A by-product hydrochloric acid dechlorination device

Abstract

The utility model discloses a byproduct hydrochloric acid dechlorination device, including stripping column and with stripping column cooperation uses reboiler, the downstream of stripping column is provided with cooler and intermediate storage tank in proper order, and the downstream connection dechlorination reactor and finished product storage tank of intermediate storage tank, be equipped with absorber between intermediate storage tank and dechlorination reactor. The utility model discloses through the cooperation use of stripping column and reboiler to byproduct hydrochloric acid stripping, and the volatilization removes a part of free chlorine, and the volatilization of a small amount of organic matter carbon tetrachloride dissolved in hydrochloric acid, then after the stripping of sodium sulfite solid and free chlorine are added in dechlorination reactor and react, remove free chlorine, therefore, the utility model discloses through above -mentioned device effectively removes organic matter and free chlorine and obtains colorless transparent finished product hydrochloric acid, and the slight reduction of hydrochloric acid from initial acidity 32 33% to acidity 31 32%. The dechlorination device can complete dechlorination and remove organic matter under the condition that the acidity of hydrochloric acid is guaranteed, and the device structure is simple, is worth the wide promotion.

Description

Technical Field

[0001] This utility model relates to the field of chemical production technology, specifically to a dechlorination device for by-product hydrochloric acid. Background Technology

[0002] Organic chlorination reactions are often perchlorination reactions, producing hydrogen chloride that carries unreacted chlorine gas. Direct absorption with water results in hydrochloric acid, a byproduct with excessive free chlorine content. Furthermore, the presence of trace amounts of organic carbon tetrachloride and free chlorine causes it to turn yellow. Therefore, dechlorination and removal of organic carbon tetrachloride from the byproduct hydrochloric acid are necessary.

[0003] In existing technologies, CN216963647U discloses a dechlorination device for by-product hydrochloric acid, which uses compressed air purging to remove free chlorine. However, this method also removes some hydrogen chloride along with the free chlorine, leading to a decrease in hydrochloric acid acidity. CN215427427U discloses a dechlorination device for removing free chlorine from waste hydrochloric acid, the core of which is activated carbon adsorption for free chlorine removal. Activated carbon has a limited adsorption capacity and cannot be used for industrial production with high free chlorine levels. Furthermore, desorption and regeneration after adsorption are difficult and generate a large amount of solid waste.

[0004] Therefore, the above-mentioned device may cause a decrease in the acidity of hydrochloric acid or generate a large amount of solid waste when dechlorinating the by-product hydrochloric acid. Utility Model Content

[0005] In view of the above-mentioned shortcomings of the existing technology, the purpose of this utility model is to provide a dechlorination device for by-product hydrochloric acid, which solves the problem that the dechlorination of by-product hydrochloric acid will lead to a decrease in hydrochloric acid acidity or the generation of a large amount of solid waste in the existing technology.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A dechlorination device for by-product hydrochloric acid includes a stripping tower and a reboiler used in conjunction with the stripping tower. A cooler and an intermediate storage tank are sequentially arranged downstream of the stripping tower. A dechlorination reactor and a finished product storage tank are connected downstream of the intermediate storage tank. An absorber is provided between the intermediate storage tank and the dechlorination reactor.

[0008] By employing the above structural design, a portion of the free chlorine in the by-product hydrochloric acid is stripped and volatilized through the combined use of a stripping tower and a reboiler. Simultaneously, a small amount of dissolved organic matter, carbon tetrachloride, is volatilized from the hydrochloric acid. Then, solid sodium sulfite is added to the stripped hydrochloric acid in a dechlorination reactor to react with and remove the free chlorine. Therefore, this invention effectively removes organic matter and free chlorine to obtain colorless and transparent finished hydrochloric acid. The acidity is slightly reduced from the initial 32-33% to 31-32%, meeting the standard. Furthermore, the dechlorination device has a simple structure and does not generate a large amount of solid waste during production.

[0009] Preferably, the top of the stripping tower is connected to an absorption unit to absorb the volatilized hydrogen chloride, and the absorption unit is connected inside the stripping tower to recover the hydrochloric acid produced by absorbing hydrogen chloride.

[0010] With the above structural design, after stripping, the volatilized hydrogen chloride gas is absorbed by water in the absorption unit to form hydrochloric acid, which is then recovered into the stripping tower, thereby reducing the loss of hydrochloric acid.

[0011] Preferably, the by-product hydrochloric acid is heated by steam in the reboiler at a temperature of 80-110°C.

[0012] Preferably, the dechlorination reactor has a sealed feed port at the top for adding sodium sulfite solid material, the top of the reactor is also connected to the absorber by a pipe, the top of the absorber is also connected to the intermediate storage tank by a pipe, and the lower end of the absorber is connected to the top of the intermediate storage tank for recovering reactants.

