A system for treating a mixture of silane and chlorosilane

Abstract

The utility model discloses a kind of silane and chlorosilane mixed gas processing system, it is related to waste gas treatment equipment technical field in polysilicon production, system includes DCS, primary showering tower, storage tank I, secondary showering tower, storage tank II, tertiary showering tower and lye storage tank;Primary showering tower is connected with mixed gas pipeline, tertiary showering tower is connected with storage tank I, storage tank II and lye storage tank respectively via circulating pipeline, primary showering tower exhaust is connected with secondary showering tower inlet via pipeline I, and secondary showering tower exhaust is connected with tertiary showering tower inlet via pipeline II.Storage tank I, II are connected with high-chlorine wastewater pipeline;Lye storage tank is connected with high-concentration lye supply pipe and is installed with pH and temperature sensor, and its outside is connected with heat exchanger for heating lye in tower;DCS controls each sensor, valve and pump.Solve the problem of large amount of lye and pure water, large pressure of rear-end wastewater treatment, high cost in prior art.

Description

Technical Field

[0001] This utility model relates to the technical field of waste gas treatment equipment in polysilicon production, specifically to a treatment system for a mixed gas containing silane and chlorosilane. Background Technology

[0002] In high-end manufacturing fields such as semiconductors and photovoltaics, silane gas (SiH4) is a core electronic-grade raw material. Its production process requires the reduction or disproportionation reaction of chlorosilanes (such as SiCl4, SiHCl3, SiH2Cl2, etc.). This process is accompanied by the emission of a large amount of mixed waste gas. The chlorosilane components are not only highly corrosive (reacting with water to form hydrochloric acid and silicon dioxide), but may also undergo secondary reactions with silane gas to generate solid impurities. Direct emission of these components will not only cause equipment corrosion and pipeline blockage, but also lead to serious environmental risks and waste of raw materials. Therefore, the efficient removal of chlorosilanes / silanes from the waste gas has become a key environmental protection and process assurance link in the silane gas production process.

[0003] Traditional industries generally use sodium hydroxide (NaOH) alkaline rinsing to purify this type of waste gas, or a combination of "pure water + sodium hydroxide alkaline solution". This process requires large amounts of alkaline solution and pure water, resulting in high waste gas treatment costs and long washing times.

[0004] Therefore, industry professionals are still optimizing existing treatment systems and / or processes to reduce treatment costs while ensuring emissions meet environmental protection requirements. Summary of the Invention

[0005] The purpose of this invention is to propose a treatment system for a mixture of silane and chlorosilane, which solves the problems of large consumption of alkali and pure water, high pressure of downstream wastewater treatment, and high cost in the existing technology for treating mixtures of silane and chlorosilane.

[0006] This invention is achieved through the following technical solution: A treatment system for a mixture of silane and chlorosilane includes a DCS, a primary scrubbing tower, a storage tank I, a secondary scrubbing tower, a storage tank II, a tertiary scrubbing tower, and an alkaline solution storage tank. The primary scrubbing tower is connected to the mixed gas pipeline. The primary, secondary, and tertiary scrubbing towers are connected to storage tanks I, II, and III, respectively, via circulation pipelines I, II, and III. A pump III is installed on circulation pipeline III between the alkali storage tank and the tertiary scrubbing tower. The exhaust port of the primary scrubbing tower is connected to the inlet of the secondary scrubbing tower via pipeline I, and the exhaust port of the secondary scrubbing tower is connected to the inlet of the tertiary scrubbing tower via pipeline II. Both storage tanks I and II are connected to high-chlorine wastewater pipelines, which are connected to the wastewater treatment system. The alkali storage tank is connected to a high-concentration alkali supply pipe and is equipped with a pH sensor and a temperature sensor. A valve I is installed on the alkali supply pipe, and a heat exchanger is connected to a heat exchange medium inlet pipe, which is equipped with a valve II. The DCS is connected to the pH sensor, temperature sensor, valve I, valve II, and pump III for control.

[0007] Furthermore, the primary, secondary, and tertiary rinsing towers are all equipped with a spraying mechanism, which includes 2 to 8 layers of spray pipes, each layer of spray pipes is equipped with multiple spiral nozzles.

[0008] Furthermore, the spiral nozzle has a spray volume of 2~3m 3 / h nozzle.

