Preparation method of high-permeability high-efficiency sulfuric acid catalyst

Abstract

The preparation method of the high-permeability high-efficiency sulfuric acid catalyst comprises the following steps: adding vanadium pentoxide powder into a potassium sulfate supersaturated solution, dispersing, and adding potassium hydroxide and sodium sulfite until potassium hydroxide and sodium sulfite are dissolved; the preparation method comprises the following steps: slowly adding dilute sulphuric acid at the constant temperature of 60-80 DEG C, adjusting the acid-base property to be neutral, adding polyethylene glycol (6000), sodium benzenesulfonate, soluble starch and organic silicon, stirring at the constant temperature for 15-30 minutes, adding macroporous silicon dioxide powder, stirring for 10 minutes, adding dilute sulphuric acid, and stirring at the constant temperature for 20-30 minutes to obtain a colloidal catalytic activity intermediate; performing equal-mass separation and reunion dispersion on disc-shaped diatomite and straight-chain diatomite to obtain a mixed carrier; and mechanically stirring and mixing the colloidal catalytic activity intermediate, the mixed carrier and the organic matter additive until the catalytic activity substance is fully dispersed in a diatomite skeleton and pore channels, molding to obtain a catalyst wet blank, drying and roasting to obtain the product. The catalyst is good in air permeability, high in catalytic activity and high in thermal stability.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, and more specifically to a method for preparing a highly permeable and efficient sulfuric acid catalyst. Background Technology

[0002] Sulfuric acid catalysts are crucial chemical materials in the contact process for sulfuric acid production. Their role is to catalytically oxidize SO2 and O2 to SO3 in the converter, which is then absorbed and converted into H2SO4. The overall performance of the catalyst directly impacts the efficiency, energy consumption, cost, and sulfur oxide content in the exhaust gas of sulfuric acid production. Currently, after a period of operation, most sulfuric acid production plants experience a significant increase in gas resistance in the catalyst bed, leading to a decrease in production efficiency. To ensure the plant's operational efficiency, the catalyst is typically screened and replenished after 2-3 years of operation, which increases the company's production costs. Research has found that the increase in catalyst bed gas resistance is directly related to the permeability of the catalyst matrix.

[0003] Currently, commercially available sulfuric acid catalysts suffer from problems such as a compact matrix, uneven distribution of active materials, and unreasonable pore structure and distribution, which severely affect the catalyst's thermal stability, catalytic activity, and gas mass transfer performance. For example, Chinese patent CN102974339A discloses a vanadium catalyst for sulfuric acid production using powdered vanadium pentoxide and its preparation method. The process involves mixing vanadium pentoxide powder with ultrafine potassium sulfate powder to form a vanadium pentoxide-potassium sulfate powder mixture, which is then mixed with refined diatomaceous earth and ultrafine sodium sulfate powder, followed by high-temperature calcination to obtain the vanadium catalyst. This preparation method uses solid-solid mixing, resulting in uneven distribution of active components and large active component clusters. Therefore, the vanadium catalyst prepared by this method has low compressive strength, poor thermal stability, and low catalytic activity.

[0004] Chinese patent CN109759052B discloses a method for preparing a catalyst for the oxidation of sulfur dioxide to sulfuric acid. The process involves first preparing a catalyst containing VO3 by combining vanadium pentoxide, caustic soda flakes, auxiliary agents, and sulfuric acid. - The process involves first preparing an active colloid, then mixing 3%–6% of the active colloid with 80% of the carrier, followed by drying, calcination, and sieving of the mixture. This mixture is then further mixed with 20% of the carrier and 6%–10% of the active colloid, and finally shaped, dried, and calcined to obtain the catalyst product. However, this preparation method employs a roller milling process, which severely damages the structure of the diatomaceous earth carrier. This also hinders the uniform dispersion of active substances within the carrier framework and pores, and the resulting compact catalyst matrix structure impedes the entry and exit of reactant gases, thus affecting mass and heat transfer efficiency. Consequently, after the catalyst prepared using this method has been loaded into the device and operated for a period of time, the gas resistance of the catalyst bed increases rapidly, leading to a decrease in its catalytic activity and thermal stability.

