Electronic grade HCl purification system and purification method

Abstract

The invention discloses an electronic grade HCl purification system and method, the electronic grade HCl purification system comprises a first scrubber tower system, a second scrubber tower system and a sulfuric acid scrubber system which are sequentially connected through pipelines, and the first scrubber tower system and the second scrubber tower system are used for washing away most impurities in a raw material HCl. The sulfuric acid gas washing system is used for washing and removing moisture and impurities in HCl through electronic-grade concentrated sulfuric acid. The two sets of gas washing systems are arranged to wash away most impurities in HCl, then washing is conducted through the sulfuric acid gas washing system to remove moisture, and therefore the electronic-grade HCl finished product is obtained, rectification equipment is not used, heating is not involved, only several centrifugal pumps consume energy, and compared with a traditional rectification scheme, the production cost is greatly saved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic grade HCl purification, in particular to an electronic grade HCl purification system and a purification method. BACKGROUND

[0002] Electronic grade HCl, as a very important electronic gas in semiconductor process, has a purity of more than 99.999%, and is mainly used in the preparation of single crystal silicon, semiconductors, optoelectronics, photovoltaics, flat panel displays and other electronic industries. Electronic grade HCl can make the purity of crystalline silicon reach the PPB level, and is also used in the steps of annealing, cleaning, etching and photolithography in the semiconductor industry. Electronic grade HCl is also needed in the manufacture of portable X-ray fluorescence instruments, high-definition imaging instruments and other equipment.

[0003] At present, the main production process of electronic grade HCl is hydrochloric acid distillation process. Industrial grade hydrochloric acid is distilled to obtain electronic grade HCl. Most of the impurities in industrial grade hydrochloric acid can be removed by distillation process because of the large difference between their boiling points and the boiling point of hydrochloric acid solution. However, some impurities, represented by arsenic, have a boiling point close to that of HCl in its trivalent form, and cannot be removed because they are distilled out with HCl during the distillation process. In addition, the distillation process requires a large amount of steam heat energy, resulting in high cost. Therefore, the present application provides a method and device with low energy consumption and high impurity removal efficiency.

[0004] In the prior art, Chinese patent document CN114082211A, published (announced) on February 25, 2022, discloses a method for producing electronic grade hydrogen chloride based on a partition plate tower. This document breaks the traditional concept of using a packed tower in fine chemical industry, and creatively uses a partition plate tower to distill hydrochloric acid to obtain electronic grade HCl. This method avoids the back mixing of intermediate components, reduces the mixing problem caused by the difference in composition of the feed and the flow on the feed plate, and is beneficial to improving the yield and purity of hydrogen chloride. However, this method also has the problems of high energy consumption and incomplete removal of arsenic elements.

[0005] In addition, Chinese patent document CN109650340A, published (announced) on December 26, 2018, discloses a production method of electronic grade hydrochloric acid. This document uses industrial hydrochloric acid as raw material and adopts a packed tower distillation process. By controlling the concentration of hydrochloric acid in the tower kettle, the concentration is maintained above the azeotropic concentration of 20%. The HCl distilled out is absorbed by ultrapure water to obtain electronic grade hydrochloric acid. This method is simple to operate and has low investment. However, it still has the problems of high energy consumption, low raw material utilization rate and incomplete removal of arsenic elements. SUMMARY

[0006] In order to solve the current technical problems, the main purpose of the present application is to provide an electronic grade HCl purification system and purification method, the present application discards the traditional rectification method, removes the impurities of HCl by adopting two-stage gas washing method, finally absorbs the acid mist in HCl by using electronic grade concentrated sulfuric acid to remove metal impurities, and ingeniously uses the height difference of liquid level between the tower kettle to realize self-flow, realizes the maximum energy saving, greatly reduces the cost of producing electronic grade HCl.

[0007] In order to overcome the problems existing in the prior art, the technical scheme adopted by the present application is: an electronic grade HCl purification system, comprising a first gas washing tower system, a second gas washing tower system and a sulfuric acid gas washing system connected in sequence through pipelines, the first gas washing tower system and the second gas washing tower system are used for washing most of the impurities in the raw material HCl, and the sulfuric acid gas washing system is used for removing water and impurities in HCl by concentrated sulfuric acid washing.