[0009] Furthermore, level sensor I and level sensor II are respectively installed on storage tank I and storage tank II. Pump I is installed on circulation pipeline I between storage tank I and the first-stage scrubbing tower, and pump II is installed on circulation pipeline II between storage tank II and the second-stage scrubbing tower. The DCS is connected to level sensor I, pump I, level sensor II and pump II for control.

[0010] Furthermore, the storage tank II is also connected to the liquid inlet of the storage tank II through a circulation pipe IV, and a pump IV is installed on the circulation pipe IV.

[0011] Furthermore, the heat exchanger is a heat exchanger that uses steam as the heat transfer medium, preferably a heat exchanger that uses steam at 165°C, which has a higher heat exchange efficiency.

[0012] Furthermore, pressure sensor I, pressure sensor II, and pressure sensor III are respectively installed on the primary, secondary, and tertiary scrubbing towers, and the DCS is connected to pressure sensor I, pressure sensor II, and pressure sensor III for control.

[0013] Furthermore, the primary and secondary scrubbing towers are both made of fiberglass, while the tertiary scrubbing tower is a composite structure with a steel outer shell and a fiberglass inner lining.

[0014] Furthermore, the storage tanks I, II, and the alkali storage tank are all made of steel lined with fiberglass.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects: I. This utility model proposes a novel treatment system for a mixed gas containing silanes and chlorosilanes. By constructing a core treatment framework of "three-stage scrubbing + DCS automated control," it achieves efficient and stable treatment of the mixed gas. Furthermore, both the primary and secondary scrubbing towers use recycled water from polysilicon production as the scrubbing liquid. This recycled water is generated by the wastewater treatment system of polysilicon production. In this system, wastewater is neutralized with quicklime, then calcium chloride is precipitated. After filtration through a filter press, the resulting supernatant is the recycled water, which is high-chlorine wastewater (alkaline). The mixed gas undergoes two stages of scrubbing with this alkaline high-chlorine wastewater, gradually removing all chlorosilanes and avoiding the problem of incomplete single-stage treatment. This significantly improves the exhaust gas purification effect and meets environmental emission requirements. A third stage of alkaline scrubbing ensures that the scrubbed gas meets emission standards. In addition, the system uses a heat exchanger to regulate the temperature of the circulating alkaline solution in the three-stage scrubbing tower, ensuring that the alkaline solution is within the suitable reaction temperature range. This prevents abnormal temperatures from affecting the reaction efficiency between silane and alkaline solution, ensuring continuous and stable system operation. The system's DCS, in conjunction with pH sensors, temperature sensors, valves, and pumps, enables real-time monitoring of the alkaline solution concentration (via pH feedback) and temperature in the storage tank. It automatically opens valve I to replenish high-concentration alkaline solution, adjusts valve II to control the heat exchange medium supply, and simultaneously regulates the operation of pump III. This ensures stable alkaline solution parameters during the scrubbing process, preventing fluctuations in treatment effectiveness caused by manual operation delays.

[0016] II. In the treatment system for mixed gas containing silane and chlorosilane proposed in this utility model, the design of the internal spraying mechanism of the scrubbing tower is optimized: multi-layer spraying with 2 to 8 layers of spray pipes arranged in layers can form a three-dimensional spraying area in the scrubbing tower, so that when the mixed gas flows from bottom to top, it can fully contact the spray liquid at different heights, avoiding the "contact dead corners" existing in traditional single-layer spraying, and increasing the reaction probability of silane, chlorosilane and spray liquid; the structural characteristics of the spiral nozzle can make the spray liquid form a uniform atomized spray state. Compared with ordinary direct nozzles, the surface area of ​​the atomized spray liquid is greatly increased, further increasing the gas-liquid contact area, accelerating the dissolution and reaction rate of silane and chlorosilane, shortening the processing time, and improving the single tower processing efficiency.

[0017] III. In this utility model, the selected spray volume is 2~3m 3 The spiral nozzles with a spray volume of / h ensure that each layer of spray pipes can provide sufficient spray liquid to cover the gas flow section in the scrubbing tower, preventing the mixed gas from being discharged before full contact due to insufficient spray volume, thus ensuring that the treatment effect meets the standards. Controlling the spray volume within a reasonable range can prevent the wastewater generation in storage tank I and storage tank II from surging due to excessive spray liquid, reducing the energy consumption of the pump body and achieving economical operation of the system.

