Trichlorosilane tail gas absorption device with pre-reaction tank

Abstract

The utility model discloses a kind of trichlorosilane tail gas absorption devices containing pre-reaction tank, including pre-reaction tank, primary caustic washing tower, secondary caustic washing tower, tail gas liquid seal tank and lye pool. First, utilize pre-reaction tank reaction to remove most of chlorosilane gas and hydrogen chloride in tail gas, significantly reduce the generation amount of sodium silicate and other colloidal precipitates in subsequent caustic washing tower, effectively improve the plugging problem of pipeline (especially tail gas import pipeline) and spray tower nozzle. Through pre-reaction+two-stage caustic washing combined treatment process, the efficient removal of chlorosilane, hydrogen chloride and other harmful substances in tail gas is realized, to ensure that treated tail gas meets the emission standard, while significantly reducing the consumption of lye, improving the process economy.

Description

Technical Field

[0001] This utility model relates to the field of chemical tail gas treatment technology, and in particular to a trichlorosilane tail gas absorption device containing a pre-reaction tank. Background Technology

[0002] Trichlorosilane, also known as trichlorosilane, is an important raw material for the production of semiconductor silicon, monocrystalline silicon, and polycrystalline silicon. It is also the most basic monomer for the synthesis of organosilanes and alkyl, aryl, and organofunctional chlorosilanes. It can be used not only in the production of high-purity silicon materials but also as an additive in plastics, rubber, coatings, and other fields.

[0003] The industrial production of trichlorosilane generates a large amount of chlorosilane tail gas, which has a complex composition, mainly consisting of easily hydrolyzed substances such as trichlorosilane and silicon tetrachloride. Currently, the industry commonly uses water or alkaline scrubbing processes to treat the tail gas from trichlorosilane production plants. In the water scrubbing method, the hydrolysis products of the tail gas are hydrogen chloride, hydrogen (H2), silicic acid (H2SiO3), and polymers (HSiO). 1.5 In the alkaline spraying method (such as NaOH solution), the reaction products are sodium chloride (NaCl), hydrogen (H2), sodium silicate (Na2SiO3) and water (H2O).

[0004] Both methods currently in use have certain drawbacks.

[0005] First, due to the products H2SiO3 and polymer (HSiO) 1.5 ) n The reaction produces a large amount of foamy scum, Na2SiO3 as gelatinous slag, and SiO2 as solid precipitate. In addition, the reaction rate is relatively fast, which often leads to blockage of pipes and spray tower nozzles in actual production.

[0006] Secondly, both methods release a large amount of heat during the reaction process. When the chlorosilane components in the exhaust gas come into contact with the absorbent, they react violently, which can easily cause local overheating inside the equipment, potentially leading to stress cracking, damage to the internal structure of the equipment, and accelerated aging of the equipment.

[0007] Third, the presence of acidic substances will exacerbate equipment corrosion under high temperature conditions, significantly reducing the service life of the absorption equipment and increasing the risk of leakage.

[0008] Fourth, traditional treatment processes result in incomplete absorption of exhaust gas due to the short contact time between the absorbent and the exhaust gas, leading to excessive emission standards. This not only pollutes the environment but may also cause serious safety accidents such as explosions. Utility Model Content

[0009] The purpose of this invention is to address the technical shortcomings of existing trichlorosilane tail gas absorption devices, such as easy clogging, aging, and corrosion, as well as incomplete tail gas treatment, by providing a trichlorosilane tail gas absorption device with a pre-reaction tank.

[0010] The technical solution adopted to achieve the purpose of this utility model is:

[0011] A trichlorosilane tail gas absorption device with a pre-reaction tank includes a pre-reaction tank, a primary alkaline scrubbing tower, a secondary alkaline scrubbing tower, a tail gas liquid seal tank, and an alkaline solution pool.