[0008] The first washing tower system comprises a first washing tower, a first washing tower overflow port is arranged at the lower part of the tower, is connected with the lower hydrochloric acid waste acid tank through a steel lining tetrafluoro pipeline, a first washing tower hydrochloric acid one-way valve is arranged on the pipeline, the bottom and the upper part are connected through a steel lining tetrafluoro pipeline, a first washing tower circulating pump is arranged on the pipeline, the top of the tower is connected with a first washing tower HCl demister through a steel lining tetrafluoro pipeline, the bottom of the demister is connected with the lower part of the tower, and the lower part of the tower is connected with an HCl raw material inlet through a steel lining tetrafluoro pipeline.

[0009] The second gas washing tower system comprises a second washing tower, the lower part of the tower is connected with the top of the first washing tower HCl demister through a steel lining tetrafluoro pipeline, the second washing tower overflow port at the lower part of the tower is connected with the lower part of the first washing tower through a steel lining tetrafluoro pipeline, a second washing tower hydrochloric acid one-way valve is arranged on the pipeline, the bottom of the tower is connected with the lower hydrochloric acid waste acid tank through a steel lining tetrafluoro pipeline, the bottom and the upper part are connected through a steel lining tetrafluoro pipeline, a second washing tower circulating pump and a second washing tower condenser are arranged on the pipeline, the top of the tower is connected with the lower part of the second washing tower HCl demister, the lower part of the tower and the bottom of the second washing tower HCl demister are connected through a steel lining tetrafluoro pipeline, the lower part of the tower is connected with an ultrapure water inlet through a PVDF pipeline, and an ultrapure water one-way valve, an ultrapure water pneumatic regulating valve and an ultrapure water flowmeter are arranged on the pipeline.

[0010] The sulfuric acid gas washing system comprises a sulfuric acid gas washing tower, the lower part of the tower is connected with the top of a second washing tower HCl demister through a steel lining Teflon pipeline, the lower part of the tower is provided with a sulfuric acid gas washing tower overflow port connected with a lower sulfuric acid waste acid tank through a steel lining Teflon pipeline, a sulfuric acid gas washing tower one-way valve is arranged on the pipeline, the bottom and the upper part of the tower are connected through a steel lining Teflon pipeline, a sulfuric acid gas washing tower circulating pump and a sulfuric acid gas washing tower condenser are arranged on the pipeline, the top of the tower is connected with the lower part of a sulfuric acid gas washing tower demister through a steel lining Teflon pipeline, the lower part is connected with the bottom of the sulfuric acid gas washing tower demister, the top of the sulfuric acid gas washing tower demister (34) is the electronic grade HCl product, the lower part of the tower is connected with a sulfuric acid inlet through a steel lining Teflon pipeline, and a sulfuric acid pneumatic regulating valve, a sulfuric acid one-way valve and a sulfuric acid flowmeter are arranged on the pipeline.

[0011] The hydrochloric acid waste acid tank is provided with a hydrochloric acid waste acid pump, and the sulfuric acid waste acid tank is provided with a sulfuric acid waste acid pump responsible for circulation and discharge.