[0018] IV. In this utility model, the liquid level sensors I and II can provide real-time feedback on the liquid level in storage tanks I and II, preventing pumps I and II from running dry due to low liquid level (dry running can easily cause pump wear and burnout), or liquid from overflowing due to high liquid level; the DCS automatically adjusts the balance of liquid replenishment and drainage based on the liquid level data to ensure a stable supply of spray liquid to the primary and secondary scrubbing towers, avoiding changes in spray intensity due to fluctuations in circulation volume, thereby ensuring a stable treatment effect of the scrubbing tower on the mixed gas and avoiding fluctuations in purification efficiency.

[0019] V. In this embodiment, a reverse cascade water replenishment method is adopted for comprehensive water utilization. The recycled water first enters the secondary scrubbing tower for spray washing, and the water in the secondary scrubbing tower then enters the primary scrubbing tower through booster pump IV. This can maximize the utilization of water resources.

[0020] VI. In this embodiment, the reaction efficiency of silane, chlorosilane and alkaline solution is sensitive to temperature. Steam can keep the alkaline solution stable within the appropriate reaction temperature range (45~55℃), avoiding the reaction rate from slowing down due to excessively low temperature (incomplete treatment), or the alkaline solution from deteriorating due to excessively high temperature or the reaction from being too violent and damaging the equipment, thus ensuring the purification effect of the three-stage rinsing.

[0021] VII. In this embodiment, pressure sensors I, II, and III can provide real-time feedback on pressure changes within each scrubbing tower. If the pressure inside the tower rises abnormally (e.g., gas flow is obstructed due to blockage in the gas phase pipeline, or the intake volume suddenly increases), the DCS can issue an early warning in a timely manner to prevent damage to the tower due to overpressure and ensure the safety of equipment and personnel. By comparing and analyzing the pressure data of each tower, the fault point can be quickly located (e.g., a sudden increase in pressure in a tower may correspond to a blockage in the exhaust pipeline of that tower), reducing the time spent on manual troubleshooting, improving system maintenance efficiency, and reducing downtime losses.

[0022] 8. In this embodiment, the primary and secondary scrubbing towers come into contact with the pre-treated mixed gas and low-concentration chlorine-containing wastewater, where the corrosiveness is relatively weak. Fiberglass has excellent corrosion resistance and is less expensive than steel-lined fiberglass, which can reduce procurement costs while ensuring equipment durability. The tertiary scrubbing tower directly contacts high-concentration alkaline solution and residual corrosive gases. As the final purification stage, its operating conditions are more complex. Steel-lined fiberglass combines the high strength of steel (capable of withstanding high internal tower pressure) with the strong corrosion resistance of fiberglass (resisting erosion by alkaline solution and corrosive gases), which can extend the service life of the tertiary scrubbing tower and avoid equipment leakage or damage caused by material corrosion.

[0023] 9. In this embodiment, storage tanks I and II store high-chlorine wastewater (chloride ions easily cause metal corrosion), while the alkali storage tank stores high-concentration alkali solution. The steel-lined fiberglass material has excellent corrosion resistance to chloride ions and strong alkalis, which can prevent leakage and perforation of the storage tanks due to corrosion, ensuring that the medium does not leak and avoiding environmental risks and safety hazards. The steel-lined fiberglass material has stable chemical properties and does not easily react with the medium inside the tank. Its service life is much longer than that of ordinary steel and fiberglass materials, which can reduce the frequency of tank replacement and reduce long-term maintenance and equipment replacement costs. It will not produce impurities due to corrosion, which can prevent impurities from mixing into the liquid inside the tank (such as alkali solution and high-chlorine wastewater), ensuring the spraying treatment effect of alkali solution and preventing impurities from interfering with the subsequent wastewater treatment system. In addition, storage tanks I, II, and the alkali storage tank in this system are also intermediate buffer tanks. They require stirring and are subject to vibration, which can reduce the frequency of tank replacement and reduce long-term maintenance and equipment replacement costs. Attached Figure Description

[0024] Figure 1 This is a schematic diagram (I) of the treatment system for a mixture of silane and chlorosilane in this utility model.

[0025] Figure 2 This is a structural schematic diagram of one implementation of a three-stage scrubbing tower.

