Hydrolysis catalyst, process for its preparation and use

Abstract

This invention relates to the field of gas purification technology, and discloses a hydrolysis catalyst, its preparation method, and its application. The preparation method of the hydrolysis catalyst includes the following steps: (1) immersing γ-alumina spheres in an alkaline solution to obtain a precursor, wherein the specific surface area of ​​the γ-alumina spheres is 280-400 m². 2 / g; (2) The precursor is subjected to gradient drying to obtain the hydrolysis catalyst. In this invention, γ-alumina spheres are used as the carrier and alkaline solution is used as the active component solution. The preparation process does not involve high-temperature calcination. The hydrolysis catalyst can be obtained by gradient drying. Therefore, the preparation of the hydrolysis catalyst can be achieved by industrial waste heat. This not only greatly reduces energy consumption, but also simplifies the process and provides an efficient and economical solution for industrial waste gas treatment.

Description

A hydrolysis catalyst, its preparation method and application Technical Field

[0001] This invention relates to the field of gas purification technology, and in particular to a hydrolysis catalyst for the fine desulfurization process of blast furnace gas, its preparation method, and its application. Background Technology

[0002] Carbonyl sulfide (COS) is a common harmful gas in industrial waste gases, widely present in steel, coal chemical, petroleum refining, and natural gas processing. Due to its stable chemical properties, carbonyl sulfide is difficult to remove by conventional adsorption or catalytic oxidation methods. Currently, metal oxide-supported catalysts are mainly used for hydrolysis to remove carbonyl sulfide. However, these catalysts require doping with precious metals such as platinum and palladium, or complex metal salts such as titanium dioxide and cerium dioxide, resulting in high raw material costs. Furthermore, these catalysts require high-temperature calcination above 300°C, making the process complex and energy-intensive. Therefore, there is an urgent need for a low-cost, low-energy-consumption, and simple hydrolysis catalyst. Summary of the Invention

[0003] In view of this, the present invention provides a hydrolysis catalyst, its preparation method and application, to solve the problems of high production cost and high energy consumption of existing desulfurization catalysts.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] On one hand, the present invention provides a method for preparing a hydrolysis catalyst, comprising the following steps:

[0006] (1) The γ-alumina spheres are immersed in an alkaline solution to obtain a precursor, wherein the specific surface area of ​​the γ-alumina spheres is 280-400 m². 2 / g;

[0007] (2) The precursor is subjected to gradient drying to obtain a hydrolysis catalyst.

[0008] Preferably, the mass-to-volume ratio of the γ-alumina spheres to the alkaline solution is 1g:0.5-5mL.

[0009] Preferably, the alkaline solution is an aqueous solution of an alkaline substance, wherein the mass concentration of the alkaline substance is 0.10-0.48 g / mL.

[0010] Preferably, the alkaline substance is composed of a weak base and a strong base in a mass ratio of 10:0-5.

[0011] Preferably, the weak base includes one or more of potassium carbonate, sodium carbonate, sodium bicarbonate, and potassium bicarbonate.

[0012] Preferably, the strong alkali includes one or more of sodium hydroxide and potassium hydroxide.

[0013] Preferably, the γ-alumina spheres have a particle size of 4.5-5.5 mm, a water absorption rate of >50%, and a compressive strength of >80 N.

[0014] Preferably, the immersion time is 0.5-8 hours.

[0015] Preferably, the loading of the alkaline substance onto the γ-alumina spheres is 5-20 wt%.

[0016] Preferably, the gradient drying includes a primary drying stage and a secondary drying stage. The primary drying stage has a drying temperature of 30-70℃ and a drying time of 2-24h. The secondary drying stage has a drying temperature of 90-150℃ and a drying time of 5min-24h.

[0017] On the other hand, the present invention provides a hydrolysis catalyst prepared by the method described in any one of the above-mentioned methods, wherein the water content of the hydrolysis catalyst is <5%.

[0018] In another aspect, the present invention also provides a hydrolysis catalyst prepared by the method described in any one of the above-mentioned methods, or the application of the above-mentioned hydrolysis catalyst in desulfurization.