[0012] The inlet of the pre-reaction tank is connected to the main exhaust gas pipeline; the outlet of the pre-reaction tank is connected to the inlet of the primary alkaline scrubbing tower; the outlet of the primary alkaline scrubbing tower is connected to the inlet of the secondary alkaline scrubbing tower; the top outlet of the secondary alkaline scrubbing tower is connected to the exhaust gas inlet of the exhaust gas liquid seal tank; an exhaust pipe is provided at the top of the exhaust gas liquid seal tank; the exhaust gas is processed sequentially through the pre-reaction tank, the primary alkaline scrubbing tower, and the secondary alkaline scrubbing tower, and then discharged into the atmosphere through the exhaust gas liquid seal tank and the exhaust pipe;

[0013] The inlet of the pre-reaction tank is connected to the alkali tank via a pre-reaction alkali inlet pipeline; an alkali feed pump is installed on the pre-reaction alkali inlet pipeline; the overflow port of the pre-reaction tank is connected to the alkali tank; the alkali in the alkali tank enters the pre-reaction tank through the pre-reaction alkali inlet pipeline under the action of the alkali feed pump, and after pre-reaction, it returns to the alkali tank through the overflow port.

[0014] The alkaline washing liquid inlet of the primary alkaline washing tower is connected to the alkaline liquid tank via a primary alkali inlet pipeline; a primary alkaline washing tower inlet pump is installed on the primary alkali inlet pipeline; a support is installed at the edge of the alkaline liquid tank, and the primary alkaline washing tower is suspended and fixed in the alkaline liquid tank by the support, with its bottom opening connected to the alkaline liquid tank; the alkaline liquid in the alkaline liquid tank enters the primary alkaline washing tower through the primary alkali inlet pipeline under the action of the primary alkaline washing tower inlet pump, and after primary alkaline washing, it falls directly into the alkaline liquid tank through the bottom opening of the tower.

[0015] The bottom outlet of the secondary alkaline washing tower is connected to the secondary alkaline washing liquid inlet on the side of the secondary alkaline washing tower via a secondary alkali inlet pipeline; a secondary alkaline washing tower inlet pump is installed on the secondary alkali inlet pipeline; under the action of the secondary alkaline washing tower inlet pump, the alkali solution forms an alkaline washing cycle between the secondary alkali inlet pipeline and the secondary alkaline washing tower.

[0016] Furthermore, the pre-reaction tank is equipped with an internally extended gas pipe inside the gas inlet; the internally extended gas pipe has uniformly opened holes; the pre-reaction tank is filled with corrosion-resistant and structured packing material with large pore size, and the alkaline solution enters from the bottom and exits from the top, so as to achieve uniform distribution and full contact of the gas and liquid phases.

[0017] Furthermore, the pre-reaction tank is connected to a remote thermometer; a first regulating valve and a flow meter are installed on the pre-reaction alkali inlet pipeline. The remote thermometer, the first regulating valve, and the flow meter constitute a temperature control system; by adjusting the opening of the first regulating valve, the temperature inside the pre-reaction tank is controlled to not exceed 70°C, thereby avoiding excessively high local reaction temperatures and ensuring a safe and stable absorption process.

[0018] Furthermore, the alkaline solution tank is equipped with baffles to divide the alkaline solution tank into a settling zone and a clear solution zone.

[0019] Furthermore, the overflow port of the pre-reaction tank is connected to the settling zone of the alkali solution tank;

[0020] The pre-reaction alkali inlet pipeline and the primary alkali inlet pipeline are respectively connected to the clear liquid zone of the alkali solution tank.

[0021] Furthermore, the settling zone of the alkali tank is equipped with an alkali replenishment pipeline; a second regulating valve is installed on the alkali replenishment pipeline; when the liquid level in the settling zone reaches the low alarm value, the system automatically opens the second regulating valve to replenish fresh alkali to ensure the liquid level in the settling zone.

[0022] Furthermore, the primary alkali inlet pipeline is connected to an alkali solution tank discharge pipeline; a first alkali concentration meter is installed on the primary alkali inlet pipeline; and a third regulating valve is installed on the alkali solution tank discharge pipeline. When the first alkali concentration meter detects that the alkali content of the alkali solution in the primary alkali inlet pipeline is ≤2wt%, the system automatically opens the third regulating valve to discharge the wastewater to the sewage treatment system.

[0023] Furthermore, a second alkali concentration meter is installed on the secondary alkali inlet pipeline; an alkali washing tower drain pipeline is connected to the secondary alkali inlet pipeline; the alkali washing tower drain pipeline is connected to the alkali solution tank (clear solution area); and a fourth regulating valve is installed on the alkali washing tower drain pipeline.

