Boron trichloride tail gas anti-blocking treatment device and method

Abstract

The invention discloses a boron trichloride tail gas anti-blocking treatment device and method.The treatment device comprises a tail gas treatment tower, the top of the tail gas treatment tower is provided with a tail gas pipeline with one end connected with the tail gas treatment tower, and the other end of the tail gas pipeline is connected with an exhaust port of a rectifying tower; a rectifying tower root valve and a tail gas emission adjusting valve which are sequentially connected with the exhaust port are arranged at the position, close to the rectifying tower, of the tail gas pipeline, a circulating pipeline is connected between the upper portion and the lower portion of the tail gas treatment tower, a treatment tower circulating pump is arranged on the circulating pipeline, a filler layer is arranged in the tail gas treatment tower, and alkaline absorption liquid is stored in the tail gas treatment tower; a heat tracing band is arranged on the tail gas pipeline. The absorption liquid is heated by the heat exchanger and the heat tracing band, so that the temperature of the absorption liquid is increased, and the solubility of borate or boric acid is greatly improved. After tail gas in the rectifying tower is exhausted every time, the tail gas pipeline is scoured by using hot absorption liquid to remove residual insoluble substances in the pipeline, so that the possibility that the tail gas pipeline is blocked is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of boron trichloride tail gas treatment, and in particular to a boron trichloride tail gas anti-clogging treatment device and method. Background Art

[0002] In recent years, boron trichloride has been increasingly used in semiconductor integrated circuits, liquid crystal displays, and solar cell PV industries, and the demand has gradually increased. The technical difficulties of electronic-grade boron trichloride purification have been gradually overcome, and domestic substitution has gradually deepened, but the problem of boron trichloride tail gas pipeline blockage has not been well solved.

[0003] During the distillation and purification process of high-purity boron trichloride, the distillation tower will continuously or intermittently discharge tail gas. The main component of the tail gas is boron trichloride. If it is directly vented to the outside, the boron trichloride will react violently with the moisture in the air to produce hydrogen chloride gas with a pungent odor, which will have a bad impact on the environment. At present, the tail gas treatment of boron trichloride is usually absorbed by alkali solution or water. However, after boron trichloride reacts with alkali solution or water, it will produce borates or boric acid with very low solubility. The precipitated insoluble matter is particularly easy to block the tail gas pipeline. Especially when the amount of boron trichloride tail gas is large and the ambient temperature is low, it will cause the local absorption effect of the absorption solution to be poor, and the outlet of the tail gas pipeline will be blocked by the borate or boric acid solids produced by the reaction, resulting in the inability to discharge the tail gas.

[0004] The patent with publication number CN208642244U discloses a boron trichloride tail gas treatment device, including a water washing system, an air supply system, a venturi tube and an induced draft system; the water washing system includes a buffer water washing tower, a primary water washing tower and a secondary water washing tower connected in series, and the air supply system includes a filter, an air compressor, a dryer and a gas buffer tank connected in sequence, and the gas buffer tank is connected to the venturi tube through a pipeline. Because it uses an induced draft fan and an air compressor to drive the tail gas flow through the venturi tube, the concentration of boron trichloride in the mixed gas is diluted very small, resulting in a reduction in the treatment efficiency of the tail gas. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a boron trichloride tail gas anti-clogging treatment device and method, which is used to solve the problem that the boron trichloride tail gas is easily blocked in the tail gas pipeline during treatment.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A boron trichloride tail gas anti-clogging treatment device comprises a tail gas treatment tower, wherein a tail gas pipeline with one end connected thereto is arranged on the top of the tail gas treatment tower, the other end of the tail gas pipeline is connected to an exhaust port of a distillation tower, a distillation tower root valve and a tail gas emission regulating valve connected to the exhaust port in sequence are arranged on the tail gas pipeline at a position close to the distillation tower, a circulation pipeline is connected between the upper and lower parts of the tail gas treatment tower, a treatment tower circulation pump is arranged on the circulation pipeline, at least one packing layer is arranged inside the tail gas treatment tower, an alkaline absorption liquid is stored in the tail gas treatment tower, and a heating belt is arranged on the tail gas pipeline.