[0019] This invention provides a hydrolysis catalyst, its preparation method, and its application. Compared with the prior art, its advantages are as follows:

[0020] This invention uses γ-alumina spheres with a specific surface area as a carrier, an alkaline solution as an active solution, and alkaline substances in the alkaline solution as active components. Through an impregnation process, the active components in the alkaline solution are loaded onto the γ-alumina spheres to obtain a precursor. Then, a gradient drying process removes free water from the precursor, ensuring that the active components are uniformly dispersed in the pores and surface of the γ-alumina spheres. The drying process does not damage the original crystal and pore structure of the γ-alumina spheres, guaranteeing sufficient contact between the active components and sulfur-containing compounds, achieving excellent desulfurization and hydrolysis effects. Testing showed that the hydrolysis catalyst achieved a maximum conversion rate of 92%, and an average conversion rate of 72% over a 40-day evaluation period, demonstrating excellent catalytic activity.

[0021] This invention does not involve a high-temperature calcination process; the hydrolysis catalyst can be obtained simply through gradient drying. Therefore, the hydrolysis catalyst can be prepared using industrial waste heat, which not only significantly reduces energy consumption but also simplifies the process, providing an efficient and economical solution for industrial waste gas treatment. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0023] Figure 1 is a crystal structure diagram of the hydrolysis catalyst of Example 2 and Comparative Example 1 of the present invention;

[0024] Figure 2 shows the activity test curves of the hydrolysis catalysts in Example 6 and Comparative Example 2;

[0025] Figure 3 shows the activity test curves of Example 1 and the commercially available hydrolysis catalyst. Detailed Implementation

[0026] The present invention will be described below through specific embodiments. Those skilled in the art will understand that the specific embodiments below are merely illustrative and do not limit the scope of the invention in any way. Furthermore, in the following embodiments, unless otherwise specified, the reagents and equipment used are commercially available. If specific processing conditions and methods are not explicitly described in the later embodiments, conditions and methods known in the art can be used for processing.

[0027] In one aspect of the invention, a method for preparing a hydrolysis catalyst is provided, comprising the following steps:

[0028] (1) The γ-alumina spheres were immersed in an alkaline solution to obtain the precursor;

[0029] (2) The precursor is subjected to gradient drying to obtain a hydrolysis catalyst.

[0030] In this invention, γ-alumina spheres are first immersed in an alkaline solution to obtain a precursor.

[0031] In some embodiments of the present invention, the mass-to-volume ratio of the γ-alumina spheres to the alkaline solution is 1 g: 0.5-5 mL, specifically 1 g: 0.5 mL, 1 g: 1 mL, 1 g: 2 mL, 1 g: 3 mL, 1 g: 4 mL, 1 g: 5 mL, etc.

[0032] In this invention, γ-alumina spheres are used as a carrier, alkaline solution is used as an active solution, and alkaline substances in the alkaline solution are used as active components. By limiting the mass-volume ratio of γ-alumina spheres to alkaline solution within this range, it can be ensured that the active components are effectively loaded onto the γ-alumina sphere carrier.

[0033] In some embodiments of the present invention, the alkaline solution is an aqueous solution of an alkaline substance, wherein the mass concentration of the alkaline substance is 0.10-0.48 g / mL, specifically 0.1 g / mL, 0.2 g / mL, 0.3 g / mL, 0.4 g / mL, 0.48 g / mL, etc. Limiting the mass concentration of the alkaline substance in the alkaline solution to this range not only ensures that the active component can be fully loaded onto the γ-alumina spheres, but also avoids corrosion of the reaction vessel due to excessively high alkaline solution concentration.

[0034] In some embodiments of the present invention, the alkaline substance is composed of a weak base and a strong base in a mass ratio of 10:0-5. Preferably, the alkaline substance is a mixture of a weak base and a strong base, wherein the weak base includes one or more of potassium carbonate, sodium carbonate, sodium bicarbonate, and potassium bicarbonate, and the strong base includes one or more of sodium hydroxide and potassium hydroxide. The mass ratio of the weak base to the strong base can specifically be 10:0.1, 10:1, 10:2, 10:3, 10:4, 10:5, etc.

