Hydrogenation catalyst for removing high-content mercaptan sulfur in natural gas and preparation method thereof

Abstract

The invention discloses a hydrogenation catalyst for removing high-content mercaptan sulfur in natural gas, which takes potassium fluoride modified titanium-containing aluminum oxide as a carrier and comprises the following components in percentage by mass: 5.0%-15.0% of MoO3, 1.0%-4.0% of CoO, 0.5%-3.6% of NiO, 1.5%-4.5% of KF and 0.5%-4.0% of CeO2, the preparation method comprises the following steps: 1, carrying out ball milling on metatitanic acid and pseudo-boehmite, and modifying with a potassium fluoride solution to prepare a carrier; and 2, impregnating the potassium fluoride modified titanium-containing alumina carrier with an impregnation liquid containing an active component raw material to prepare the hydrogenation catalyst. According to the invention, potassium fluoride modified titanium-containing aluminum oxide is adopted as a carrier, and rare earth cerium is introduced for modification, so that dispersion of active metal molybdenum, cobalt and nickel components is promoted, adsorption activation and dissociation of mercaptan molecules are enhanced, and mercaptan catalytic conversion activity and sintering resistance of the catalyst are improved; the preparation method is simple and easy to implement.

Description

Technical Field

[0001] This invention belongs to the field of natural gas purification technology, specifically relating to a hydrogenation catalyst for removing high levels of mercaptan sulfur from natural gas and its preparation method. Background Technology

[0002] Natural gas, as a clean energy source, is accounting for an increasing proportion of my country's primary energy consumption structure year by year. Its purification process is a crucial step in ensuring safe transmission and efficient use. Currently, GB17820-2018 "Natural Gas" sets the limit for total sulfur concentration in Class I commercial natural gas at 200 mg / m³. 3 Upgraded to 20mg / m 3 In addition to H2S, natural gas also contains certain organic sulfides. Thiols are common organic sulfides in natural gas, which not only have a strong odor and are corrosive, but also easily poison and deactivate downstream catalysts. For natural gas containing high concentrations of thiols (thiols per ppm), the deep purification and removal of thiols is a key technology for its effective utilization.

[0003] Currently, commonly used mercaptan removal technologies both domestically and internationally include alkaline washing, Merox extraction-oxidation, fiber membrane technology, adsorption-based mercaptan removal, catalytic oxidation-adsorption, and hydroconversion-absorption. Among these, alkaline washing effectively removes mercaptan with low boiling points, but its drawbacks include high alkali consumption, generating large amounts of waste residue, and potential secondary environmental pollution. Merox extraction-oxidation has a low overall desulfurization rate, and the catalyst is prone to aggregation and deactivation. Fiber membrane technology offers high removal precision, but its disadvantages include high investment costs and the potential for impurities to clog pipelines. Adsorption-based mercaptan removal and catalytic oxidation-adsorption both face limitations in the effective adsorption capacity of the adsorbent for mercaptan. Hydroconversion-absorption converts mercaptan to hydrogen sulfide under the action of a hydrogenation catalyst, and then removes the hydrogen sulfide using an adsorbent. Its advantages include high removal precision, but its disadvantage is high operating temperature. Traditional cobalt-molybdenum hydrogenation catalysts, nickel-molybdenum hydrogenation catalysts, and zinc-based catalysts suffer from problems such as low active metal dispersion, easy sintering, and carbon deposition leading to deactivation. Especially when processing high concentrations of thiols, the catalyst can overheat locally due to intense exothermic reactions, accelerating sintering and deactivation.

[0004] Patent CN02101986.X discloses a gas-phase fluorination preparation method for a CoMo / TiO2-Al2O3 hydrodesulfurization catalyst, which improves the hydrogenation activity of the catalyst by fluorinating the support with Freon-rich moist air. Although this method improves the catalyst performance, its removal efficiency for thiols, especially higher thiols, is still insufficient, and it uses harmful Freon as a fluorinating agent, which does not meet environmental protection requirements.

