A method for preparing a desulfurization purification catalyst

Abstract

This invention belongs to the field of desulfurization catalyst technology, specifically relating to a method for preparing a desulfurization purification catalyst. This invention prepares a high-performance honeycomb desulfurization purification catalyst through the synergistic effect of multiple active components and innovative process control. The active components constitute a ZnO-CuO-CeO2-CaO quaternary system. The desulfurization purification catalyst of this invention can withstand temperatures up to 300℃ and a space velocity of 3000 h⁻¹. ‑1 Under operating conditions, the outlet H2S is ≤10ppb, COS removal rate is 99.3%, and sulfur capacity exceeds 26%, far surpassing traditional desulfurizers. In terms of process, mixed alkali co-precipitation achieves molecular-level mixing of metal ions, high-energy ball milling and programmed temperature calcination construct high-quality active centers, and γ-Al2O3 and calcium aluminate cement form a stable skeleton through steam curing, achieving a lateral compressive strength of 172 N / cm. This results in strong resistance to pulverization and abrasion, stable bed resistance reduction, and significantly extended service life.

Description

Technical Field

[0001] This invention belongs to the field of desulfurization catalyst technology, specifically relating to a method for preparing a desulfurization purification catalyst. Background Technology

[0002] Gas desulfurization is a key process in energy, chemical, semiconductor, and new energy fields, directly affecting product quality, equipment lifespan, and compliance with environmental emission standards. Currently, the mainstream desulfurizers are mainly divided into two categories: (1) Zinc oxide desulfurizer: Zinc oxide is used as the active component and aluminum oxide is used as the carrier. It has the advantages of simple preparation and low cost, but it has significant defects. The highest desulfurization accuracy can only reach 50ppb, which cannot meet the requirements of semiconductor, high-end chemical and other fields. Moreover, the removal efficiency of organic sulfur (such as COS and CS2) is low, and an additional organic sulfur conversion device is required, which increases the complexity of the process. (2) Copper-zinc-aluminum series fine desulfurizer: Through the copper-based active component, the hydrogenation reaction of organic sulfur can be promoted, which can effectively improve the removal rate of organic sulfur. However, the copper-based active component needs to be pre-reduced before use, which increases the process steps and energy consumption. In addition, the sulfur capacity is relatively low, the catalyst replacement frequency is high, and the operation and maintenance costs increase.

[0003] In addition, existing desulfurizing agents and catalysts have insufficient mechanical strength and are prone to pulverization during the start-up and shutdown of industrial plants, which will increase bed resistance and affect the stable operation of the plant.

[0004] Therefore, developing a desulfurization and purification catalyst with high desulfurization precision, high sulfur capacity, no need for pre-reduction, excellent mechanical strength, and a green and environmentally friendly preparation process has become the key to solving the current technological bottlenecks. Summary of the Invention

[0005] The purpose of this invention is to address the existing problems by providing a method for preparing a desulfurization and purification catalyst.

[0006] This invention is achieved through the following technical solution:

[0007] A method for preparing a desulfurization purification catalyst includes the following steps:

[0008] S1. Disperse boehmite in deionized water to prepare a boehmite suspension, transfer it to a reaction vessel, heat it to 60~70℃, and simultaneously add a mixed salt solution and a mixed precipitant solution dropwise while stirring at 500~600rpm. After the addition is complete, stir the mixture at a constant temperature of 500~600rpm. After the reaction is complete, hot filter the mixture and wash it with deionized water until the conductivity of the filtrate is ≤20μS / cm. Collect the filter cake.

[0009] S2. Add the filter cake obtained in step S1, activated alumina, and polyethylene glycol (PEG-400, dispersant, purity ≥99.0%) into a ball mill jar, ball mill to obtain a slurry, and dry to obtain a dried product.

[0010] S3. Transfer the dried product obtained in step S2 into a muffle furnace, introduce nitrogen into the furnace, and perform programmed temperature rise calcination. After calcination, maintain the nitrogen atmosphere and allow it to cool naturally to obtain active powder.