[0035] The working process of a hydrolysis catalyst involves first adsorbing sulfur-containing compounds and then converting them into hydrogen sulfide. The hydrogen sulfide then leaves the catalyst surface. If the alkalinity is too weak, the sulfur-containing compounds cannot be adsorbed onto the catalyst surface; if the alkalinity is too strong, the hydrogen sulfide cannot leave. If the hydrogen sulfide cannot leave the catalyst surface in time, it will occupy the active sites on the catalyst surface. Furthermore, the hydrogen sulfide adsorbed on the catalyst surface is easily oxidized by oxygen in the coal gas into elemental sulfur, which then covers the catalyst surface, causing pore blockage and affecting the catalyst's performance. CO2-TPD analysis shows that by limiting the ratio of strong to weak bases within the specified range, good activity of the hydrolysis catalyst can be ensured.

[0036] In some embodiments of the present invention, the specific surface area of ​​the γ-alumina spheres is 280-400 m². 2 / g. That is, the specific surface area of ​​the γ-alumina spheres used in this invention only needs to be within the above-mentioned range. The γ-alumina spheres in this invention, as a carrier, have a high specific surface area, providing more exposed active sites and favorable conditions for loading the active components. This results in higher dispersion of the active components, thereby improving the reaction rate and selectivity of the hydrolysis reaction. Furthermore, the cost of γ-alumina spheres within this specific surface area range is lower. If the specific surface area is higher, the cost of γ-alumina spheres will increase to 8000-10000 yuan / ton, higher than the 4500-6000 yuan / ton cost of this invention. Moreover, the pore volume and pore size of γ-alumina spheres with this specific surface area will decrease, making them prone to clogging by dust, tar, etc., in industrial applications, causing catalyst poisoning.

[0037] In some embodiments of the present invention, the particle size of the γ-alumina spheres is 4.5-5.5 mm. That is, the particle size of the γ-alumina spheres used in the present invention only needs to be within the above-mentioned range. The γ-alumina spheres used in the present invention have a concentrated particle size and stable porosity, which is beneficial to reducing the gas flow loss of the hydrolysis catalyst in the reaction vessel and can effectively reduce the probability of clogging.

[0038] In some embodiments of the present invention, the water absorption rate of the γ-alumina spheres is >50%. That is, the water absorption rate of the γ-alumina spheres used in the present invention only needs to be greater than 50%. It is understood that the concentration of the alkaline solution is related to the water absorption rate of the γ-alumina spheres. If the water absorption rate of the γ-alumina spheres is too low, a higher concentration of alkaline solution needs to be prepared to achieve the same loading capacity. However, a high concentration of alkaline solution may cause corrosion of the γ-alumina sphere carrier. Therefore, in order to ensure the loading capacity of the γ-alumina sphere carrier and avoid corrosion of the carrier by excessively high alkaline solution concentration, the water absorption rate of the γ-alumina spheres is limited to greater than 50%.

[0039] In some embodiments of the present invention, to prevent the catalyst at the bottom of the tower from being crushed, the compressive strength of the γ-alumina spheres is >80 N. That is, the compressive strength of the γ-alumina spheres used in the present invention only needs to be greater than 80 N.

[0040] In a specific embodiment of the present invention, the various indicators of the γ-alumina spheres meet the conditions listed in Table 1.

[0041] Table 1

[0042]

[0043] In some embodiments of the present invention, the loading amount of the alkaline substance on the γ-alumina spheres is 5-20 wt%, specifically 5 wt%, 10 wt%, 15 wt%, 20 wt%, etc. In some embodiments of the present invention, to ensure sufficient loading of the active component, the impregnation time is 0.5-8 h, specifically 0.5 h, 1 h, 2 h, 4 h, 5 h, 6 h, 8 h, etc. It is understood that the impregnation time can be shortened or extended according to the actual loading amount, and there is no special limitation on this; it can be adjusted according to the actual situation.

[0044] In this invention, after obtaining the precursor, the precursor is subjected to gradient drying to obtain a hydrolysis catalyst.

[0045] In some embodiments of the present invention, in order to promote the uniform distribution of the active component on the surface of the γ-alumina sphere carrier, before the precursor is subjected to gradient drying, the process further includes: removing the precursor and allowing it to stand for 2-24 hours, specifically 2 hours, 6 hours, 12 hours, 18 hours, 20 hours, 24 hours, etc. XRD analysis shows that after standing, the grain size distribution of the active component is more uniform.