[0005] Patent CN105749925A describes a catalyst for heavy oil hydrotreating, employing a silicon- or fluorine-containing alumina support and a cobalt-nickel bimetallic component. No characteristic MoO3 peak appears at a diffraction angle of 2θ = 26° ± 2°, indicating high metal dispersion. However, this catalyst is designed for heavy oil processing and has poor adaptability for natural gas desulfurization, particularly exhibiting poor selective adsorption of thiols. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide a hydrogenation catalyst for removing high-content thiol sulfur from natural gas, addressing the shortcomings of the prior art. The hydrogenation catalyst of this invention uses potassium fluoride-modified titanium-containing alumina as a support and introduces rare earth cerium modification, which promotes the dispersion of active metal molybdenum, cobalt, and nickel components, helps maintain the active centers of the catalyst, enhances the adsorption, activation, and dissociation of thiol molecules, significantly improves the thiol catalytic conversion activity and anti-sintering properties of the catalyst, and solves the problems of low catalyst activity, easy deactivation, and poor selectivity in the prior art.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a hydrogenation catalyst for removing high-content mercaptan sulfur from natural gas, characterized in that it uses potassium fluoride-modified titanium-containing alumina as a support, and comprises the following components by mass percentage of the total hydrogenation catalyst: MoO3 5.0%~15.0%, CoO 1.0%~4.0%, NiO 0.5%~3.6%, KF 1.5%~4.5%, CeO2 0.5%~4.0%.

[0008] The above-mentioned hydrogenation catalyst for removing high-content mercaptan sulfur from natural gas is characterized in that it is composed of the following components by mass percentage of the total hydrogenation catalyst: MoO 35.0%~15.0%, CoO 1.0%~4.0%, NiO 0.5%~3.6%, KF 1.5%~4.5%, CeO 20.5%~4.0%, Al2O 356.3%~73.8%, and TiO 25.0%~21.0%.

[0009] Meanwhile, this invention also discloses a method for preparing a hydrogenation catalyst for removing high-content mercaptan sulfur from natural gas as described above, characterized in that the method includes the following steps: Step 1: After ball milling and mixing metatitanic acid and pseudoboehmite, the powder particles with a diameter greater than 0.04 mm are sieved out to obtain mixed powder. Then, the mixed powder is impregnated with potassium fluoride solution for modification treatment. It is then transferred to a kneader and kneaded evenly. Guess powder and nitric acid solution are added and mixed evenly. After kneading, extrusion molding, drying and calcination, potassium fluoride modified titanium-containing alumina carrier is obtained. Step 2: Mix the molybdenum-containing compound, cobalt-containing compound, nickel-containing compound and cerium-containing compound with an ammonia solution and stir until homogeneous to obtain a stable impregnation solution. Then, impregnate the potassium fluoride-modified titanium-containing alumina support obtained in Step 1 with the impregnation solution using an equal-volume impregnation method. After drying and calcination, the hydrogenation catalyst is obtained.

[0010] The above preparation method is characterized in that the mass concentration of the potassium fluoride solution in step one is 5.0%~12.26%.

[0011] The above preparation method is characterized in that the mass of guar gum powder added in step one is 1.0% to 3.0% of the total dry mass of metatitanic acid and pseudoboehmite, the concentration of the nitric acid solution is 5.0%, and the ratio of the volume of the added nitric acid solution to the mass of the raw material powder, i.e., metatitanic acid and pseudoboehmite spheres, is 20 mL to 40 mL: 100 g.

[0012] The preparation method described above is characterized in that the drying temperature in step one is 80℃~120℃ and the calcination temperature is 540℃~600℃.

[0013] The above preparation method is characterized in that the molybdenum-containing compound in step two is selected from one or more of molybdic acid, ammonium heptamolybdate, and ammonium tetramolybdate; the cobalt-containing compound and the nickel-containing compound are both selected from one or more of chloride salts, nitrate salts, sulfate salts, and acetate salts; and the cerium-containing compound is selected from one or more of cerium nitrate, cerium chloride, cerium sulfate, and cerium fluoride.

[0014] The above preparation method is characterized in that the concentration of the ammonia solution in step two is 15%~23%.

[0015] The above preparation method is characterized in that the impregnation time in step two is 4h~12h, the drying temperature is 60℃~120℃ and the drying time is 4h~20h, and the calcination temperature is 450℃~550℃.