[0011] S4. Molding and Steam Curing:

[0012] Add calcium aluminate cement, guar gum powder, glycerin, and deionized water to the active powder, knead to obtain a plastic material, and then extrude, cure, and dry the plastic material in sequence.

[0013] Furthermore, the solid content of the pseudoboehmite suspension mentioned in step S1 is 10-15%;

[0014] The total dripping time should be controlled between 90 and 120 minutes, and the pH should be controlled between 7.5 and 8.5.

[0015] The stirring reaction time is 2-3 hours;

[0016] The heat filtration is specifically performed at 60°C using a plate and frame filter press.

[0017] Further, the preparation method of the mixed salt solution in step S1 is as follows: according to the mass ratio of zinc oxide (ZnO), copper oxide (CuO), cerium oxide (CeO2), and calcium oxide (CaO) in the final catalyst (40~42):(6~7):(2~2.5):(3~4), take basic zinc carbonate (ZnCO3·2Zn(OH)2·H2O), copper nitrate (Cu(NO3)2·3H2O), cerium nitrate (Ce(NO3)3·6H2O), and calcium nitrate (Ca(NO3)2·4H2O), add deionized water, and then add 1~2% of the total metal mass of citric acid. Stir and dissolve at 50~60℃ and 300~400rpm to obtain a mixed salt solution with a total metal ion concentration of 0.8~1.2mol / L.

[0018] Further, the method for preparing the mixed precipitant solution in step S1 is as follows: sodium carbonate (Na2CO3, purity ≥99.8%) and ammonia water (NH3·H2O, concentration 25~28%) are dissolved in deionized water at a molar ratio of (3~4):1, and stirred until completely dissolved to prepare a mixed precipitant solution with a concentration of 0.6mol / L.

[0019] Further, the volume ratio of the pseudoboehmite suspension, mixed salt solution, and mixed precipitant solution in step S1 is 1:(0.5~0.7):(0.9~1.3).

[0020] Furthermore, the activated alumina mentioned in step S2 is γ-Al2O3 with a particle size of 1~2μm;

[0021] The mass ratio of the filter cake (dry basis), activated alumina, and polyethylene glycol is 1:(1.2~2.5):(0.005~0.01).

[0022] Furthermore, the ball milling described in step S2 is a wet ball milling, using deionized water as the medium, with a solid content of 40-50%, a ball-to-material ratio of 8:1, a speed of 250-350 rpm, and a time of 2-3 hours.

[0023] The drying process specifically involves feeding the slurry into a centrifugal spray dryer, setting the inlet temperature to 270~290℃, the outlet temperature to 115~125℃, and the feed rate to 15~20mL / min, and collecting the spray-dried product.

[0024] Furthermore, the flow rate of nitrogen gas in step S3 is 50~100 mL / min;

[0025] The temperature program is divided into two stages: the first stage: the temperature is increased to 250℃ at a rate of 2℃ / min and held for 1~1.5h;

[0026] Second stage: Increase the temperature by 5℃ to 400℃ and keep it at that temperature for 3~3.5 hours.

[0027] Furthermore, in step S4, the amounts of calcium aluminate cement, guar gum powder, glycerin, and deionized water added are 3-5%, 0.5-1%, 1-2%, and 25-30% of the mass of the active powder, respectively.

[0028] The kneading temperature is 40~50℃ and the rotation speed is 60~80rpm.

[0029] Further, the extrusion molding, curing, and drying described in step S4 are as follows: the plastic material is placed in a screw extruder and extruded through a honeycomb mold to obtain a honeycomb preform; the honeycomb preform is transferred to an autoclave, saturated steam is introduced, and it is cured at 0.8~1.0MPa and 170~180℃ for 8~10h. After oxidation, the pressure is released, the preform is taken out, and it is first placed naturally for 24h (room temperature, humidity 40~60%), and then transferred to a drying oven and dried at 100℃ for 8h until the moisture content of the preform is ≤1%, finally obtaining a honeycomb desulfurization and purification catalyst.

