A honeycomb hydrolysis catalyst suitable for coal gas desulfurization and its preparation method

Abstract

This invention discloses a honeycomb hydrolysis catalyst suitable for coal gas desulfurization and its preparation method, belonging to the field of catalyst technology. The preparation method includes the following steps: (a) using TiO2, SiO2, silica-alumina molecular sieve, titanium-silicon molecular sieve (types 0-4) and Al2O3 as carriers, adding organic binders, molding aids, and water to mix together to obtain a slurry; (b) after aging and filtration, the mixed slurry is extruded into shape through a mold, then dried and calcined to prepare honeycomb catalysts with different pore numbers, wall thicknesses, and external dimensions. This honeycomb catalyst is used as the finished catalyst, or the honeycomb catalyst is further loaded with alkali metals, aged, dried, and calcined a second time to obtain the final catalyst, which is used as the finished catalyst. The catalyst of this invention has the characteristics of high porosity, low bed pressure drop, allowing operation at high space velocities, large single-tower coal gas processing capacity, long service life, and convenient loading.

Description

Technical Field

[0001] This invention relates to the field of coal gas purification technology in the iron and steel metallurgical industry, and more specifically, to a honeycomb hydrolysis catalyst suitable for coal gas desulfurization and its preparation method. Background Technology

[0002] Blast furnace gas and coke oven gas contain various organic sulfides, such as carbonyl sulfide (COS), carbon disulfide (CS2), thiophene (C4H4S), thiols (R-SH), and sulfides (RS-R'). These organic sulfides not only pollute the environment but also corrode downstream equipment and poison downstream catalysts, affecting the subsequent utilization of the gas. Therefore, efficient and low-cost organic sulfur removal technology has become an important issue in the field of gas purification.

[0003] Currently, various organic sulfur removal technologies have been proposed, including physical adsorption, chemical adsorption, catalytic oxidation, and catalytic hydrolysis. However, due to the stable chemical properties of organic sulfur, it is impossible to achieve deep purification using simple alkaline absorption or adsorption with iron oxide or zinc oxide, as is the case with inorganic sulfur. Catalytic hydrolysis, with its low reaction temperature and high purification rate, is considered one of the most promising methods for treating organic sulfur in blast furnace and coke oven gas.

[0004] However, catalytic hydrolysis technology still faces many challenges in practical applications. First, existing catalytic hydrolysis desulfurization technologies are all based on particulate catalysts (such as the small spherical hydrolysis catalysts prepared by the rolling spherical method in patents CN115106108A and CN114192135A). The porosity of packed beds composed of these catalysts is relatively small (30-40%). Given the large gas flow rates in the steel and metallurgical industries, this results in high bed pressure drop (single-tower resistance 1-3 kPa) and high operating energy consumption. Furthermore, pressure loss in the fine desulfurization unit can easily lead to insufficient pressure at downstream gas consumption points, interfering with the normal operation of downstream equipment. Second, to control bed pressure drop, the operating space velocity needs to be kept at a low level (500-1500 h⁻¹). -1 The amount of catalyst used increases; at the same time, the amount of gas that can be processed in a single tower is limited (80,000-100,000 Nm³). 3 / h), but blast furnaces or coke ovens often have large gas flow rates (200,000-1,000,000 Nm³). 3 Since the current process involves multiple parallel reactors (approximately 1000 m³ / h), the overall construction cost and catalyst replacement cost are relatively high. Furthermore, traditional granular catalysts are prone to dust and water accumulation and clogging, and the bottom of the bed is easily damaged by pressure, resulting in a shorter catalyst lifespan. Installation and replacement are also time-consuming and labor-intensive. These various shortcomings of current hydrolysis catalysts significantly limit the promotion of coal gas desulfurization technology in the iron and steel metallurgical industry.

[0005] Therefore, there is an urgent need to develop a catalytic technology for efficiently removing organic sulfur from coal gas. This catalyst should possess advantages such as low pressure drop, tolerance to high space velocity operation, large single-tower coal gas processing capacity, low risk of dust and water accumulation, and ease of installation and replacement. Integral extruded honeycomb catalysts combine these advantages; however, fine desulfurization hydrolysis catalysts typically use metal oxides such as alumina as supports. These metal oxides have high thermal shrinkage rates, making extrusion honeycomb molding difficult. This application achieves a breakthrough for the first time, completing the extrusion molding of a high-porous honeycomb catalyst using metal oxides such as alumina as the main raw material and the preparation of an integral fine desulfurization hydrolysis catalyst. Therefore, this research has significant scientific research and practical application value. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a honeycomb hydrolysis catalyst suitable for coal gas desulfurization and its preparation method. This hydrolysis catalyst has high porosity (60-90%), low bed pressure drop (<500 Pa), and can operate at high space velocities (2000-5000 h⁻¹). -1 A single tower can process a large amount of coal gas (200,000-400,000 Nm³). 3 Features include / h); in addition, the honeycomb structure, when used with a soot blower, can reduce the risk of dust and water accumulation and extend the life of the catalyst; furthermore, the honeycomb catalyst is designed with modular filling, the bottom catalyst is not easily squeezed and damaged, and it is also convenient for quick filling.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for preparing a honeycomb hydrolysis catalyst suitable for coal gas desulfurization.