[0046] In some embodiments of the present invention, the gradient drying includes a primary drying stage and a secondary drying stage. The drying temperature of the primary drying stage is 30-70℃, specifically 30℃, 40℃, 50℃, 60℃, 70℃, etc., and the drying time is 2-24 h, specifically 2 h, 6 h, 12 h, 18 h, 20 h, 24 h, etc. Through the low-temperature drying of the primary drying stage, free moisture can be slowly removed, so that the moisture content of the precursor can be reduced to about 10%.

[0047] The drying temperature in the secondary drying stage is 90-150℃, specifically 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, etc., and the drying time is 5 min-24 h, specifically 5 min, 30 min, 1 h, 6 h, 12 h, 24 h, etc. Drying within the range of 90-150℃ can effectively avoid the destruction of the crystal lattice of the active components and reduce the moisture content to below 5%, resulting in a hydrolysis catalyst with good desulfurization hydrolysis effect.

[0048] Specifically, in the secondary drying stage, the active components can be uniformly dispersed in the channels and surface of the γ-alumina spheres. The γ-alumina spheres have a cubic crystal structure. During the drying process, the lattice parameters of the γ-alumina spheres change very little, and the crystal structure can remain basically stable. After drying, the original crystal structure and channel structure will not be destroyed, which can ensure sufficient contact between the active components and sulfur-containing compounds and achieve good desulfurization and hydrolysis effect.

[0049] Furthermore, weak bases, due to their alkalinity and good thermal stability, can form a layer of alkaline active sites on the surface of γ-alumina spheres during the secondary drying stage. Strong bases, due to their strong alkalinity, can further enhance the activity of the catalyst. When strong and weak bases are loaded onto γ-alumina spheres in a specific ratio, they can mutually promote each other during the secondary drying stage, forming a stable alkaline environment that is conducive to the hydrolysis reaction of sulfur-containing compounds, converting them into substances that are easily removed. Taking carbonyl sulfide as an example, carbonyl sulfide is a difficult-to-remove organic sulfur compound; through a hydrolysis catalyst, carbonyl sulfide can be converted into hydrogen sulfide, which is easily adsorbed and removed.

[0050] Furthermore, traditional roasting processes may cause strong and weak bases to react or decompose chemically, altering their chemical properties and ratio, thereby affecting the catalyst's performance. In contrast, the drying process of this invention does not disrupt the synergistic effect of strong and weak bases, preserving their ratio and ensuring the catalyst's activity and stability.

[0051] In addition, it should be noted that the drying temperature of this invention is up to 150°C, and the heat source selection is highly flexible. It can use standard electric ovens, microwave heating devices, or integrate industrial flue gas waste heat resource utilization systems to prepare hydrolysis catalysts through industrial waste heat, thereby reducing energy consumption. The production cost is reduced by 22-25% compared to commercially available catalysts, and equipment investment is reduced by 15%, providing an efficient and economical solution for industrial waste gas treatment.

[0052] In another aspect of the invention, the present invention provides a hydrolysis catalyst prepared by the method described in any of the preceding claims, wherein the water content of the hydrolysis catalyst is <5%. Since this hydrolysis catalyst is prepared by the above-described method, it possesses all the advantages described above, which will not be repeated here. Furthermore, by limiting the water content of the hydrolysis catalyst to less than 5%, the conversion rate of the hydrolysis catalyst can be effectively improved.

[0053] In another aspect, the present invention also provides a hydrolysis catalyst prepared by the method described in any of the above-mentioned claims, or the application of the above-mentioned hydrolysis catalyst in desulfurization.

[0054] The hydrolysis catalyst of this invention can maintain high efficiency in hydrolysis catalysis over a wide temperature range (100-130℃), making it suitable for various desulfurization processes. Experimental studies have shown that using the hydrolysis catalyst of this invention to treat carbonyl sulfur in blast furnace gas, in an industrial side-stream test, at a space velocity of 6000 h⁻¹, [the following parameters are not specified in the original text]. -1 Under conditions of 100℃ and 40 h, the average conversion rate of carbonyl sulfide can reach over 70%, and in practical industrial applications (reaction temperature 100-130℃, space velocity 1000 h⁻¹), the conversion rate can also be achieved. -1 The service life of the hydrolysis catalyst can reach 200 days (the conversion rate can be maintained at over 95% for 200 days).