[0005] Chinese patent CN102489320A discloses a nano-vanadium catalyst for sulfuric acid production from sulfur dioxide and its preparation method. The process involves reacting vanadium pentoxide with potassium hydroxide or sodium hydroxide to convert it into a potassium metavanadate or sodium metavanadate solution, which is then reacted with dilute sulfuric acid to form a colloidal substance. This substance is then mixed with diatomaceous earth under mechanical stirring to disperse it on the surface of a support, and finally calcined at high temperature to obtain the vanadium catalyst. However, this preparation method releases a large amount of heat when dilute sulfuric acid is added, forming a colloidal substance of vanadium pentoxide with relatively large particles, which is not conducive to the uniform dispersion of the active material on the surface and in the pores of the diatomaceous earth. Furthermore, during the catalytic oxidation process, a relatively thick alkali metal-vanadium sulfate molten liquid film is easily formed, thereby hindering the mass transfer efficiency of the reactant gas in the catalyst matrix. Therefore, the catalyst prepared by this method has low activity. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a method for preparing a highly permeable and efficient sulfuric acid catalyst with good permeability, high catalytic activity, and high thermal stability.

[0007] The present invention provides a method for preparing a highly permeable and efficient sulfuric acid catalyst, comprising the following steps: (1) Add 28~35Kg of water to the reaction vessel, and add 0~1.9 Kg of sodium sulfate (Na2SO4) and 6.0~8.0Kg of potassium sulfate (K2SO4) under stirring at room temperature to dissolve them and form a supersaturated solution; (2) Add 3.6~4.8 Kg of vanadium pentoxide (V2O5) powder to the supersaturated solution and stir mechanically at 180~200 r / min to disperse it. Then add 3.0~4.5 Kg of potassium hydroxide (KOH) and 2.5~3.3 Kg of sodium sulfite (Na2SO3) and continue stirring mechanically until it dissolves. (3) Under constant temperature of 60~80℃ and mechanical stirring at 180~200 r / min, slowly add 12.8~17.0 Kg of 50% dilute sulfuric acid to adjust the acidity to neutral (pH about 7), then add 2~3.5 Kg of polyethylene glycol (6000), 0.5~1.2 Kg of sodium benzenesulfonate, 1.2~3.0 Kg of soluble starch, and 3~5 Kg of organosilicon. Stir at constant temperature for 15~30 min. (4) Under the conditions of maintaining a constant temperature of 60~80℃ and mechanical stirring at 180~200 r / min, add 9.0~12.0 kg of macroporous silica powder, stir mechanically for 10 min, then add 15.6~20.7 kg of dilute sulfuric acid with a volume concentration of 50%, stir at a constant temperature for 20~30 min to obtain a colloidal catalytically active intermediate; (5) Disperse disc-shaped diatomaceous earth and linear diatomaceous earth of equal mass to obtain a mixed carrier for later use; (6) Weigh 15~20Kg of colloidal catalytic active intermediate, 6~13Kg of mixed support and 3~6Kg of organic matter additive, and mechanically stir and mix until the catalytic active material is fully dispersed in the diatomite skeleton and pores of the support. Then, shape the mixture with a molding machine to obtain the catalyst wet blank. (7) The wet catalyst blank is dried at 105~110 ℃ until the moisture content is less than 10%, and then placed in a ventilated muffle furnace and calcined at 550~650 ℃ for 30~40 min to obtain the catalyst product.

[0008] The above-mentioned method for preparing a highly permeable and efficient sulfuric acid catalyst, wherein the organic additives in step (6) are coconut shell activated carbon and fine wood fiber.

[0009] The above-mentioned method for preparing a highly permeable and efficient sulfuric acid catalyst includes a ratio of fine wood fiber to coconut shell activated carbon of 1:1.

[0010] Compared with existing technologies, this invention has significant advantages. As can be seen from the above technical solution, this invention employs a highly soluble and stable vanadium oxysulfate process to prepare a sol-gel active intermediate from vanadium pentoxide, potassium hydroxide, organic additives (polyethylene glycol, sodium benzenesulfonate, soluble starch), and organosilicon. The introduction of organosilicon significantly improves the dispersion performance of the catalytic active intermediate, enhances the matrix bonding performance and radial compressive strength, and effectively regulates the microporous structure and distribution in the catalyst matrix. Furthermore, it strengthens the bonding between the vanadium-containing active material and the diatomaceous earth support surface, thereby improving the catalyst's thermal stability and catalytic activity, extending its service life, and reducing catalyst bed gas resistance, resulting in good economic benefits. Detailed Implementation