[0016] The above preparation method is characterized in that the hydrogenation catalyst described in step two is sulfided and then reacted with natural gas at a reaction pressure of 0.5 MPa to 3.0 MPa, a reaction temperature of 280°C to 320°C, and a reaction space velocity of 1000 h⁻¹. -1 ~3000h -1 Under the specified reaction conditions, the removal rate of mercaptans sulfur in natural gas with a content as high as 2400 ppm reaches over 99.9%. Compared to the optimal reaction temperature of 350℃~380℃ for traditional hydrogenation catalysts, the hydrogenation catalyst of this invention exhibits significant low-temperature reaction activity.

[0017] Compared with the prior art, the present invention has the following advantages: 1. The hydrogenation catalyst of the present invention uses potassium fluoride-modified titanium-containing alumina as a support. The interaction between potassium fluoride and the TiO2-Al2O3 surface forms strong acidic sites, which enhances the acidity of the support surface, promotes the dispersion of active metal molybdenum, cobalt and nickel components, and enhances the adsorption and activation of thiol molecules, effectively improving the catalytic conversion activity and selectivity of the hydrogenation catalyst for thiol sulfur.

[0018] 2. The hydrogenation catalyst of this invention incorporates rare earth metal cerium as an auxiliary component. By impregnating a cerium-containing compound on a support and calcining it to form highly dispersed nano-sized cerium oxide particles, the oxygen vacancies and hydroxyl groups on the surface of these particles serve as strong anchoring sites for active metal ions. This makes the precursor compounds of other active metals more inclined to interact strongly with cerium oxide during heat treatment, rather than agglomerating with each other. This achieves high dispersion of active metal particles at the atomic or nanoscale, thereby improving the anti-sintering properties of the hydrogenation catalyst. At the same time, the introduction of rare earth metal cerium enriches the oxygen vacancies on the catalyst surface, promoting the adsorption and dissociation of thiol molecules in subsequent desulfurization processes, further improving the catalytic conversion activity of the hydrogenation catalyst for thiol sulfur, making it suitable for the removal of high-content thiol sulfur.

[0019] 3. In the hydrogenation catalyst of this invention, potassium fluoride is used as a modifier to precisely adjust the acidity and acid site distribution on the support surface, and strong alkaline metal ions K+ are used. + and F, which has extremely high electronegativity - The synergistic effect of these factors, through induction, generates new Lewis acid sites of moderate strength on the support surface, reducing the large number of strong Lewis acid sites (coordinate-unsaturated Al) present on the support surface. 3+ The addition of ions and some Brewster acid sites (-OH groups) weakens the strong acid centers that cause high-temperature carbonization of hydrocarbons, while retaining sufficient acidity for CS bond breaking (the intrinsic reaction of HDS). This changes the acidity distribution of the catalyst from "more strong acids" which is unfavorable to the reaction to "more medium-strong acids" which is favorable to the reaction, greatly inhibiting the occurrence of acid-catalyzed carbonization reactions. At the same time, by introducing cerium into the support for surface modification to form a TiO2-Al2O3-CeO2 composite support, the hierarchical pore structure with both macroporous and mesoporous structures achieves selective adsorption of thiol molecules and repulsion of macromolecular carbonization precursors, improving the activity and stability of the hydrogenation catalyst and increasing the thiol conversion rate.

[0020] 4. In this invention, cobalt, molybdenum, nickel and cerium components are first prepared into a uniform impregnation solution, and then each component is introduced into the carrier by an equal volume impregnation method. After drying and calcination, a hydrogenation catalyst is obtained. This preparation method is simple, easy to implement, and suitable for widespread application.

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the performance evaluation device for the hydrogenation catalyst of the present invention.