[0030] The present invention has the following advantages over the prior art:

[0031] 1. This invention successfully prepared a high-performance honeycomb desulfurization and purification catalyst by combining the synergistic effect of multiple active components with innovative process control. At the active component level, a quaternary synergistic system of ZnO-CuO-CeO2-CaO was constructed. ZnO, as the main component, provides high sulfur capacity, ensuring deep removal of H2S. CuO directly catalyzes the hydrolysis reaction of organic sulfur in its oxidized state, and the generated H2S is removed in situ, eliminating the need for the pre-reduction process and additional organic sulfur hydrolysis reactor required by existing copper-based catalysts, simplifying the process and reducing energy consumption and safety risks. CeO2, with its excellent oxygen storage / release capacity, flexibly adjusts the redox potential of the reaction microenvironment and acts as a structural aid to significantly improve the dispersion of active components and inhibit high-temperature sintering, which is key to maintaining the high stability of the catalyst. CaO promotes the dissociation and adsorption of H2S by adjusting the surface alkalinity, further optimizing the reaction pathway. This synergistic mechanism enables the catalyst to maintain high stability at 300℃ and a space velocity of 3000h⁻¹. -1 Under normal operating conditions, the outlet H2S concentration is consistently below 10 ppb, the COS removal rate is as high as 99.3%, and the sulfur capacity exceeds 26%, with performance indicators far exceeding those of traditional zinc oxide desulfurizers and conventional copper-zinc-aluminum catalysts.

[0032] 2. The catalyst of this invention has a stable and robust structure, meeting the requirements for long-term operation. The mixed-alkali co-precipitation method utilizes ammonia complexation to achieve molecular-level uniform mixing of metal ions, avoiding component segregation and particle coarsening, thus laying the foundation for high performance. High-energy ball milling is used to nanoscale composite the active precursor with the γ-Al₂O₃ micron framework, followed by programmed temperature calcination under nitrogen protection to prevent Ce₂O₃ degradation. 3+ The catalyst undergoes excessive oxidation to precisely construct active centers with high specific surface area, suitable pore structure, and good thermal stability. γ-Al2O3, as the core reinforcing phase, works synergistically with calcium aluminate cement through steam curing to form a stable supporting framework, enabling the catalyst's lateral compressive strength to reach 172 N / cm. This structure ensures excellent resistance to pulverization and abrasion under harsh conditions such as start-up and shutdown of industrial plants and gas flow impacts, resulting in stable bed resistance and a significantly extended service life. Detailed Implementation

[0033] To further explain the present invention, the following specific embodiments are described.

[0034] Unless otherwise specified, the raw materials used in this invention are all from commercially available conventional products.

[0035] Example 1

[0036] A method for preparing a desulfurization purification catalyst includes the following steps:

[0037] S1. Preparation of active component solution:

[0038] According to the mass ratio of ZnO, CuO, CeO2, and CaO in the final catalyst of 40:6:2:3, take ZnCO3·2Zn(OH)2·H2O, Cu(NO3)2·3H2O, Ce(NO3)3·6H2O, and Ca(NO3)2·4H2O, add deionized water, and then add 1% of the total metal mass of citric acid. In a metal melting vessel, stir and dissolve at 50℃ and 300 rpm to obtain a mixed salt solution with a total metal ion concentration of 0.8 mol / L.

[0039] S2. Preparation of mixed precipitant solution:

[0040] Dissolve Na2CO3 (purity ≥99.8%) and NH3·H2O (concentration 25%) in deionized water at a molar ratio of 3:1, stir until completely dissolved, and prepare a mixed precipitant solution with a concentration of 0.6mol / L for later use.

[0041] S3, co-precipitation:

[0042] Boehmite was dispersed in deionized water to prepare a boehmite suspension with a solid content of 10%. The suspension was transferred to a reaction vessel and heated to 60°C. A mixed salt solution and a mixed precipitant solution were added dropwise simultaneously under stirring at 500 rpm for a total dropwise time of 90 min. The pH was controlled at 7.5. After the dropwise addition was completed, the mixture was stirred at a constant temperature of 500 rpm for 2 h. After the reaction was completed, the mixture was hot filtered at 60°C using a plate and frame filter press. The filter cake was washed with deionized water until the conductivity of the filtrate was ≤20 μS / cm.