[0009] (a) Using TiO2, SiO2, silica-alumina molecular sieve, titanium-silicon molecular sieve (types 0-4) and Al2O3 as carriers, organic binders, molding aids and water are added and mixed together to obtain mud.

[0010] (b) After the well-mixed mud is aged and filtered, it is extruded into shape through a mold, and then dried and calcined to prepare honeycomb catalysts with different pore numbers, wall thicknesses and external dimensions. The honeycomb catalyst is used as the finished catalyst or the honeycomb catalyst is further loaded with alkali metals, aged, dried and calcined a second time to obtain the final catalyst as the finished catalyst.

[0011] The present invention is further configured such that the product catalyst has an integral extruded honeycomb structure, the catalyst mesh size is 1-500 CPSI, and the catalyst mesh shape is one of square, rectangular, triangular, hexagonal, and circular.

[0012] The present invention is further configured such that, in the carrier, the proportion of Al2O3 is 50-100wt%, the proportion of TiO2 is 0-50wt%, the proportion of SiO2 is 0-50wt%, the proportion of silicon-aluminum molecular sieve is 0-50wt%, and the proportion of titanium-silicon molecular sieve is 0-50wt%.

[0013] The present invention is further configured such that the organic binder is one or more of polyvinyl alcohol (PVA), polyethylene glycol (PEG), polyethylene oxide (PEO), carboxymethyl cellulose (CMC), hydroxypropyl methyl cellulose (HPMC), and polyacrylic acid (PAA), wherein the organic binder accounts for 0.1-10 wt% of the total mass of the mud. At least one of the organic binders has a molecular weight greater than or equal to 100,000.

[0014] The present invention is further configured such that the molding aid is one or more of glass fiber, kapok, chopped synthetic fiber, glycerin, vegetable oil, and lactic acid, wherein the molding aid accounts for 0.1-5 wt% of the total mass of the clay.

[0015] The present invention is further configured such that, when loading alkali metals, one or more of sodium, potassium, lithium, magnesium, and calcium metal salt solutions are used for loading, including but not limited to sodium carbonate, potassium carbonate, lithium carbonate, magnesium carbonate, calcium carbonate, sodium hydroxide, potassium hydroxide, lithium hydroxide, magnesium hydroxide, and calcium hydroxide, wherein the loading amount of alkali metal accounts for 0-20 wt% of the mass of the finished catalyst; alkali metal loading is carried out by impregnation, and the alkali metal solution needs to be aged for 12-24 hours after impregnation.

[0016] The present invention is further configured such that, in step (b), the moisture content of the mud obtained by mixing is controlled at 25%-35%; the aging of the mixed mud is to place the mixed mud in a container and seal it for standing, and the aging time should be 12-24 hours.

[0017] The present invention is further configured such that the drying of the clay material after extrusion molding is carried out in stages and stepwise drying. The first stage drying temperature is 30-50℃ and the time is 8-15 days; the second stage drying temperature is 60-100℃ and the time is 2-5 days.

[0018] The present invention is further configured such that the calcination of the clay material after extrusion molding adopts a programmed heating method with a heating rate of less than 3℃ / min, a maximum calcination temperature range of 500-600℃, and a residence time of 3-5 hours.

[0019] The calcination after alkali metal loading adopts programmed heating with a heating rate of less than 5℃ / min, a maximum calcination temperature range of 400-500℃, and a residence time of 2-3 hours.

[0020] A honeycomb hydrolysis catalyst suitable for coal gas fine desulfurization prepared according to the above method.

[0021] In summary, the present invention has the following beneficial effects:

[0022] 1. Low pressure drop: The pressure drop of a single tower of traditional granular hydrolysis catalysts is between 1-3 kPa when placed after a TRT turbine power generation unit, and it is even higher when placed before a TRT turbine power generation unit, reaching 5-10 kPa; however, the pressure drop of honeycomb hydrolysis catalysts can be controlled within 500 Pa whether placed before or after a TRT turbine power generation unit. The low pressure drop not only ensures a stable supply and smooth use of downstream gas, but also reduces energy consumption during operation.