[0024] The upper branch of the secondary alkali inlet pipeline is connected to the alkali washing tower replenishment pipeline; a fifth regulating valve is installed on the alkali washing tower replenishment pipeline;

[0025] When the second alkali concentration meter detects that the alkali concentration in the secondary alkali inlet pipeline is ≤5wt%, the system automatically opens the fourth regulating valve to recover the alkali to the clear liquid area of ​​the alkali tank; at the same time, the fifth regulating valve is opened to replenish fresh alkali.

[0026] Furthermore, a mixer is installed on the upper branch of the secondary alkali inlet pipeline.

[0027] Furthermore, a flame arrester is installed on the exhaust pipe to effectively prevent backfire and ensure the safety of the entire exhaust gas treatment system.

[0028] Furthermore, the bottom outlet of the tail gas liquid seal tank is connected to the alkali pool via a drain pipeline; excess alkali is recovered to the alkali pool (clear liquid area).

[0029] Furthermore, the settling zone of the alkaline solution tank is equipped with a sludge pipeline; a sludge pump is installed on the sludge pipeline; the outlet of the sludge pipeline is connected to a filter press; the filtrate outlet of the filter press is connected to the clear liquid zone; when a large amount of solid sediment is observed to be generated in the settling zone, the sludge pump and filter press are started to transport the solid sediment to the filter press through the sludge pipeline, where the filter press separates the filtrate and sludge; the filtrate is returned to the clear liquid zone, and the sludge is transported off-site for treatment.

[0030] Compared with the prior art, the beneficial effects of this utility model are:

[0031] 1. The trichlorosilane tail gas absorption device provided by this utility model utilizes a pre-reaction tank to pre-react and remove most of the chlorosilane gas and hydrogen chloride from the tail gas, significantly reducing the formation of colloidal precipitates such as sodium silicate in the subsequent alkaline scrubbing tower, and effectively improving the clogging problem of pipelines (especially the tail gas inlet pipeline) and spray tower nozzles. Simultaneously, the pre-reaction neutralizes acidic gases in the tail gas, thereby reducing the degree of corrosion of equipment and pipelines and improving the overall lifespan of the equipment.

[0032] 2. The trichlorosilane tail gas absorption device provided by this utility model adopts a pre-reaction + two-stage alkaline washing combined treatment process, which can achieve efficient removal of harmful substances such as chlorosilane and hydrogen chloride in the tail gas, ensuring that the treated tail gas meets the emission standards, while significantly reducing the consumption of alkaline solution and improving the economic efficiency of the process.

[0033] 3. The trichlorosilane tail gas absorption device provided by this utility model features a baffle structure inside the alkaline solution tank, dividing the tank into a settling zone and a clear liquid zone. The upper clear liquid in the settling zone overflows to the clear liquid zone on the other side of the baffle and is then recycled to the top of the primary alkaline scrubbing tower via a circulating pump. The solids generated during the reaction remain in the settling zone and are periodically pumped to a filter press for filtration using a sludge pump. This eliminates the need for manual sludge removal from the wastewater tank in traditional treatment processes, achieving automated treatment, reducing the intensity of personnel operations, and improving the safety of the device.

[0034] 4. The trichlorosilane tail gas absorption device provided by this utility model has a liquid seal tank and a flame arrester for final venting, which can effectively prevent backfire accidents and ensure system safety. Attached Figure Description

[0035] Figure 1 The diagram shown is a schematic of the structure of a trichlorosilane tail gas absorption device.

[0036] Figure 2 The diagram shown is a schematic of the pre-reaction tank.

[0037] Figure 3 The diagram shown is a schematic of the structure of a primary alkali washing tower.

[0038] Figure 4 The diagram shown is a schematic of the structure of a two-stage alkaline scrubbing tower.

[0039] Figure 5 The diagram shown is a schematic of the alkali solution tank.