[0023] Explanation of reference numerals in the attached figures Detailed Implementation

[0024] like Figure 1 As shown, the performance evaluation device for the hydrogenation catalyst of the present invention includes a reactor 7, and a hydrogen cylinder 1, a raw material gas cylinder 2, a nitrogen cylinder 3, and a sulfurizing agent storage tank 5 are connected in parallel at the inlet of the reactor 7. A first pressure reducing valve 6-1, a second pressure reducing valve 6-2, and a third pressure reducing valve 6-3 are respectively installed on the pipelines connecting the hydrogen cylinder 1, the raw material gas cylinder 2, and the nitrogen cylinder 3. A horizontal flow pump 4 is installed on the pipeline connecting the sulfurizing agent storage tank 5. A condenser 8, a water separator 9, a rotor flow meter 10, and a wet gas flow meter 11 are sequentially connected at the outlet of the reactor 7.

[0025] at the same time, Figure 1 The performance evaluation device for hydrogenation catalysts can also be used as an in-cabin sulfidation device for hydrogenation catalysts.

[0026] The sulfidation process of the hydrogenation catalyst in this invention is as follows: the oxidized hydrogenation catalyst is loaded into reactor 7. First, the third pressure reducing valve 6-3 is controlled to replace the reactor 7 with nitrogen gas. Then, the first pressure reducing valve 6-1 is switched to introduce hydrogen gas into reactor 7. Then, the temperature of reactor 7 is raised to 190°C. Carbon disulfide is introduced into reactor 7 through the horizontal flow pump 4, and the temperature is slowly raised to 350°C. At the same time, the hydrogen sulfide content at the outlet of reactor 7 is detected by a hydrogen sulfide detection tube. When the hydrogen sulfide content at the outlet reaches 10,000 ppm, the sulfidation of the hydrogenation catalyst is considered to be completed.

[0027] The performance evaluation process of the hydrogenation catalyst in this invention is as follows: The sulfidated hydrogenation catalyst is loaded into reactor 7 according to its original particle size. Simulated natural gas is used as the feed gas. Simulated natural gas is introduced into reactor 7 by controlling the second pressure reducing valve 6-2, allowing the sulfidated hydrogenation catalyst to react with the natural gas to remove mercaptans from the natural gas. Typically, the reaction pressure of the sulfidated hydrogenation catalyst reacting with natural gas is 0.5 MPa to 3.0 MPa, the reaction temperature is 280℃ to 320℃, and the reaction space velocity is 1000 h⁻¹. -1 ~3000h -1 .

[0028] Example 1 The hydrogenation catalyst in this embodiment uses potassium fluoride-modified titanium-containing alumina as a support and includes the following components by mass percentage of the total hydrogenation catalyst: MoO 35.0%, CoO 1.02%, NiO 3.59%, KF 4.5%, CeO 20.5%, Al2O 369.96%, and TiO 214.43%.

[0029] The preparation method of the hydrogenation catalyst in this embodiment includes the following steps: Step 1: Place 37.82g of metatitanic acid and 205.76g of pseudoboehmite into a ball mill and ball mill them together for 8 hours. Then, sieve out the powder with a particle size greater than 0.04mm to obtain the mixed powder. Weigh 9.0g of potassium fluoride and dissolve it in 64.4mL of deionized water to prepare a potassium fluoride solution with a concentration of 12.26%. Then, the mixed powder and potassium fluoride solution were added to a kneader and kneaded evenly for 30 minutes. Then, 7.58 g of guar gum powder and 48.72 mL of 5% nitric acid solution were added and mixed evenly. After kneading, the mixture was placed in an extruder and extruded into shape. After being placed at room temperature for 24 hours, it was dried at 110℃ for 12 hours and calcined at 550℃ for 4 hours to obtain potassium fluoride modified titanium-containing alumina carrier. Step 2: Mix 6.26g ammonium heptamolybdate, 4.04g cobalt nitrate, 14.26g nickel nitrate and 1.29g cerium nitrate with 62.92mL of 15% ammonia solution and stir until homogeneous to obtain a stable impregnation solution. Then, impregnate 89.89g of the potassium fluoride-modified titanium-containing alumina support obtained in Step 1 with the impregnation solution at room temperature for 12h using the equal-volume impregnation method. After drying at 100℃ for 20h and calcining at 450℃ for 4h, the hydrogenation catalyst is obtained, denoted as Catalyst I.