[0023] 2. High space velocity: The operating space velocity of traditional granular hydrolysis catalysts generally needs to be controlled at 500-1500 h⁻¹. -1 In the TRT (Transmission Time Reduction) range, excessively high space velocity leads to excessive catalyst pressure drop, resulting in insufficient downstream gas supply pressure or excessive impact on the power generation efficiency of the TRT turbine. Conversely, excessively low space velocity increases the required catalyst quantity and raises costs. The honeycomb hydrolysis catalyst of this invention can achieve a lifespan of 2000-5000 hours. -1 Even when operating at high space velocities, it still maintains low bed pressure drop (<500Pa) and high hydrolysis efficiency (>80%), thus reducing the amount of catalyst required.

[0024] 3. Large single-tower gas processing capacity: The single-tower gas processing capacity of reaction towers using traditional granular hydrolysis catalysts is generally 80,000-100,000 Nm³. 3 / h, but blast furnaces or coke ovens often have large gas flow rates (200,000-1,000,000 Nm³). 3 Because the gas velocity of a honeycomb hydrolysis catalyst is 3-5 times higher than that of a traditional spherical catalyst, the gas throughput of a single reactor filled with a honeycomb catalyst can reach 200,000-400,000 Nm³ / h. 3 / h, reducing the number of reaction towers, thereby reducing the construction cost of the equipment;

[0025] 4. Long lifespan: Compared with traditional granular catalysts, honeycomb hydrolysis catalysts greatly reduce the risk of dust accumulation, water accumulation and breakage, resulting in a longer service life;

[0026] 5. Convenient installation and replacement: Thanks to the modular design of the honeycomb hydrolysis catalyst, it can be quickly installed and replaced on the construction site by hoisting, making it more convenient and faster to install and replace than the traditional granular hydrolysis catalyst.

[0027] 6. Low cost: The advantages of the honeycomb hydrolysis catalyst mentioned above make the overall construction and operation costs of this technology lower than those of traditional technologies using granular hydrolysis catalysts. Attached Figure Description

[0028] Figure 1 The images show samples of the catalysts prepared in Examples 1 and 4, and commercially available particulate catalysts; (a) Example 1 catalyst with square honeycomb mesh; (b) Example 4 catalyst with hexagonal honeycomb mesh; (c) Commercially available particulate catalyst #1;

[0029] Figure 2 Comparative examples 2 and 3 show the catalysts obtained and their comparisons: (a) Comparative example 2 has a square honeycomb mesh; (b) Comparative example 3 has a hexagonal honeycomb mesh.

[0030] Figure 3 Comparison chart of materials after mixing in Comparative Example 4 and Example 3: (a) Material that cannot be clump together after mixing in Comparative Example 4; (b) Material that clumps together well after mixing in Example 3;

[0031] Figure 4 This is a comparison graph showing the hydrolysis efficiency and stability of the catalysts prepared in Examples 1, 3, and Comparative Example 1.

[0032] Figure 5 This is a comparison chart of the hydrolysis efficiency of the honeycomb catalyst prepared in Example 3 and the commercially available granular desulfurization catalyst. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] This invention relates to a method for preparing a honeycomb hydrolysis catalyst for coal gas desulfurization, comprising the following steps:

[0035] (a) Using TiO2, SiO2, silica-alumina molecular sieve, titanium-silicon molecular sieve (0-4 types) and Al2O3 as carriers (the proportion of Al2O3 in the carrier is 50-100wt%, the proportion of TiO2 is 0-50wt%, the proportion of SiO2 is 0-50wt%, the proportion of silica-alumina molecular sieve is 0-50wt%, and the proportion of titanium-silicon molecular sieve is 0-50wt%), organic binders, molding aids, and water are added and mixed together to obtain mud.

[0036] The organic binder is one or more of polyvinyl alcohol (PVA), polyethylene glycol (PEG), polyethylene oxide (PEO), carboxymethyl cellulose (CMC), hydroxypropyl methyl cellulose (HPMC), and polyacrylic acid (PAA), wherein the organic binder accounts for 0.1-10 wt% of the total mass of the clay; the molding aid is one or more of glass fiber, kapok, chopped synthetic fiber, glycerin, vegetable oil, and lactic acid, wherein the molding aid accounts for 0.1-5 wt% of the total mass of the clay.