[0040] In the diagram: 1-Pre-reaction tank, 1-1-Air inlet, 1-2-Air outlet, 1-3-Liquid inlet, 1-4-Overflow outlet, 1-5-Internal gas distribution pipe, 2-First-stage alkaline washing tower, 2-1-First-stage alkaline washing air inlet, 2-2-First-stage alkaline washing air outlet, 2-3-Alkaline washing liquid inlet, 3-Second-stage alkaline washing tower, 3-1-Second-stage alkaline washing air inlet, 3-2-Second-stage alkaline washing tower top gas outlet, 3-3-Tower bottom liquid outlet, 3-4-Second-stage alkaline washing liquid inlet, 4-Tail gas liquid seal tank, 4-1-Tail gas inlet, 5-Alkali solution tank, 5-1-Settling zone, 5-2-Clear liquid zone, 6-Discharge pipe, 7-Alkali solution feed pump, 8-First-stage alkaline washing tower alkali inlet pump, 9-Second-stage alkaline washing tower alkali inlet pump, 10-Flame arrester, 11-Baffle, 12-Sludge pump, 13-Filter press, 14-Mixer;

[0041] L1 - Pre-reaction alkali inlet pipeline, L2 - Primary alkali inlet pipeline, L3 - Secondary alkali inlet pipeline, L4 - Sludge pipeline, L5 - Alkali replenishment pipeline for alkali solution tank, L6 - Alkali solution tank sewage discharge pipeline, L7 - Alkali washing tower sewage discharge pipeline, L8 - Alkali replenishment pipeline for alkali washing tower, L9 - Liquid discharge pipeline.

[0042] T1 - Remote thermometer, A1 - First regulating valve, H1 - Flow meter, A2 - Second regulating valve, A3 - Third regulating valve, A4 - Fourth regulating valve, A5 - Fifth regulating valve. B1 - First alkali concentration meter, B2 - Second alkali concentration meter. Detailed Implementation

[0043] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0044] The alkaline solution described in this invention is a caustic soda solution or a calcium hydroxide solution.

[0045] Example 1

[0046] A trichlorosilane tail gas absorption device including a pre-reaction tank, such as Figure 1 As shown, it includes a pre-reaction tank 1, a primary alkaline scrubbing tower 2, a secondary alkaline scrubbing tower 3, a tail gas liquid seal tank 4, and an alkaline solution pool 5.

[0047] The inlet 1-1 of the pre-reaction tank 1 is connected to the main tail gas pipeline; the outlet 1-2 of the pre-reaction tank 1 is connected to the primary alkaline washing inlet 2-1 of the primary alkaline washing tower 2; the primary alkaline washing outlet 2-2 of the primary alkaline washing tower 2 is connected to the secondary alkaline washing inlet 3-1 of the secondary alkaline washing tower 3; the top gas outlet 3-2 of the secondary alkaline washing tower 3 is connected to the tail gas inlet 4-1 of the tail gas liquid seal tank 4; and a discharge pipe 6 is provided at the top of the tail gas liquid seal tank 4.

[0048] The inlet 1-3 of the pre-reaction tank 1 is connected to the alkali tank 5 via a pre-reaction alkali inlet pipeline L1; an alkali feed pump 7 is installed on the pre-reaction alkali inlet pipeline L1; the overflow port 1-4 of the pre-reaction tank 1 is connected to the alkali tank 5; the alkali in the alkali tank 5 enters the pre-reaction tank 1 through the pre-reaction alkali inlet pipeline L1 under the action of the alkali feed pump 7, and the foam, scum and other substances generated by the pretreatment reaction overflow into the alkali tank 5 through the overflow port 1-4 under the alkali entrainment, and settle in the alkali tank 5 to form sludge.

[0049] The alkaline washing liquid inlet 2-3 of the primary alkaline washing tower 2 is connected to the alkaline liquid tank 5 via a primary alkaline inlet pipeline L2; a primary alkaline washing tower inlet pump 8 is installed on the primary alkaline inlet pipeline L2; the bottom opening of the primary alkaline washing tower 2 is connected to the alkaline liquid tank 5, and the solid precipitate generated by the primary alkaline washing settles in the alkaline liquid tank 5 through the bottom opening; the alkaline liquid in the alkaline liquid tank 5 enters the primary alkaline washing tower 2 through the primary alkaline inlet pipeline L2 under the action of the primary alkaline washing tower inlet pump 8, and returns to the alkaline liquid tank 5 through the bottom opening after the primary alkaline washing.