[0012] An electronic grade HCl purification system and a purification method, the method comprises the following steps: S1, electronic grade sulfuric acid is introduced into the sulfuric acid gas washing tower until the sulfuric acid gas washing tower overflow port begins to overflow, a certain flow of ultrapure water is introduced into the second washing tower until the first washing tower overflow port begins to overflow, and condensate water is introduced into the second washing tower condenser and the sulfuric acid gas washing tower condenser; S2, the sulfuric acid gas washing tower circulating pump, the first washing tower circulating pump and the second washing tower circulating pump are started; S3, a certain flow of HCl raw material is introduced through the HCl raw material inlet, the HCl gas is washed in the first washing tower and the second washing tower to remove most of the impurities, and the HCl acid mist carried out is removed through the first washing tower HCl demister and the second washing tower HCl demister respectively; S4, the washed HCl gas removes water mist and impurities in the sulfuric acid gas washing tower, and the carried-out sulfuric acid mist is removed through the sulfuric acid gas washing tower demister to obtain the HCl product; The present application has the following beneficial effects: The present application removes the impurities of HCl by adopting a two-stage gas washing method, and finally removes the acid mist in HCl by using electronic grade sulfuric acid, so that the problem that the boiling point of arsenic element is close to the boiling point of hydrochloric acid is not considered, the difficulty that arsenic element cannot be removed by rectification is avoided, and the height difference between the tower bottoms is ingeniously used for self-flow, the energy consumption of only a few circulating pumps in the whole process is realized, the energy is saved to the greatest extent, and the cost of producing electronic grade HCl is greatly reduced.

[0013] The technical solution of this invention can achieve a metal ion content of less than 10 ppt and a stabilization period of at least 3 weeks. In particular, As, which is difficult to remove in the art, can be reduced to less than 10 ppt. The metal ions are listed in Table 1. Attached Figure Description

[0014] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the structure of an electronic-grade HCl purification system according to the present invention.

[0016] Figure label: HCl feedstock inlet 1, HCl feedstock pneumatic regulating valve 2, HCl feedstock flow meter 3, First scrubbing tower hydrochloric acid check valve 4, Hydrochloric acid waste tank 5, Hydrochloric acid waste pump 6, First scrubbing tower overflow port 7, First scrubbing tower 8, First scrubbing tower HCl demister 9, First scrubbing tower vent valve 10, First scrubbing tower circulation pump 11, Second scrubbing tower hydrochloric acid check valve 12, Second scrubbing tower overflow port 13, Second scrubbing tower 14, Second scrubbing tower HCl demister 15, Second scrubbing tower vent valve 16, Second scrubbing tower circulation pump 17, Ultrapure water 18. One-way valve, 19. Ultrapure water pneumatic regulating valve, 20. Ultrapure water flow meter, 21. Ultrapure water inlet, 22. Second washing tower condenser, 23. Sulfuric acid waste tank, 24. Sulfuric acid waste pump, 25. Sulfuric acid scrubbing tower one-way valve, 26. Sulfuric acid scrubbing tower concentration meter, 27. Sulfuric acid scrubbing tower circulation pump, 28. Sulfuric acid pneumatic regulating valve, 29. Sulfuric acid one-way valve, 30. Sulfuric acid inlet, 31. Sulfuric acid scrubbing tower overflow port, 32. Sulfuric acid scrubbing tower condenser, 33. Sulfuric acid scrubbing tower demister, 34. Sulfuric acid scrubbing tower vent valve, 35. Sulfuric acid flow meter. Detailed Implementation

[0017] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1 An electronic-grade HCl purification system includes a first gas scrubbing tower system, a second gas scrubbing tower system, and a sulfuric acid gas scrubbing system connected in sequence by pipelines. The first and second gas scrubbing tower systems are mainly used to wash away most of the impurities in the raw material HCl, and the sulfuric acid gas scrubbing system is mainly used to remove moisture and impurities from the HCl by washing with concentrated sulfuric acid. The first gas scrubbing tower system includes a feeding system, a gas scrubbing system, and a waste acid system. The gas scrubbing system includes a first scrubbing tower 8 and a first scrubbing tower HCl demister 9, which are connected by a steel-lined PTFE pipe. The second gas scrubbing tower system includes a gas scrubbing system and an ultrapure water system. The gas scrubbing system includes a second scrubbing tower 14, a second scrubbing tower HCl demister 15, and a second scrubbing tower condenser 22, which are connected by steel-lined PTFE pipes. The sulfuric acid scrubbing tower system includes a sulfuric acid feed system, a scrubbing system, and a waste acid system. The scrubbing system includes a sulfuric acid scrubbing tower condenser 32, a sulfuric acid scrubbing tower 33, and a sulfuric acid scrubbing tower demister 34, which are connected by PTFE-lined steel pipes.