[0037] The moisture content of the clay should be controlled between 25% and 35%. Too low a moisture content will cause the clay to clump and be difficult to extrude, while too high a moisture content will make the clay too soft, making it difficult to form and extrude, or the extruded sample will have insufficient strength, making it difficult to carry out subsequent processing and transfer.

[0038] (b) After the mixed clay is aged and filtered (aging involves placing the mixed clay in a sealed container and letting it stand for 12-24 hours; filtration involves extruding the aged clay through a filter to remove air from the clay, thereby increasing the density of the extruded blank; at the same time, the filter screen removes impurities from the raw material to ensure smooth extrusion and improve the quality of the extruded blank. A 30-60 mesh filter screen is generally used for the clay filtration process), the clay is extruded into shape using a die (generally using a 6-132 hole die, an extrusion length of 100-500 mm, an extrusion pressure of 2-15 MPa, and an extrusion speed of 1-5 m / min), followed by drying (drying the extruded clay is done in stages; the first stage drying temperature is 30-50℃ for 8-15 days; the second stage drying temperature is 60-100℃ for 2-5 days), and calcination (calcination uses a programmed heating method). Honeycomb catalysts with different pore numbers, wall thicknesses, and external dimensions are prepared by heating at a rate of less than 3℃ / min, with a maximum calcination temperature range of 500-600℃ and a residence time of 3-5 hours. These honeycomb catalysts are used as the finished catalyst, or the honeycomb catalysts are further subjected to alkali metal loading (using impregnation, employing one or more of sodium, potassium, lithium, magnesium, and calcium metal salts, including but not limited to sodium carbonate, potassium carbonate, lithium carbonate, magnesium carbonate, calcium carbonate, sodium hydroxide, potassium hydroxide, lithium hydroxide, magnesium hydroxide, and calcium hydroxide, with the alkali metal loading accounting for 0-20 wt% of the finished catalyst mass). After aging for 12-24 hours, the catalysts are dried and subjected to a second calcination (calcination using programmed temperature rise, with a heating rate of less than 3℃ / min, a maximum calcination temperature range of 400-500℃, and a residence time of 2-3 hours) to obtain the final catalyst, which is then used as the finished catalyst. Alkali metal loading can enhance the number and strength of basic centers in the catalyst, thereby improving its catalytic hydrolysis ability.

[0039] The product catalyst has an integral extruded honeycomb structure with a catalyst mesh size of 1-500 CPSI; the catalyst mesh shape is one of square, rectangular, triangular, hexagonal, or circular.

[0040] Example 1

[0041] Catalyst preparation: 9.0 kg of active Al2O3 powder, 1.0 kg of TiO2 powder, 0.2 kg of CMC (carboxymethyl cellulose) powder with a molecular weight of 200,000, 0.2 kg of PEO (polyethylene oxide) powder with a molecular weight of 3.5 million, 0.3 kg of molding aid (glass fiber), and 4.5 kg of deionized water were mixed in a mixer for 1 hour, then filtered through a 40-mesh sieve. The resulting catalyst preform was aged for 12 hours. The catalyst preform was extruded through a 46 CPSI die, with square honeycomb mesh and a preform length of 250 mm. It was first dried in a primary drying chamber at 40°C for 10 days to reduce the moisture content to below 15%, and then dried in a secondary drying chamber at 80°C for 3 days. When the moisture content was reduced to below 5%, it was calcined in a kiln at a heating rate of 2°C / min, a maximum temperature of 550°C, and a residence time of 4 hours. Based on the water absorption rate of the prepared honeycomb carrier, a Na₂CO₃ solution of suitable concentration was prepared. The catalyst was loaded with 10% Na through impregnation, aged for 12 hours, and then dried and calcined a second time. The second calcination heating rate was 2℃ / min, the maximum temperature was 400℃, and the residence time was 2 hours, thus completing the catalyst preparation. Figure 1 (a) is shown.

[0042] Catalyst activity testing: Activity experiments were conducted in a fixed-bed reactor with a catalyst loading of 16*16*200mm. Initial gas concentrations were: [COS] = 200ppm, [O2] = 0.5vol%, [H2O] = 0.5vol%, [CO2] = 25vol%, N2 as the equilibrium gas, and space velocity (SV) = 2500h⁻¹. -1 The catalyst exhibited an average hydrolysis efficiency of 95.3% for COS at 80℃, a selectivity for H2S greater than 90%, and good stability, with no obvious deactivation observed after 5 hours of reaction at 80℃.