[0011] Example 1: A method for preparing a highly permeable and efficient sulfuric acid catalyst, the technical solution of which includes the following steps: (1) Add 28 kg of water to the reaction vessel, and add 6.0 kg of potassium sulfate (K2SO4) under stirring at room temperature to dissolve it and form a supersaturated solution; (2) Add 3.6 kg of vanadium pentoxide (V2O5) powder to the supersaturated solution and stir mechanically at 200 r / min to disperse it. Then add 3.0 kg of potassium hydroxide (KOH) solid and 3.3 kg of sodium sulfite (Na2SO3) and continue stirring mechanically until dissolved. (3) Under constant temperature of 60℃ and mechanical stirring at 200 r / min, slowly add 12.8 Kg of 50% dilute sulfuric acid to adjust the acidity of the system to neutral (pH about 7), add 2 Kg of polyethylene glycol (6000), 1.2 Kg of sodium benzenesulfonate, 1.2 Kg of soluble starch, and 3 Kg of organosilicon, and stir at constant temperature for 15 min; (4) Under the conditions of maintaining the system temperature at 60℃ and mechanical stirring at 200 r / min, 9.0 kg of macroporous silica powder was added and mechanically stirred for 10 min. Then, 20.7 kg of dilute sulfuric acid with a volume concentration of 50% was added and stirred at a constant temperature for 20 min to obtain a colloidal catalytic active intermediate. (5) Disperse disc-shaped diatomaceous earth and linear diatomaceous earth of equal mass to obtain a mixed carrier for later use; (6) Weigh 20 kg of the colloidal catalytic active intermediate described in step (4), 13 kg of the mixed support described in step (5) and 3 kg of organic matter additive (fine wood fiber: coconut shell activated carbon = 1:1), and mechanically stir and mix to fully disperse the catalytic active material in the diatomaceous earth support skeleton and pores. Then, shape the mixture using a molding machine to obtain the catalyst wet blank. (7) The wet catalyst blank is placed at 105°C and dried until the moisture content is less than 10%. Then it is placed in a ventilated muffle furnace and calcined at 550°C for 30 min to obtain the catalyst product.

[0012] Testing revealed that the catalyst exhibited a radial compressive strength of 56 N / cm, a wear rate of 3.2%, a catalytic activity of 90.59% at 485℃, a catalyst porosity of 69%, and a catalyst bed packing height of 80 cm. F The gas resistance (60 cm) is reduced to 0.13 kPa.

[0013] Example 2 A method for preparing a highly permeable and efficient sulfuric acid catalyst, the technical solution of which includes the following steps: (1) Add 35 kg of water to the reaction vessel, and add 1.9 kg of sodium sulfate (Na2SO4) and 8.0 kg of potassium sulfate (K2SO4) under stirring at room temperature, and stir to dissolve them to form a supersaturated solution; (2) Add 4.8 kg of vanadium pentoxide (V2O5) powder to the supersaturated solution and stir mechanically at 180 r / min to disperse it. Then add 3.0 kg of potassium hydroxide (KOH) solid and 2.5 kg of sodium sulfite (Na2SO3) and continue stirring mechanically until it dissolves. (3) Under constant temperature of 80℃ and mechanical stirring at 180r / min, slowly add 17.0 Kg of 50% dilute sulfuric acid to adjust the acidity of the system to neutral (pH about 7), add 3.5 Kg of polyethylene glycol (6000), 0.5 Kg of sodium benzenesulfonate, 3.0 Kg of soluble starch and 5 Kg of organosilicon, and stir at constant temperature for 30 min; (4) Under the conditions of maintaining the system temperature at 80℃ and mechanical stirring at 180r / min, 12.0 kg of macroporous silica powder was added and mechanically stirred for 10 min. Then, 15.6 kg of dilute sulfuric acid with a volume concentration of 50% was added and stirred at a constant temperature for 30 min to obtain a colloidal catalytic active intermediate. (5) Disperse disc-shaped diatomaceous earth and linear diatomaceous earth of equal mass to obtain a mixed carrier for later use; (6) Weigh 15 kg of the colloidal catalytic active intermediate described in step (4), 6 kg of the mixed support described in step (5) and 5 kg of organic matter additive (fine wood fiber: coconut shell activated carbon = 1:1), and mechanically stir and mix for 15 min to fully disperse the catalytic active material in the diatomaceous earth support skeleton and pores. Then, shape the mixture using a molding machine to obtain the catalyst wet blank. (7) The wet catalyst blank is placed at 110 °C and dried until the moisture content is less than 10%. Then it is placed in a ventilated muffle furnace and calcined at 650 °C for 40 min to obtain the catalyst product.

[0014] Testing revealed that the catalyst exhibited a radial compressive strength of 60 N / cm, a wear rate of 2.8%, a catalytic activity of 92.30% at 485℃, a catalyst porosity of 73%, and a catalyst bed packing height of 80 cm. F The gas resistance (60 cm) is reduced to 0.17 kPa.

