A method and equipment for treating tail gas in chlorination production

Abstract

A method and equipment for treating tail gas in chlorination production, comprising the following steps: drying and filtering: drying and filtering the tail gas generated in the chlorination production; nitrogen separation: passing the tail gas after drying and filtering into an absorbent solution, using the absorbent solution as a solvent to absorb hydrogen chloride and chlorine to obtain a pre-distillation solution, and separating the nitrogen; primary distillation: passing the pre-distillation solution into a first distillation tower for primary distillation, separating the hydrogen chloride and chlorine in the pre-distillation solution to obtain hydrogen chloride gas and chlorine solution; hydrochloric acid preparation: passing the hydrogen chloride gas into an appropriate amount of pure water to obtain high-purity hydrochloric acid; absorbing the tail gas with an absorbent to obtain high-purity hydrochloric acid.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of fine chemical products, and specifically relates to a method and equipment for treating tail gas in chlorination production. Background Art

[0002] The tail gas from the chlorination production process such as chlorothalonil contains mixed tail gas such as hydrogen chloride, chlorine, nitrogen, etc. If it is directly discharged, it will cause great harm to the environment. In the existing technology, most of them are directly introduced into water to make the hydrogen chloride, chlorine, etc. in the tail gas directly dissolve in the water to obtain a hydrochloric acid solution with a low content, and the nitrogen is recycled or directly discharged to treat the tail gas; however, the hydrochloric acid solution obtained after treatment by this method has a low purity and cannot be directly used. Summary of the invention

[0003] In view of the above situation, in order to overcome the defects of the prior art, an embodiment of the present invention provides a method for treating tail gas in chlorination production, which at least solves some of the problems in the prior art.

[0004] The technical solution adopted by the present invention is as follows: A method for treating tail gas in chlorination production, comprising the following steps:

[0005] Drying and filtration: Drying and filtration of tail gas generated in chlorination production;

[0006] Nitrogen separation: The tail gas after drying and filtration is passed into the absorbent solution, and the absorbent solution is used as a solvent to absorb hydrogen chloride and chlorine to obtain a pre-distillation solution to separate the nitrogen;

[0007] Primary distillation: passing the pre-distillation solution into a first distillation tower for primary distillation, separating the hydrogen chloride and chlorine in the pre-distillation solution to obtain hydrogen chloride gas and chlorine solution;

[0008] Preparation of hydrochloric acid: Pass the hydrogen chloride gas into an appropriate amount of pure water to obtain high-purity hydrochloric acid.

[0009] In a further embodiment, a secondary distillation is further included: the chlorine solution in the primary distillation is passed into a second distillation tower for secondary distillation to obtain high-purity chlorine and an absorbent solution, and the absorbent solution is recovered for reuse.

[0010] In a further embodiment, the nitrogen obtained in the nitrogen separation is passed into a molecular sieve for adsorption and desorption treatment to obtain high-purity nitrogen and waste gas, the high-purity nitrogen is recovered and treated, and the waste gas is directly discharged.

[0011] In a further embodiment, the mass ratio of hydrogen chloride gas to pure water in the preparation of hydrochloric acid is 1:(1.8-2.7).

[0012] In a further embodiment, the hydrogen chloride gas used in the preparation of hydrochloric acid contains nitrogen. The nitrogen mixed in the hydrogen chloride gas can be separated by passing the hydrogen chloride gas into pure water, and the separated nitrogen can be recovered together with the nitrogen separated in the nitrogen separation process.

[0013] In a further embodiment, the absorbent solution is a mixture of one or more of methanol, ethanol, ethylene glycol, acetonitrile, glycerol, formic acid, and acetic acid.

[0014] In a further embodiment, the mass ratio of the absorbent solution to the tail gas is 1:(0.3-0.6).