[0019] The feeding system is equipped with an HCl raw material pneumatic regulating valve 2 and an HCl raw material flow meter 3, which are interlocked to ensure control of the HCl feed rate.

[0020] The hydrochloric acid in the first washing tower 8 is circulated from bottom to top by the first washing tower circulation pump 11, and the first washing tower vent valve 10 is installed at the bottom of the tower.

[0021] The waste acid system includes a hydrochloric acid waste acid tank 5 and a hydrochloric acid waste acid pump 6. A first scrubbing tower hydrochloric acid check valve 4 is installed above the hydrochloric acid waste acid tank 5 to prevent impurities in the waste hydrochloric acid from entering the scrubbing system.

[0022] The hydrochloric acid in the second washing tower 14 is circulated from bottom to top by the second washing tower circulation pump 17. The second washing tower 14 and the first washing tower 8 are connected by a steel-lined PTFE pipe. A second washing tower hydrochloric acid check valve 12 is installed on the pipe, and a second washing tower vent valve 16 is installed at the bottom of the tower.

[0023] The ultrapure water system includes an ultrapure water check valve 18, an ultrapure water pneumatic regulating valve 19, and an ultrapure water flow meter 20. The three are connected by PVDF pipes. The ultrapure water pneumatic regulating valve 19 and the ultrapure water flow meter 20 are interlocked to ensure control of the ultrapure water flow.

[0024] The sulfuric acid feeding system includes a sulfuric acid pneumatic regulating valve 28, a sulfuric acid flow meter 36, and a sulfuric acid check valve 29. The sulfuric acid pneumatic regulating valve 28 and the sulfuric acid flow meter 36 are interlocked to ensure control of the sulfuric acid flow.

[0025] Sulfuric acid in sulfuric acid scrubbing tower 33 is circulated from bottom to top by sulfuric acid scrubbing tower circulation pump 27, and sulfuric acid scrubbing tower vent valve 35 is installed at the bottom of the tower.

[0026] The waste acid system includes a sulfuric acid waste acid tank 23 and a sulfuric acid waste acid pump 24. A one-way valve 25 for a sulfuric acid scrubbing tower is installed above the sulfuric acid waste acid tank 23 to prevent impurities in the waste acid from entering the scrubbing system.

[0027] Example 2 See Figure 1 This invention provides an electronic-grade HCl purification system, comprising a first gas washing tower system, a second gas washing tower system, and a sulfuric acid gas washing system connected sequentially by pipelines. The first and second gas washing tower systems are used to wash away most of the impurities in the raw material HCl, and the sulfuric acid gas washing system is used to remove moisture and impurities from the HCl by washing with concentrated sulfuric acid. This purification system removes most of the impurities in the HCl by setting up two gas washing systems, and then removes moisture and impurities by washing with the sulfuric acid gas washing system, thereby obtaining electronic-grade HCl product.

[0028] In this embodiment, the first scrubbing tower system includes a first scrubbing tower 8. The outer shell of the tower is made of polished 316L stainless steel, the inner lining material is N-PTFE, the lower layer of packing is structured packing with a height of 3000mm and made of PTFE, and the upper layer of packing is Pall ring packing with a height of 3000mm and a Pall ring size of φ25 and made of PTFE. HCl feedstock is fed from the bottom of the tower through HCl feedstock inlet 1. The feed pipe is equipped with HCl feedstock pneumatic regulating valve 2 and HCl feedstock flow meter 3, which are interlocked to remotely control the HCl feedstock flow rate. After entering the first washing tower 8, the HCl feedstock flows from bottom to top. The hydrochloric acid liquid in the tower bottom is pumped into the upper part of the tower by the first washing tower circulation pump 11 and flows from top to bottom in the tower. The gas and liquid are fully mixed and contacted in the packing. After the impurities in the HCl gas are washed away by the hydrochloric acid, it enters the first washing tower HCl demister 9 at the top of the tower. The demister is filled with a corrugated and regular packing material of high-purity PTFE. The acid mist in the HCl is intercepted inside the demister and flows into the lower part of the first washing tower 8 through the pipeline for reuse. The bottom of the first washing tower 8 is connected to the hydrochloric acid waste tank 5 via a pipe. When the tower bottom needs to be emptied, the first washing tower vent valve 10 can be opened to empty the hydrochloric acid in the tower bottom. The overflow port 7 of the first washing tower at the bottom is also connected to the hydrochloric acid waste tank 5 via a pipe. The pipe is equipped with a first washing tower hydrochloric acid check valve 4. The hydrochloric acid in the tower bottom can overflow into the waste acid tank through the pipe. Neither gaseous nor liquid impurities in the waste acid tank can enter the tower bottom and contaminate the hydrochloric acid inside. The hydrochloric acid in the hydrochloric acid waste tank 5 can be circulated and discharged through the hydrochloric acid waste acid pump 6.