[0055] The technical solutions of this invention will be clearly and completely described below with reference to specific embodiments. The embodiments of this application are only examples, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0056] Example 1

[0057] This embodiment provides a method for preparing a hydrolysis catalyst, the specific steps of which are as follows:

[0058] (1) Dissolve 1 g of potassium carbonate and 0.3 g of sodium hydroxide in 5.2 mL of deionized water and stir until completely dissolved to obtain an alkaline solution;

[0059] (2) 10 g of γ-alumina balls were immersed in an alkaline solution for 30 min to obtain a precursor, wherein the loading of the γ-alumina balls on the active component was 13 wt%.

[0060] (3) After the precursor is left to stand for 2 hours, it is placed in an oven and dried at 30°C for 10 hours. Then, it is dried at 90°C for 3 hours to obtain a hydrolysis catalyst with a water content of less than 5%.

[0061] Example 2

[0062] This embodiment provides a method for preparing a hydrolysis catalyst, the specific steps of which are as follows:

[0063] (1) Dissolve 6 g of potassium carbonate and 1.5 g of sodium hydroxide in 26 mL of deionized water and stir until completely dissolved to obtain an alkaline solution;

[0064] (2) 10 g of γ-alumina balls were immersed in an alkaline solution for 2 h to obtain a precursor, wherein the loading of the γ-alumina balls on the active component was 15 wt%.

[0065] (3) After the precursor is left to stand for 2 hours, it is placed in an oven and dried at 50°C for 12 hours. Then, it is dried at 110°C for 1 hour to obtain a hydrolysis catalyst with a water content of less than 5%.

[0066] Example 3

[0067] This embodiment provides a method for preparing a hydrolysis catalyst, the specific steps of which are as follows:

[0068] (1) Dissolve 2 g of potassium carbonate and 0.6 g of sodium hydroxide in 10.4 mL of deionized water and stir until completely dissolved to obtain an alkaline solution;

[0069] (2) 10 g of γ-alumina balls were immersed in an alkaline solution for 8 h to obtain a precursor, wherein the loading of the γ-alumina balls on the active component was 13 wt%.

[0070] (3) After the precursor is left to stand for 2 hours, it is placed in an oven and dried at 70°C for 24 hours. Then, it is dried at 110°C for 5 minutes to obtain a hydrolysis catalyst with a water content of less than 5%.

[0071] Example 4

[0072] This embodiment provides a method for preparing a hydrolysis catalyst, the specific steps of which are as follows:

[0073] (1) Dissolve 2 g of potassium carbonate and 0.4 g of sodium hydroxide in 10.4 mL of deionized water and stir until completely dissolved to obtain an alkaline solution;

[0074] (2) 10 g of γ-alumina balls were immersed in an alkaline solution for 4 h to obtain a precursor, wherein the loading of the γ-alumina balls on the active component was 12 wt%.

[0075] (3) After the precursor is left to stand for 24 h, it is placed in an oven and dried at 50℃ for 12 h, and then dried at 110℃ for 10 min to obtain a hydrolysis catalyst with a water content of less than 5%.

[0076] Example 5

[0077] This embodiment provides a method for preparing a hydrolysis catalyst, the specific steps of which are as follows:

[0078] (1) Dissolve 2 g of potassium carbonate and 1 g of potassium hydroxide in 10.4 mL of deionized water and stir until completely dissolved to obtain an alkaline solution;

[0079] (2) 10 g of γ-alumina balls were immersed in an alkaline solution for 4 h to obtain a precursor, wherein the loading of the γ-alumina balls on the active component was 11 wt%.

[0080] (3) After the precursor is left to stand for 24 h, it is placed in an oven and dried at 50℃ for 12 h, and then dried at 110℃ for 10 min to obtain a hydrolysis catalyst with a water content of less than 5%.

[0081] Example 6

[0082] This embodiment provides a method for preparing a hydrolysis catalyst, the specific steps of which are as follows:

[0083] (1) Dissolve 2 g of sodium bicarbonate, 0.6 g of potassium hydroxide and 0.4 g of sodium hydroxide in 10.4 mL of deionized water and stir until completely dissolved to obtain an alkaline solution;

[0084] (2) 10 g of γ-alumina balls were immersed in an alkaline solution for 4 h to obtain a precursor, wherein the loading of the γ-alumina balls on the active component was 15 wt%.