[0043] Example 2

[0044] Catalyst preparation: 9.0 kg of activated Al2O3 powder, 1.0 kg of SiO2 powder, 0.2 kg of CMC powder with a molecular weight of 200,000, 0.2 kg of PEG (polyethylene glycol) liquid with a molecular weight of 400, 0.3 kg of molding aid (kapok), and 4.5 kg of deionized water were mixed in a mixer for 1 hour, then filtered through a 40-mesh sieve. The resulting catalyst preform was aged for 12 hours. The catalyst preform was extruded through a 46 CPSI die, with square honeycomb mesh and a preform length of 250 mm. It was first dried in a primary drying chamber at 40°C for 10 days to reduce the moisture content to below 15%, and then dried in a secondary drying chamber at 80°C for 3 days. When the moisture content was reduced to below 5%, it was calcined in a kiln at a heating rate of 2°C / min, a maximum temperature of 550°C, and a residence time of 4 hours. Based on the water absorption rate of the prepared honeycomb carrier, a K2CO3 solution of suitable concentration was prepared. The catalyst was loaded with 10% K by impregnation and aged for 12 hours. Then, it was dried and calcined a second time. The heating rate of the second calcination was 2℃ / min, the maximum temperature was 400℃, and the residence time was 2 hours, thus completing the preparation of the catalyst.

[0045] Catalyst activity testing: Activity experiments were conducted in a fixed-bed reactor with a catalyst loading of 16*16*200mm. Initial gas concentrations were: [COS] = 200ppm, [O2] = 0.5vol%, [H2O] = 0.5vol%, [CO2] = 25vol%, N2 as the equilibrium gas, and space velocity (SV) = 2500h⁻¹. -1 The catalyst exhibited an average hydrolysis efficiency of 95.0% for COS at 80℃, a selectivity for H2S greater than 90%, and good stability, with no obvious deactivation observed after 5 hours of reaction at 80℃.

[0046] Compared with Example 1, Example 2 showed that the COS hydrolysis efficiency was basically the same, indicating that the addition of TiO2 or SiO2 can achieve the same catalytic hydrolysis performance.

[0047] Example 3

[0048] Catalyst preparation: 10.0 kg of activated Al2O3 powder, 0.2 kg of CMC powder with a molecular weight of 200,000, 0.2 kg of PVA (polyvinyl alcohol) powder with a molecular weight of 20,000, 0.3 kg of molding aid (polypropylene short fiber), and 4.5 kg of deionized water were mixed in a mixer for 1 hour, then filtered through a 40-mesh sieve. The resulting catalyst preform was aged for 12 hours. The catalyst preform was extruded through a 46 CPSI die, with square honeycomb mesh and a preform length of 250 mm. It was first dried in a primary drying chamber at 40°C for 10 days to reduce the moisture content to below 15%, then dried in a secondary drying chamber at 80°C for 3 days to reduce the moisture content to below 5%. Finally, it was calcined in a kiln at a heating rate of 2°C / min, with a maximum temperature of 550°C and a residence time of 4 hours. Based on the water absorption rate of the prepared honeycomb carrier, a NaOH solution of suitable concentration was prepared. The catalyst was loaded with 10% Na by impregnation and aged for 12 hours. Then, it was dried and calcined a second time. The heating rate of the second calcination was 2℃ / min, the maximum temperature was 400℃, and the residence time was 2 hours, thus completing the preparation of the catalyst.

[0049] Catalyst activity testing: Activity experiments were conducted in a fixed-bed reactor with a catalyst loading of 16*16*200mm. Initial gas concentrations were: [COS] = 200ppm, [O2] = 0.5vol%, [H2O] = 0.5vol%, [CO2] = 25vol%, N2 as the equilibrium gas, and space velocity (SV) = 2500h⁻¹. -1 The catalyst exhibited an average hydrolysis efficiency of 97.1% for COS at 80℃, a selectivity for H2S greater than 90%, and good stability. No obvious deactivation was observed after 5 hours of reaction at 80℃.

[0050] Example 3 shows that increasing the proportion of Al2O3 in the support increases the COS hydrolysis efficiency, indicating that the Al2O3 support has better COS catalytic hydrolysis performance than SiO2 and TiO2. However, adding appropriate amounts of SiO2 and TiO2 can improve the smoothness of molding and extrusion, and also enhance the mechanical strength of the honeycomb after calcination.