[0029] In this embodiment, the second scrubbing tower system includes a second scrubbing tower 14. The tower shell is made of polished 316L stainless steel, and the tower lining is made of N-PTFE. The lower layer of packing is structured packing with a height of 3000mm and made of PTFE. The upper layer of packing is Pall ring packing with a height of 3000mm and a Pall ring size of φ25, also made of PTFE. Ultrapure water enters the tower bottom through a PVDF pipeline from the ultrapure water inlet 21 at the bottom of the second scrubbing tower 14. An ultrapure water check valve 18, an ultrapure water pneumatic regulating valve 19, and an ultrapure water flow meter 20 are installed in the middle of the pipeline. The check valve can prevent hydrochloric acid in the tower bottom from entering the ultrapure water pipeline and contaminating the ultrapure water system. The ultrapure water pneumatic regulating valve 19 and the ultrapure water flow meter 20 are interlocked to ensure remote control of the ultrapure water feed rate. HCl enters the second washing tower 14 through a pipeline from above the HCl demister 9 in the first washing tower. After entering the second washing tower 14, the HCl raw material flows from bottom to top. The hydrochloric acid liquid in the bottom of the tower is pumped into the upper part of the tower by the second washing tower circulation pump 17 and flows from top to bottom in the tower. The second washing tower condenser 22 is connected in the middle to cool the hydrochloric acid solution. The gas and liquid are fully mixed and contacted in the packing. After the impurities in the HCl gas are washed away by the hydrochloric acid, it enters the second washing tower HCl demister 15 at the top of the tower. The demister is filled with a regular corrugated packing material made of high-purity PTFE. The acid mist in the HCl is intercepted inside the demister and flows into the lower part of the second washing tower 14 through the pipeline for reuse. The bottom of the second washing tower 14 is connected to the hydrochloric acid waste tank 5 through a pipe. When the tower bottom needs to be emptied, the second washing tower vent valve 16 can be opened to empty the hydrochloric acid in the tower bottom. When there is excess hydrochloric acid in the second washing tower 14, it can overflow into the first washing tower 8 through the pipe. The pipe is equipped with a second washing tower hydrochloric acid check valve 12 to ensure that waste hydrochloric acid and acid mist will not flow back.