[0026] Figure 3 This is a schematic diagram (II) of the treatment system for a mixture of silane and chlorosilane in this utility model.

[0027] Figure 4 This is a schematic diagram (III) of the treatment system for a mixture of silane and chlorosilane in this utility model.

[0028] Figure 5 This is a schematic diagram (IV) of the treatment system for a mixture of silane and chlorosilane in this utility model.

[0029] The components include: 1. DCS; 2. Primary scrubbing tower; 3. Storage tank I; 4. Secondary scrubbing tower; 5. Storage tank II; 6. Tertiary scrubbing tower; 7. Alkali storage tank; 8. Mixed gas pipeline; 9. Circulation pipeline I; 10. Circulation pipeline II; 11. Circulation pipeline III; 12. Pump I; 13. Pump II; 14. Pump III; 15. Pipeline I; 16. Pipeline II; 17. High-chlorine wastewater pipeline; 18. Wastewater treatment system; 19. High-concentration alkali supply pipe; 20. pH sensor; 21. Temperature... 21. Temperature sensor; 22. Valve I; 23. Heat exchange medium inlet pipe; 24. Valve II; 25. Spray mechanism; 26. Liquid level sensor I; 27. Liquid level sensor II; 28. Circulation pipeline IV; 29. ​​Pump IV; 30. Pressure sensor I; 31. Pressure sensor II; 32. Pressure sensor III; 33. Heat exchanger; 34. Vent line; 35. Outlet pipeline; 25.1. Spray pipe; 25.2. Spiral nozzle; 6.1. Air inlet III; 6.2. Rinse liquid inlet III. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0031] Example 1 This embodiment is one of the basic implementation methods, a treatment system for a mixed gas containing silane and chlorosilane, including DCS1, primary scrubbing tower 2, storage tank I 3, secondary scrubbing tower 4, storage tank II 5, tertiary scrubbing tower 6 and alkali storage tank 7.

[0032] refer to Figure 1 , 2 The primary scrubbing tower 2 is connected to the mixed gas pipeline 8. The primary scrubbing tower 2, the secondary scrubbing tower 4 and the tertiary scrubbing tower 6 are respectively connected to the storage tanks I3, II5 and III11 through circulation pipeline I9, circulation pipeline II10 and circulation pipeline III11. A heat exchanger 33 and a pump Ⅲ14 are installed on the circulation pipeline Ⅲ11 between the alkali storage tank 7 and the three-stage scrubbing tower 6; The exhaust port of the primary scrubbing tower 2 is connected to the air inlet of the secondary scrubbing tower 4 through pipe I15, and the exhaust port of the secondary scrubbing tower 4 is connected to the air inlet of the tertiary scrubbing tower 6 through pipe II16. Both storage tanks I3 and II5 are connected to a high-chlorine wastewater pipeline 17, which in turn connects to a wastewater treatment system 18. Alkali storage tank 7 is connected to a high-concentration alkali supply pipe 19, and is equipped with a pH sensor 20 and a temperature sensor 21. The alkali supply pipe is equipped with valve I 22, and heat exchanger 33 is connected to a heat exchange medium inlet pipe 23, which is equipped with valve II 24. Once the concentration of the rinsing solution in storage tanks I3, II5, and alkali storage tank 7 falls below a preset value, it is discharged from the system through the corresponding external discharge pipeline 35 connected to the tanks (generally sent to the wastewater treatment system for centralized treatment).

[0033] DCS1 is connected to pH sensor 20, temperature sensor 21, valve I 22, valve II 24 and pump III 14 for control.

[0034] In this embodiment, the pH value and temperature of the scrubbing liquid in the three-stage scrubbing tower 6 are controlled to regulate the silane and chlorosilane content in the waste gas after treatment by the three-stage scrubbing tower 6, ensuring that the silane and chlorosilane content in the washed gas is ≤1.0 mg / m³. 3 The gas meets emission standards, and the washed gas is discharged from the vent pipeline 34.

[0035] Specifically, the pH signal of the rinsing solution in the alkali storage tank 7 is collected by the pH sensor 20 installed on the alkali storage tank 7 and uploaded to DCS1. DCS1 processes the received signal, determines the real-time pH value of the rinsing solution based on the corresponding signal, and then compares the real-time pH value with the preset pH value. Based on the comparison result, DCS1 sends a corresponding signal to valve I 22 and controls valve I 22 to adjust its opening. The adjusted pH value signal is then returned to DCS1 for comparison again until the real-time pH value equals the preset pH value.

