argon gas at a etching rate of 20 nm / min for 5 min. After etching, 1 kg of magnesium oxide powder was placed in 5 kg of ethanolamine ethanol solution with a mass fraction of 2% and stirred for 10 min. The magnesium oxide powder was then separated by filtration to obtain loaded magnesium oxide. The average particle size of the magnesium oxide powder was 30 μm. Polyethylene glycol was placed in ethanol and stirred until completely dissolved. The polyethylene glycol was polyethylene glycol 1000, resulting in a 5% (w / w) polyethylene glycol ethanol solution. 0.18 kg of magnesium oxide nanosheets with an average particle size of 200 nm were added to 1 kg of the polyethylene glycol ethanol solution. The magnesium oxide nanosheets were then added and ultrasonically dispersed at 20 kHz for 10 min. After mixing evenly, the polyethylene glycol composite material was obtained. Magnesium oxide and polyethylene glycol composite were mixed at a mass ratio of 100:6, dried at 120°C for 2 hours, and then sintered at 580°C for 4 hours to obtain modified magnesium oxide with an average particle size of less than 50 μm. Example

[0039] Example 1: A method for preparing a high-temperature and sulfur-resistant shift catalyst: S1. Boehmite and magnesium oxide are combined to obtain a composite matrix; S2. The composite matrix is ​​immersed in a composite solution of cobalt nitrate, ammonium molybdate, cerium nitrate, bismuth nitrate, and antimony nitrate to obtain the loaded material. S3. Add binder to the load material and knead. The amount of binder added is 5% of the load material. The binder is a polyvinyl alcohol solution. The polyvinyl alcohol solution is a 1% (w / w) aqueous solution of polyvinyl alcohol. Then dry at 120°C for 2 hours and sinter at 580°C for 4 hours to obtain the finished product. The finished product contains: 4% cobalt oxide, 6% molybdenum oxide, 70% aluminum oxide, 15% magnesium oxide, 3% cerium oxide, 1.2% bismuth oxide, and 0.8% antimony oxide.

[0040] Example 2: The difference between this example and Example 1 is that: S3. Add binder to the load material and knead. The amount of binder added is 5% of the load material. The binder is a polyvinyl alcohol solution. The polyvinyl alcohol solution is a 1% (w / w) aqueous solution of polyvinyl alcohol. Then dry at 100°C for 2 hours and sinter at 500°C for 4 hours to obtain the finished product. The finished product contains: 2% cobalt oxide, 8% molybdenum oxide, 77% aluminum oxide, 10% magnesium oxide, 2% cerium oxide, 0.5% bismuth oxide, and 0.5% antimony oxide.

[0041] Example 3: The difference between this example and Example 1 is that: S3. Add binder to the load material and knead. The amount of binder added is 5% of the load material. The binder is a polyvinyl alcohol solution, which is a 1% (w / w) polyvinyl alcohol aqueous solution. Then dry at 130℃ for 2 hours and sinter at 600℃ for 4 hours to obtain the finished product. The finished product contains: 5% cobalt oxide, 5% molybdenum oxide, 62% aluminum oxide, 20% magnesium oxide, 5% cerium oxide, 2% bismuth oxide, and 1% antimony oxide.

[0042] Example 4: The difference between this example and Example 1 is that: The boehmite in the raw materials was the boehmite prepared in Preparation Example 1, and the magnesium oxide was the modified magnesium oxide prepared in Preparation Example 4.

[0043] Example 5: The difference between this example and Example 1 is that: The boehmite in the raw materials was the boehmite prepared in Preparation Example 2, and the magnesium oxide was the modified magnesium oxide prepared in Preparation Example 5.

[0044] Example 6: The difference between this example and Example 1 is that: The boehmite in the raw materials was the boehmite prepared in Preparation Example 3, and the magnesium oxide was the modified magnesium oxide prepared in Preparation Example 6.

[0045] Example 7: The difference between this example and Example 4 is that: No hydroxyapatite nanowires were added during the preparation of the modified boehmite in the raw materials.

[0046] Example 8: The difference between this example and Example 4 is that: No polyethylene glycol composite material was added during the preparation of modified magnesium oxide.

