A process for treating industrial silicon-containing waste gas

Abstract

The present invention relates to a process for treating industrial silicon-containing waste gas, and belongs to the technical field of waste gas treatment. The process of the present invention hydrolyzes the organosilicon components in the waste gas into water-soluble substances through gradient alkali washing pretreatment, effectively avoids the formation of silicon dioxide crystals, improves the treatment efficiency, solves the problem of equipment blockage, reduces the burden of operation and maintenance, prolongs the life of the equipment, and enhances the economy and feasibility of the process; at the same time, a high-efficiency catalytic oxidation catalyst is prepared, and the catalyst activity is improved through phosphoric acid treatment, ball milling and uniform loading of platinum nanoparticles, and the oxygen vacancies formed by high-temperature calcination further enhance the catalytic activity; a metal organic framework is synthesized in situ on the surface of attapulgite after calcination, which increases the specific surface area and pore structure of the catalyst, improves the catalytic efficiency through adsorption-enrichment effect, enhances the structural stability, and prolongs the service life of the catalyst.

Description

Technical Field

[0001] The invention belongs to the technical field of waste gas treatment and relates to a process for treating industrial silicon-containing waste gas. Background Art

[0002] With the widespread use of silicon-containing organic compounds such as silane in various industries, more and more companies are emitting waste gas containing organic silicon components. Organic silicon is insoluble in water and cannot be treated with traditional methods such as spray towers. In addition, organic silicon reacts with oxygen under high temperature conditions to produce silicon dioxide crystals, which will block the honeycomb-like porous structure. Currently commonly used organic waste gas (VOCs) treatment processes, such as catalytic oxidation (CO), regenerative catalytic oxidation (RCO), regenerative thermal oxidation (RTO), etc., have porous structures for their key structures, catalysts and thermal storage ceramics. The silicon dioxide crystals produced during the waste gas treatment process are easily adsorbed in such porous structures, causing blockage of thermal storage ceramics or catalysts, affecting the operation of the equipment.

[0003] Some patents report equipment for treating silicon-containing waste gas. For example, Chinese patent CN116293738A discloses a process flow of treating silicon-containing organic waste gas incinerators. A heat storage incinerator with a double-layer heat storage layer inside is used to treat silicon-containing tail gas, which can reduce blockage and is easier to clean after blockage. Chinese patent CN114345109A discloses a process and equipment for treating silicon-containing organic waste gas. The process uses alkaline washing, demisting, and direct-fired furnaces to treat silicon-containing organic waste gas. The process uses alkaline washing to remove acidic gases and oil stains, and uses a direct-fired furnace for high-temperature thermal oxidation to oxidize and decompose organic waste gas components into inorganic components such as water and carbon dioxide. At the same time, the silicon element in the waste gas is oxidized to generate silicon dioxide crystals. The silicon dioxide crystals and other particulate matter are gradually brought into high-temperature filters for filtration under the action of the exhaust gas flow. These technologies do not fundamentally solve the problem that the silicon dioxide crystals generated during the waste gas treatment process are adsorbed in the porous structure to cause blockage of the heat storage body or catalyst pores, and there is still the disadvantage of heavy operation and maintenance burden. Summary of the invention

[0004] The purpose of the present invention is to provide a process flow for treating industrial silicon-containing waste gas. By adopting this process flow, the organic silicon components in the silicon-containing waste gas can be effectively removed in the pretreatment stage, thereby solving the disadvantage of producing silicon dioxide crystals in the waste gas treatment process of the prior art, and at the same time preparing a catalytic oxidation catalyst for efficiently treating VOCs in industrial silicon-containing waste gas.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A process for treating industrial silicon-containing waste gas, the specific steps of the process are as follows:

[0007] S1-1: The industrial silicon-containing waste gas is sent to the bottom of the alkali washing tower for primary alkali washing, and the alkali liquor in the tower bottom is used for countercurrent washing. The alkali liquor in the tower bottom is sent to the top of the primary alkali washing filler for spraying through the primary circulation pump, and the remaining small amount of alkali liquor wastewater is sent to the outside of the boundary area for treatment;