[0008] Furthermore, a connecting pipe is provided between the tail gas treatment tower and the tail gas pipeline, one end of the connecting pipe is connected to the bottom of the tail gas treatment tower, and the other end is connected to the part of the tail gas pipeline near the outlet of the tail gas emission regulating valve. The connecting pipe is provided with a bottom valve of the treatment tower near the tail gas treatment tower, and the connecting pipe is provided with a sedimentation tank circulation pump and a heat exchanger which are connected in sequence to the bottom valve of the treatment tower.

[0009] Furthermore, it also includes a sedimentation tank, and the connecting pipe includes a first pipe and a second pipe, the first pipe is arranged between the sedimentation tank and the tail gas treatment tower, the second pipe is arranged between the sedimentation tank and the tail gas pipe, one end of the first pipe is connected to the bottom of the tail gas treatment tower, and the other end is connected to the top of the sedimentation tank, and the bottom valve of the treatment tower is arranged on the first pipe; one end of the second pipe is connected to the bottom of the sedimentation tank, and the other end is connected to the tail gas pipe near the outlet of the tail gas emission regulating valve.

[0010] Furthermore, a transverse sieve plate is detachably connected to the middle of the sedimentation tank, and a condenser is provided above the sieve plate in the sedimentation tank.

[0011] Furthermore, the refrigerant used in the condenser is ice salt water, and the temperature of the ice salt water is 0 to 5°C.

[0012] Furthermore, the heat exchanger is connected to a hot water tank, and the hot water tank is provided with an electric heater. The hot water temperature provided by the hot water tank to the heat exchanger is 40 to 90°C.

[0013] A boron trichloride tail gas anti-clogging treatment method, using the boron trichloride tail gas anti-clogging treatment device, comprises the following steps:

[0014] S1, close the bottom valve of the treatment tower, start the circulation pump of the treatment tower, open the root valve of the distillation tower and the tail gas emission regulating valve, and the tail gas generated by the distillation tower enters the tail gas treatment tower through the tail gas pipeline and is absorbed by the absorption liquid sprayed into the tail gas treatment tower through the circulation pipeline;

[0015] S2, after the tail gas generated in the distillation tower is discharged, close the tail gas discharge regulating valve.

[0016] Further, S3, the electric heater heats the water in the hot water tank to raise the temperature of the water to 40 to 90°C, heats the heat exchanger, and the heating belt heats the exhaust gas pipeline, and the heating temperature is set to 70°C;

[0017] S4, after closing the tail gas emission regulating valve for 10 minutes, close the treatment tower circulation pump, open the bottom valve of the treatment tower, and the absorption liquid in the tail gas treatment tower flows into the sedimentation tank. After the liquid level of the sedimentation tank reaches 40%, start the sedimentation tank circulation pump;

[0018] S5, the absorption liquid in the sedimentation tank flows into the tail gas pipeline through the second pipeline, and flushes the tail gas pipeline for 5 to 30 minutes;

[0019] S6, slowly close the bottom valve of the treatment tower, and when the liquid level in the tail gas treatment tower reaches 40% to 70%, close the bottom valve of the treatment tower and the circulation pump of the sedimentation tank in turn, and start the circulation pump of the treatment tower.

[0020] Further, S7, borate or boric acid is precipitated:

[0021] S7.1, turn off the circulating pump of the treatment tower, open the bottom valve of the treatment tower, and introduce circulating ice brine into the condenser, and the temperature of the ice brine is controlled at 0 to 5°C;

[0022] S7.2, install the screen into the settling tank;

[0023] S7.3, start the circulation pump of the sedimentation tank, turn off the hot water circulation of the heat exchanger, and stop the heating of the exhaust gas pipeline by the heating belt;

[0024] S7.4, borate or boric acid continues to precipitate above the sieve plate, forming solid particles that settle on the sieve plate. After the circulating pump of the sedimentation tank runs for 30 to 60 minutes, the circulating brine of the condenser is turned off, and the precipitation of solid particles on the sieve plate ends;

[0025] S7.5, taking out the sieve plate, dissolving the solid particles with hot water, cooling them down several times to precipitate them, and drying the precipitates;

[0026] Furthermore, steps S3 to S6 are repeated two to three times to flush the residual particulate matter in the exhaust pipe.