[0036] In addition, a valve II 24 is installed on the heat exchange medium inlet pipe 23 connected to the heat exchanger 33 on the alkali storage tank 7. The temperature signal of the rinsing liquid in the alkali storage tank 7 is collected by the temperature sensor 21 installed on the alkali storage tank 7 and uploaded to DCS1. DCS1 processes the received signal, determines the real-time temperature of the rinsing liquid according to the corresponding signal, and then compares the real-time temperature value with the preset temperature value. According to the comparison result, DCS1 sends a corresponding signal to valve II 24 and controls valve II 24 to adjust its opening degree. The adjusted temperature signal is then returned to DCS1 for comparison again until the real-time temperature value equals the preset temperature value.

[0037] Example 2 This embodiment is a further optimization of embodiment 1. The difference is that the primary scrubbing tower 2, the secondary scrubbing tower 4 and the tertiary scrubbing tower 6 are all equipped with a spraying mechanism 25. The spraying mechanism 25 includes 2 to 8 layers of spray pipes 25.1, and each layer of spray pipes 25.1 is equipped with multiple spiral nozzles 25.2.

[0038] refer to Figure 2 , Figure 2The diagram illustrates the structure of a three-stage scrubbing tower 6. Its internal spraying mechanism 25 includes five layers of spray pipes 25.1, each with multiple spiral nozzles 25.2. The exhaust gas, after being scrubbed by the two-stage scrubbing tower 4, enters the three-stage scrubbing tower 6 through pipe II 16 and inlet III 6.1. The scrubbing liquid from the alkali storage tank 7 enters the tower through inlet III 6.2 and scrubs the exhaust gas until it meets emission standards. The remaining gas is then discharged through vent pipe 34.

[0039] Example 3 The difference between this embodiment and embodiments 1 and 2 is that the spiral nozzle 25.2 has a spray volume of 2-3m. 3 / h nozzle.

[0040] Example 4 Compared with Examples 1-3, the difference in this embodiment is that liquid level sensor I26 and liquid level sensor II27 are respectively installed on storage tank I3 and storage tank II5, respectively. (Refer to...) Figure 3 Pump I12 is installed on the circulation pipeline I9 between storage tank I3 and primary scrubbing tower 2, and pump II13 is installed on the circulation pipeline II10 between storage tank II5 and secondary scrubbing tower 4. DCS1 is connected to level sensor I26, pump I12, level sensor II27 and pump II13 respectively.

[0041] Example 5 Compared with Examples 1-4, the difference in this embodiment is that the storage tank II5 is also connected to the liquid inlet of the storage tank II5 through the circulation pipe IV28, and the circulation pipe IV28 is equipped with a pump IV29. (Refer to...) Figure 4 After a period of use, the high-chlorine wastewater in storage tank II5 is sent to storage tank I3 through circulation pipeline IV28 to serve as the scrubbing liquid in primary scrubbing tower 2 for primary scrubbing of the mixed gas. When the concentration of the scrubbing liquid in storage tank I3 and alkaline storage tank 7 is lower than the preset value, it is discharged from the system through the corresponding external discharge pipeline 35 connected to the storage tank (generally sent to the wastewater treatment system for centralized treatment).

[0042] Example 6 Compared with Examples 1 to 5, the difference in this embodiment is that the heat exchanger 33 is a heat exchanger 33 that uses steam or high-temperature circulating water as the heat transfer medium, preferably a heat exchanger using steam at 165°C.

[0043] Example 7 Compared with Examples 1-6, the difference in this embodiment is that pressure sensors I 30, II 31, and III 32 are respectively installed on the primary scrubbing tower 2, the secondary scrubbing tower 4, and the tertiary scrubbing tower 6. The DCS1 is connected to pressure sensors I 30, II 31, and III 32 for control purposes. (Refer to...) Figure 5 .

[0044] Example 8 Compared with Examples 1-7, the difference in this embodiment is that the primary scrubbing tower 2 and the secondary scrubbing tower 4 are both made of fiberglass, while the tertiary scrubbing tower 6 is a composite structure with a steel outer shell and a fiberglass inner lining.