[0008] S1-2: The waste gas after the primary alkali washing is subjected to secondary alkali washing, and the upper alkali solution is used for countercurrent washing to further remove the silicon-containing components in the waste gas. The upper alkali solution is recycled through the secondary circulation pump, and the remaining alkali solution is sent to the primary alkali washing, mixed with the alkali solution in the tower kettle, and then pumped to the upper part of the primary alkali washing filler for spraying;

[0009] S1-3: The alkali washing tower needs to be continuously replenished with desalted water and alkali solution. The alkali solution is transported into the secondary alkali washing circulating liquid through the alkali solution feeding pump. The desalted water is pumped to the secondary alkali washing section through the desalted water pump. The wastewater is continuously discharged from the kettle of the primary alkali washing tower and pumped to the outside of the boundary area for treatment;

[0010] S1-4: The waste gas after alkali washing is sent to the catalytic oxidation unit, where VOCs are treated under the action of a catalytic oxidation catalyst and then discharged.

[0011] As a preferred technical solution of the present invention, the preparation method of the catalytic oxidation catalyst in S1-4 is as follows:

[0012] S2-1: Add attapulgite to phosphoric acid solution, stir at 60-80 °C for 4 h, wash with deionized water until the pH value of the solution is 6.5-7, dry in a vacuum drying oven at 60 °C for 8-12 h, and then ball mill in a ball mill for 1-3 h to obtain powder A;

[0013] S2-2: 1.5-2.5 parts by weight of chloroplatinic acid was dissolved in 100 parts by weight of deionized water, 0.5-1.5 parts by weight of polyvinyl pyrrolidone was added, and the mixture was stirred at a speed of 600-700 r / min for 10-30 min, followed by the addition of 15-25 parts by weight of powder A, and the stirring was continued for 30-60 min. 0.5-1.5 parts by weight of 0.5 M sodium borohydride solution was added dropwise while maintaining the stirring state, and the mixture was stirred at 40-60 °C for 1-2 h. The mixture was filtered and dried in a vacuum drying oven at 60 °C for 8-12 h, and then transferred to a muffle furnace and calcined in a hydrogen atmosphere for 1 h to obtain powder B;

[0014] S2-3: 2-Methylimidazole and zinc nitrate are mixed, then added to a methanol solution, ultrasonicated for 1-2 h, then 10-20 wt% powder B is added, stirred at a speed of 550-650 r / min at room temperature for 1-2 h, then washed with deionized water and dried in a 60 °C vacuum drying oven for 8-12 h, then calcined in a muffle furnace for 1 h at a calcination temperature of 350-450 °C to obtain the catalytic oxidation catalyst.

[0015] As a preferred technical solution of the present invention, the operating temperature of the alkali washing tower is 5-60°C and the operating pressure is normal pressure.

[0016] As a preferred technical solution of the present invention, the alkali solution is a sodium hydroxide solution with a mass concentration of 0.1-30%.

[0017] As a preferred technical solution of the present invention, the operating temperature of the catalytic oxidation unit is 300-600°C, and the operating pressure is normal pressure.

[0018] As a preferred technical solution of the present invention, the mass fraction of the phosphoric acid solution in S2-1 is 5-10%.

[0019] As a preferred technical solution of the present invention, the ball milling speed in S2-1 is 200~300 r / min.

[0020] As a preferred technical solution of the present invention, the calcination temperature in S2-2 is 500-600°C.

[0021] As a preferred technical solution of the present invention, the 2-methylimidazole and zinc nitrate in S2-3 are mixed in a molar ratio of 10:1.

[0022] As a preferred technical solution of the present invention, the amount of the methanol solution in S2-3 is 20 to 30 times the total mass of 2-methylimidazole and zinc nitrate.