[0015] On the other hand, the present invention also provides a treatment device for tail gas in chlorination production: comprising a filter dryer, an absorption tower, a molecular sieve, a first distillation tower, and a water absorption tower, wherein the filter dryer, the absorption tower, the first distillation tower, and the water absorption tower are connected in sequence, and the molecular sieve is connected to the absorption tower;

[0016] The filter dryer is used for filtering and drying the tail gas, and the tail gas after filtering and drying is passed into an absorption tower, in which an absorbent solution is arranged, and after the tail gas is absorbed by the absorption tower, a pre-distillation solution is passed into a first distillation tower, and the separated nitrogen is passed into a molecular sieve, and the molecular sieve is used for screening the nitrogen, and the first distillation tower is used for primary distillation, and the hydrogen chloride gas after the primary distillation is passed into a water absorption tower, in which pure water is arranged, and the water absorption tower absorbs the hydrogen chloride gas.

[0017] In a further embodiment, a second distillation tower is further included, wherein the second distillation tower is connected to the first distillation tower;

[0018] The bottom material of the first distillation tower is passed into the second distillation tower, and the second distillation tower is used for secondary distillation. After distillation in the second distillation tower, the top of the tower is chlorine gas, and the bottom material is a regenerated qualified absorbent solution, and the regenerated qualified absorbent solution is recycled.

[0019] Beneficial effects:

[0020] In the treatment method of the present invention, the tail gas is absorbed by an absorbent, and then the tail gas is subjected to adsorption and desorption treatment by a molecular sieve, so that the air present in the tail gas due to production can be removed to obtain high-purity nitrogen. The solution absorbed by the absorbent is distilled out of the high-purity hydrogen chloride gas through a distillation tower and then introduced into pure water to obtain high-purity hydrochloric acid.

[0021] Through the processing equipment of the present invention, the bottom material of the first distillation is subjected to a second distillation to separate the chlorine in the material, so that the material is regenerated into a qualified absorbent solution, and the absorbent solution can be recycled, thereby reducing the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of a flow chart of an embodiment of the present invention;

[0023] Figure 2 is a process flow chart of an embodiment of the present invention;

[0024] In the figure: 1-filter dryer; 2-absorption tower; 3-molecular sieve; 4-first distillation tower; 5-water absorption tower; 6-second distillation tower. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0026] The disclosure below provides many different embodiments or examples for implementing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numbers and / or reference letters in different examples. This repetition is for the purpose of simplicity and clarity, and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but a person of ordinary skill in the art may be aware of the application of other processes and / or the use of other materials.

[0027] The tail gas generated in the chlorination production contains a large amount of hydrogen chloride, chlorine, nitrogen, etc. In the prior art, the tail gas generated in the chlorination production is mostly treated by directly passing the tail gas into water, so that the hydrogen chloride, chlorine, etc. in the tail gas are directly dissolved in the water to obtain a hydrochloric acid solution with a low content, and the nitrogen is treated by recycling or directly discharging the tail gas; however, the hydrochloric acid solution obtained after treatment by this method has a low purity and cannot be directly used.

[0028] The embodiment of the present invention adopts an absorbent solution to absorb the tail gas, and then undergoes two distillation treatments to obtain high-purity hydrochloric acid, chlorine and regenerated qualified absorbent respectively; and the nitrogen is subjected to molecular sieve adsorption and desorption treatment, so that the air that may exist in the tail gas during production can be separated from the nitrogen, thereby obtaining nitrogen with higher purity.

[0029] like Figure 1 As shown, in order to solve the above problems, an embodiment of the present invention provides a method for treating tail gas in chlorination production, comprising the following steps:

[0030] Drying and filtration: Drying and filtration of tail gas generated in chlorination production;

[0031] Nitrogen separation: The tail gas after drying and filtration is passed into the absorbent solution, and the absorbent solution is used as a solvent to absorb hydrogen chloride and chlorine to obtain a pre-distillation solution to separate the nitrogen;

[0032] Primary distillation: passing the pre-distillation solution into a first distillation tower for primary distillation, separating the hydrogen chloride and chlorine in the pre-distillation solution to obtain hydrogen chloride gas and chlorine solution;

[0033] Preparation of hydrochloric acid: Pass the hydrogen chloride gas into an appropriate amount of pure water to obtain high-purity hydrochloric acid.