[0030] In this embodiment, the sulfuric acid scrubbing system includes a sulfuric acid scrubbing tower 33. The tower shell is made of polished 316L stainless steel, and the tower lining is made of N-PTFE. The lower layer of packing is structured packing with a height of 3000mm and made of PTFE. The upper layer of packing is Pall ring packing with a height of 3000mm and a Pall ring size of φ25, also made of PTFE. Electronic-grade sulfuric acid enters the tower bottom from the sulfuric acid inlet 30 at the bottom of the sulfuric acid scrubbing tower 33 through a PTFE-lined steel pipe. A sulfuric acid pneumatic regulating valve 28, a sulfuric acid flow meter 36, and a sulfuric acid check valve 29 are installed in the middle of the pipe. The sulfuric acid pneumatic regulating valve 28 and the sulfuric acid flow meter 36 are interlocked to remotely control the sulfuric acid feed rate. The sulfuric acid check valve 29 prevents sulfuric acid in the tower bottom from entering the sulfuric acid pipe and contaminating the sulfuric acid system. HCl enters the sulfuric acid scrubbing tower 33 from above the HCl demister 15 in the second scrubbing tower through a pipeline and flows upward inside the tower. The sulfuric acid liquid in the tower bottom is pumped into the upper part of the tower by the sulfuric acid scrubbing tower circulation pump 27 and flows downward inside the tower. The sulfuric acid scrubbing tower condenser 32 is connected in the middle to cool the sulfuric acid. The gas and liquid materials are fully mixed and contacted in the packing. The water mist in the HCl gas is absorbed by the sulfuric acid and enters the sulfuric acid scrubbing tower demister 34 at the top of the tower. The demister is filled with a regular corrugated packing made of high-purity PTFE. The sulfuric acid mist in the HCl is intercepted inside the demister and flows into the lower part of the sulfuric acid scrubbing tower 33 through the pipeline for reuse. Electronic grade hydrochloric acid product can be obtained at the outlet above the sulfuric acid scrubbing tower demister 34. The bottom of the sulfuric acid scrubbing tower 33 is connected to the sulfuric acid waste tank 23 via a pipeline. When the tower needs to be emptied, the sulfuric acid in the tower can be emptied by opening the sulfuric acid scrubbing tower vent valve 35. When there is excess sulfuric acid in the sulfuric acid scrubbing tower 33, it can overflow into the sulfuric acid waste tank 23 through the pipeline. A one-way valve 25 of the sulfuric acid scrubbing tower is installed on the pipeline to ensure that waste sulfuric acid and acid mist will not flow back.

[0031] Table 1 shows the detection results of HCl metal impurities before and after purification by this device. The HCl raw material used was HCl produced by the company's chlor-alkali industry. Two batches of samples were taken from each batch. The HCl metal impurity detection method was absorption-gravimetric method. After the HCl was absorbed by ultrapure water, it was weighed, and then the metal ions were detected by ICP-MS. The content of metal impurities in HCl could be obtained by weight conversion. It can be seen that the metal impurity content of the raw material HCl decreased significantly after water washing, and was basically below 100 ppt. In particular, arsenic, which is not easily removed by distillation, was reduced to below 10 ppt. After washing with electronic-grade sulfuric acid, the overall metal ion content was controlled below 10 ppt, achieving a good purification effect.

[0032] Table 1 Results of metal impurity detection in samples

[0033] The technical solutions of this invention have been explained through the above embodiments, but this invention is not limited to the above embodiments, that is, it does not mean that this invention must rely on the above specific embodiments to be implemented. Any improvements made by those skilled in the art based on this invention, or equivalent substitutions for the materials selected in this invention, fall within the protection scope of this patent.

Claims

1. An electronic-grade HCl purification system, characterized in that: It includes a first gas scrubbing tower system, a second gas scrubbing tower system, and a sulfuric acid gas scrubbing system connected in sequence by pipelines. The first and second gas scrubbing tower systems are mainly used to wash away most of the impurities in the raw material HCl, and the sulfuric acid gas scrubbing system is mainly used to remove moisture and impurities from HCl by washing with concentrated sulfuric acid. The first gas scrubbing tower system includes a feeding system, a gas scrubbing system and a waste acid system. The gas scrubbing system includes a first scrubbing tower (8) and a first scrubbing tower HCl demister (9), which are connected by a steel-lined PTFE pipe. The second gas scrubbing tower system includes a gas scrubbing system and an ultrapure water system. The gas scrubbing system includes a second scrubbing tower (14), a second scrubbing tower HCl demister (15), and a second scrubbing tower condenser (22), which are connected by steel-lined PTFE pipes. The sulfuric acid scrubbing tower system includes a sulfuric acid feed system, a scrubbing system, and a waste acid system. The scrubbing system includes a sulfuric acid scrubbing tower condenser (32), a sulfuric acid scrubbing tower (33), and a sulfuric acid scrubbing tower demister (34), which are connected by a steel-lined PTFE pipe.