[0023] In traditional waste gas treatment technology, silicon-containing waste gas is prone to form silicon dioxide crystals after treatment. These crystals will gradually clog key equipment components such as heat storage bodies, catalysts or filters during a long period of accumulation, seriously affecting the normal operation of the equipment and increasing the operating and maintenance burden of the equipment. The process of the present invention first pre-treats the silicon-containing waste gas through gradient alkali washing, and effectively hydrolyzes the organic silicon components in the waste gas that are originally insoluble or difficult to dissolve in water into water-soluble substances. This conversion process not only improves the efficiency of waste gas treatment, but also avoids the formation of silicon dioxide crystals in the subsequent treatment process.

[0024] A highly efficient catalytic oxidation catalyst was prepared to remove VOCs. First, the attapulgite was impregnated with a phosphoric acid solution and then subjected to a ball milling refinement step, which optimized its crystal structure, significantly increased its specific surface area, and improved its porosity accordingly. This process not only improved the physical and chemical properties of the attapulgite, but also provided abundant active sites for the subsequent platinum nanoparticle loading.

[0025] Platinum has excellent catalytic activity and can significantly reduce the activation energy required for catalytic VOCs oxidation reactions, thereby accelerating the reaction rate. Polyvinyl pyrrolidone can significantly disperse the active components evenly in attapulgite, prevent the agglomeration of nanoparticles during the preparation process, and ensure that the catalyst has a uniform structure and efficient catalytic activity. Under the stable dispersion of polyvinyl pyrrolidone, chloroplatinic acid is reduced to platinum nanoparticles and uniformly loaded on the pretreated attapulgite carrier, effectively preventing the agglomeration of platinum nanoparticles during the preparation process, which leads to a decrease in catalytic activity. The high-temperature calcination process makes the combination of platinum nanoparticles and attapulgite more stable. In addition, when calcined under a hydrogen atmosphere, the interaction between attapulgite and platinum nanoparticles causes some oxygen atoms to escape from the lattice, thereby forming oxygen vacancies on the surface or inside of the attapulgite; the hydrogen atmosphere can reduce the re-adsorption of oxygen atoms and the refilling of oxygen vacancies, which is conducive to the stable existence of oxygen vacancies. Oxygen vacancies can act as electron traps to change the electronic structure of the material; they can also activate oxygen molecules and convert them into more reactive oxygen species, further promoting the oxidation reaction of VOCs.

[0026] In addition, the performance of the catalyst was further enhanced by in-situ synthesis of a metal-organic framework on the surface of attapulgite loaded with platinum nanoparticles. As a porous material, the metal-organic framework has an extremely high specific surface area and rich pore structure. These characteristics enable the metal-organic framework to adsorb more gaseous VOCs molecules and enrich them on the surface of the precious metal platinum. This adsorption-enrichment effect not only increases the local concentration of the catalytic reaction, but also promotes the effective contact between the reactants and the active sites of the catalyst, thereby further improving the catalytic efficiency. At the same time, the wrapping effect of the metal-organic framework effectively reduces the risk of platinum nanoparticles falling off during the catalytic process. The interaction between platinum nanoparticles and the metal-organic framework enhances the structural stability of the catalyst, allowing the catalyst to maintain a high activity after multiple cycles. This feature extends the service life of the catalyst, reduces production costs, and improves its economy and feasibility in practical applications.

[0027] Beneficial effects of the present invention:

[0028] (1) The present invention provides a process for treating industrial silicon-containing waste gas. The process effectively hydrolyzes the organic silicon components in the silicon-containing waste gas that are insoluble or poorly soluble in water into water-soluble substances through a gradient alkali washing pretreatment stage, thereby avoiding the formation of silicon dioxide crystals in the subsequent treatment process. This conversion not only improves the efficiency of waste gas treatment, but also fundamentally solves the problem of equipment blockage caused by the accumulation of silicon dioxide crystals, not only improves the efficiency and quality of subsequent waste gas treatment, but also significantly reduces the burden of equipment operation and maintenance, prolongs the service life of the equipment, and improves the economy and feasibility of the overall process.