[0034] It should be noted that the absorbent solution can absorb the hydrogen chloride gas and chlorine gas in the tail gas, and in the subsequent distillation process, the absorbent solution will not undergo chemical reactions. After the hydrogen chloride gas and chlorine gas in the absorbent solution are removed by distillation, the physical and chemical properties of the absorbent solution will not change. After distillation, if the purity of the absorbent solution meets the requirements, it can be recycled again.

[0035] In a further implementation manner of this embodiment, a secondary distillation is further included: the chlorine solution in the primary distillation is passed into a second distillation tower for secondary distillation to obtain high-purity chlorine and an absorbent solution, and the absorbent solution is recovered for reuse.

[0036] In a further implementation of this embodiment, the nitrogen obtained in the nitrogen separation is passed into a molecular sieve for adsorption and desorption treatment to obtain high-purity nitrogen and waste gas, the high-purity nitrogen is recovered and treated, and the waste gas is directly discharged.

[0037] It should be noted that during the production process of chlorination production processes such as chlorothalonil, a small amount of air may be mixed in, so there may be some air in the exhaust gas. The air that may be contained in the nitrogen can be screened and removed by molecular sieves to obtain high-purity nitrogen. The air mixed in the nitrogen and the trace nitrogen that may be missed by the molecular sieve can be directly discharged, which will not cause harm to the environment and meets environmental protection standards.

[0038] In a further implementation of this embodiment, the mass ratio of hydrogen chloride gas to pure water in the preparation of hydrochloric acid is 1:(1.8-2.7).

[0039] It should be noted that the mass ratio of hydrogen chloride gas to pure water can ensure that all the hydrogen chloride gas is absorbed by the pure water and the concentration of hydrogen chloride meets the requirements, and the purity of the prepared high-purity hydrochloric acid is tested.

[0040] In a further implementation of this embodiment, the hydrogen chloride gas in the preparation of hydrochloric acid contains nitrogen. The nitrogen mixed in the hydrogen chloride gas can be separated by passing the hydrogen chloride gas into pure water, and the separated nitrogen can be recovered together with the nitrogen separated in the nitrogen separation.

[0041] It should be noted that: because a small amount of nitrogen will be absorbed in the absorbent solution, a small amount of nitrogen may exist in the hydrogen chloride gas during the primary distillation process. The nitrogen will be separated by passing the gas obtained at the top of the tower after the primary distillation into pure water, and the separated nitrogen will be recycled together with the nitrogen separated in the previous step.

[0042] In a further implementation of this embodiment, the absorbent solution is a mixture of one or more of methanol, ethanol, ethylene glycol, acetonitrile, glycerol, formic acid, and acetic acid.

[0043] In a further implementation of this embodiment, the mass ratio of the absorbent solution to the tail gas is 1:(0.3-0.6).

[0044] like Figure 2 The embodiment of the present invention also provides a treatment device for tail gas in chlorination production: comprising a filter dryer 1, an absorption tower 2, a molecular sieve 3, a first distillation tower 4, and a water absorption tower 5, wherein the filter dryer 1, the absorption tower 2, the first distillation tower 4, and the water absorption tower 5 are connected in sequence, and the molecular sieve 3 is connected to the absorption tower 2;

[0045] The filter dryer 1 is used for filtering and drying the tail gas, and the tail gas after filtering and drying is passed into the absorption tower 2, and the absorption tower 2 is provided with an absorbent solution. After the absorption tower 2 absorbs the tail gas, the pre-distillation solution is passed into the first distillation tower 4, and the separated nitrogen is passed into the molecular sieve 3, and the molecular sieve 3 is used for screening the nitrogen. The first distillation tower 4 is used for primary distillation, and the hydrogen chloride gas after the primary distillation is passed into the water absorption tower 5, and the water absorption tower 5 is provided with pure water. The water absorption tower 5 absorbs the hydrogen chloride gas.

[0046] In a further embodiment of this embodiment, a second distillation tower 6 is further included, and the second distillation tower 6 is connected to the first distillation tower 4;

[0047] The bottom material of the first distillation tower 4 is passed into the second distillation tower 6, and the second distillation tower 6 is used for secondary distillation. After distillation in the second distillation tower 6, the top of the tower is chlorine gas, and the bottom material is a regenerated qualified absorbent solution, which is recycled for reuse.