[0027] The positive effects of the present invention are:

[0028] The present invention is provided with an exhaust pipe, an exhaust treatment tower and a connecting pipe, a heating belt is wound on the exhaust pipe, a heat exchanger is provided on the connecting pipe, and a settling tank circulation pump is provided on the connecting pipe. The absorption liquid flows from the exhaust treatment tower through the second pipe and the exhaust pipe in sequence, and is heated by the heat exchanger and the heating belt, thereby increasing the temperature of the absorption liquid and greatly improving the solubility of borate or boric acid. After each exhaust gas discharge in the distillation tower is completed, the exhaust pipe is flushed with hot absorption liquid to remove the insoluble matter remaining in the pipe, thereby reducing the possibility of blockage of the exhaust pipe. In addition, the present invention is also provided with a settling tank, and a sieve plate and a condenser are provided in the settling tank. The borate or boric acid can be precipitated on the sieve plate, and the borate or boric acid with a purity of about 90% can be separated while solving the problem of blockage of the exhaust pipe. After subsequent multiple dissolutions and precipitations, borate or boric acid with a purity of about 95% can be produced, which can reduce the processing burden of the exhaust treatment tower and generate certain additional economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the present invention;

[0030] 1. Distillation tower; 2. Root valve of distillation tower; 3. Tail gas emission regulating valve; 4. Tail gas treatment tower; 5. Treatment tower circulation pump; 6. Treatment tower bottom valve; 7. Packing layer; 8. Tail gas pipeline; 9. Sedimentation tank; 10. Sieve plate; 11. Condenser; 12. Sedimentation tank circulation pump; 13. Heat exchanger; 14. Hot water tank; 15. Electric heater; 16. First pipeline; 17. Second pipeline; 18. Circulation pipeline; 19. Connecting pipe; 20. Hot water pipe; 21. Hot water circulation pump. DETAILED DESCRIPTION

[0031] Example 1

[0032] like Figure 1 As shown, a boron trichloride tail gas anti-clogging treatment device includes a tail gas treatment tower 4 arranged above the ground, the tail gas treatment tower 4 adopts a vertical structure, the top of the tail gas treatment tower 4 is provided with a tail gas pipeline 8 connected to the right end, and the left end of the tail gas pipeline 8 is connected to the exhaust port at the bottom of the distillation tower 1. The left end of the tail gas pipeline 8 is provided with a distillation tower root valve 2 and a tail gas emission regulating valve 3 connected to the exhaust port from left to right in sequence, and a circulation pipeline 18 is connected between the upper and lower parts of the tail gas treatment tower 4, and a treatment tower circulation pump 5 is provided on the circulation pipeline 18.

[0033] The tail gas treatment tower 4 is provided with two upper and lower packing layers 7, and each packing layer 7 is provided with a nozzle connected to the upper end of the circulation pipe 18. The tail gas treatment tower 4 stores alkaline absorption liquid, and the absorption liquid is an aqueous solution of NaOH or KOH. The tail gas pipe 8 is wound with a heating belt with electric heating, which is used to heat the tail gas pipe 8.

[0034] A connecting pipe 19 is provided between the tail gas treatment tower 4 and the tail gas pipeline 8, one end of the connecting pipe 19 is connected to the bottom of the tail gas treatment tower 4, and the other end is connected to the tail gas pipeline 8 near the right outlet of the tail gas emission regulating valve 3. The connecting pipe 19 is provided with a treatment tower bottom valve 6 near the tail gas treatment tower 4, and a settling tank circulation pump 12 and a heat exchanger 13 connected to the treatment tower bottom valve 6 are provided on the connecting pipe 19 from right to left.

[0035] The present invention is also provided with a sedimentation tank 9 whose top is connected to the outside atmosphere, the sedimentation tank 9 is lower than the tail gas treatment tower 4, the connecting pipe 19 includes a first pipe 16 and a second pipe 17, the sedimentation tank 9 is connected between the first pipe 16 and the second pipe 17, the first pipe 16 is arranged between the sedimentation tank 9 and the tail gas treatment tower 4, the second pipe 17 is arranged between the sedimentation tank 9 and the tail gas pipe 8, the upper end of the first pipe 16 is connected to the bottom of the tail gas treatment tower 4, and the lower end is connected to the top of the sedimentation tank 9, and the bottom valve 6 of the treatment tower is arranged on the first pipe 16.