2. The electronic-grade HCl purification system according to claim 1, characterized in that: The feeding system is equipped with an HCl raw material pneumatic regulating valve (2) and an HCl raw material flow meter (3), which are interlocked to ensure control of the HCl feed rate.

3. The electronic-grade HCl purification system according to claim 1, characterized in that: The hydrochloric acid in the first washing tower (8) is circulated from bottom to top by the first washing tower circulation pump (11), and the first washing tower vent valve (10) is installed at the bottom of the tower.

4. The electronic-grade HCl purification system according to claim 1, characterized in that: The waste acid system includes a hydrochloric acid waste tank (5) and a hydrochloric acid waste pump (6). A first scrubbing tower hydrochloric acid check valve (4) is installed above the hydrochloric acid waste tank (5) to prevent impurities in the waste hydrochloric acid from entering the scrubbing system.

5. The electronic-grade HCl purification system according to claim 1, characterized in that: The hydrochloric acid in the second washing tower (14) is circulated from bottom to top by the second washing tower circulation pump (17). The second washing tower (14) and the first washing tower (8) are connected by a steel-lined PTFE pipe. A second washing tower hydrochloric acid check valve (12) is installed on the pipe, and a second washing tower vent valve (16) is installed at the bottom of the tower.

6. The electronic-grade HCl purification system according to claim 5, characterized in that: The ultrapure water system includes an ultrapure water check valve (18), an ultrapure water pneumatic regulating valve (19), and an ultrapure water flow meter (20). The three are connected by a PVDF material pipe. The ultrapure water pneumatic regulating valve (19) and the ultrapure water flow meter (20) are interlocked to ensure control of the ultrapure water flow.

7. The electronic-grade HCl purification system according to claim 1, characterized in that: The sulfuric acid feeding system includes a sulfuric acid pneumatic regulating valve (28), a sulfuric acid flow meter (36), and a sulfuric acid check valve (29). The sulfuric acid pneumatic regulating valve (28) and the sulfuric acid flow meter (36) are interlocked to ensure control of the sulfuric acid flow.

8. The electronic-grade HCl purification system according to claim 1, characterized in that: Sulfuric acid in the sulfuric acid scrubbing tower (33) is circulated from bottom to top by the sulfuric acid scrubbing tower circulation pump (27), and a sulfuric acid scrubbing tower vent valve (35) is installed at the bottom of the tower.

9. The electronic-grade HCl purification system according to claim 1, characterized in that: The waste acid system includes a sulfuric acid waste acid tank (23) and a sulfuric acid waste acid pump (24). A one-way valve (25) for a sulfuric acid scrubbing tower is installed above the sulfuric acid waste acid tank (23) to prevent impurities in the waste acid from entering the scrubbing system.

10. A method for purifying electronic-grade HCl, characterized in that: The method employs an electronic-grade HCl purification system according to any one of claims 1-9, comprising the following steps: S1. Electronic grade sulfuric acid is introduced into the sulfuric acid scrubbing tower (33) until the overflow port (31) of the sulfuric acid scrubbing tower begins to overflow. Ultrapure water is introduced into the second scrubbing tower (14) at a certain flow rate until the overflow port (7) of the first scrubbing tower begins to overflow. Condensate is introduced into the condenser (22) of the second scrubbing tower and the condenser (32) of the sulfuric acid scrubbing tower. S2. Start the sulfuric acid scrubbing tower circulation pump (27), the first scrubbing tower circulation pump (11), and the second scrubbing tower circulation pump (17). S3. HCl raw material is introduced through HCl raw material inlet (1) at a certain flow rate. HCl gas is washed in the first scrubbing tower (8) and the second scrubbing tower (14) to remove most of the impurities. It is then removed by the first scrubbing tower HCl demister (9) and the second scrubbing tower HCl demister (15) to remove the hydrochloric acid mist carried by HCl. S4. The washed HCl gas passes through a sulfuric acid scrubbing tower (33) to remove water mist and impurities. After passing through a sulfuric acid scrubbing tower demister (34) to remove the sulfuric acid mist carried out, the HCl product is obtained.

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