[0029] (2) Catalytic oxidation catalysts were prepared. The specific surface area and porosity of attapulgite were increased through phosphoric acid treatment and ball milling, providing abundant active sites for platinum nanoparticle loading. The uniform loading of platinum nanoparticles reduced the activation energy of VOCs oxidation reaction, accelerated the reaction rate, and the oxygen vacancies formed by high-temperature calcination enhanced the catalytic activity. In-situ synthesis of metal organic frameworks further increased the specific surface area and pore structure of the catalyst, and improved the catalytic efficiency through adsorption-enrichment effect. In addition, the encapsulation of the metal organic framework enhanced the structural stability of the catalyst, extended its service life, and reduced production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0031] Figure 1 The present invention is a process flow chart for treating industrial silicon-containing waste gas.

[0032] Among them, 1-alkaline washing tower; 2-primary circulation pump; 3-secondary circulation pump; 4-desalting water pump; 5-alkaline solution feeding pump; 6-catalytic oxidation unit. DETAILED DESCRIPTION

[0033] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0034] Example 1

[0035] A process for treating industrial silicon-containing waste gas, the specific steps of the process are as follows:

[0036] S1-1: The industrial silicon-containing waste gas is sent to the bottom of the alkali washing tower for primary alkali washing. The alkali liquor in the tower bottom is used for countercurrent washing. The alkali liquor in the tower bottom is pumped to the top of the primary alkali washing filler for spraying through the primary circulation pump. The remaining small amount of alkali liquor wastewater is sent to the outside of the boundary area for treatment. The operating temperature of the alkali washing tower is 30 ℃ and the operating pressure is normal pressure.

[0037] S1-2: The waste gas after the primary alkali washing is subjected to secondary alkali washing, and the upper alkali solution is used for countercurrent washing to further remove the silicon-containing components in the waste gas. The upper alkali solution is recycled through the secondary circulation pump, and the remaining alkali solution is sent to the primary alkali washing, mixed with the alkali solution in the tower kettle, and then pumped to the upper part of the primary alkali washing filler for spraying;

[0038] S1-3: The alkali washing tower needs to be continuously replenished with desalted water and alkali solution. The alkali solution is a sodium hydroxide solution with a mass concentration of 15%. The alkali solution is transported into the secondary alkali washing circulating liquid through the alkali solution feeding pump, and the desalted water is pumped to the secondary alkali washing section through the desalted water pump. The wastewater is continuously discharged from the kettle of the primary alkali washing tower and pumped to the outside of the boundary area for treatment;

[0039] S1-4: The waste gas after alkali washing is sent to the catalytic oxidation unit. The operating temperature of the catalytic oxidation unit is 450°C and the operating pressure is normal pressure. VOCs are treated under the action of the catalytic oxidation catalyst and then discharged.

[0040] Wherein, the preparation method of the catalytic oxidation catalyst in S1-4 is as follows:

[0041] S2-1: Add attapulgite to a phosphoric acid solution with a mass fraction of 8%, stir at 70 °C for 4 h, wash with deionized water until the pH value of the solution is 6.8, dry in a vacuum drying oven at 60 °C for 10 h, and then mill in a ball mill for 2 h at a speed of 250 r / min to obtain powder A;

[0042] S2-2: 2 parts by weight of chloroplatinic acid were dissolved in 100 parts by weight of deionized water, 1 part by weight of polyvinyl pyrrolidone was added, and the mixture was stirred at a speed of 650 r / min for 20 min, followed by the addition of 20 parts by weight of powder A, and the stirring was continued for 45 min. While maintaining the stirring state, 1 part by weight of 0.5 M sodium borohydride solution was added dropwise, and the mixture was stirred at 50 °C for 1.5 h. The mixture was filtered and dried in a vacuum drying oven at 60 °C for 10 h, and then transferred to a muffle furnace and calcined in a hydrogen atmosphere for 1 h at a calcination temperature of 550 °C to obtain powder B;

[0043] S2-3: 2-methylimidazole and zinc nitrate are mixed in a molar ratio of 10:1, and then added to a methanol solution, wherein the amount of methanol solution is 25 times the total mass of 2-methylimidazole and zinc nitrate, ultrasonicated for 1.5 h, and then 15 wt% powder B is added, stirred at room temperature for 1.5 h, washed with deionized water and dried in a vacuum drying oven at 60 °C for 10 h, and then calcined in a muffle furnace for 1 h at a calcination temperature of 400 °C to obtain the catalytic oxidation catalyst.

