Chlorosulfonic acid tail gas treatment device

Abstract

The utility model discloses a chlorosulfonic acid tail gas treatment device and relates to the technical field of chemical chlorosulfonic acid production. The device comprises a falling film absorber, a diluted hydrochloric acid head tank, a first hydrochloric acid gas absorption tower, a second hydrochloric acid gas absorption tower, a third hydrochloric acid gas absorption tower, a fourth hydrochloric acid gas absorption tower, a fifth hydrochloric acid gas absorption tower and an electric demister, the lower parts of the hydrochloric acid gas first absorption tower, the hydrochloric acid gas second absorption tower, the hydrochloric acid gas third absorption tower, the hydrochloric acid gas fourth absorption tower and the hydrochloric acid gas fifth absorption tower are all communicated with eduction pipes, and the upper parts are all communicated with ingress pipes; the lead-out pipes are communicated with the corresponding lead-in pipes through circulating pumps; the ingress pipe communicated with the hydrochloric acid gas secondary absorption tower is communicated with a branch pipe; the branch pipe is communicated with the diluted hydrochloric acid head tank; the diluted hydrochloric acid head tank is communicated with the falling film absorber through a flow guide pipe. The chlorosulfonic acid tail gas treatment device has the beneficial effects that the content of residual sulfuric acid mist and hydrogen chloride gas in the chlorosulfonic acid tail gas can be obviously reduced, and the environmental pollution caused by the emission of the chlorosulfonic acid tail gas is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical chlorosulfonic acid production, in particular to a chlorosulfonic acid tail gas treatment device. Background Art

[0002] Among various chlorosulfonic acid production processes in China, the synthesis process of chlorosulfonic acid is basically controlled to be relatively stable, but the tail gas of chlorosulfonic acid is greatly affected by the production process, operation control, and instrumentation. The control of chlorosulfonic acid tail gas has always been a difficult problem in the industry. Poor tail gas control has a great impact on the recovery of sulfate in hydrochloric acid, and serious corrosion of related equipment for tail gas recovery. In addition, non-compliance with emission standards will cause serious environmental pollution. Therefore, there is an urgent need for a device that can effectively remove acid mist from chlorosulfonic acid tail gas. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a chlorosulfonic acid tail gas treatment device in view of the above-mentioned technical deficiencies, which can significantly reduce the content of residual sulfuric acid mist and hydrogen chloride gas in the chlorosulfonic acid tail gas and reduce the pollution to the environment caused by the emission of chlorosulfonic acid tail gas.

[0004] The technical solution adopted by the utility model is: to provide a chlorosulfonic acid tail gas treatment device, including a falling film absorber, a dilute hydrochloric acid high-level tank, a hydrochloric acid gas first absorption tower, a hydrochloric acid gas second absorption tower, a hydrochloric acid gas third absorption tower, a hydrochloric acid gas fourth absorption tower, a hydrochloric acid gas fifth absorption tower and an electric demister;

[0005] The hydrochloric acid gas absorption tower 1, hydrochloric acid gas absorption tower 2, hydrochloric acid gas absorption tower 3, hydrochloric acid gas absorption tower 4 and hydrochloric acid gas absorption tower 5 are all connected with an outlet pipe at the bottom and an inlet pipe at the top; the outlet pipe is connected with the corresponding inlet pipe through a circulation pump; the inlet pipe connected with the hydrochloric acid gas absorption tower 2 is connected with a branch pipe; the branch pipe is connected with the dilute hydrochloric acid high-level tank; the dilute hydrochloric acid high-level tank is connected with the falling film absorber through a guide pipe; the chlorosulfonic acid tail gas washed by the sulfuric acid gas washing tower enters the falling film absorber; the gas outlet of the falling film absorber It is connected with the hydrochloric acid gas first absorption tower through an exhaust pipe, and the liquid outlet of the falling film absorber is connected with the hydrochloric acid gas first absorption tower through a drain pipe; the hydrochloric acid gas first absorption tower, the hydrochloric acid gas second absorption tower, the hydrochloric acid gas third absorption tower, the hydrochloric acid gas fourth absorption tower, the hydrochloric acid gas fifth absorption tower and the electric precipitator are arranged in sequence and are connected in sequence through the tail gas conveying pipe; the hydrochloric acid gas fifth absorption tower is connected with a water injection pipe; the bottoms of the hydrochloric acid gas fifth absorption tower, the hydrochloric acid gas fourth absorption tower, the hydrochloric acid gas third absorption tower and the hydrochloric acid gas second absorption tower are connected in sequence through a liquid replenishment pipe; the electric precipitator is connected with a discharge port.