[0048] It should be noted that: first, the tail gas produced in the production is passed into the filter dryer 1 to filter and dry the tail gas, remove part of the particulate impurities and moisture in the tail gas, and pass the filtered and dried tail gas into the absorption tower 2. Before the tail gas is passed into the absorption tower 2, a correspondingly measured absorbent is passed into the absorption tower 2. The tail gas is passed into the absorption tower 2 to absorb the hydrogen chloride gas and nitrogen gas in the tail gas through the absorbent, and the nitrogen in the tail gas and the air component in the tail gas during the production are discharged through the exhaust pipe in the absorption tower 2;

[0049] The gas discharged from the exhaust pipe is filtered through the molecular sieve 3 to remove a small amount of air remaining in the nitrogen, the nitrogen is recycled, and the air and trace nitrogen are discharged as waste gas;

[0050] The solution in the absorption tower 2 is passed into the first distillation tower 4 for distillation, and hydrogen chloride gas containing a small amount of light components such as nitrogen is obtained at the top of the first distillation tower 4. The hydrogen chloride gas at the top is passed into the water absorption tower 5. Before passing into the water absorption tower 5, an appropriate amount of pure water is passed into the water absorption tower 5. The hydrogen chloride gas containing a small amount of light components such as nitrogen at the top of the first distillation tower 4 after distillation is absorbed by the pure water to obtain a high-purity hydrochloric acid solution;

[0051] The bottom solution of the first distillation tower 4 after distillation is passed into the second distillation tower 6 for secondary distillation. After the secondary distillation of the second distillation tower 6, a qualified chlorine product is obtained at the top of the tower, and the chlorine product is recycled; the bottom of the second distillation tower 6 after the secondary distillation obtains a regenerated qualified absorbent, which is recycled for reuse.

[0052] Example 1

[0053] 2009 kg of tail gas is passed into the filter dryer 1, and the tail gas is filtered and dried in the filter dryer 1 to remove part of the particulate impurities and moisture in the tail gas to obtain filtered and dried tail gas;

[0054] The filtered and dried tail gas is passed into an absorption tower 2 in which 1000 kg of absorbent has been stored to absorb the filtered and dried tail gas to obtain a mixed solution. The nitrogen and a small amount of air in the tail gas are discharged into the molecular sieve 3 through the discharge pipe of the absorption tower 2. The nitrogen and air are sieved by the molecular sieve 3, and the sieved air and trace nitrogen are emptied and processed, and the remaining nitrogen is recycled, wherein the emptied waste gas is 272 kg and the nitrogen is 1086 kg;

[0055] The mixed solution is introduced into the first distillation tower 4 for primary distillation, and hydrogen chloride gas containing a small amount of light components such as nitrogen is obtained at the top of the first distillation tower 4. The hydrogen chloride gas containing a small amount of light components such as nitrogen at the top is introduced into a water absorption tower 5 containing 1195 kg of pure water, and the hydrogen chloride is absorbed by the pure water to obtain 1732 kg of high-purity hydrochloric acid solution, and the high-purity hydrochloric acid solution is tested. The remaining nitrogen insoluble in pure water is recycled together with the nitrogen recycled by the absorption tower 2. It is determined that the nitrogen discharged from the water absorption tower 5 is 74 kg;

[0056] The material in the bottom of the first distillation tower 4 is passed into the second distillation tower 6 for secondary distillation, and 40 kg of chlorine is obtained at the top of the second distillation tower 6. The bottom of the second distillation tower 6 is the absorbent, and the purity of the absorbent is tested.