[0030] In step two of this embodiment, the molybdenum-containing compound may also be selected from one or more of molybdic acid, ammonium heptamolybdate, and ammonium tetramolybdate, excluding ammonium heptamolybdate. The cobalt-containing compound and the nickel-containing compound may also be selected from one or more of chloride, nitrate, sulfate, and acetate, excluding nitrate. The cerium-containing compound may also be selected from one or more of cerium nitrate, cerium chloride, cerium sulfate, and cerium fluoride, excluding cerium nitrate.

[0031] Example 2 The hydrogenation catalyst in this embodiment uses potassium fluoride-modified titanium-containing alumina as a support and includes the following components by mass percentage of the total hydrogenation catalyst: MoO 39.55%, CoO 3.52%, NiO 3.13%, KF 3.72%, CeO 21.44%, Al2O 357.64%, and TiO 21.0%.

[0032] The preparation method of the hydrogenation catalyst in this embodiment includes the following steps: Step 1: Place 51.48g of metatitanic acid and 169.52g of pseudoboehmite into a ball mill and ball mill them together for 8 hours. Then, sieve out the powder with a particle size greater than 0.04mm to obtain the mixed powder. Weigh 7.44g of potassium fluoride and dissolve it in 67.8mL of deionized water to prepare a potassium fluoride solution with a concentration of 9.89%. Then, the mixed powder and potassium fluoride solution were added to a kneader and kneaded evenly for 30 minutes. Then, 5.48 g of guar gum powder and 70.18 mL of 5% nitric acid solution were added and mixed evenly. After kneading, the mixture was placed in an extruder and extruded into shape. After being placed at room temperature for 24 hours, it was dried at 80℃ for 20 hours and calcined at 580℃ for 4 hours to obtain potassium fluoride modified titanium-containing alumina carrier. Step 2: Mix 11.95g ammonium heptamolybdate, 13.96g cobalt nitrate, 12.44g nickel nitrate and 3.71g cerium nitrate with 57.65mL of 18% ammonia solution and stir until homogeneous to obtain a stable impregnation solution. Then, impregnate 82.36g of the potassium fluoride-modified titanium-containing alumina support obtained in Step 1 with the impregnation solution at room temperature for 4h using the equal-volume impregnation method. After drying at 60℃ for 20h and calcining at 500℃ for 4h, the hydrogenation catalyst is obtained and designated as Catalyst II.

[0033] Example 3 The hydrogenation catalyst in this embodiment uses potassium fluoride-modified titanium-containing alumina as a support and includes the following components by mass percentage of the total hydrogenation catalyst: MoO3 10.31%, CoO 2.84%, NiO 2.06%, KF 3.01%, CeO2 1.87%, Al2O3 69.02%, and TiO2 10.89%.

[0034] The preparation method of the hydrogenation catalyst in this embodiment includes the following steps: Step 1: Place 26.7g of metatitanic acid and 203g of pseudoboehmite into a ball mill and ball mill them together for 8 hours. Then, sieve out the powder with a particle size greater than 0.04mm to obtain the mixed powder. Weigh 6.02g of potassium fluoride and dissolve it in 81.2mL of deionized water to prepare a potassium fluoride solution with a concentration of 6.9%. Then, the mixed powder and potassium fluoride solution were added to a kneader and kneaded evenly for 30 minutes. Then, 4.94 g of guar gum powder and 60.71 mL of 5% nitric acid solution were added and mixed evenly. After kneading, the mixture was placed in an extruder and extruded into shape. After being placed at room temperature for 24 hours, it was dried at 100℃ for 12 hours and calcined at 580℃ for 4 hours to obtain potassium fluoride modified titanium-containing alumina carrier. Step 2: Mix 12.9g ammonium heptamolybdate, 11.26g cobalt nitrate, 8.18g nickel nitrate and 4.81g cerium nitrate with 58.04mL of 21% ammonia solution and stir until homogeneous to obtain a stable impregnation solution. Then, impregnate 82.92g of potassium fluoride-modified titanium-containing alumina support obtained in Step 1 with the impregnation solution at room temperature for 8h using the equal-volume impregnation method. After drying at 120℃ for 4h and calcining at 510℃ for 4h, the hydrogenation catalyst is obtained and designated as catalyst III.