[0006] To further optimize the technical solution, the upper part of the dilute hydrochloric acid high-level tank of a chlorosulfonic acid tail gas treatment device is connected to the hydrochloric acid gas secondary absorption tower through a reflux pipe.

[0007] To further optimize the technical solution, a rotor flowmeter is installed on the guide pipe of a chlorosulfonic acid tail gas treatment device.

[0008] To further optimize the technical solution, a chlorosulfonic acid tail gas treatment device is provided with at least two falling film absorbers.

[0009] To further optimize the technical solution, the bottom of the hydrochloric acid gas absorption tower of a chlorosulfonic acid tail gas treatment device is connected to a hydrochloric acid intermediate tank through an acidity meter.

[0010] To further optimize the technical solution, a recovery pipe is connected to the electric demister of a chlorosulfonic acid tail gas treatment device; the recovery pipe is used to be connected to the sulfuric acid gas washing tower.

[0011] The beneficial effects of the utility model are:

[0012] 1. A branch pipe is connected to the inlet pipe connected to the hydrochloric acid gas secondary absorption tower. The branch pipe is connected to the dilute hydrochloric acid high-level tank. The dilute hydrochloric acid high-level tank is connected to the falling film absorber through a guide pipe. The chlorosulfonic acid tail gas washed by the sulfuric acid gas washing tower enters the falling film absorber. The dilute hydrochloric acid liquid with a certain concentration can be introduced into the dilute hydrochloric acid high-level tank through the branch pipe. The dilute hydrochloric acid is injected into the falling film absorber through the guide pipe and can be used as a washing liquid to wash the chlorosulfonic acid tail gas injected from the outside, so that part of the hydrogen chloride gas in the chlorosulfonic acid tail gas is absorbed by the washing liquid, thereby reducing the hydrogen chloride gas content in the tail gas.

[0013] 2. The washing liquid after the falling film absorber absorbs the hydrogen chloride gas and the unabsorbed hydrogen chloride gas can enter the hydrochloric acid gas first absorption tower, and the hydrochloric acid gas first absorption tower continues to absorb the hydrogen chloride gas in the chlorosulfonic acid tail gas; the hydrochloric acid gas first absorption tower, the hydrochloric acid gas second absorption tower, the hydrochloric acid gas third absorption tower, the hydrochloric acid gas fourth absorption tower, and the hydrochloric acid gas fifth absorption tower are arranged in sequence and connected in sequence through the tail gas conveying pipe, so that the hydrogen chloride gas in the chlorosulfonic acid tail gas is absorbed step by step, and the content of the hydrogen chloride gas is gradually reduced.

[0014] 3. A water injection pipe is connected to the hydrochloric acid gas five absorption tower, through which water can be added to the hydrochloric acid gas five absorption tower for use in absorbing hydrogen chloride gas; the bottoms of the hydrochloric acid gas five absorption tower, the hydrochloric acid gas four absorption tower, the hydrochloric acid gas three absorption tower and the hydrochloric acid gas two absorption tower are connected in sequence through a liquid replenishment pipe, so that the water added to the hydrochloric acid gas five absorption tower can gradually enter the hydrochloric acid gas five absorption tower, the hydrochloric acid gas four absorption tower, the hydrochloric acid gas three absorption tower and the hydrochloric acid gas two absorption tower, each forming a concentration gradient, thereby ensuring the step-by-step absorption effect of the hydrogen chloride gas in the tail gas.