[0051] Example 4

[0052] Catalyst preparation: 10.0 kg of active Al2O3 powder, 0.2 kg of HPMC (hydroxypropyl methylcellulose) powder with a molecular weight of 100,000, 0.2 kg of PEO powder with a molecular weight of 3.5 million, 0.3 kg of molding aid (glass fiber), and 4.5 kg of deionized water were mixed in a mixer for 1 hour, then filtered through a 40-mesh sieve. The resulting catalyst preform was aged for 12 hours. The catalyst preform was extruded through a 46 CPSI die, with hexagonal honeycomb mesh and a preform length of 250 mm. It was first dried in a primary drying chamber at 40°C for 10 days to reduce the moisture content to below 15%, then dried in a secondary drying chamber at 80°C for 3 days to reduce the moisture content to below 5%. Finally, it was calcined in a kiln at a heating rate of 2°C / min, with a maximum temperature of 550°C and a residence time of 4 hours. Based on the water absorption rate of the prepared honeycomb carrier, a KOH solution of suitable concentration was prepared. The catalyst was then loaded with 10% K through impregnation, aged for 12 hours, and subsequently dried and calcined a second time. The second calcination was carried out at a heating rate of 2℃ / min, with a maximum temperature of 400℃ and a residence time of 2 hours, thus completing the catalyst preparation. Figure 1 (b) is shown.

[0053] Catalyst activity testing: Activity experiments were conducted in a fixed-bed reactor with a catalyst loading of 16*16*200mm. Initial gas concentrations were: [COS] = 200ppm, [O2] = 0.5vol%, [H2O] = 0.5vol%, [CO2] = 25vol%, N2 as the equilibrium gas, and space velocity (SV) = 2500h⁻¹. -1 The catalyst exhibited an average hydrolysis efficiency of 97.0% for COS at 80℃, a selectivity for H2S greater than 90%, and good stability. No obvious deactivation was observed after 5 hours of reaction at 80℃.

[0054] Example 4, compared with Example 3, demonstrates that, under the same mesh size (46 CPSI), different pore shapes of the honeycomb catalyst have no effect on hydrolysis performance.

[0055] Comparative Example 1

[0056] Catalyst preparation: 10.0 kg of active Al2O3 powder, 0.2 kg of CMC powder with a molecular weight of 200,000, 0.2 kg of PVA powder with a molecular weight of 20,000, 0.3 kg of molding aid (polypropylene short fiber), 0.1 kg of inorganic binder (the inorganic binder can be any one of water glass, bauxite, montmorillonite, kaolin, or clay; water glass was used in this comparative example), and 4.5 kg of deionized water were added to a mixer and mixed for 1 hour. The mixture was then filtered through a 40-mesh sieve, and the resulting catalyst preform was aged for 12 hours. The catalyst preform was extruded through a 46 CPSI die, with square honeycomb mesh and a preform length of 250 mm. It was first dried in a primary drying chamber at 40°C for 10 days to reduce the moisture content to below 15%, then dried again in a secondary drying chamber at 80°C for 3 days to reduce the moisture content to below 5%. Finally, it was calcined in a kiln at a heating rate of 2°C / min, with a maximum temperature of 550°C and a residence time of 4 hours. Based on the water absorption rate of the prepared honeycomb carrier, a NaOH solution of suitable concentration was prepared. The catalyst was loaded with 10% Na by impregnation and aged for 12 hours. Then, it was dried and calcined a second time. The heating rate of the second calcination was 2℃ / min, the maximum temperature was 400℃, and the residence time was 2 hours, thus completing the preparation of the catalyst.

[0057] Catalyst activity testing: Activity experiments were conducted in a fixed-bed reactor with a catalyst loading of 16*16*200mm. Initial gas concentrations were: [COS] = 200ppm, [O2] = 0.5vol%, [H2O] = 0.5vol%, [CO2] = 25vol%, N2 as the equilibrium gas, and space velocity (SV) = 2500h⁻¹. -1 The catalyst initially exhibited a COS hydrolysis efficiency of 92.0% at 80℃, but this efficiency decreased to 82.1% after 5 hours of reaction, showing clear signs of deactivation (e.g., ...). Figure 4 (As shown).

[0058] Comparative Example 1 has a similar formulation to Example 3, except that a small amount of inorganic binder was added. The stability of the catalyst decreased significantly. This is because the complex components in the inorganic binder react with the product H2S to generate sulfates or thiosulfates that cover the alkaline active sites on the surface of the catalyst, leading to catalyst deactivation.