[0035] Example 4 The hydrogenation catalyst in this embodiment uses potassium fluoride-modified titanium-containing alumina as a support and includes the following components by mass percentage of the total hydrogenation catalyst: MoO3 11.65%, CoO 2.46%, NiO 1.66%, KF 2.56%, CeO2 2.86%, Al2O3 73.8%, and TiO2 5.01%.

[0036] The preparation method of the hydrogenation catalyst in this embodiment includes the following steps: Step 1: Place 12.28g of metatitanic acid and 217g of pseudoboehmite into a ball mill and ball mill them together for 8 hours. Then, sieve out the powder with a particle size greater than 0.04mm to obtain the mixed powder. Weigh 5.12g of potassium fluoride and dissolve it in 86.8mL of deionized water to prepare a potassium fluoride solution with a concentration of 5.75%. Then, the mixed powder and potassium fluoride solution were added to a kneader and kneaded evenly for 30 minutes. Then, 3.52 g of guar gum powder and 81.7 mL of 5% nitric acid solution were added and mixed evenly. After kneading, the mixture was placed in an extruder and extruded into shape. After being placed at room temperature for 24 hours, it was dried at 120℃ for 12 hours and calcined at 540℃ for 4 hours to obtain potassium fluoride modified titanium-containing alumina carrier. Step 2: Mix 14.58g ammonium heptamolybdate, 9.75g cobalt nitrate, 6.6g nickel nitrate and 7.36g cerium nitrate with 56.96mL of 23% ammonia solution and stir until homogeneous to obtain a stable impregnation solution. Then, impregnate 81.37g of the potassium fluoride-modified titanium-containing alumina support obtained in Step 1 with the impregnation solution at room temperature for 10h using the equal-volume impregnation method. After drying at 100℃ for 10h and calcining at 550℃ for 4h, the hydrogenation catalyst is obtained and designated as catalyst IV.

[0037] Example 5 The hydrogenation catalyst in this embodiment uses potassium fluoride-modified titanium-containing alumina as a support and includes the following components by mass percentage of the total hydrogenation catalyst: MoO3 15.0%, CoO 3.99%, NiO 0.51%, KF 1.50%, CeO2 3.99%, Al2O3 56.36%, TiO2 18.65%.

[0038] The preparation method of the hydrogenation catalyst in this embodiment includes the following steps: Step 1: Place 45.72g of metatitanic acid and 173.36g of pseudoboehmite into a ball mill and ball mill them together for 8 hours. Then, sieve out the powder with a particle size greater than 0.04mm to obtain the mixed powder. Weigh 3.0g of potassium fluoride and dissolve it in 59.5mL of deionized water to prepare a potassium fluoride solution with a concentration of 5.04%. Then, the mixed powder and potassium fluoride solution were added to a kneader and kneaded evenly for 30 minutes. Then, 2.24 g of guar gum powder and 87.63 mL of 5% nitric acid solution were added and mixed evenly. After kneading, the mixture was placed in an extruder and extruded into shape. After being placed at room temperature for 24 hours, it was dried at 90℃ for 16 hours and calcined at 600℃ for 4 hours to obtain potassium fluoride modified titanium-containing alumina carrier. Step 2: Mix 18.77g ammonium heptamolybdate, 15.82g cobalt nitrate, 3.30g nickel nitrate and 10.27g cerium nitrate with 53.56mL of 23% ammonia solution and stir until homogeneous to obtain a stable impregnation solution. Then, impregnate 76.51g of the potassium fluoride-modified titanium-containing alumina support obtained in Step 1 with the impregnation solution at room temperature for 10h using the equal-volume impregnation method. After drying at 90℃ for 16h and calcining at 480℃ for 4h, the hydrogenation catalyst is obtained and designated as catalyst V.

[0039] Comparative Example 1 The hydrogenation catalyst in this comparative example uses potassium fluoride-modified alumina as a support and comprises the following components by mass percentage of the total hydrogenation catalyst: MoO3 11.65%, CoO 2.46%, NiO 1.66%, KF 2.56%, CeO2 2.86%, and Al2O3 78.81%.