[0015] 4. A strong electric field can be generated inside the electrostatic precipitator, producing a large number of positive and negative ions, which move in a directional manner in the electric field, capturing the acid mist in the exhaust gas onto the electrode plate, and then flowing out of the electrostatic precipitator under the action of gravity, thereby achieving the purpose of purifying the exhaust gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the utility model.

[0017] In the figure, 1. falling film absorber; 2. dilute hydrochloric acid high-level tank; 3. hydrochloric acid gas first absorption tower; 4. hydrochloric acid gas second absorption tower; 5. hydrochloric acid gas third absorption tower; 6. hydrochloric acid gas fourth absorption tower; 7. hydrochloric acid gas fifth absorption tower; 8. electrostatic demister; 9. outlet pipe; 10. inlet pipe; 11. circulation pump; 12. branch pipe; 13. guide pipe; 14. exhaust pipe; 15. drainage pipe; 16. tail gas conveying pipe; 17. water injection pipe; 18. liquid replenishment pipe; 19. discharge port; 20. reflux pipe; 21. rotor flowmeter; 22. acidity meter; 23. hydrochloric acid intermediate tank; 24. recovery pipe. DETAILED DESCRIPTION

[0018] The utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0019] like Figure 1 As shown, a chlorosulfonic acid tail gas treatment device includes a falling film absorber 1, a dilute hydrochloric acid high-level tank 2, a hydrochloric acid gas first absorption tower 3, a hydrochloric acid gas second absorption tower 4, a hydrochloric acid gas third absorption tower 5, a hydrochloric acid gas fourth absorption tower 6, a hydrochloric acid gas fifth absorption tower 7 and an electric demister 8;

[0020] The hydrochloric acid gas first absorption tower 3, the hydrochloric acid gas second absorption tower 4, the hydrochloric acid gas third absorption tower 5, the hydrochloric acid gas fourth absorption tower 6 and the hydrochloric acid gas fifth absorption tower 7 are all connected with an outlet pipe 9 at the bottom and an inlet pipe 10 at the top; the outlet pipe 9 is connected to the corresponding inlet pipe 10 through a circulating pump 11; the inlet pipe 10 connected to the hydrochloric acid gas second absorption tower 4 is connected with a branch pipe 12; the branch pipe 12 is connected to the dilute hydrochloric acid high-level tank 2; the dilute hydrochloric acid high-level tank 2 is connected to the falling film absorber 1 through a guide pipe 13; the chlorosulfonic acid tail gas washed by the sulfuric acid gas washing tower enters the falling film absorber 1; the gas outlet of the falling film absorber 1 It is connected with the hydrochloric acid gas first absorption tower 3 through the exhaust pipe 14, and the liquid outlet of the falling film absorber 1 is connected with the hydrochloric acid gas first absorption tower 3 through the drain pipe 15; the hydrochloric acid gas first absorption tower 3, the hydrochloric acid gas second absorption tower 4, the hydrochloric acid gas third absorption tower 5, the hydrochloric acid gas fourth absorption tower 6, the hydrochloric acid gas fifth absorption tower 7 and the electric precipitator 8 are arranged in sequence and are connected in sequence through the tail gas conveying pipe 16; the hydrochloric acid gas fifth absorption tower 7 is connected with a water injection pipe 17; the bottoms of the hydrochloric acid gas fifth absorption tower 7, the hydrochloric acid gas fourth absorption tower 6, the hydrochloric acid gas third absorption tower 5 and the hydrochloric acid gas second absorption tower 4 are connected in sequence through the liquid replenishment pipe 18; the electric precipitator 8 is connected with a discharge port 19.