[0043] The volume ratio of the pseudoboehmite suspension, mixed salt solution, and mixed precipitant solution is 1:0.5:0.9;

[0044] S4, Nanocomposite and Enhanced Dispersion:

[0045] The filter cake obtained in step S3, activated alumina (γ-Al2O3, particle size 1~2μm), and 0.5% by weight of polyethylene glycol (PEG-400, dispersant, purity ≥99.0%) were added to a ball mill jar with a ball-to-material ratio of 8:1 (agate balls). The mixture was wet-milled at 250 rpm with deionized water as the medium and a solid content of 40% for 2 hours to obtain a slurry.

[0046] The slurry is fed into a centrifugal spray dryer, with the inlet temperature set at 270℃, the outlet temperature at 115℃, and the feed rate at 15mL / min. The spray-dried product is then collected.

[0047] S5. Programmed temperature roasting and activation:

[0048] The dried product obtained in step S4 is transferred into a muffle furnace, nitrogen is introduced into the furnace, the nitrogen flow rate is set to 50 mL / min, and then programmed temperature rise calcination is performed.

[0049] The temperature program is divided into two stages: the first stage: the temperature is increased to 250℃ at a rate of 2℃ / min and held for 1 hour;

[0050] Second stage: Increase the temperature by 5℃ to 400℃ and keep it warm for 3 hours;

[0051] After calcination, maintain a nitrogen atmosphere and allow it to cool naturally to below 80°C to obtain active powder;

[0052] S6. Molding and Steam Curing:

[0053] Add 3% calcium aluminate cement, 0.5% guar gum powder, 1% glycerol, and 25% deionized water to the active powder, and knead at 40℃ and 60 rpm to obtain a plastic material.

[0054] Plastic material is placed in a screw extruder and extruded through a honeycomb die to obtain a honeycomb preform;

[0055] The honeycomb preform was transferred into an autoclave, saturated steam was introduced, and it was cured at 0.8 MPa and 170℃ for 8 hours. After oxidation, the pressure was released, the preform was taken out, and it was first placed at room temperature for 24 hours (humidity 40%), and then transferred to a drying oven and dried at 100℃ for 8 hours until the moisture content of the preform was ≤1%, and finally the honeycomb desulfurization and purification catalyst was obtained.

[0056] Example 2

[0057] A method for preparing a desulfurization purification catalyst includes the following steps:

[0058] S1. Preparation of active component solution:

[0059] According to the mass ratio of ZnO, CuO, CeO2, and CaO in the final catalyst of 41:6.5:2.2:3.5, ZnCO3·2Zn(OH)2·H2O, Cu(NO3)2·3H2O, Ce(NO3)3·6H2O, and Ca(NO3)2·4H2O were taken, deionized water was added, and then citric acid of 1.5% of the total metal mass was added. The mixture was stirred and dissolved in a metal melting vessel at 55°C and 350 rpm to obtain a mixed salt solution with a total metal ion concentration of 1 mol / L.

[0060] S2. Preparation of mixed precipitant solution:

[0061] Dissolve Na2CO3 (purity ≥99.8%) and NH3·H2O (concentration 26%) in deionized water at a molar ratio of 3.5:1, stir until completely dissolved, and prepare a mixed precipitant solution with a concentration of 0.6mol / L for later use.

[0062] S3, co-precipitation:

[0063] Boehmite was dispersed in deionized water to prepare a boehmite suspension with a solid content of 12%. The suspension was transferred to a reaction vessel and heated to 65°C. A mixed salt solution and a mixed precipitant solution were added dropwise simultaneously under stirring at 550 rpm for a total dropwise time of 100 min. The pH was controlled at 8. After the dropwise addition was completed, the mixture was stirred at a constant temperature of 550 rpm for 2.5 h. After the reaction was completed, the mixture was hot filtered at 60°C using a plate and frame filter press. The filter cake was washed with deionized water until the conductivity of the filtrate was ≤20 μS / cm.