[0047] Example 9: The difference between this example and Example 4 is that: In the preparation of modified magnesium oxide, polyethylene glycol composites were used to prepare magnesium oxide nanosheets without the addition of magnesium oxide.

[0048] Comparative Example Comparative Example 1: The difference between this comparative example and Example 1 is that: Bismuth nitrate and antimony nitrate were not added to the raw materials.

[0049] Performance testing 1. Activity detection The finished catalysts were prepared using the methods of Examples 1-9 and Comparative Example 1, respectively. The conversion rate of petroleum was tested according to SH / T0579, and the data were recorded.

[0050] 2. Structural stability testing Finished catalysts were prepared using the methods of Examples 1-9 and Comparative Example 1, respectively. The specific surface area of ​​the catalysts was measured, and then the catalysts were run at 400°C for 12 hours. The specific surface area was measured again, and the rate of decrease in specific surface area was recorded. The higher the rate of decrease in specific surface area, the more severe the sintering phenomenon or the collapse of the pores, which would lead to a decrease in the structural stability of the catalyst.

[0051] 3. Heat resistance test The finished catalysts were prepared using the methods of Examples 1-9 and Comparative Example 1, respectively. The catalysts were used at 400°C for 12 hours, and then the conversion rate of petroleum was detected and the data were recorded.

[0052] 4. Sulfur conversion test The finished catalysts were prepared using the methods of Examples 1-9 and Comparative Example 1, respectively. The catalysts were exposed to hydrogen sulfide for 12 hours, and then the conversion rate of petroleum was measured and the data were recorded.

[0053] Table 1 Performance Test Table

[0054] As can be seen from Examples 1-3 and Table 1, the catalyst prepared in this application has a high conversion rate, maintains a high catalytic rate at high temperatures and under hydrogen sulfide conditions, and is not easily sintered at high temperatures, indicating that the finished catalyst has high catalytic activity, high temperature resistance, sulfur conversion resistance, and structural stability.

[0055] As can be seen from Examples 1 and 4-6 and Table 1, the modified boehmite and magnesium oxide can further improve catalytic activity, enhance structural stability, and also improve high temperature resistance and sulfur conversion resistance.

[0056] Combining Examples 4 and 7-9 with Table 1, it can be seen that in the preparation process of modified boehmite in Example 7, no hydroxyapatite nanowires were added. Compared with Example 4, the conversion rate of the catalyst in Example 7 was lower than that in Example 4, the specific surface area decreased more than that in Example 4, and the heat resistance conversion rate was lower than that in Example 4. This indicates that the addition of hydroxyapatite nanowires can not only provide structural support and ensure porosity, but also improve the catalyst's conversion rate and heat resistance due to its high heat resistance and high specific surface area expansion effect.

[0057] In Example 8, no polyethylene glycol composite was added during the preparation of modified magnesium oxide. Compared to Example 4, the conversion rate of the catalyst in Example 8 was lower than that in Example 4, the decrease rate of specific surface area was higher than that in Example 4, and the heat resistance conversion rate was lower than that in Example 4. This indicates that with the addition of polyethylene glycol composite, magnesium oxide nanosheets have a higher specific surface area and more active sites. Under the condition of polyethylene glycol ethanol solution, magnesium oxide nanosheets do not easily adsorb moisture. After binding to the surface of magnesium oxide powder, a composite network structure of magnesium oxide particles and magnesium oxide nanosheets is formed, thereby further improving the activity and catalytic effect of magnesium oxide and enhancing the catalytic effect of the catalyst.

[0058] In Example 9, during the preparation of modified magnesium oxide, the polyethylene glycol composite material was prepared without the addition of magnesium oxide nanosheets. Compared to Example 4, the conversion rate of the catalyst in Example 9 was lower than that in Example 4, the decrease rate of specific surface area was higher than that in Example 4, and the heat resistance conversion rate was lower than that in Example 4. This indicates that the magnesium oxide nanosheets adhere to the surface of micron-sized particles, preferentially exposing high surface energy crystal planes, increasing the oxygen vacancy density and the number of basic sites, thereby improving the activity of the catalyst. Furthermore, the nanosheet layer acts as a rigid "skeleton" to encapsulate the matrix particles, physically preventing direct contact between adjacent MgO grains, inhibiting grain boundary migration, and ensuring structural stability. The oxygen vacancies on the surface of the nanosheets preferentially adsorb hydrogen sulfide, forming reversible Mg-S bonds, thus preventing permanent sulfidation of active sites.