[0045] Example 9 Compared with Examples 1-8, the difference in this embodiment is that the storage tank I3, storage tank II5 and alkali storage tank 7 are all made of steel lined with fiberglass material.

[0046] Example 10 To facilitate public understanding of this solution, this embodiment uses a preferred treatment system for a mixture of silane and chlorosilane as an example for further explanation.

[0047] refer to Figure 5 The treatment system includes DCS1, primary scrubbing tower 2, storage tank I 3, secondary scrubbing tower 4, storage tank II 5, tertiary scrubbing tower 6, and alkali storage tank 7.

[0048] The primary scrubbing tower 2 is connected to the mixed gas pipeline 8. The primary scrubbing tower 2, the secondary scrubbing tower 4, and the tertiary scrubbing tower 6 are respectively connected to storage tanks I3, II5, and alkali storage tank 7 via circulation pipelines I9, II10, and III11. A heat exchanger 33 and a pump III14 are installed on circulation pipeline III11 between alkali storage tank 7 and tertiary scrubbing tower 6. The exhaust port of the primary scrubbing tower 2 is connected to the inlet of the secondary scrubbing tower 4 via pipeline I15, and the exhaust port of the secondary scrubbing tower 4 is connected to the inlet of the tertiary scrubbing tower 6 via pipeline II16. Both storage tanks I3 and II5 are connected to a high-chlorine wastewater pipeline 17, which is connected to a wastewater treatment system 18. Alkali storage tank 7 is connected to a high-concentration alkali supply pipe 19, and a pH sensor 20 and a temperature sensor 21 are installed on it. A valve I 22 is installed on the alkali supply pipe. Heat exchanger 33 is connected to a heat exchange medium inlet pipe 23, and a valve II 24 is installed on the heat exchange medium inlet pipe 23. DCS1 is connected to the pH sensor 20, the temperature sensor 21, the valve I 22, the valve II 24, and the pump III 14 for control.

[0049] In this embodiment, the washing liquid flowing in the high-chlorine wastewater pipeline 17 originates from the product obtained after neutralization treatment of acidic waste residue and acidic wastewater discharged from the silane manufacturing plant—high-chlorine wastewater. The high-chlorine wastewater has a pH value of 8-9 and contains Ca. 2+ Cl - Na + And Cl - The content is 15,000~25,000 ppm.

[0050] In this embodiment, the primary scrubbing tower 2, the secondary scrubbing tower 4, and the tertiary scrubbing tower 6 are all equipped with a spraying mechanism 25. The spraying mechanism 25 includes five layers of spray pipes 25.1, and each layer of spray pipes 25.1 is equipped with ten spiral nozzles 25.2. The spiral nozzles 25.2 have a spray volume of 2.4m. 3 / h nozzle.

[0051] refer to Figure 2 , Figure 2 The diagram illustrates the structure of a three-stage scrubbing tower 6. Its internal spraying mechanism 25 includes five layers of spray pipes 25.1, each with multiple spiral nozzles 25.2. The exhaust gas, after being scrubbed by the two-stage scrubbing tower 4, enters the three-stage scrubbing tower 6 through pipe II 16 and inlet III 6.1. The scrubbing liquid from the alkali storage tank 7 enters the tower through inlet III 6.2 and scrubs the exhaust gas until it meets emission standards. The remaining gas is then discharged through vent pipe 34.

[0052] In this embodiment, level sensors I26 and II27 are installed on storage tank I3 and storage tank II5 respectively. Pump I12 is installed on circulation pipe I9 between storage tank I3 and primary scrubbing tower 2, and pump II13 is installed on circulation pipe II10 between storage tank II5 and secondary scrubbing tower 4. DCS1 is connected to level sensors I26, pump I12, level sensors II27 and pump II13 respectively.

[0053] In this embodiment, the storage tank II5 is also connected to the liquid inlet of the storage tank II5 through the circulation pipe IV28, and the circulation pipe IV28 is equipped with a pump IV29. The high-chlorine wastewater in the storage tank II5 after a period of use is sent to the storage tank I3 through the circulation pipe IV28 as the scrubbing liquid of the first-stage scrubbing tower 2 to perform the first-stage scrubbing of the mixed gas. When the concentration of the scrubbing liquid in the storage tank I3 and the alkaline solution storage tank 7 is lower than the preset value, it is discharged from the system through the corresponding external discharge pipeline 35 connected to the storage tank (generally sent to the wastewater treatment system for centralized treatment).