[0036] The lower end of the second pipeline 17 is connected to the bottom of the sedimentation tank 9 , and the upper end is connected to the tail gas pipeline 8 near the outlet of the tail gas emission regulating valve 3 .

[0037] A boron trichloride tail gas anti-clogging treatment method, using the above-mentioned treatment device, comprises the following steps:

[0038] S1, close the bottom valve 6 of the treatment tower, start the treatment tower circulation pump 5, open the root valve 2 of the distillation tower and the tail gas emission regulating valve 3, the treatment tower circulation pump 5 extracts the absorption liquid in the tail gas treatment tower 4 from the bottom, and then sends it to the upper part of the tail gas treatment tower 4, and sprays it to the top of the two layers of packing layers 7 inside the tail gas treatment tower 4 through the nozzle. When the tail gas generated by the distillation tower 1 enters the tail gas treatment tower 4 through the tail gas pipeline 8, it is absorbed by the absorption liquid sprayed into the tail gas treatment tower 4. The packing layer 7 can increase the contact area and contact time between the tail gas and the absorption liquid, so that the tail gas is fully absorbed, and at the same time, the impurities in the tail gas can be filtered.

[0039] S2, after the tail gas generated in the distillation tower 1 is discharged, the tail gas discharge regulating valve 3 is closed.

[0040] S3, the heat exchanger 13 works, the temperature rises to 40 to 90°C, the absorption liquid flowing through the heat exchanger 13 is heated, and the heating belt heats the tail gas pipeline 8, and the heating temperature is set to 70°C;

[0041] S4, close the tail gas emission regulating valve 3 for ten minutes, close the treatment tower circulation pump 5, open the treatment tower bottom valve 6, and the absorption liquid in the tail gas treatment tower 4 flows into the sedimentation tank 9. After the liquid level of the sedimentation tank 9 reaches 40%, start the sedimentation tank circulation pump 12.

[0042] S5, the absorption liquid in the sedimentation tank 9 flows into the tail gas pipeline 8 through the second pipeline 17, and flushes the tail gas pipeline 8 for 5 to 30 minutes.

[0043] S6, slowly close the bottom valve 6 of the treatment tower, and after the liquid level in the tail gas treatment tower 4 reaches 40% to 70%, close the bottom valve 6 of the treatment tower and the circulating pump 12 of the sedimentation tank in turn, and start the circulating pump 5 of the treatment tower.

[0044] Since both the tail gas pipeline 8 and the absorption liquid are heated, the solubility of the borate or boric acid can be increased, preventing the borate or boric acid from precipitating in the tail gas pipeline 8 and then blocking the tail gas pipeline 8, thereby ensuring the smooth flow of the tail gas pipeline 8.

[0045] Example 2

[0046] The difference between this embodiment and embodiment 1 is that:

[0047] A transverse sieve plate 10 is detachably connected to the middle of the sedimentation tank 9, and a condenser 11 is provided above the sieve plate 10 in the sedimentation tank 9. The pore size of the sieve plate 10 is 1 to 40 mm, and the pore size can be selected according to the size of the filtered particles. The sieve plate 10 can be mounted on a boss on the wall of the sedimentation tank 9 to facilitate the disassembly and assembly of the sieve plate 10.

[0048] A boron trichloride tail gas anti-clogging treatment method also includes the following steps:

[0049] S7, borate or boric acid precipitation:

[0050] S7.1, turn off the treatment tower circulation pump 5, open the treatment tower bottom valve 6, and introduce circulating ice brine into the condenser 11, and the temperature of the ice brine is controlled at 0 to 5°C;

[0051] S7.2, installing the sieve plate 10 into the sedimentation tank 9;

[0052] S7.3, start the circulation pump 12 of the sedimentation tank, close the hot water circulation of the heat exchanger 13, and stop the heating belt from heating the exhaust gas pipeline 8;

[0053] S7.4, after the absorption liquid flows from the first pipeline 16 to the upper part of the sedimentation tank 9, it is cooled by the condenser 11, and the borate or boric acid continues to precipitate above the sieve plate 10 to form solid particles and settle on the sieve plate 10. After the sedimentation tank circulation pump 12 runs for 30 to 60 minutes, the circulating brine of the condenser 11 is turned off, and the precipitation of solid particles on the sieve plate 10 is completed.