[0059] Comparative Example 2

[0060] Catalyst preparation: 10.0 kg of activated Al2O3 powder, 0.2 kg of CMC powder with a molecular weight of 200,000, 0.2 kg of PVA powder with a molecular weight of 20,000, 0.3 kg of molding aid (polypropylene short fiber), and 4.5 kg of deionized water were added to a mixer and mixed for 1 hour. The mixture was then filtered through a 40-mesh sieve, and the resulting catalyst preform was aged for 12 hours. The catalyst preform was extruded through a 46 CPSI die, with square honeycomb mesh and a preform length of 250 mm. It was then dried in a drying chamber at 60°C for 10 days. Severe cracking of the preform occurred (e.g., ...). Figure 2 (as shown in (a)) makes it impossible to complete subsequent preparation operations.

[0061] Comparative Example 2 had the same formulation as Example 3, except that the temperature in the drying chamber was increased from 40°C to 60°C for 10 days, resulting in excessively rapid water loss from the embryo and large-area cracking. Therefore, controlling the temperature during the drying process is crucial for preparing a qualified carrier.

[0062] Comparative Example 3

[0063] Catalyst preparation: 10.0 kg of active Al2O3 powder, 0.2 kg of HPMC powder with a molecular weight of 100,000, 0.2 kg of PEO powder with a molecular weight of 3.5 million, 0.3 kg of molding aid (glass fiber), and 4.5 kg of deionized water were mixed in a mixer for 1 hour, then filtered through a 40-mesh sieve. The resulting catalyst preform was aged for 12 hours. The catalyst preform was extruded through a 46 CPSI die, with hexagonal honeycomb mesh and a preform length of 250 mm. It was first dried in a primary drying chamber at 40°C for 10 days to reduce the moisture content to below 15%, then dried in a secondary drying chamber at 80°C for 3 days to reduce the moisture content to below 5%. The catalyst was then calcined in a kiln at a heating rate of 5°C / min, with a maximum temperature of 550°C and a residence time of 4 hours. However, the honeycomb carrier after calcination showed severe cracking (e.g., Figure 2 (b) is shown.

[0064] The formulations of Comparative Example 3 and Example 4 were completely identical, except that the heating rate during calcination was increased from 2°C / min to 5°C / min. Due to the high thermal shrinkage rate of Al2O3, excessively rapid heating during calcination would cause the honeycomb carrier to expand rapidly, leading to severe cracking. Therefore, even if no cracks are observed in the carrier after drying, controlling the heating rate during the calcination process remains crucial.

[0065] Comparative Example 4

[0066] Catalyst preparation: 10.0 kg of activated Al2O3 powder, 0.2 kg of CMC powder with a molecular weight of 50,000, 0.2 kg of PEG liquid with a molecular weight of 400, 0.3 kg of molding aid (polypropylene short fiber), and 4.5 kg of deionized water were added to a mixer and mixed for 1 hour. It was found that the Al2O3 powder could not agglomerate (e.g., Figure 3 (a) shows that the extrusion molding failed.

[0067] The main reason for the failure of Comparative Example 4 was that the molecular weight of the organic binder used was too low and the viscosity was insufficient, resulting in the material failing to agglomerate during mixing. However, Examples 1-4 all used at least one organic binder with a molecular weight greater than or equal to 100,000, and the powder agglomeration was good after mixing (the material after mixing in Example 3 was as shown). Figure 3 (b) shows that it was thus successfully extruded.

[0068] Comparative Example 5

[0069] Catalyst preparation: 10.0 kg of active Al2O3 powder, 0.4 kg of HPMC powder with a molecular weight of 20,000, 0.4 kg of PVA powder with a molecular weight of 20,000, 0.3 kg of molding aid (glass fiber) and 4.6 kg of deionized water were added to a mixer and mixed for 2 hours. It was found that the Al2O3 powder still could not clump together and the extrusion molding failed.

[0070] In Comparative Example 5, despite increasing the amount of organic binder and extending the mixing time, the powder still failed to agglomerate. Therefore, selecting an organic binder with an appropriate molecular weight is crucial for the molding and extrusion of the honeycomb hydrolysis desulfurization catalyst.

[0071] Comparative Example 6

[0072] Purchased commercially available granular hydrolysis desulfurization catalysts from 3 different manufacturers (commercially available granular hydrolysis desulfurization catalyst #1, etc.) Figure 1 (c) As shown, its hydrolysis efficiency was evaluated under the same reaction conditions as in the examples, i.e., the activity experiment was conducted in a fixed-bed reactor. The packing volume of the granular catalyst was the same as that of the honeycomb catalyst, both being 0.0512 L. The initial gas concentrations were: [COS] = 200 ppm, [O2] = 0.5 vol%, [H2O] = 0.5 vol%, [CO2] = 25 vol%, N2 was the equilibrium gas, and the space velocity SV = 2500 h⁻¹. -1 The results show (e.g.) Figure 5 As shown, the average COS hydrolysis efficiency of the three commercially available particulate catalysts was between 88.3% and 89.3%, which was significantly lower than the hydrolysis efficiency of the honeycomb catalyst in Example 3.