[0044] In this embodiment, the toluene removal rate in the exhaust gas is 98.6%.

[0045] Example 2

[0046] A process for treating industrial silicon-containing waste gas, the specific steps of the process are as follows:

[0047] S1-1: The industrial silicon-containing waste gas is sent to the bottom of the alkali washing tower for primary alkali washing. The alkali liquor in the tower bottom is used for countercurrent washing. The alkali liquor in the tower bottom is sent to the upper part of the primary alkali washing filler for spraying through the primary circulation pump. The remaining small amount of alkali liquor wastewater is sent to the outside of the boundary area for treatment. The operating temperature of the alkali washing tower is 5 ℃ and the operating pressure is normal pressure.

[0048] S1-2: The waste gas after the primary alkali washing is subjected to secondary alkali washing, and the upper alkali solution is used for countercurrent washing to further remove the silicon-containing components in the waste gas. The upper alkali solution is recycled through the secondary circulation pump, and the remaining alkali solution is sent to the primary alkali washing, mixed with the alkali solution in the tower kettle, and then pumped to the upper part of the primary alkali washing filler for spraying;

[0049] S1-3: The alkali washing tower needs to be continuously replenished with desalted water and alkali solution. The alkali solution is a sodium hydroxide solution with a mass concentration of 0.1%. The alkali solution is transported into the secondary alkali washing circulating liquid through the alkali solution feeding pump, and the desalted water is pumped to the secondary alkali washing section through the desalted water pump. The wastewater is continuously discharged from the kettle of the primary alkali washing tower and pumped to the outside of the boundary area for treatment;

[0050] S1-4: The waste gas after alkali washing is sent to the catalytic oxidation unit. The operating temperature of the catalytic oxidation unit is 300°C and the operating pressure is normal pressure. The VOCs are treated under the action of the catalytic oxidation catalyst and then discharged.

[0051] Wherein, the preparation method of the catalytic oxidation catalyst in S1-4 is as follows:

[0052] S2-1: Add attapulgite to a 5% phosphoric acid solution, stir at 60 °C for 4 h, wash with deionized water until the pH value of the solution is 6.5, dry in a vacuum oven at 60 °C for 8 h, and then mill in a ball mill for 1 h at a speed of 200 r / min to obtain powder A;

[0053] S2-2: 1.5 parts by weight of chloroplatinic acid was dissolved in 100 parts by weight of deionized water, 0.5 parts by weight of polyvinyl pyrrolidone was added, and the mixture was stirred at a speed of 600 r / min for 10 min, followed by the addition of 15 parts by weight of powder A, and the stirring was continued for 30 min. 0.5 parts by weight of 0.5 M sodium borohydride solution was added dropwise while maintaining the stirring state, and the mixture was stirred at 40°C for 1 h. The mixture was filtered and dried in a vacuum drying oven at 60°C for 8 h, and then transferred to a muffle furnace and calcined in a hydrogen atmosphere for 1 h at a calcination temperature of 400°C to obtain powder B;

[0054] S2-3: 2-methylimidazole and zinc nitrate are mixed in a molar ratio of 10:1, and then added to a methanol solution, wherein the amount of methanol solution is 20 times the total mass of 2-methylimidazole and zinc nitrate, ultrasonicated for 1 h, and then 10 wt% powder B is added, stirred at room temperature for 1 h, then washed with deionized water and dried in a vacuum drying oven at 60 °C for 8 h, and then calcined in a muffle furnace for 1 h at a calcination temperature of 350 °C to obtain the catalytic oxidation catalyst.

[0055] In this embodiment, the toluene removal rate in the exhaust gas is 97.2%.