[0013] Using the above structural design, sodium sulfite solid is added to the dechlorination reactor to react with free chlorine and remove the free chlorine. At the same time, a small amount of sulfur dioxide will be generated in the dechlorination reactor. The sulfur dioxide is introduced into the absorber to react with the free chlorine in the hydrochloric acid in the intermediate storage tank to remove the sulfur dioxide.

[0014] Preferably, the top of the absorber is provided with a tail gas treatment device for treating the volatilized hydrogen chloride gas.

[0015] Preferably, the exhaust gas treatment device includes a water scrubbing tower and an alkaline scrubbing tower connected in series.

[0016] By adopting the above structural design, the volatilized hydrogen chloride gas is washed with water and alkali through water washing tower and alkali washing tower. This not only recovers hydrochloric acid, but also reduces the amount of alkali used and lowers the treatment cost.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] This invention utilizes a stripping tower and a reboiler to strip byproduct hydrochloric acid, volatilizing and removing a portion of free chlorine, while simultaneously volatilizing a small amount of dissolved organic matter, carbon tetrachloride. The stripped hydrochloric acid is then reacted with solid sodium sulfite in a dechlorination reactor to remove the free chlorine. Therefore, this invention effectively removes organic matter and free chlorine to obtain colorless and transparent finished hydrochloric acid, with the acidity slightly reduced from the initial 32-33% to 31-32%. This dechlorination device can complete dechlorination and removal of organic matter while maintaining the acidity of the hydrochloric acid, and its simple structure makes it worthy of widespread application. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of this utility model.

[0020] In the picture:

[0021] 1. Stripping tower; 2. Reboiler; 3. Cooler; 4. Intermediate storage tank; 5. Dechlorination reactor; 5. Sealed feed port; 5a. Agitator; 5b. Finished product storage tank; 6. Absorber; 7. Absorption unit; 8. Tail gas treatment device; 9. Detailed Implementation

[0022] To explain in detail the technical content, structural features, objectives and effects of this utility model, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0023] The technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model. In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0024] Please refer to 1, a dechlorination device for by-product hydrochloric acid, comprising a stripping tower 1 and a reboiler 2 used in conjunction with the stripping tower 1. The stripping tower 1 and the reboiler 2 are connected by a pipeline. The by-product hydrochloric acid is heated by steam in the reboiler 2 at a temperature of 80-110℃. After stripping through the stripping tower 1, some chlorine gas (free chlorine) and hydrogen chloride will volatilize, while the organic matter carbon tetrachloride in the hydrochloric acid will also volatilize. Downstream of the stripping tower 1, a cooler 3 and an intermediate storage tank 4 are sequentially arranged for cooling and intermediate storage of the stripped hydrochloric acid. Downstream of the intermediate storage tank 4, a dechlorination reactor 5 and a finished product storage tank 6 are connected. The hydrochloric acid in the intermediate storage tank 4 is injected into the dechlorination reactor 5 by a pump for dechlorination reaction. After the reaction is completed, the finished hydrochloric acid is collected into the finished product storage tank 6. The dechlorination reactor 5 and the finished product storage tank 6 are connected by a pipeline, and a pump can be installed on the pipeline to provide power. Alternatively, the dechlorination reactor 5 and the finished product storage tank 6 can be set at a certain height difference. An absorber 7 is provided between the intermediate storage tank 4 and the dechlorination reactor 5. The main function of the absorber 7 is to absorb the sulfur dioxide generated in the dechlorination reactor 5.

[0025] The top of the stripping tower 1 is connected to an absorption unit 8 to absorb the volatilized hydrogen chloride. The absorption unit 8 uses water to recover the hydrogen chloride gas, and it is also connected inside the stripping tower 1 to recover the hydrochloric acid produced during hydrogen chloride absorption, further ensuring the acidity of the hydrochloric acid. Since the hydrogen chloride volatilized after stripping is more soluble in water than chlorine and carbon tetrachloride, chlorine and carbon tetrachloride are separated and recovered after passing through the absorption unit 8.

[0026] Specifically, the dechlorination reactor 5 has a sealed feed port 5a at the top for adding sodium sulfite solid material. The amount of sodium sulfite added is 1.05-1.1 times the amount required for full reaction to ensure sufficient reaction of free chlorine. It needs to be added in small amounts multiple times, and stirred by a stirrer 5b to improve reaction efficiency. The reaction time is generally 1-3 hours, yielding colorless and transparent hydrochloric acid. The top of the reactor 5 is also connected to the absorber 7 via a pipe to send the sulfur dioxide gas escaping from the dechlorination reactor 5 into the absorber 7. Simultaneously, the top of the absorber 7 is also connected to the intermediate storage tank 4 via a pipe to send the stripped hydrochloric acid into the absorber 7. Since the hydrochloric acid in the intermediate storage tank 4 contains approximately 200-600 ppm of free chlorine, this free chlorine reacts with the escaping sulfur dioxide to produce sulfuric acid and hydrochloric acid. The sulfuric acid produced is in small quantities and does not affect product quality. The lower end of the absorber 7 is connected to the top of the intermediate storage tank 4 via a pipe.