[0054] In this embodiment, the heat exchanger 33 is a heat exchanger that uses steam as the heat transfer medium.

[0055] In this embodiment, pressure sensor I30, pressure sensor II31, and pressure sensor III32 are respectively installed on the primary scrubbing tower 2, the secondary scrubbing tower 4, and the tertiary scrubbing tower 6. The DCS1 is connected to pressure sensor I30, pressure sensor II31, and pressure sensor III32 for control.

[0056] In this embodiment, the primary scrubbing tower 2 and the secondary scrubbing tower 4 are both made of fiberglass, and the tertiary scrubbing tower 6 is a steel shell lined with fiberglass composite structure; the storage tank I 3, storage tank II 5 and alkali storage tank 7 are all made of steel lined with fiberglass.

[0057] In this scheme, the pH value and temperature of the scrubbing liquid in the three-stage scrubbing tower 6 are controlled to regulate the silane and chlorosilane content in the waste gas after treatment, ensuring that the silane and chlorosilane content in the washed gas is ≤1.0 mg / m³. 3 The gas meets emission standards, and the washed gas is discharged from the vent pipeline 34.

[0058] Specifically, the pH signal of the rinsing solution in the alkali storage tank 7 is collected by the pH sensor 20 installed on the alkali storage tank 7, and the pH signal is uploaded to the DCS1. The DCS1 processes the received signal, determines the real-time pH value of the rinsing solution based on the corresponding signal, and then compares the real-time pH value with the preset pH value. When the real-time pH value equals the preset pH value, DCS1 sends a signal to valve I22 to maintain the current opening degree; When the real-time pH value is lower than the preset pH value, DCS1 sends a signal to valve I22 to increase the flow rate and controls the opening of valve I22. The pH value signal after adjustment is then returned to DCS1 for comparison again until the real-time pH value equals the preset pH value. When the real-time pH value is greater than the preset pH value, DCS1 sends a signal to valve I22 to reduce the flow rate and controls the opening of valve I22. The pH value signal after adjustment is returned to DCS1 and compared again until the real-time pH value equals the preset pH value. This can maintain the pH value of the alkali solution in the alkali storage tank 7 at around 12, ensuring the washing effect of the three-stage scrubbing tower 6 on the final tail gas.

[0059] In addition, a valve II 24 is installed on the heat exchange medium inlet pipe 23 connected to the heat exchanger 33 on the alkali storage tank 7. The temperature signal of the rinsing liquid in the alkali storage tank 7 is collected by the temperature sensor 21 installed on the alkali storage tank 7 and uploaded to the DCS1. The DCS1 processes the received signal, determines the real-time temperature of the rinsing liquid according to the corresponding signal, and then compares the real-time temperature value with the preset temperature value. When the real-time temperature value equals the preset temperature value, DCS1 sends a signal to valve II24 to maintain the current opening degree; When the real-time temperature is lower than the preset temperature, DCS1 sends a signal to temperature valve II 24 to increase the flow rate of the heat exchange medium and controls the opening of regulating valve II. The adjusted temperature value signal is then returned to DCS1 for comparison again until the real-time temperature value equals the preset temperature value. When the real-time temperature exceeds the preset temperature, DCS1 sends a signal to temperature valve II 24 to reduce the flow rate of the heat exchange medium and controls the opening of valve II 24. The adjusted temperature signal is then returned to DCS1 for comparison again until the real-time temperature equals the preset temperature. This maintains the temperature of the alkali solution in alkali storage tank 7 within the range of 45~55℃, improving the reaction efficiency of the alkali solution with silanes and chlorosilanes in the waste gas.