[0064] The volume ratio of the pseudoboehmite suspension, mixed salt solution, and mixed precipitant solution is 1:0.6:1.1;

[0065] S4, Nanocomposite and Enhanced Dispersion:

[0066] The filter cake obtained in step S3, activated alumina (γ-Al2O3, particle size 1~2μm), and 0.7% by weight of polyethylene glycol (PEG-400, dispersant, purity ≥99.0%) were added together into a ball mill jar with a ball-to-material ratio of 8:1 (agate balls). The mixture was wet-milled at 300rpm with deionized water as the medium, and the solid content was 45%. The slurry was obtained after milling for 2.5h.

[0067] The slurry is fed into a centrifugal spray dryer, with the inlet temperature set at 280℃, the outlet temperature at 120℃, and the feed rate at 17mL / min. The spray-dried product is then collected.

[0068] S5. Programmed temperature roasting and activation:

[0069] The dried product obtained in step S4 is transferred into a muffle furnace, nitrogen is introduced into the furnace, the nitrogen flow rate is set to 80 mL / min, and then programmed temperature rise calcination is performed.

[0070] The temperature program is divided into two stages: the first stage: the temperature is increased to 250℃ at a rate of 2℃ / min and held for 1.2 hours;

[0071] Second stage: Increase the temperature by 5°C to 400°C and hold for 3.2 hours;

[0072] After calcination, maintain a nitrogen atmosphere and allow to cool naturally to below 80°C to obtain active powder;

[0073] S6. Molding and Steam Curing:

[0074] Add 4% calcium aluminate cement, 0.75% guar gum powder, 1.5% glycerol, and 27% deionized water to the active powder, and knead at 45°C and 70 rpm to obtain a plastic material.

[0075] Plastic material is placed in a screw extruder and extruded through a honeycomb die to obtain a honeycomb preform;

[0076] The honeycomb preform was transferred into an autoclave, saturated steam was introduced, and it was cured at 0.9 MPa and 175℃ for 9 hours. After oxidation, the pressure was released, the preform was taken out, and it was first placed at room temperature for 24 hours (humidity 50%), and then transferred to a drying oven and dried at 100℃ for 8 hours until the moisture content of the preform was ≤1%, and finally the honeycomb desulfurization and purification catalyst was obtained.

[0077] Example 3

[0078] A method for preparing a desulfurization purification catalyst includes the following steps:

[0079] S1. Preparation of active component solution:

[0080] According to the mass ratio of ZnO, CuO, CeO2, and CaO in the final catalyst of 42:7:2.5:4, take ZnCO3·2Zn(OH)2·H2O, Cu(NO3)2·3H2O, Ce(NO3)3·6H2O, and Ca(NO3)2·4H2O, add deionized water, and then add 2% of the total metal mass of citric acid. In a metal melting vessel, stir and dissolve at 60℃ and 400rpm to obtain a mixed salt solution with a total metal ion concentration of 1.2mol / L.

[0081] S2. Preparation of mixed precipitant solution:

[0082] Dissolve Na2CO3 (purity ≥99.8%) and NH3·H2O (concentration 28%) in deionized water at a molar ratio of 4:1, stir until completely dissolved, and prepare a mixed precipitant solution with a concentration of 0.6mol / L for later use.

[0083] S3, co-precipitation:

[0084] Boehmite was dispersed in deionized water to prepare a boehmite suspension with a solid content of 15%. The suspension was transferred to a reaction vessel and heated to 70°C. A mixed salt solution and a mixed precipitant solution were added dropwise simultaneously under stirring at 600 rpm for a total dropwise time of 120 min. The pH was controlled at 8.5. After the dropwise addition was completed, the mixture was stirred at a constant temperature of 600 rpm for 3 h. After the reaction was completed, the mixture was hot filtered at 60°C using a plate and frame filter press. The filter cake was washed with deionized water until the conductivity of the filtrate was ≤20 μS / cm.