[0054] S7.5, take out the sieve plate 10, dissolve the solid particles with hot water, cool them down several times to precipitate, and then dry the precipitate;

[0055] S8, repeating steps S3 to S6 two or three times to flush the residual particulate matter in the exhaust pipe 8.

[0056] Borates or boric acid can be precipitated on the sieve plate 10 in the sedimentation tank 9, and the borate or boric acid with a purity of about 90% can be separated while solving the blockage problem of the boron trichloride tail gas pipeline 8. After subsequent multiple dissolutions and precipitations, borate or boric acid with a purity of about 95% can be produced, which can reduce the processing burden of the tail gas treatment tower 4 and generate certain additional economic benefits.

[0057] Example 3

[0058] The difference between this embodiment and embodiment 1 is that:

[0059] The heat exchanger 13 is connected to a hot water tank 14 through a hot water pipe 20. A hot water circulation pump 21 is provided on the hot water pipe 20. An electric heater 15 is provided on the hot water tank 14. When the hot water circulation pump 21 is running, hot water is circulated between the hot water tank 14 and the heat exchanger 13, and the absorption liquid flowing through the heat exchanger 13 in the second pipe 17 can be heated. The hot water provided by the hot water tank 14 to the heat exchanger 13 has a temperature of 40 to 90°C.

[0060] The above-mentioned embodiments are described in a relatively detailed and specific manner, expressing the preferred embodiments of the present invention, and are only used to illustrate the technical ideas and features of the present invention. The purpose is to enable technicians in this field to understand the contents of the present invention and implement them accordingly, but are not limited to the present invention. The patent scope of the present invention cannot be limited only by this embodiment, that is, any equivalent changes or modifications made to the spirit disclosed by the present invention, for researchers or technicians in this field, without departing from the structure of the present invention, local improvements within the system and changes and conversions between subsystems, etc., are still within the patent scope of the present invention.

Claims

1. A boron trichloride tail gas anti-clogging treatment device, characterized in that: The invention comprises a tail gas treatment tower (4), wherein a tail gas pipeline (8) connected to the tail gas treatment tower (4) is provided at the top of the tail gas treatment tower (4), the other end of the tail gas pipeline (8) being connected to the exhaust port of the distillation tower (1), the tail gas pipeline (8) being provided with a distillation tower root valve (2) and a tail gas emission regulating valve (3) connected to the exhaust port in sequence at a position close to the distillation tower (1), a circulation pipeline (18) being connected between the upper and lower parts of the tail gas treatment tower (4), a treatment tower circulation pump (5) being provided on the circulation pipeline (18), at least one packing layer (7) being provided inside the tail gas treatment tower (4), an alkaline absorption liquid being stored in the tail gas treatment tower (4), and a heating belt being provided on the tail gas pipeline (8).

2. A boron trichloride tail gas anti-clogging treatment device according to claim 1, characterized in that: A connecting pipe (19) is provided between the tail gas treatment tower (4) and the tail gas pipeline (8); one end of the connecting pipe (19) is connected to the bottom of the tail gas treatment tower (4), and the other end is connected to a portion of the tail gas pipeline (8) close to the outlet of the tail gas emission regulating valve (3); the connecting pipe (19) is provided with a treatment tower bottom valve (6) at a position close to the tail gas treatment tower (4); and the connecting pipe (19) is provided with a sedimentation tank circulation pump (12) and a heat exchanger (13) which are sequentially connected to the treatment tower bottom valve (6).

3. A boron trichloride tail gas anti-clogging treatment device according to claim 2, characterized in that: It also comprises a settling tank (9), wherein the connecting pipe (19) comprises a first pipe (16) and a second pipe (17), wherein the first pipe (16) is arranged between the settling tank (9) and the tail gas treatment tower (4), and the second pipe (17) is arranged between the settling tank (9) and the tail gas pipeline (8), wherein one end of the first pipe (16) is connected to the bottom of the tail gas treatment tower (4), and the other end is connected to the top of the settling tank (9), and the bottom valve (6) of the treatment tower is arranged on the first pipe (16); and one end of the second pipe (17) is connected to the bottom of the settling tank (9), and the other end is connected to a position of the tail gas pipeline (8) close to the outlet of the tail gas emission regulating valve (3).