[0085] (3) After the precursor is left to stand for 24 h, it is placed in an oven and dried at 50℃ for 12 h, and then dried at 110℃ for 10 min to obtain a hydrolysis catalyst with a water content of less than 5%.

[0086] Example 7

[0087] This embodiment provides a method for preparing a hydrolysis catalyst, the specific steps of which are as follows:

[0088] (1) Dissolve 1 g of potassium carbonate, 1 g of sodium carbonate and 0.6 g of potassium hydroxide in 10.4 mL of deionized water and stir until completely dissolved to obtain an alkaline solution;

[0089] (2) 10 g of γ-alumina balls were immersed in an alkaline solution for 4 h to obtain a precursor, wherein the loading of the γ-alumina balls on the active component was 13 wt%.

[0090] (3) After the precursor is left to stand for 24 h, it is placed in an oven and dried at 50℃ for 12 h, and then dried at 110℃ for 10 min to obtain a hydrolysis catalyst with a water content of less than 5%.

[0091] Example 8

[0092] This embodiment provides a method for preparing a hydrolysis catalyst, the specific steps of which are as follows:

[0093] (1) Dissolve 2 g of potassium carbonate and 1 g of sodium hydroxide in 10.4 mL of deionized water and stir until completely dissolved to obtain an alkaline solution;

[0094] (2) 10 g of γ-alumina balls were immersed in an alkaline solution for 4 h to obtain a precursor, wherein the loading of the γ-alumina balls on the active component was 15 wt%.

[0095] (3) After the precursor is left to stand for 24 h, it is placed in an oven and dried at 50℃ for 12 h, and then dried at 110℃ for 10 min to obtain a hydrolysis catalyst with a water content of less than 5%.

[0096] Example 9

[0097] This embodiment provides a method for preparing a hydrolysis catalyst, the specific steps of which are as follows:

[0098] (1) Dissolve 2 g of potassium carbonate and 0.8 g of potassium hydroxide in 10.4 mL of deionized water and stir until completely dissolved to obtain an alkaline solution;

[0099] (2) 10 g of γ-alumina balls were immersed in an alkaline solution for 4 h to obtain a precursor, wherein the loading of the γ-alumina balls on the active component was 14 wt%.

[0100] (3) After the precursor is left to stand for 24 h, it is placed in an oven and dried at 50℃ for 12 h, and then dried at 110℃ for 10 min to obtain a hydrolysis catalyst with a water content of less than 5%.

[0101] Example 10

[0102] This embodiment provides a method for preparing a hydrolysis catalyst, the specific steps of which are as follows:

[0103] (1) Dissolve 1 g of potassium carbonate in 10.4 mL of deionized water and stir until completely dissolved to obtain an alkaline solution;

[0104] (2) 10 g of γ-alumina balls were immersed in an alkaline solution for 4 h to obtain a precursor, wherein the loading of the γ-alumina balls on the active component was 5 wt%;

[0105] (3) After the precursor is left to stand for 24 h, it is placed in an oven and dried at 50℃ for 12 h, and then dried at 110℃ for 10 min to obtain a hydrolysis catalyst with a water content of less than 5%.

[0106] Comparative Example 1

[0107] This comparative example is basically the same as Example 2, except that step (3) is replaced with the following steps:

[0108] After the precursor was allowed to stand for 24 hours, it was first dried at 110℃ for 2 hours, and then calcined at 550℃ for 2 hours to obtain a hydrolysis catalyst with a water content of less than 5%.

[0109] Figure 1 shows the crystal structure diagrams of the hydrolysis catalysts of Example 2 (curve a) and Comparative Example 1 (curve b) of the present invention. It can be seen from the figure that the hydrolysis catalyst obtained after calcination in Comparative Example 1 can only retain γ-Al₂O₃, but cannot retain layered carbonates. In contrast, the hydrolysis catalyst prepared in Example 2 of the present invention, by controlling the drying process, can retain Na₂O₃. 1.2 The KAl2O2(CO3)2•2.16H2O / γ-Al2O3 mixed crystal form (XRD characteristic peaks: 2θ=45.9°, 66.8° for γ-Al2O3, 2θ=12.3°, 24.7° for layered carbonates) hydrolysis catalyst of the present invention has a mixed crystal structure, which combines ion exchange, mesoporous diffusion and acid-base synergistic functions.