[0073] The main reason why honeycomb catalysts have higher hydrolysis desulfurization efficiency than granular catalysts is that honeycomb has a higher geometric specific surface area, providing more active contact sites during the catalytic reaction. In addition, honeycomb desulfurization catalysts also have many advantages, such as lower pressure drop, ability to operate at higher space velocities, larger gas throughput per tower, lower risk of dust and water accumulation and breakage, easier installation and replacement, and lower overall construction and operating costs. Therefore, the honeycomb hydrolysis desulfurization technology of this invention is significantly superior to the traditional granular hydrolysis desulfurization technology.

[0074] Table 1. Comparison of key material information and COS hydrolysis efficiency for each embodiment and comparative example.

[0075]

[0076]

[0077] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a honeycomb hydrolysis catalyst suitable for coal gas desulfurization, characterized in that, Includes the following steps: (a) Using TiO2, SiO2, silica-alumina molecular sieve, titanium-silicon molecular sieve (types 0-4) and Al2O3 as carriers, organic binders, molding aids, and water are added and mixed together to obtain clay. The molding aids are one or more of glass fiber, kapok, chopped synthetic fiber, glycerin, vegetable oil, and lactic acid, wherein the molding aids account for 0.1-5 wt% of the total mass of the clay. (b) After the well-mixed mud is aged and filtered, it is extruded into shape through a mold, and then dried and calcined to prepare honeycomb catalysts with different pore numbers, wall thicknesses and external dimensions. The honeycomb catalyst is used as the finished catalyst or the honeycomb catalyst is further loaded with alkali metals, aged, dried and calcined a second time to obtain the final catalyst as the finished catalyst. In the carrier, the proportions of Al2O3 are 50-100wt%, TiO2 are 0-50wt%, SiO2 are 0-50wt%, silicon-aluminum molecular sieves are 0-50wt%, and titanium-silicon molecular sieves are 0-50wt%; the moisture content of the mixed mud is controlled at 25%-35%. The organic binder is one or more of polyvinyl alcohol, polyethylene glycol, carboxymethyl cellulose, hydroxypropyl methyl cellulose, and polyacrylic acid, wherein the organic binder accounts for 0.1-10 wt% of the total mass of the mud; at least one of the organic binders has a molecular weight greater than or equal to 100,000; The drying of the extruded clay is carried out in stages. The first stage of drying is at a temperature of 30-50°C for 8-15 days; the second stage of drying is at a temperature of 60-100°C for 2-5 days. The calcination of the extruded clay is carried out using programmed heating with a heating rate of less than 3℃ / min, a maximum calcination temperature range of 500-600℃, and a residence time of 3-5 hours.

2. The method for preparing a honeycomb hydrolysis catalyst suitable for coal gas desulfurization according to claim 1, characterized in that, The finished catalyst has an integral extruded honeycomb structure with a catalyst mesh size of 1-500 CPSI; the catalyst mesh shape is one of square, rectangular, triangular, hexagonal, or circular.

3. The method for preparing a honeycomb hydrolysis catalyst suitable for coal gas desulfurization according to claim 1, characterized in that, When loading alkali metals, one or more of sodium, potassium, and lithium metal salt solutions are used for loading. The metal salt is at least one of sodium carbonate, potassium carbonate, and lithium carbonate. The loading amount of alkali metal accounts for 0-20 wt% of the mass of the finished catalyst and is not 0. The alkali metal loading is carried out by impregnation. After impregnation, the alkali metal salt solution needs to be aged for 12-24 hours.

4. The method for preparing a honeycomb hydrolysis catalyst suitable for coal gas fine desulfurization according to claim 1, characterized in that, In step (b), the aging of the mixed mud involves placing the mixed mud in a sealed container and letting it stand for 12-24 hours.

5. The method for preparing a honeycomb hydrolysis catalyst suitable for coal gas desulfurization according to claim 1, characterized in that, The calcination after alkali metal loading adopts programmed heating with a heating rate of less than 3℃ / min, the highest calcination temperature range is 400-500℃, and the residence time is 2-3 hours.

6. A honeycomb hydrolysis catalyst suitable for coal gas fine desulfurization prepared by the method according to any one of claims 1-5.

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