[0040] The preparation method of the hydrogenation catalyst in this comparative example includes the following steps: Step 1: Place 239.32g of pseudoboehmite into a ball mill and ball mill for 8 hours. After mixing, sieve out the powder with a particle size greater than 0.04mm to obtain a mixed powder. Weigh 5.12g of potassium fluoride and dissolve it in 86.8mL of deionized water to prepare a 5.75% potassium fluoride solution. Then, the mixed powder and potassium fluoride solution were added to a kneader, followed by 6.03g of guar gum powder and 73.86mL of 5% nitric acid solution. After kneading, the mixture was placed in an extruder and extruded. After being left at room temperature for 24 hours, it was dried at 110℃ for 16 hours and calcined at 540℃ for 4 hours to obtain potassium fluoride modified alumina carrier. Step 2: Mix 14.58g ammonium heptamolybdate, 9.75g cobalt nitrate, 6.60g nickel nitrate and 7.36g cerium nitrate with 56.96mL of 23% ammonia solution and stir until homogeneous to obtain a stable impregnation solution. Then, impregnate 81.37g of the alumina support obtained in Step 1 with the impregnation solution at room temperature for 10h using the equal volume impregnation method. After drying at 100℃ for 16h and calcining at 500℃ for 4h, the hydrogenation catalyst is obtained and designated as catalyst VI.

[0041] Comparative Example 2 The hydrogenation catalyst in this comparative example uses titanium-containing alumina as a support and comprises the following components by mass percentage of the total hydrogenation catalyst: MoO3 11.65%, CoO 2.46%, NiO 1.66%, Al2O3 79.22%, and TiO2 5.01%.

[0042] The preparation method of the hydrogenation catalyst in this comparative example includes the following steps: Step 1: 12.28g of metatitanic acid and 233g of pseudoboehmite were ball-milled for 8 hours. Powder particles larger than 0.04mm were sieved out. The resulting mixed powder was added to a kneader with 98.16ml of deionized water and kneaded evenly for 30 minutes. Then, 3.68g of guar gum powder and 74.48mL of 5% nitric acid solution were added and mixed evenly. After kneading, the mixture was placed in an extruder and extruded into shape. It was left at room temperature for 24 hours, dried at 120℃ for 12 hours and calcined at 540℃ for 4 hours to obtain potassium fluoride modified titanium-containing alumina carrier. Step 2: Mix 14.58g ammonium heptamolybdate, 9.75g cobalt nitrate, 6.6g nickel nitrate with 58.96mL of 23% ammonia solution and stir until homogeneous to obtain a stable impregnation solution. Then, impregnate 84.23g of potassium fluoride-modified titanium-containing alumina support obtained in Step 1 with the impregnation solution at room temperature for 10h using the equal-volume impregnation method. After drying at 100℃ for 10h and calcining at 510℃ for 4h, the hydrogenation catalyst is obtained and designated as catalyst VII.

[0043] The performance of the hydrogenation catalysts in Examples 1-5 and Comparative Examples 1 and 2 of this invention was evaluated under the following test conditions: the simulated natural gas composition, by volume fraction (vol%), included: N2 0.44%, CO 0.07%, CH4 90.05%, CO2 2.47%, H2 6.97%, and methanethiol 145 ppm, ethanethiol 513 ppm, n-propanethiol 853 ppm, n-butanethiol 966 ppm, and H2S 75 ppm; the loading amount of the sulfided hydrogenation catalyst was 30 mL, the height-to-diameter ratio (i.e., the ratio of the loading height to the cross-sectional diameter of reactor 7) was 2.7, the reaction pressure was 2.0 MPa, the reaction temperature was 300 °C, and the reaction space velocity was 2000 h⁻¹. -1The content of mercaptan and hydrogen sulfide in the outlet gas of the performance evaluation device was analyzed, and the mercaptan conversion rate was calculated. The results are shown in Table 1 below.

[0044] Table 1. Activity Evaluation Table for Desulfurization Hydrogenation Catalysts

[0045] As can be seen from Table 1, the thiol hydrogenation conversion activities of catalysts I, II, III, IV, and V in Examples 1-5 of the present invention all exceeded those of catalyst VI in Comparative Example 1 and catalyst VII in Comparative Example 2. Among them, catalyst IV in Example 4 showed the best thiol hydrogenation conversion activity, with a thiol conversion rate of 99.9%. This indicates that the hydrogenation catalyst of the present invention, by using potassium fluoride-modified titanium-containing alumina as a support and introducing rare earth cerium modification, significantly improved the thiol catalytic conversion activity of the catalyst, and achieved effective removal of high-content thiol sulfur from natural gas.