[0015] Example 3 A method for preparing a highly permeable and efficient sulfuric acid catalyst, the technical solution of which includes the following steps: (1) Add 32 kg of water to the reaction vessel, and add 1 kg of sodium sulfate (Na2SO4) and 7 kg of potassium sulfate (K2SO4) under stirring at room temperature to dissolve them and form a supersaturated solution; (2) Add 4.2 kg of vanadium pentoxide (V2O5) powder to the supersaturated solution and stir mechanically at 190 r / min to disperse it. Then add 4.5 kg of potassium hydroxide (KOH) solid and 3 kg of sodium sulfite (Na2SO3) and continue stirring mechanically until it dissolves. (3) Under constant temperature of 70℃ and mechanical stirring at 190 r / min, slowly add 15.0 Kg of 50% dilute sulfuric acid to adjust the acidity of the system to neutral (pH about 7), add 3 Kg of polyethylene glycol (6000), 1 Kg of sodium benzenesulfonate, 2.5 Kg of soluble starch and 4 Kg of organosilicon, and stir at constant temperature for 20 min; (4) Under the conditions of maintaining the system temperature at 70℃ and mechanical stirring at 190 r / min, 10 kg of macroporous silica powder was added and mechanically stirred for 10 min. Then, 18 kg of dilute sulfuric acid with a volume concentration of 50% was added and stirred at a constant temperature for 25 min to obtain a colloidal catalytic active intermediate. (5) Disperse disc-shaped diatomaceous earth and linear diatomaceous earth of equal mass to obtain a mixed carrier for later use; (6) Weigh 19.3 Kg of the colloidal catalytic active intermediate described in step (4), 10.8 Kg of the mixed support described in step (5) and 6 Kg of organic matter additive (fine wood fiber: coconut shell activated carbon = 1:1), and mechanically stir and mix to fully disperse the catalytic active material in the diatomaceous earth support skeleton and pores. Then, shape the mixture using a molding machine to obtain the catalyst wet blank. (7) The wet catalyst blank is placed at 108 °C and dried until the moisture content is less than 10%. Then it is placed in a ventilated muffle furnace and calcined at 630 °C for 35 min to obtain the catalyst product.

[0016] Testing revealed that the catalyst exhibited a radial compressive strength of 53 N / cm, a wear rate of 3.13%, a catalytic activity of 91.87% at 485℃, a catalyst porosity of 72%, and a catalyst bed packing height of 80 cm. F The gas resistance (60 cm) is reduced to 0.15 kPa.

[0017] The above methods are merely preferred embodiments of the present invention and do not impose any limitations on the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from any technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a highly permeable and efficient sulfuric acid catalyst, comprising the following steps: (1) Add 0-1.9 kg of sodium sulfate and 6.0-8.0 kg of potassium sulfate to 28-35 kg of water at room temperature and stir to dissolve them and form a supersaturated solution; (2) Add 3.6~4.8Kg of vanadium pentoxide powder to the supersaturated solution and stir mechanically at 180~200r / min to disperse it. Then add 3.0~4.5Kg of potassium hydroxide and 2.5~3.3Kg of sodium sulfite and continue stirring mechanically until it dissolves. (3) Under constant temperature of 60~80℃ and mechanical stirring at 180~200r / min, slowly add 12.8~17.0Kg of 50% dilute sulfuric acid to adjust the acidity to neutral. Then add 2~3.5Kg of polyethylene glycol (6000), 0.5~1.2Kg of sodium benzenesulfonate, 1.2~3.0Kg of soluble starch, and 3~5Kg of organosilicon. Stir at constant temperature for 15~30min. (4) Under the conditions of maintaining a constant temperature of 60~80℃ and mechanical stirring at 180~200r / min, add 9.0~12.0kg of macroporous silica powder, stir mechanically for 10min, then add 15.6~20.7Kg of dilute sulfuric acid with a volume concentration of 50%, stir at a constant temperature for 20~30min to obtain a colloidal catalytically active intermediate; (5) Disperse disc-shaped diatomaceous earth and linear diatomaceous earth of equal mass to obtain a mixed carrier for later use; (6) Weigh 15~20Kg of colloidal catalytic active intermediate, 6~13Kg of mixed support and 3~6Kg of organic matter additive, and mechanically stir and mix until the catalytic active material is fully dispersed in the diatomite skeleton and pores of the support. Then, shape the mixture with a molding machine to obtain the catalyst wet blank. (7) The wet catalyst blank is dried at 105~110℃ until the moisture content is less than 10%, and then placed in a ventilated muffle furnace and calcined at 550~650℃ for 30~40 minutes to obtain the catalyst product.

2. The method for preparing a high-permeability, high-efficiency sulfuric acid catalyst as described in claim 1, wherein: The organic additives mentioned in step (6) are coconut shell activated carbon and fine wood fiber.

3. The method for preparing a high-permeability, high-efficiency sulfuric acid catalyst as described in claim 1, wherein: Fine wood fiber: coconut shell activated carbon = 1:1.