[0057] Example 2

[0058] The tail gas is passed into the filter dryer 1 at a rate of 2009 kg / h, and the tail gas is filtered and dried in the filter dryer 1 to remove part of the particulate impurities and moisture in the tail gas to obtain the filtered and dried tail gas;

[0059] The tail gas after filtration and drying is passed into an absorption tower 2 in which an absorbent has been stored to absorb the tail gas after filtration and drying to obtain a mixed solution, wherein the absorbent is passed into the absorption tower 2 at a speed of 1000 kg / h, and the absorption tower 2 passes the solution after absorbing the tail gas into the first distillation tower 4 at the same speed, and the nitrogen and a small amount of air in the tail gas are discharged into the molecular sieve 3 through the discharge pipe of the absorption tower 2, and the nitrogen and air are sieved by the molecular sieve 3, and the sieved air and trace nitrogen are emptied and processed, and the remaining nitrogen is recycled, wherein the exhaust gas rate of the molecular sieve 3 is 272 kg / h, and the nitrogen rate collected is 1086 kg / h;

[0060] The mixed solution is introduced into the first distillation tower 4 for primary distillation, and hydrogen chloride gas containing a small amount of light components such as nitrogen is obtained at the top of the first distillation tower 4. The hydrogen chloride gas containing a small amount of light components such as nitrogen at the top is introduced into the water absorption tower 5 added with pure water, wherein the flow rate of pure water in the water absorption tower 5 is 1195 kg / h, and the hydrogen chloride is absorbed by the pure water to obtain a high-purity hydrochloric acid solution of 1732 kg / h, and the high-purity hydrochloric acid solution is tested, and the remaining nitrogen insoluble in pure water is recycled together with the nitrogen recycled by the absorption tower 2. It is measured that the nitrogen rate discharged from the water absorption tower 5 is 74 kg / h;

[0061] The material in the bottom of the first distillation tower 4 is passed into the second distillation tower 6 for secondary distillation. The rate of obtaining chlorine gas at the top of the second distillation tower 6 is 40 kg / h. The bottom of the second distillation tower 6 is the absorbent, and the purity of the absorbent is tested.

[0062] Example 3

[0063] The tail gas is passed into the filter dryer 1 at a rate of 2009 kg / h, and the tail gas is filtered and dried in the filter dryer 1 to remove part of the particulate impurities and moisture in the tail gas to obtain the filtered and dried tail gas;

[0064] The tail gas after filtration and drying is passed into an absorption tower 2 in which an absorbent has been stored to absorb the tail gas after filtration and drying to obtain a mixed solution, wherein the absorbent is passed into the absorption tower 2 at a speed of 1200 kg / h, and the absorption tower 2 passes the solution after absorbing the tail gas into the first distillation tower 4 at the same speed, and the nitrogen and a small amount of air in the tail gas are discharged into the molecular sieve 3 through the discharge pipe of the absorption tower 2, and the nitrogen and air are sieved by the molecular sieve 3, and the sieved air and trace nitrogen are emptied for treatment, and the remaining nitrogen is recycled, wherein the exhaust gas rate of the molecular sieve 3 is 272 kg / h, and the nitrogen rate collected is 1086 kg / h;

[0065] The mixed solution is introduced into the first distillation tower 4 for primary distillation, and hydrogen chloride gas containing a small amount of light components such as nitrogen is obtained at the top of the first distillation tower 4. The hydrogen chloride gas containing a small amount of light components such as nitrogen at the top is introduced into the water absorption tower 5 added with pure water, wherein the flow rate of pure water in the water absorption tower 5 is 1195 kg / h, and the hydrogen chloride is absorbed by the pure water to obtain a high-purity hydrochloric acid solution of 1732 kg / h, and the high-purity hydrochloric acid solution is tested, and the remaining nitrogen insoluble in pure water is recycled together with the nitrogen recycled by the absorption tower. It is measured that the nitrogen rate discharged from the water absorption tower 5 is 74 kg / h;

[0066] The material in the bottom of the first distillation tower 4 is passed into the second distillation tower 6 for secondary distillation. The rate of obtaining chlorine gas at the top of the second distillation tower 6 is 40 kg / h. The bottom of the second distillation tower 6 is the absorbent, and the purity of the absorbent is tested.

[0067] The purity test results of the high-purity hydrochloric acid of Examples 1 to 3 are shown in Table 1 below:

[0068] Table 1

[0069]

[0070] It should be noted that: in the serial number of Table 1, 1 represents the measurement and analysis data of Example 1, 2 represents the measurement and analysis data of Example 2, and 3 represents the measurement and analysis data of Example 3. The measurement and analysis standards adopted are all in accordance with the national standard for detection and analysis except for the absorbent, and the purity of the absorbent is detected by liquid chromatography.