[0085] The volume ratio of the pseudoboehmite suspension, mixed salt solution, and mixed precipitant solution is 1:0.7:1.3;

[0086] S4, Nanocomposite and Enhanced Dispersion:

[0087] The filter cake obtained in step S3, activated alumina (γ-Al2O3, particle size 1~2μm), and 1% by weight of polyethylene glycol (PEG-400, dispersant, purity ≥99.0%) based on the filter cake were added together into a ball mill jar. The ball-to-material ratio was set to 8:1 (agate balls). Wet ball milling was performed at 350 rpm with deionized water as the medium and a solid content of 50% for 3 hours to obtain a slurry.

[0088] The slurry is fed into a centrifugal spray dryer, with the inlet temperature set at 290℃, the outlet temperature at 125℃, and the feed rate at 20mL / min. The spray-dried product is then collected.

[0089] S5. Programmed temperature roasting and activation:

[0090] The dried product obtained in step S4 is transferred into a muffle furnace, nitrogen is introduced into the furnace, the nitrogen flow rate is set to 100 mL / min, and then programmed temperature rise calcination is performed.

[0091] The temperature program is divided into two stages: the first stage: the temperature is increased to 250℃ at a rate of 2℃ / min and held for 1.5 hours;

[0092] Second stage: Increase the temperature by 5℃ to 400℃ and keep it at that temperature for 3.5 hours;

[0093] After calcination, maintain a nitrogen atmosphere and allow it to cool naturally to below 80°C to obtain active powder;

[0094] S6. Molding and Steam Curing:

[0095] Add 5% calcium aluminate cement, 1% guar gum powder, 2% glycerol, and 30% deionized water to the active powder, and knead at 50°C and 80 rpm to obtain a plastic material.

[0096] Plastic material is placed in a screw extruder and extruded through a honeycomb die to obtain a honeycomb preform;

[0097] The honeycomb preform was transferred into an autoclave, saturated steam was introduced, and it was cured at 1.0 MPa and 180℃ for 10 hours. After oxidation, the pressure was released, the preform was taken out, and it was first placed at room temperature for 24 hours (humidity 60%), and then transferred to a drying oven and dried at 100℃ for 8 hours until the moisture content of the preform was ≤1%, and finally the honeycomb desulfurization and purification catalyst was obtained.

[0098] Comparative Example 1

[0099] Compared with Example 2, the preparation of the active component solution in Comparative Example 1 was replaced with the following steps, while the other steps were the same as in Example 2.

[0100] According to the mass ratio of ZnO, CuO, and CaO in the final catalyst of 43:6.5:3.5, take ZnCO3·2Zn(OH)2·H2O, Cu(NO3)2·3H2O, and Ca(NO3)2·4H2O, add deionized water, and then add 1.5% of the total metal mass of citric acid. In a metal melting vessel, stir and dissolve at 55℃ and 350rpm to obtain a mixed salt solution with a total metal ion concentration of 1mol / L.

[0101] Comparative Example 2

[0102] Compared with Example 2, Comparative Example 2 omits the addition of NH3·H2O in the preparation of the mixed precipitant solution, while the other steps are the same as in Example 2.

[0103] Comparative Example 3

[0104] Compared with Example 2, Comparative Example 3 omits the activated alumina (γ-Al2O3) in step S4, while the other steps are the same as in Example 2.

[0105] Comparative Example 4

[0106] Compared with Example 2, Comparative Example 4 replaces the programmed temperature rise calcination in step S5 with conventional calcination, that is, the programmed temperature rise is deleted and replaced with "directly rise to 400°C and hold for 4.4 hours". The other steps are the same as in Example 2.

[0107] Comparative Example 5

[0108] Compared with Example 2, this Comparative Example 5 replaces step S1 with the following operation, while the other steps are the same as in Example 2.