[0056] Example 3

[0057] A process for treating industrial silicon-containing waste gas, the specific steps of the process are as follows:

[0058] S1-1: The industrial silicon-containing waste gas is sent to the bottom of the alkali washing tower for primary alkali washing. The alkali liquor in the tower bottom is used for countercurrent washing. The alkali liquor in the tower bottom is sent to the upper part of the primary alkali washing filler for spraying through the primary circulation pump. The remaining small amount of alkali liquor wastewater is sent to the outside of the boundary area for treatment. The operating temperature of the alkali washing tower is 60 ℃ and the operating pressure is normal pressure.

[0059] S1-2: The waste gas after the primary alkali washing is subjected to secondary alkali washing, and the upper alkali solution is used for countercurrent washing to further remove the silicon-containing components in the waste gas. The upper alkali solution is recycled through the secondary circulation pump, and the remaining alkali solution is sent to the primary alkali washing, mixed with the alkali solution in the tower kettle, and then pumped to the upper part of the primary alkali washing filler for spraying;

[0060] S1-3: The alkali washing tower needs to be continuously replenished with desalted water and alkali solution. The alkali solution is a sodium hydroxide solution with a mass concentration of 30%. The alkali solution is transported into the secondary alkali washing circulating liquid through the alkali solution feeding pump, and the desalted water is pumped to the secondary alkali washing section through the desalted water pump. The wastewater is continuously discharged from the first alkali washing tower kettle and pumped to the outside of the boundary area for treatment;

[0061] S1-4: The waste gas after alkali washing is sent to the catalytic oxidation unit. The operating temperature of the catalytic oxidation unit is 600°C and the operating pressure is normal pressure. The VOCs are treated under the action of the catalytic oxidation catalyst and then discharged.

[0062] The preparation method of the catalytic oxidation catalyst in S1-4 is as follows:

[0063] S2-1: Add attapulgite to a 10% phosphoric acid solution, stir at 80 °C for 4 h, wash with deionized water until the pH value of the solution is 7, dry in a vacuum oven at 60 °C for 12 h, and then mill in a ball mill for 3 h at a speed of 300 r / min to obtain powder A;

[0064] S2-2: 2.5 parts by weight of chloroplatinic acid were dissolved in 100 parts by weight of deionized water, 1.5 parts by weight of polyvinyl pyrrolidone was added, and the mixture was stirred at a speed of 700 r / min for 30 min, followed by the addition of 25 parts by weight of powder A, and the stirring was continued for 60 min. 1.5 parts by weight of 0.5 M sodium borohydride solution was added dropwise while maintaining the stirring state, and the mixture was stirred at 60 °C for 2 h. The mixture was filtered and dried in a vacuum drying oven at 60 °C for 12 h, and then transferred to a muffle furnace and calcined in a hydrogen atmosphere for 1 h at a calcination temperature of 500 °C to obtain powder B;

[0065] S2-3: 2-methylimidazole and zinc nitrate are mixed in a molar ratio of 10:1, and then added to a methanol solution, wherein the amount of methanol solution is 30 times the total mass of 2-methylimidazole and zinc nitrate, ultrasonicated for 2 h, and then 20 wt% powder B is added, stirred at room temperature for 2 h, then washed with deionized water and dried in a vacuum drying oven at 60 °C for 12 h, and then calcined in a muffle furnace for 1 h at a calcination temperature of 450 °C to obtain the catalytic oxidation catalyst.

[0066] In this embodiment, the toluene removal rate in the exhaust gas is 98.1%.

[0067] Comparative Example 1

[0068] In the preparation process of the catalytic oxidation catalyst, no calcination treatment is performed in step S2-2, and the remaining steps are consistent with Example 1.

[0069] In this comparative example, the toluene removal rate in the exhaust gas is 96.2%.

[0070] Comparative Example 2

[0071] The preparation process of the catalytic oxidation catalyst does not include step S2-3, and the remaining steps are consistent with those in Example 1.

[0072] In this comparative example, the toluene removal rate in the exhaust gas is 93.8%.