[0059] Combining Example 1 and Comparative Example 1 with Table 1, it can be seen that Comparative Example 1 did not add bismuth nitrate and antimony nitrate to its raw materials. Compared with Example 1, the conversion rate of the catalyst in Comparative Example 1 was lower than that in Example 1, the specific surface area reduction rate was higher than that in Example 1, and the heat resistance conversion rate and sulfur conversion rate were both lower than those in Example 1. This indicates that the addition of bismuth nitrate and antimony nitrate enhances the catalytic activity and structural stability of the catalyst, and can also improve the catalyst's high temperature resistance and sulfur conversion resistance.

[0060] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing a high-temperature and sulfur-resistant shift catalyst, characterized in that, Includes the following steps: S1. Boehmite and magnesium oxide are combined to obtain a composite matrix; S2. The composite matrix is ​​immersed in a composite solution of cobalt nitrate, ammonium molybdate, cerium nitrate, bismuth nitrate, and antimony nitrate to obtain the loaded material. S3. Add binder to the load material and knead, then dry and sinter to obtain the finished product.

2. The preparation method of a high-temperature and sulfur-resistant shift catalyst according to claim 1, characterized in that: The pseudoboehmite is a modified pseudoboehmite, which is prepared by the following method: Boehmite powder was soaked and dispersed in nitric acid solution for 5-10 minutes, and then the boehmite powder was separated to obtain loaded boehmite. Hydroxyapatite nanowires were soaked and dispersed in citric acid solution, and the nanowires were filtered out to obtain loaded nanowires. Loaded boehmite and loaded nanowires were mixed at a mass ratio of 1:0.05-0.1 and dispersed in water. After heating, filtering, and drying, modified boehmite was obtained.

3. The method for preparing a high-temperature and sulfur-resistant shift catalyst according to claim 2, characterized in that, The pseudoboehmite powder has an average particle size of 20-40 μm, and the hydroxyapatite nanowires have an average length of 15-25 μm.

4. The preparation method of a high-temperature and sulfur-resistant shift catalyst according to claim 1, characterized in that, The magnesium oxide is modified magnesium oxide, which is prepared by the following method: Magnesium oxide powder is plasma etched and then treated with ethanolamine solution to obtain carrier magnesium oxide. The carrier magnesium oxide is mixed with polyethylene glycol composite material at a mass ratio of 100:2-6, and then dried and sintered to obtain modified magnesium oxide.

5. The preparation method of a high-temperature and sulfur-resistant shift catalyst according to claim 4, characterized in that, The polyethylene glycol composite material is prepared by mixing polyethylene glycol ethanol solution and magnesium oxide nanosheets in a mass ratio of 1:0.1-0.

18.

6. The preparation method of a high-temperature and sulfur-resistant shift catalyst according to claim 4, characterized in that, The magnesium oxide powder has an average particle size of 10-30 μm, and the magnesium oxide nanosheets have an average particle size of 80-200 nm.

7. The preparation method of a high-temperature and sulfur-resistant shift catalyst according to claim 1, characterized in that, In step S2, the composite matrix is ​​first soaked and dispersed in cobalt nitrate, cerium nitrate, and antimony nitrate, and then ammonium molybdate is added for soaking and dispersion to complete the impregnation treatment and obtain the loaded material.

8. The method for preparing a high-temperature and sulfur-resistant shift catalyst according to claim 1, characterized in that, The adhesive is a polyvinyl alcohol solution.

9. The method for preparing a high-temperature and sulfur-resistant shift catalyst according to claim 1, characterized in that, The drying temperature is 100-130℃, and the sintering temperature is 500-600℃.

10. A high-temperature and sulfur-resistant shift catalyst prepared by the preparation method according to any one of claims 1-9, characterized in that, It contains the following raw materials by weight percentage: cobalt oxide 2-5%, molybdenum oxide 5-8%, aluminum oxide 62-77%, magnesium oxide 10-20%, cerium oxide 2-5%, bismuth oxide 0.5-2%, and antimony oxide 0.5-1%.

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