[0050] The bottom outlet 3-3 of the secondary alkaline washing tower 3 is connected to the secondary alkaline washing liquid inlet 3-4 on the side of the secondary alkaline washing tower 3 via a secondary alkali inlet pipeline L3; a secondary alkaline washing tower inlet pump 9 is installed on the secondary alkaline washing tower inlet pipeline L3. Under the action of the secondary alkaline washing tower inlet pump 9, the alkaline solution circulates between the secondary alkaline inlet pipeline L3 and the secondary alkaline washing tower 3.

[0051] The exhaust gas from the main exhaust pipeline is processed sequentially through the pre-reaction tank 1, the primary alkaline scrubbing tower 2, and the secondary alkaline scrubbing tower 3, and then discharged into the atmosphere through the exhaust gas liquid seal tank 4 and the discharge pipeline 6.

[0052] An inner gas pipe 1-5 is provided inside the air inlet 1-1 of the pre-reaction tank 1; the inner gas pipe 1-5 has uniformly opened holes; the pre-reaction tank 1 is filled with corrosion-resistant and structured packing with large pores.

[0053] The pre-reaction tank 1 is connected to a remote thermometer T1; the pre-reaction alkali inlet pipeline L1 is equipped with a first regulating valve A1 and a flow meter H1. The remote thermometer T1, the first regulating valve A1, and the flow meter H1 constitute a temperature control system; by adjusting the opening of the first regulating valve A1, the temperature inside the pre-reaction tank 1 is controlled to not exceed 70°C, thereby avoiding excessively high local reaction temperatures and ensuring a safe and stable absorption process.

[0054] A flame arrester 10 is installed on the exhaust pipe to effectively prevent backfire and ensure the safety of the entire exhaust gas treatment system.

[0055] In this embodiment, two pre-reaction tanks 1 (each equipped with a temperature control system) are connected in parallel, one in operation and one on standby, ensuring continuous system operation. Pre-reaction tank 1 can pre-react and remove most of the chlorosilane gas and hydrogen chloride from the tail gas, significantly reducing the formation of colloidal precipitates such as sodium silicate in the subsequent alkaline scrubbing tower, effectively improving the clogging problem of pipelines (especially the tail gas inlet pipeline) and spray tower nozzles. Simultaneously, the pre-reaction neutralizes acidic gases in the tail gas, thereby reducing the corrosion of equipment and pipelines. Furthermore, it reduces the circulation volume of the absorbent in the water scrubbing tower, achieving continuous tail gas treatment. The primary alkaline scrubbing tower 2 and the secondary alkaline scrubbing tower 3, through two-stage alkaline absorption, ensure thorough tail gas treatment with low alkaline consumption, meeting environmental protection requirements.

[0056] Example 2

[0057] This embodiment is based on Embodiment 1 and introduces its alkaline solution tank structure and sludge discharge method.

[0058] like Figure 5 As shown, the alkaline solution tank 5 is equipped with a baffle 11, which divides the alkaline solution tank 5 into a settling zone 5-1 and a clear liquid zone 5-2. The alkaline solution that has settled in the settling zone 5-1 overflows through the baffle 11 and enters the clear liquid zone 5-2.

[0059] The overflow port 1-4 of the pre-reaction tank 1 is connected to the settling zone 5-1 of the alkaline solution tank 5; the foam, scum and other substances generated by the pretreatment reaction overflow into the settling zone 5-1 through the overflow port 1-4 under the influence of the alkaline solution, and settle in the settling zone 5-1 to form sludge.

[0060] The pre-reaction alkali inlet pipeline L1 and the primary alkali inlet pipeline L2 are respectively connected to the clear liquid zone 5-2 of the alkali tank 5 to ensure that the alkali entering the pre-reaction tank 1 and the primary alkali washing tower 2 are free of solid impurities.

[0061] The settling zone 5-1 of the alkaline tank 5 is equipped with a sludge pipeline L4; a sludge pump 12 is installed on the sludge pipeline L4; the outlet of the sludge pipeline L4 is connected to a filter press 13; the filtrate outlet of the filter press 13 is connected to the clear liquid zone 5-2; when a large amount of solid precipitate is observed to be generated in the settling zone 5-1, the sludge pump 12 and the filter press 13 are started to transport the solid precipitate to the filter press 13 through the sludge pipeline L4, and the filter press 13 separates the filtrate and sludge; the filtrate is returned to the clear liquid zone 5-2, and the sludge is transported off-site for treatment.