[0073] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A process for treating industrial silicon-containing waste gas, characterized in that: The specific steps of the process are as follows: S1-1: The industrial silicon-containing waste gas is sent to the bottom of the alkali washing tower for primary alkali washing, and the alkali liquor in the tower bottom is used for countercurrent washing. The alkali liquor in the tower bottom is sent to the top of the primary alkali washing filler for spraying through the primary circulation pump, and the remaining small amount of alkali liquor wastewater is sent to the outside of the boundary area for treatment; S1-2: The waste gas after the primary alkali washing is subjected to secondary alkali washing, and the upper alkali solution is used for countercurrent washing to further remove the silicon-containing components in the waste gas. The upper alkali solution is recycled through the secondary circulation pump, and the remaining alkali solution is sent to the primary alkali washing, mixed with the alkali solution in the tower kettle, and then pumped to the upper part of the primary alkali washing filler for spraying; S1-3: The alkali washing tower needs to be continuously replenished with desalted water and alkali solution. The alkali solution is transported into the secondary alkali washing circulating liquid through the alkali solution feeding pump. The desalted water is pumped to the secondary alkali washing section through the desalted water pump. The wastewater is continuously discharged from the kettle of the primary alkali washing tower and pumped to the outside of the boundary area for treatment; S1-4: sending the waste gas after alkali washing to the catalytic oxidation unit, treating VOCs under the action of the catalytic oxidation catalyst and then discharging; The preparation method of the catalytic oxidation catalyst in S1-4 is as follows: S2-1: Add attapulgite to phosphoric acid solution, stir at 60-80 °C for 4 h, wash with deionized water until the pH value of the solution is 6.5-7, dry in a vacuum oven at 60 °C for 8-12 h, and then mill in a ball mill for 1-3 h to obtain powder A; S2-2: 1.5-2.5 parts by weight of chloroplatinic acid are dissolved in 100 parts by weight of deionized water, 0.5-1.5 parts by weight of polyvinyl pyrrolidone is added, and the mixture is stirred at a speed of 600-700 r / min for 10-30 min, followed by the addition of 15-25 parts by weight of powder A, and the stirring is continued for 30-60 min. 0.5-1.5 parts by weight of 0.5 M sodium borohydride solution is added dropwise while maintaining the stirring state, and the mixture is stirred at 40-60 °C for 1-2 h. The mixture is filtered and placed in a vacuum drying oven at 60 °C for drying for 8-12 h, and then transferred to a muffle furnace and calcined in a hydrogen atmosphere for 1 h to obtain powder B; S2-3: 2-Methylimidazole and zinc nitrate are mixed, then added to a methanol solution, ultrasonicated for 1-2 h, then 10-20 wt% powder B is added, stirred at a speed of 550-650 r / min at room temperature for 1-2 h, then washed with deionized water and dried in a vacuum drying oven at 60°C for 8-12 h, then calcined in a muffle furnace for 1 h at a calcination temperature of 350-450°C to obtain the catalytic oxidation catalyst.

2. A process for treating industrial silicon-containing waste gas according to claim 1, characterized in that: The operating temperature of the alkali washing tower is 5-60°C, and the operating pressure is normal pressure.

3. A process for treating industrial silicon-containing waste gas according to claim 1, characterized in that: The alkali solution is a sodium hydroxide solution with a mass concentration of 0.1-30%.

4. A process for treating industrial silicon-containing waste gas according to claim 1, characterized in that: The operating temperature of the catalytic oxidation unit is 300-600°C, and the operating pressure is normal pressure.

5. The process for treating industrial silicon-containing waste gas according to claim 1, characterized in that: The mass fraction of the phosphoric acid solution in S2-1 is 5-10%.

6. A process for treating industrial silicon-containing waste gas according to claim 1, characterized in that: The ball milling speed in S2-1 is 200-300 r / min.

7. A process for treating industrial silicon-containing waste gas according to claim 1, characterized in that: The calcination temperature in S2-2 is 500-600°C.

8. The process for treating industrial silicon-containing waste gas according to claim 1, characterized in that: In the S2-3, 2-methylimidazole and zinc nitrate are mixed in a molar ratio of 10:

1.

9. A process for treating industrial silicon-containing waste gas according to claim 1, characterized in that: The amount of the methanol solution in S2-3 is 20 to 30 times the total mass of 2-methylimidazole and zinc nitrate.

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