[0110] In addition, the pore structure of the hydrolysis catalysts of Example 2 and Comparative Example 1 was analyzed, and the results are shown in Table 2.

[0111] Table 2

[0112]

[0113] As can be seen from Table 2, compared with the calcination process, the drying treatment method adopted in this invention can make the hydrolysis catalyst have a larger specific surface area, pore volume and average pore size, thereby ensuring sufficient contact between the active components and sulfur-containing compounds and achieving a good desulfurization hydrolysis effect.

[0114] Comparative Example 2

[0115] This comparative example is basically the same as Example 6, except that: after the precursor is left to stand for 2 hours, it is placed in an oven and dried at 50°C for 12 hours to obtain a hydrolysis catalyst with a water content of 12.6%.

[0116] Figure 2 shows the activity test curves of the hydrolysis catalysts in Example 6 and Comparative Example 2. It can be seen from the figure that the hydrolysis catalyst with a water content of less than 5% has higher catalytic activity, while when the water content of the hydrolysis catalyst is too high, its catalytic activity will be significantly reduced.

[0117] Comparative Example 3

[0118] This comparative example is basically the same as Example 1, except that the specific surface area of ​​the γ-alumina spheres is distributed in the range of 200-260 μm. 2 Within the range of / g.

[0119] The hydrolysis catalysts prepared in Examples 1-10 and Comparative Examples 1-3, along with commercially available hydrolysis catalysts, were subjected to industrial side-line tests for the removal of carbonyl sulfide from blast furnace gas. The concentration of carbonyl sulfide at the inlet was 100-150 mg / Nm³. 3 The reaction temperature was 100℃ and the space velocity was 6000 h⁻¹. -1 The evaluation period was 40 hours. The highest and average conversion rates of carbonyl sulfide during the evaluation period were statistically analyzed, and the results are shown in Table 3.

[0120] Table 3

[0121]

[0122] As can be seen from the table, the hydrolysis catalyst prepared by this invention can achieve a maximum conversion rate of over 75%, exhibiting excellent catalytic activity. Furthermore, Figure 3 shows the activity test curves for Example 1 and a commercially available hydrolysis catalyst. The figure shows that the hydrolysis catalyst of Example 1 has a higher conversion rate, indicating that the hydrolysis catalyst prepared by this invention has better catalytic activity.

[0123] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a hydrolysis catalyst, characterized in that, Includes the following steps: (1) A precursor is obtained by immersing γ-alumina spheres in an alkaline solution, wherein the specific surface area of ​​the γ-alumina spheres is 280-400 m². 2 / g; (2) The precursor is subjected to gradient drying to obtain a hydrolysis catalyst; the mass-volume ratio of the γ-alumina spheres and the alkaline solution is 1g:0.5-5mL; the alkaline solution is an aqueous solution of an alkaline substance, wherein the mass concentration of the alkaline substance is 0.10-0.48g / mL; the alkaline substance is composed of a weak base and a strong base with a mass ratio of 10:1-5; the gradient drying includes a primary drying stage and a secondary drying stage; the drying temperature of the primary drying stage is 30-50℃ and the drying time is 2-24h; the drying temperature of the secondary drying stage is 90-110℃ and the drying time is 5min-24h.

2. The method for preparing the hydrolysis catalyst according to claim 1, characterized in that, The weak base includes one or more of potassium carbonate, sodium carbonate, sodium bicarbonate, and potassium bicarbonate; the strong base includes one or more of sodium hydroxide and potassium hydroxide.

3. The method for preparing the hydrolysis catalyst according to claim 1, characterized in that, The γ-alumina spheres have a particle size of 4.5-5.5 mm, a water absorption rate of >50%, and a compressive strength of >80 N.

4. The method for preparing the hydrolysis catalyst according to claim 1, characterized in that, The soaking time is 0.5-8 hours.

5. The method for preparing the hydrolysis catalyst according to claim 1, characterized in that, The loading of the alkaline substance onto the γ-alumina spheres is 5-20 wt%.

6. A hydrolysis catalyst prepared by the method according to any one of claims 1-5, characterized in that, The water content of the hydrolysis catalyst is <5%.

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