[0021] The chlorosulfonic acid tail gas is first washed by an external sulfuric acid gas washing tower to remove most of the sulfuric acid mist, and then enters the falling film absorber 1. By reacting with the washing liquid inside the falling film absorber 1, part of the hydrogen chloride gas in the tail gas can be washed and absorbed by the washing liquid. The remaining tail gas enters the hydrochloric acid gas absorption tower 3 through the exhaust pipe 14, and the washing liquid after absorbing the hydrogen chloride gas also enters the hydrochloric acid gas absorption tower 3 through the drain pipe 15.

[0022] The hydrochloric acid gas first absorption tower 3, the hydrochloric acid gas second absorption tower 4, the hydrochloric acid gas third absorption tower 5, the hydrochloric acid gas fourth absorption tower 6 and the hydrochloric acid gas fifth absorption tower 7 are connected in sequence through the tail gas delivery pipe 16, and can constitute a tail gas recovery system of a five-tower series process. The hydrogen chloride gas in the chlorosulfonic acid tail gas is subjected to countercurrent contact reaction in the tower, so that the hydrogen chloride gas in the tail gas is absorbed by the hydrochloric acid gas first absorption tower 3, the hydrochloric acid gas second absorption tower 4, the hydrochloric acid gas third absorption tower 5, the hydrochloric acid gas fourth absorption tower 6 and the hydrochloric acid gas fifth absorption tower 7 in sequence, and the concentration gradually decreases. Of course, the absorption liquid in the hydrochloric acid gas first absorption tower 3 to the hydrochloric acid gas fifth absorption tower 7 will form dilute hydrochloric acid due to the absorption of hydrogen chloride gas, and because the absorption amount of hydrogen chloride gas decreases step by step, the concentration of dilute hydrochloric acid is gradually reduced from the hydrochloric acid gas first absorption tower 3 to the hydrochloric acid gas fifth absorption tower 7.

[0023] The water source of the absorption liquid in the hydrochloric acid gas first absorption tower 3, the hydrochloric acid gas second absorption tower 4, the hydrochloric acid gas third absorption tower 5, the hydrochloric acid gas fourth absorption tower 6 and the hydrochloric acid gas fifth absorption tower 7 is injected through the water injection pipe 17 connected to the hydrochloric acid gas fifth absorption tower 7. By injecting water (soft water can be used) into the hydrochloric acid gas fifth absorption tower 7 and combining the effect of the connection of the liquid replenishment pipe 18, the hydrochloric acid gas fifth absorption tower 7, the hydrochloric acid gas fourth absorption tower 6, the hydrochloric acid gas third absorption tower 5 and the hydrochloric acid gas second absorption tower 4 are replenished step by step, and each forms a concentration gradient to ensure the step-by-step absorption effect of the hydrogen chloride gas in the tail gas. Of course, since the absorption liquid in the hydrochloric acid gas first absorption tower 3 comes from the washing liquid flowing out of the falling film absorber 1, there is no need to inject water specifically.

[0024] The washing liquid in the dilute hydrochloric acid high-level tank 2 comes from the hydrochloric acid gas secondary absorption tower 4. The circulating pump 11 injects a part of the absorption liquid in the hydrochloric acid gas secondary absorption tower 4 into the dilute hydrochloric acid high-level tank 2 through the branch pipe 12. The reason why the washing liquid uses the absorption liquid in the hydrochloric acid gas secondary absorption tower 4 is that the hydrochloric acid concentration in the absorption liquid in the hydrochloric acid gas secondary absorption tower 4 is basically in the range of 10%-20%, which meets the concentration requirement of the washing liquid required in the falling film absorber 1.

[0025] The function of the circulation pump 11 is to suck the absorption liquid from the bottom of the tower, and then form a dynamic circulation in the tower, so that the liquid can fully contact and absorb the hydrogen chloride gas in the chlorosulfonic acid tail gas to achieve a better absorption effect. In addition, by adjusting the working flow of the circulation pump 11, the circulation speed of the absorption liquid in the tower can be controlled, thereby realizing precise control of the absorption speed.