[0109] Preparation of active ingredient solution:

[0110] According to the mass ratio of ZnO, CuO, CeO2, and CaO in the final catalyst of 32:15.5:2.2:3.5, ZnCO3·2Zn(OH)2·H2O, Cu(NO3)2·3H2O, Ce(NO3)3·6H2O, and Ca(NO3)2·4H2O were taken, deionized water was added, and then citric acid of 1.5% of the total metal mass was added. The mixture was stirred and dissolved in a metal melting vessel at 55℃ and 350 rpm to obtain a mixed salt solution with a total metal ion concentration of 1 mol / L.

[0111] With a fixed feed gas composition (H2S 500ppm, COS 100ppm, N2 balance gas), at 300℃ for 3000h... -1Under space velocity conditions, the outlet H2S concentration (ppd) was determined by gas chromatography, and the COS removal rate (%) and sulfur capacity (%) were calculated. The lateral pressure strength (N / cm) of the catalyst was tested using a lateral pressure strength tester. Each group of experiments was repeated three times.

[0112] The comparative data of the experiment are shown in Table 1 below.

[0113] Table 1. Catalyst performance test results for each example and comparative example.

[0114]

[0115] As can be seen from Table 1 above, the experimental results of Examples 1 to 3 show a high degree of performance consistency, proving that the preparation process of the present invention has good stability and repeatability.

[0116] Compared to Example 2, Comparative Example 1 showed a significant decline in performance. The outlet H2S concentration increased by 174%, COS removal rate decreased by 9.8%, and sulfur capacity decreased by 20.5%. This is likely due to the absence of CeO2, which prevented the formation of a CuO-CeO2 solid solution, thus hindering the formation of CuO-CeO2 solid solution. 2+ The reduction barrier increases, which reduces the catalytic hydrolysis activity of organic sulfur.

[0117] Comparative Example 2, using a single Na2CO3 precipitant, showed a 335% increase in outlet H2S concentration, a 7.3% decrease in COS removal rate, a 23.5% decrease in sulfur capacity, and a 9.3% decrease in lateral pressure strength, indicating a significant performance decline. This suggests that the absence of NH3·H2O not only caused uneven distribution and severe agglomeration of active components but also reduced effective active sites. Furthermore, it affected the uniformity of the carrier structure, leading to a decrease in mechanical strength.

[0118] In Comparative Example 3, omitting activated alumina resulted in a 50% increase in outlet H2S concentration, a 0.6% decrease in COS removal rate, a 6.3% decrease in sulfur capacity, and a 33.1% decrease in lateral pressure strength. This demonstrates that the absence of activated alumina has the greatest impact on the lateral pressure strength of the catalyst. The absence of activated alumina disrupts the pseudoboehmite-activated alumina composite support structure, leading to a significant reduction in mechanical strength. This proves that activated alumina is a key component for ensuring the mechanical performance of the catalyst.

[0119] Comparative Example 4 used conventional roasting, resulting in a 127% increase in outlet H2S concentration, a 4.1% decrease in COS removal rate, and a 15.3% decrease in sulfur capacity. The performance degradation caused by the conventional roasting method of directly heating to 400℃ may be due to the incomplete decomposition of organic matter at low temperatures, leading to rapid growth of ZnO grains, which in turn reduces the specific surface area and thus the desulfurization performance.

[0120] Comparative Example 5 changed the composition ratio of the active component solution, using a high copper and low zinc formulation. The outlet H2S concentration increased by 31.7%, the COS removal rate decreased by 0.4%, and the sulfur capacity decreased by 28.3%. It can be seen that high copper will lead to a reduction in the amount of sulfur adsorbed per unit mass of catalyst.