[0071] It can be seen from the above embodiments and Table 1 that the total acidity of the hydrochloric acid recovered by the present method and the free chlorine concentration in the hydrochloric acid solution exceed the requirements of the high-purity hydrochloric acid solution, and the absorbent has a high purity, so the absorbent can be well recovered and reused. The recovered chlorine has a high purity, which makes it more convenient to recycle the chlorine, greatly reducing the production cost.

[0072] The present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and the same effect as the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for treating tail gas in chlorination production, characterized in that: The following steps are involved: Drying and filtration: Drying and filtration of tail gas generated in chlorination production, the tail gas includes nitrogen, hydrogen chloride and chlorine; Nitrogen separation: the tail gas after drying and filtration is passed into an absorbent solution, and the absorbent solution is used as a solvent to absorb hydrogen chloride and chlorine to obtain a pre-distillation solution, and the nitrogen is separated. The nitrogen obtained in the nitrogen separation is passed into a molecular sieve for adsorption and desorption treatment to obtain high-purity nitrogen and waste gas. The high-purity nitrogen is recovered and the waste gas is directly discharged; Primary distillation: passing the pre-distillation solution into a first distillation tower for primary distillation, separating the hydrogen chloride and chlorine in the pre-distillation solution to obtain hydrogen chloride gas and chlorine solution; Passing the chlorine solution in the primary distillation into a second distillation tower for secondary distillation; Preparation of hydrochloric acid: Pass the hydrogen chloride gas into an appropriate amount of pure water to obtain high-purity hydrochloric acid.

2. The method for treating tail gas in chlorination production according to claim 1, characterized in that: After the secondary distillation, high-purity chlorine gas and absorbent solution are obtained, and the absorbent solution is recovered and reused.

3. The method for treating tail gas in chlorination production according to claim 1, characterized in that: The mass ratio of hydrogen chloride gas to pure water in the preparation of hydrochloric acid is 1:(1.8-2.7).

4. The method for treating tail gas in chlorination production according to claim 1, characterized in that: The hydrogen chloride gas in the preparation of hydrochloric acid contains nitrogen. The nitrogen mixed in the hydrogen chloride gas can be separated by passing the hydrogen chloride gas into pure water, and the separated nitrogen can be recovered together with the nitrogen separated in the nitrogen separation.

5. The method for treating tail gas in chlorination production according to claim 1, characterized in that: The absorbent solution is a mixture of one or more of methanol, ethanol, ethylene glycol, acetonitrile, glycerol, formic acid and acetic acid.

6. The method for treating tail gas in chlorination production according to claim 5, characterized in that: The mass ratio of the absorbent solution to the tail gas is 1:(0.3-0.6).

7. A treatment device for tail gas in chlorination production, characterized in that: It comprises a filter dryer, an absorption tower, a molecular sieve, a first distillation tower, and a water absorption tower, wherein the filter dryer, the absorption tower, the first distillation tower, and the water absorption tower are connected in sequence, and the molecular sieve is connected to the absorption tower; the filter dryer is used to filter and dry the tail gas, and the tail gas after the filtration and drying treatment is passed into the absorption tower, the absorption tower is provided with an absorbent solution, the absorption tower absorbs the tail gas and then passes the pre-distillation solution into the first distillation tower, and the separated nitrogen is passed into the molecular sieve, the molecular sieve is used to screen the nitrogen, the first distillation tower is used to perform a primary distillation, and the hydrogen chloride gas after the primary distillation is passed into the water absorption tower, the water absorption tower is provided with pure water, and the water absorption tower absorbs the hydrogen chloride gas; Also included is a second distillation tower, the second distillation tower is connected to the first distillation tower; The bottom material of the first distillation tower is passed into the second distillation tower, and the second distillation tower is used for secondary distillation. After distillation in the second distillation tower, the top of the tower is chlorine gas, and the bottom material is a regenerated qualified absorbent solution, and the regenerated qualified absorbent solution is recycled.

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