[0062] The alkaline solution tank structure and sludge discharge method in this embodiment avoid the manual sludge removal process in the wastewater tank in the traditional treatment process, realize automated treatment, reduce the intensity of personnel operation, and improve the safety of the device.

[0063] Example 3

[0064] This embodiment is based on Example 1 and describes its alkali circulation method.

[0065] like Figure 5 As shown, the settling zone 5-1 of the alkali tank 5 is equipped with an alkali replenishment pipeline L5; the alkali replenishment pipeline L5 is equipped with a second regulating valve A2; when the liquid level in the settling zone 5-1 reaches the low alarm value, the system automatically opens the second regulating valve A2 to replenish fresh alkali to ensure the liquid level in the settling zone 5-1.

[0066] like Figure 3 As shown, the primary alkali inlet pipeline L2 is connected to an alkali solution tank discharge pipeline L6; a first alkali concentration meter B1 is installed on the primary alkali inlet pipeline; and a third regulating valve A3 is installed on the alkali solution tank discharge pipeline L6. When the first alkali concentration meter B1 detects that the alkali content of the alkali solution in the primary alkali inlet pipeline is ≤2wt%, the system automatically opens the third regulating valve A3 to discharge the wastewater to the sewage treatment system. The alkali concentration in the replenishment alkali pipeline L5 is 5%, and the alkali concentration in the alkali solution tank 5 is greater than 2% and ≤5%.

[0067] like Figure 4As shown, the secondary alkaline washing tower 3 is equipped with two sections of packing absorption (a total of three secondary alkaline washing liquid inlets 3-4 are provided; the first section of packing is between the two at the top and the two in the middle, and the second section of packing is between the two in the middle and the two at the bottom). The spray liquid of the first section of packing uses a mixture of circulating alkaline liquid and fresh alkaline liquid, while the second section of packing uses a circulating alkaline liquid absorption method. A second alkali concentration meter B2 is installed on the secondary alkali inlet pipeline; the secondary alkali inlet pipeline L3 is connected to the alkaline washing tower drain pipeline L7; the alkaline washing tower drain pipeline L7 is connected to the alkaline liquid tank 5 (clear liquid zone 5-2); a fourth regulating valve A4 is installed on the alkaline washing tower drain pipeline L7; an upper branch of the secondary alkali inlet pipeline L3 is connected to the alkaline washing tower replenishment pipeline L8; a fifth regulating valve A5 is installed on the alkaline washing tower replenishment pipeline L8; a mixer 14 is installed on the upper branch of the secondary alkali inlet pipeline L3 to mix the circulating alkaline liquid and fresh alkaline liquid.

[0068] When the second alkali concentration meter detects that the alkali concentration in the secondary alkali inlet pipeline is ≤5wt%, the system automatically opens the fourth regulating valve A4 to recover the alkali to the alkali tank 5; simultaneously, the fifth regulating valve A5 is opened to replenish fresh alkali. The concentration of the fresh alkali is 10%, and the concentration of the alkali used for scrubbing in the secondary alkali scrubbing tower 3 is maintained between 5wt% and 10wt%. The concentration of the alkali used for scrubbing in the secondary alkali scrubbing tower 3 is higher than that in the primary alkali scrubbing tower 2 and the pre-reaction tank 1; this concentration gradient setting helps to ensure the tail gas treatment effect.

[0069] The two-stage alkali absorption design significantly improves absorption efficiency, ensuring that the treated exhaust gas meets emission standards. Furthermore, the addition of fresh alkali solution is controlled by the alkali concentration meter CT02 and the fourth regulating valve A4, effectively reducing alkali consumption and lowering production costs while maintaining absorption effectiveness.

[0070] The bottom outlet of the tail gas liquid seal tank 4 is connected to the alkaline solution tank 5 via a drain pipeline L9; excess alkaline solution is recovered to the alkaline solution tank 5 (clear liquid area 5-1).