4. A boron trichloride tail gas anti-clogging treatment device according to claim 3, characterized in that: A transverse sieve plate (10) is detachably connected to the middle of the sedimentation tank (9), and a condenser (11) is provided above the sieve plate (10) in the sedimentation tank (9).

5. A boron trichloride tail gas anti-clogging treatment device according to claim 4, characterized in that: The refrigerant used in the condenser (11) is ice-salt water, and the temperature of the ice-salt water is 0 to 5°C.

6. A boron trichloride tail gas anti-clogging treatment device according to claim 2, characterized in that: The heat exchanger (13) is connected to a hot water tank (14), and the hot water tank (14) is provided with an electric heater (15). The hot water provided by the hot water tank (14) to the heat exchanger (13) has a temperature of 40 to 90°C.

7. A method for preventing boron trichloride tail gas from being blocked, using a boron trichloride tail gas anti-blocking treatment device according to any one of claims 1 to 6, characterized in that: The steps include: S1, close the bottom valve (6) of the treatment tower, start the circulation pump (5) of the treatment tower, open the root valve (2) of the distillation tower and the tail gas discharge regulating valve (3), and the tail gas generated by the distillation tower (1) enters the tail gas treatment tower (4) through the tail gas pipeline (8), and is absorbed by the absorption liquid sprayed into the tail gas treatment tower (4) through the circulation pipeline (18); S2, after the tail gas generated in the distillation tower (1) is discharged, the tail gas discharge regulating valve (3) is closed.

8. A boron trichloride tail gas anti-clogging treatment method according to claim 7, characterized in that: S3, the electric heater (15) heats the water in the hot water tank (14) to a temperature of 40 to 90°C, heats the heat exchanger (13), and the heating belt heats the exhaust gas pipeline (8), and the heating temperature is set to 70°C; S4, after closing the tail gas emission regulating valve (3) for 10 minutes, the treatment tower circulation pump (5) is closed, and the bottom valve (6) of the treatment tower is opened, and the absorption liquid in the tail gas treatment tower (4) flows into the sedimentation tank (9). After the liquid level of the sedimentation tank (9) reaches 40%, the sedimentation tank circulation pump (12) is turned on; S5, the absorption liquid in the sedimentation tank (9) flows into the tail gas pipeline (8) through the second pipeline (17), and flushes the tail gas pipeline (8) for 5 to 30 minutes; S6, slowly close the bottom valve (6) of the treatment tower, and when the liquid level in the tail gas treatment tower (4) reaches 40% to 70%, close the bottom valve (6) of the treatment tower and the circulation pump (12) of the sedimentation tank in turn, and start the circulation pump (5) of the treatment tower.

9. A boron trichloride tail gas anti-clogging treatment method according to claim 8, characterized in that: S7, borate or boric acid precipitation: S7.1, turn off the treatment tower circulation pump (5), open the treatment tower bottom valve (6), and introduce circulating ice brine into the condenser (11), and control the temperature of the ice brine to be between 0 and 5°C; S7.2, installing the sieve plate (10) into the sedimentation tank (9); S7.3, start the circulation pump (12) of the sedimentation tank, close the hot water circulation of the heat exchanger (13), and stop the heating belt from heating the exhaust gas pipeline (8); S7.4, borate or boric acid continues to precipitate above the sieve plate (10), forming solid particles that settle on the sieve plate (10). After the circulating pump (12) in the sedimentation tank runs for 30 to 60 minutes, the circulating brine of the condenser (11) is turned off, and the precipitation of solid particles on the sieve plate (10) is completed; S7.5, take out the sieve plate (10), dissolve the solid particles with hot water, cool them down several times to precipitate them, and then dry the precipitates.

10. A boron trichloride tail gas anti-clogging treatment method according to claim 8 or 9, characterized in that: Repeat steps S3 to S6 two or three times to flush the residual particulate matter in the exhaust pipe (8).

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