[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A hydrogenation catalyst for removing high levels of mercaptans from natural gas, characterized in that, Using potassium fluoride-modified titanium-containing alumina as a support, the following components are included by mass percentage of the total hydrogenation catalyst: MoO3 5.0%~15.0%, CoO 1.0%~4.0%, NiO 0.5%~3.6%, KF 1.5%~4.5%, CeO2 0.5%~4.0%.

2. The hydrogenation catalyst for removing high-content mercaptan sulfur from natural gas according to claim 1, characterized in that, The catalyst is composed of the following components by mass percentage of the total hydrogenation catalyst: MoO3 5.0%~15.0%, CoO 1.0%~4.0%, NiO 0.5%~3.6%, KF 1.5%~4.5%, CeO2 0.5%~4.0%, Al2O3 56.3%~73.8%, and TiO2 5.0%~21.0%.

3. A method for preparing a hydrogenation catalyst for removing high-content mercaptan sulfur from natural gas as described in claim 1 or 2, characterized in that, The method includes the following steps: Step 1: After ball milling and mixing metatitanic acid and pseudoboehmite, the powder particles with a diameter greater than 0.04 mm are sieved out to obtain mixed powder. Then, the mixed powder is impregnated with potassium fluoride solution for modification treatment. It is then transferred to a kneader and kneaded evenly. Guess powder and nitric acid solution are added and mixed evenly. After kneading, extrusion molding, drying and calcination, potassium fluoride modified titanium-containing alumina carrier is obtained. Step 2: Mix the molybdenum-containing compound, cobalt-containing compound, nickel-containing compound and cerium-containing compound with an ammonia solution and stir until homogeneous to obtain a stable impregnation solution. Then, impregnate the potassium fluoride-modified titanium-containing alumina support obtained in Step 1 with the impregnation solution using an equal-volume impregnation method. After drying and calcination, the hydrogenation catalyst is obtained.

4. The preparation method according to claim 3, characterized in that, The mass concentration of the potassium fluoride solution mentioned in step one is 5.0%~12.26%.

5. The preparation method according to claim 3, characterized in that, In step one, the added mass of guar gum powder is 1.0% to 3.0% of the total dry mass of metatitanic acid and boehmite, the concentration of the nitric acid solution is 5.0%, and the ratio of the added volume of nitric acid solution to the mass of the raw material powder, i.e., metatitanic acid and boehmite balls, is 20 mL to 40 mL: 100 g.

6. The preparation method according to claim 3, characterized in that, The drying temperature in step one is 80℃~120℃, and the calcination temperature is 540℃~600℃.

7. The preparation method according to claim 3, characterized in that, In step two, the molybdenum-containing compound is selected from one or more of molybdic acid, ammonium heptamolybdate, and ammonium tetramolybdate; the cobalt-containing compound and the nickel-containing compound are selected from one or more of chloride salts, nitrate salts, sulfate salts, and acetate salts; and the cerium-containing compound is selected from one or more of cerium nitrate, cerium chloride, cerium sulfate, and cerium fluoride.

8. The preparation method according to claim 3, characterized in that, The concentration of the ammonia solution in step two is 15% to 23%.

9. The preparation method according to claim 3, characterized in that, The soaking time in step two is 4h~12h, the drying temperature is 60℃~120℃, the drying time is 4h~20h, and the calcination temperature is 450℃~550℃.

10. The preparation method according to claim 3, characterized in that, The hydrogenation catalyst described in step two is sulfided and then reacted with natural gas at a reaction pressure of 0.5 MPa to 3.0 MPa, a reaction temperature of 280°C to 320°C, and a reaction space velocity of 1000 h⁻¹. -1 ~3000h -1 Under the given reaction conditions, the removal rate of mercaptans sulfur in natural gas with a content as high as 2400 ppm reaches over 99.9%.

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