[0027] Hydrochloric acid participates in the reaction within absorber 7, resulting in the volatilization of a small amount of hydrochloric acid. Therefore, a tail gas treatment device 9 is installed at the top of absorber 7 to treat the volatilized hydrogen chloride gas. The tail gas treatment device 9 includes a water scrubbing tower and an alkali scrubbing tower connected in series. The hydrogen chloride gas is washed with water in the water scrubbing tower, and then an acid-base neutralization reaction is carried out in the alkali scrubbing tower, which can reduce the amount of alkali used and lower the tail gas treatment cost.

[0028] The working principle of this utility model is as follows:

[0029] The byproduct hydrochloric acid enters stripping tower 1 and is heated in reboiler 2 at a controlled temperature of 80-110℃. During this process, stripping tower 1 vaporizes some chlorine, hydrogen chloride, and organic carbon tetrachloride. The volatile chlorine, hydrogen chloride, and organic carbon tetrachloride are then absorbed by absorption unit 8. Since hydrogen chloride is more soluble in water, it is absorbed and returned to stripping tower 1. At this point, chlorine and organic carbon tetrachloride are separated and recovered. This step effectively removes organic matter and some free chlorine. After the stripping process, the byproduct hydrochloric acid changes from an initial acidity of 32-33% and free chlorine of 0.1-0.2%, with a yellow color, to an acidity of 31.5-32% and free chlorine of 0.02-0.06%. After stripping, the material is cooled by cooler 3 and stored in intermediate storage tank 4. Then, it is pumped and metered by a flow meter into dechlorination reactor 5. Simultaneously, metered sodium sulfite solid material is added to dechlorination reactor 5, and the mixture is stirred by stirrer 5b for 1-3 hours. The resulting product is colorless and transparent hydrochloric acid. However, a small amount of sulfur dioxide gas is generated during the reaction. Therefore, the sulfur dioxide gas is introduced into absorber 7 to react with the free chlorine in the hydrochloric acid introduced into intermediate storage tank 4, removing and recovering it into intermediate storage tank 4. A small amount of hydrogen chloride gas is volatilized during the reaction in absorber 7; therefore, a tail gas treatment device 9 is installed above it for water washing and acid-base reaction. The hydrochloric acid obtained after the reaction in dechlorination reactor 5 in this invention has an acidity of 31-32% and contains no free chlorine. Therefore, the by-product hydrochloric acid dechlorination device of this application can effectively dechlorinate, ensure the acidity of the hydrochloric acid, and has a low cost, without generating other processed solid waste.

[0030] Based on the disclosure and teachings of the above specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, this utility model is not limited to the specific embodiments disclosed and described above, and some modifications and changes to this utility model should also fall within the protection scope of the claims of this utility model. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on this utility model.

Claims

1. A dechlorination device for by-product hydrochloric acid, characterized in that, It includes a stripping tower (1) and a reboiler (2) used in conjunction with the stripping tower (1). Downstream of the stripping tower (1), a cooler (3) and an intermediate storage tank (4) are arranged in sequence. Downstream of the intermediate storage tank (4), a dechlorination reactor (5) and a finished product storage tank (6) are connected. An absorber (7) is provided between the intermediate storage tank (4) and the dechlorination reactor (5).

2. The by-product hydrochloric acid dechlorination device as described in claim 1, characterized in that, The top of the stripping tower (1) is connected to an absorption unit (8) to absorb the volatilized hydrogen chloride, and the absorption unit (8) is connected to the stripping tower (1) to recover the hydrochloric acid produced by absorbing hydrogen chloride.

3. The by-product hydrochloric acid dechlorination device as described in claim 1, characterized in that, The by-product hydrochloric acid is heated by steam in the reboiler (2) at a temperature of 80-110°C.

4. The by-product hydrochloric acid dechlorination device as described in claim 1, characterized in that, The dechlorination reactor (5) is provided with a sealed feed port (5a) at the top for adding sodium sulfite solid material. The top of the reactor (5) is also provided with a pipe connected to the absorber (7). The top of the absorber (7) is also provided with a pipe connected to the intermediate storage tank (4). The lower end of the absorber (7) is provided with a pipe connected to the top of the intermediate storage tank (4) for recovering reactants.

5. The by-product hydrochloric acid dechlorination device as described in claim 4, characterized in that, The top of the absorber (7) is provided with a tail gas treatment device (9) for treating the volatilized hydrogen chloride gas.

6. The by-product hydrochloric acid dechlorination device as described in claim 5, characterized in that, The exhaust gas treatment device (9) includes a water washing tower and an alkaline washing tower connected in series.

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