[0060] To handle 1000Nm 3 Taking a mixture of silane and chlorosilane-containing gas per hour as an example, compared with the traditional method of using a "three-stage scrubbing tower (pure water + pure water + alkali solution)," approximately 2600 m³ / h of such gas can be saved per month. 3 Using pure water and 500 cubic meters of 30wt% alkaline solution, the treatment time can be shortened by approximately 10%; in addition, the system can consume approximately 2600 cubic meters per month. 3 The waste gas treatment system can save approximately 15,000 yuan in wastewater treatment costs by eliminating the high-chlorine wastewater generated.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A system for treating a mixture of silane and chlorosilane, characterized in that: It includes DCS (1), primary scrubbing tower (2), storage tank I (3), secondary scrubbing tower (4), storage tank II (5), tertiary scrubbing tower (6) and alkali storage tank (7); The primary scrubbing tower (2) is connected to the mixed gas pipeline (8). The primary scrubbing tower (2), the secondary scrubbing tower (4), and the tertiary scrubbing tower (6) are connected to the storage tanks I (3), II (5), and III (7) respectively through circulation pipeline I (9), circulation pipeline II (10), and circulation pipeline III (11). A heat exchanger (33) and a pump III (14) are installed on the circulation pipeline III (11) between the alkali storage tank (7) and the tertiary scrubbing tower (6). The exhaust port of the primary scrubbing tower (2) is connected to the air inlet of the secondary scrubbing tower (4) through pipeline I (15), and the exhaust port of the secondary scrubbing tower (4) is connected to the air inlet of the tertiary scrubbing tower (6) through pipeline II (16). The storage tanks I (3) and II (5) are connected to a high-chlorine wastewater pipeline (17), which is connected to the wastewater treatment system (18). The alkaline storage tank (7) is connected to a high-concentration alkaline supply pipe (19), and a pH sensor (20) and a temperature sensor (21) are installed on the alkaline storage tank (7). A valve I (22) is installed on the alkaline supply pipe. A heat exchanger (33) is connected to a heat exchange medium inlet pipe (23), and a valve II (24) is installed on the heat exchange medium inlet pipe (23). The DCS (1) is connected to the pH sensor (20), the temperature sensor (21), the valve I (22), the valve II (24), and the pump III (14) for control.

2. The system for treating a mixed gas containing silane and chlorosilane according to claim 1, characterized in that: The primary scrubbing tower (2), the secondary scrubbing tower (4) and the tertiary scrubbing tower (6) are all equipped with a spraying mechanism (25). The spraying mechanism (25) includes 2 to 8 layers of spray pipes (25.1), and each layer of spray pipe is equipped with multiple spiral nozzles (25.2).

3. The system for treating a mixed gas containing silane and chlorosilane according to claim 2, characterized in that: The spiral nozzle (25.2) has a spray volume of 2~3m. 3 / h nozzle.

4. The system for treating a mixed gas containing silane and chlorosilane according to claim 1, characterized in that: Level sensor I (26) and level sensor II (27) are installed on tank I (3) and tank II (5) respectively. Pump I (12) is installed on the circulation pipe I (9) between tank I (3) and primary scrubbing tower (2). Pump II (13) is installed on the circulation pipe II (10) between tank II (5) and secondary scrubbing tower (4). DCS (1) is connected to level sensor I (26), pump I (12), level sensor II (27) and pump II (13) respectively.

5. The system for treating a mixed gas containing silane and chlorosilane according to claim 1, characterized in that: The storage tank II (5) is also connected to the liquid inlet of the storage tank II (5) through the circulation pipe IV (28), and the circulation pipe IV (28) is equipped with a pump IV (29).

6. The system for treating a mixed gas containing silane and chlorosilane according to claim 1, characterized in that: The heat exchanger (33) is a heat exchanger through which steam is used as the heat transfer medium.

7. The system for treating a mixed gas containing silane and chlorosilane according to claim 1, characterized in that: Pressure sensor I (30), pressure sensor II (31), and pressure sensor III (32) are respectively installed on the primary scrubbing tower (2), the secondary scrubbing tower (4), and the tertiary scrubbing tower (6). The DCS (1) is connected to pressure sensor I (30), pressure sensor II (31), and pressure sensor III (32) for control.

8. The system for treating a mixed gas containing silane and chlorosilane according to claim 1, characterized in that: The primary scrubbing tower (2) and the secondary scrubbing tower (4) are both made of fiberglass, and the tertiary scrubbing tower (6) is a steel shell lined with fiberglass composite structure.

9. The system for treating a mixed gas containing silane and chlorosilane according to claim 1, characterized in that: The storage tanks I (3), II (5) and alkali storage tank (7) are all made of steel-lined fiberglass.

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