[0121] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a desulfurization purification catalyst, characterized in that, Includes the following steps: S1. Disperse boehmite in deionized water to prepare a boehmite suspension, transfer it to a reaction vessel, heat it to 60~70℃, and simultaneously add a mixed salt solution and a mixed precipitant solution dropwise under stirring at 500~600rpm. After the addition is complete, stir the mixture at a constant temperature of 500~600rpm. After the reaction is complete, filter the mixture hot, wash it with deionized water, and collect the filter cake. The solid content of the pseudoboehmite suspension is 10-15%; The method for preparing the mixed salt solution is as follows: according to the mass ratio of ZnO, CuO, CeO2, and CaO in the final catalyst (40~42):(6~7):(2~2.5):(3~4), take ZnCO3·2Zn(OH)2·H2O, Cu(NO3)2·3H2O, Ce(NO3)3·6H2O, and Ca(NO3)2·4H2O, add deionized water, and then add 1~2% of the total metal mass of citric acid. Stir and dissolve at 50~60℃ and 300~400rpm to obtain a mixed salt solution with a total metal ion concentration of 0.8~1.2mol / L. The method for preparing the mixed precipitant solution is as follows: Na2CO3 and NH3·H2O are dissolved in deionized water at a molar ratio of (3~4):1, and stirred until completely dissolved to prepare a mixed precipitant solution with a concentration of 0.6mol / L. The volume ratio of the pseudoboehmite suspension, mixed salt solution, and mixed precipitant solution is 1:(0.5~0.7):(0.9~1.3); S2. Add the filter cake, activated alumina, and polyethylene glycol obtained in step S1 into a ball mill jar, ball mill to obtain a slurry, and dry to obtain a dried product. The activated alumina is γ-Al2O3 with a particle size of 1~2μm; The mass ratio of the filter cake, activated alumina, and polyethylene glycol is 1:(1.2~2.5):(0.005~0.01); S3. Transfer the dried product obtained in step S2 into a muffle furnace, introduce nitrogen into the furnace, and perform programmed temperature rise calcination. After calcination, maintain the nitrogen atmosphere and allow it to cool naturally to obtain active powder. The flow rate of the nitrogen gas is 50~100 mL / min; The temperature program is divided into two stages: the first stage: the temperature is increased to 250℃ at a rate of 2℃ / min and held for 1~1.5h; Second stage: Increase the temperature by 5℃ to 400℃ and keep it at that temperature for 3~3.5 hours; S4. Molding and Steam Curing: Add calcium aluminate cement, guar gum powder, glycerin, and deionized water to the active powder, then knead to obtain a plastic material. The plastic material is then extruded, cured, and dried in sequence.

2. The method for preparing a desulfurization purification catalyst according to claim 1, characterized in that, The total dripping time in step S1 is controlled at 90-120 min, and the pH is controlled at 7.5-8.

5. The stirring reaction time is 2-3 hours; The heat filtration is specifically performed at 60°C using a plate and frame filter press.

3. The method for preparing a desulfurization purification catalyst according to claim 1, characterized in that, The ball milling described in step S2 is a wet ball milling, using deionized water as the medium, with a solid content of 40-50%, a ball-to-material ratio of 8:1, a speed of 250-350 rpm, and a time of 2-3 hours. The drying process specifically involves feeding the slurry into a centrifugal spray dryer, setting the inlet temperature to 270~290℃, the outlet temperature to 115~125℃, and the feed rate to 15~20mL / min, and collecting the spray-dried product.

4. The method for preparing a desulfurization purification catalyst according to claim 1, characterized in that, The amounts of calcium aluminate cement, guar gum powder, glycerin, and deionized water added in step S4 are 3-5%, 0.5-1%, 1-2%, and 25-30% of the mass of the active powder, respectively. The kneading temperature is 40~50℃ and the rotation speed is 60~80rpm.

5. The method for preparing a desulfurization purification catalyst according to claim 1, characterized in that, The extrusion molding, curing, and drying described in step S4 are as follows: the plastic material is placed in a screw extruder and extruded through a honeycomb mold to obtain a honeycomb preform; the honeycomb preform is transferred to an autoclave, saturated steam is introduced, and it is cured at 0.8~1.0MPa and 170~180℃ for 8~10h. After oxidation, the pressure is released, the preform is taken out, and it is first placed at room temperature for 24h, and then transferred to a drying oven and dried at 100℃ for 8h until the moisture content of the preform is ≤1%, finally obtaining a honeycomb desulfurization and purification catalyst.

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