[0071] The above description is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A trichlorosilane tail gas absorption device including a pre-reaction tank, characterized in that, Includes a pre-reaction tank, a primary alkaline scrubbing tower, a secondary alkaline scrubbing tower, a tail gas liquid seal tank, and an alkaline solution pool; The inlet of the pre-reaction tank is connected to the main tail gas pipeline; the outlet of the pre-reaction tank is connected to the primary alkaline scrubbing inlet of the primary alkaline scrubbing tower; the primary alkaline scrubbing outlet of the primary alkaline scrubbing tower is connected to the secondary alkaline scrubbing inlet of the secondary alkaline scrubbing tower; the top gas outlet of the secondary alkaline scrubbing tower is connected to the tail gas inlet of the tail gas liquid seal tank; and a discharge pipe is provided at the top of the tail gas liquid seal tank. The inlet of the pre-reaction tank is connected to the alkali solution tank via a pre-reaction alkali inlet pipeline; an alkali inlet pump is installed on the pre-reaction alkali inlet pipeline; and the overflow port of the pre-reaction tank is connected to the alkali solution tank. The alkaline washing liquid inlet of the primary alkaline washing tower is connected to the alkaline liquid tank via a primary alkali inlet pipeline; a primary alkaline washing tower inlet pump is installed on the primary alkali inlet pipeline; and the bottom opening of the primary alkaline washing tower is connected to the alkaline liquid tank. The bottom liquid outlet of the secondary alkaline washing tower is connected to the secondary alkaline washing liquid inlet on the side of the secondary alkaline washing tower via a secondary alkali inlet pipeline; a secondary alkaline washing tower inlet pump is installed on the secondary alkali inlet pipeline.

2. The trichlorosilane tail gas absorption device as described in claim 1, characterized in that, The pre-reaction tank is equipped with an inner gas-distributing pipe inside its air inlet; the inner gas-distributing pipe has evenly spaced holes.

3. The trichlorosilane tail gas absorption device as described in claim 2, characterized in that, The pre-reaction tank is filled with corrosion-resistant structured packing material with large pores.

4. The trichlorosilane tail gas absorption device as described in claim 1, characterized in that, The pre-reaction tank is connected to a remote thermometer; a first regulating valve and a flow meter are installed on the pre-reaction alkali inlet pipeline.

5. The trichlorosilane tail gas absorption device as described in claim 1, characterized in that, The alkaline solution tank is equipped with baffles, which divide the alkaline solution tank into a settling zone and a clear solution zone.

6. The trichlorosilane tail gas absorption device as described in claim 4, characterized in that, The overflow port of the pre-reaction tank is connected to the settling zone of the alkali solution tank; The pre-reaction alkali inlet pipeline and the primary alkali inlet pipeline are respectively connected to the clear liquid zone of the alkali solution tank.

7. The trichlorosilane tail gas absorption device as described in claim 5, characterized in that, The settling zone of the alkali tank is equipped with an alkali replenishment pipeline; a fifth regulating valve is installed on the alkali replenishment pipeline.

8. The trichlorosilane tail gas absorption device as described in claim 1, characterized in that, The primary alkali inlet pipeline is connected to an alkali solution tank discharge pipeline; a first alkali concentration meter is installed on the primary alkali inlet pipeline; and a third regulating valve is installed on the alkali solution tank discharge pipeline.

9. The trichlorosilane tail gas absorption device as described in claim 1, characterized in that, A second alkali concentration meter is installed on the secondary alkali inlet pipeline; an alkali washing tower drain pipeline is connected to the secondary alkali inlet pipeline; the alkali washing tower drain pipeline is connected to the alkali solution tank; a fourth regulating valve is installed on the alkali washing tower drain pipeline. The upper branch of the secondary alkali inlet pipeline is connected to the alkali washing tower replenishment pipeline; a fifth regulating valve is installed on the alkali washing tower replenishment pipeline.

10. The trichlorosilane tail gas absorption device as described in claim 9, characterized in that, A mixer is installed on the upper branch of the secondary alkali inlet pipeline.

11. The trichlorosilane tail gas absorption device as described in claim 1, characterized in that, A flame arrester is installed on the discharge pipe.

12. The trichlorosilane tail gas absorption device as described in claim 11, characterized in that, The bottom outlet of the tail gas liquid seal tank is connected to the alkaline solution tank via a drain pipeline.

13. The trichlorosilane tail gas absorption device as described in claim 5, characterized in that, The settling zone of the alkaline solution tank is equipped with a sludge pipeline; a sludge pump is installed on the sludge pipeline; the outlet of the sludge pipeline is connected to a filter press; and the filtrate outlet of the filter press is connected to the clear liquid zone.

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