[0026] After the chlorosulfonic acid tail gas passes through the falling film absorber 1, the hydrochloric acid gas first absorption tower 3, the hydrochloric acid gas second absorption tower 4, the hydrochloric acid gas third absorption tower 5, the hydrochloric acid gas fourth absorption tower 6 and the hydrochloric acid gas fifth absorption tower 7 for absorption and washing, the sulfuric acid mist and hydrogen chloride still remaining in the tail gas are already difficult to wash off, at this time, electricity can be sent to the middle pole line of the electric precipitator 8, a strong electric field is formed between the cathode and the anode, a large amount of positive and negative ions are generated, and the positive and negative ions are made to move in a directional manner under the action of the electric field force, thereby capturing the acid mist on the pole plate, when the charged ions release the electric charge on the pole plate, they can flow out of the electric precipitator 8 under the action of gravity, further achieving the purpose of removing the sulfuric acid mist and hydrogen chloride remaining in the chlorosulfonic acid gas, and improving the purification effect on the tail gas. The tail gas after successful purification can be discharged through the discharge port 19, which greatly reduces the pollution caused to the environment.

[0027] The electric demister 8 in the technical solution can adopt a multi-gear mode. If the acid mist value in the chlorosulfonic acid tail gas is low, the electric demister 8 can automatically adjust the gear number according to the voltage setting to control the tail gas emission. As an embodiment of the present application, the electric demister 8 is equipped with a power distribution cabinet and a control panel, and the voltage of the pole line in the electric demister 8 can be adjusted according to the content of acid mist and hydrogen chloride in the inlet gas of the electric demister 8 to ensure that the tail gas discharged from the discharge port 19 meets the standard.

[0028] When the electric precipitator 8 is used for the first time or before it is operated again after being parked for a long time, it should be sprayed first, firstly, to wash away the impurities attached to the internal pole wires of the electric precipitator 8, and secondly, to make the internal space of the electric precipitator 8 in a humid operating condition to achieve a better demisting effect.

[0029] The upper part of the dilute hydrochloric acid high-level tank 2 is connected to the hydrochloric acid gas secondary absorption tower 4 through the reflux pipe 20, so that after excessive injection of washing liquid, it can flow back to the hydrochloric acid gas secondary absorption tower 4 through the reflux pipe 20, ensuring that a stable liquid level is maintained in the dilute hydrochloric acid high-level tank 2.

[0030] A rotor flowmeter 21 is installed on the flow guide pipe 13, which can control the flow rate of the washing liquid when it is injected into the falling film absorber 1 from the dilute hydrochloric acid high-level tank 2 according to demand.

[0031] At least two falling film absorbers 1 are provided to ensure the absorption efficiency of the tail gas.

[0032] The bottom of the hydrochloric acid gas absorption tower 3 is connected to the hydrochloric acid intermediate tank 23 through the acidity meter 22. When treating the tail gas, the liquid level, acid concentration and temperature in each tower need to be strictly controlled according to the operating procedures. After the acid concentration of the hydrochloric acid gas absorption tower 3 reaches 30%-31%, it can be automatically extracted to the hydrochloric acid intermediate tank 23 through the acidity meter 22 to avoid the acid concentration or the washing liquid temperature being too high to affect the absorption effect, resulting in excessive sulfuric acid mist and hydrogen chloride content in the tail gas entering the electric precipitator 8, which exceeds the working range of the electric precipitator and cannot achieve a good treatment effect.

[0033] The electrostatic precipitator 8 is connected with a recovery pipe 24, which is used to be connected to a sulfuric acid gas washing tower. The acid liquid flowing out of the electrostatic precipitator 8 under the action of gravity can be connected to an external sulfuric acid gas washing tower for recovery and use, thereby improving utilization efficiency.

[0034] It is understood that the present invention is described by some embodiments, and those skilled in the art are aware that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A chlorosulfonic acid tail gas treatment device, characterized in that: It comprises a falling film absorber (1), a dilute hydrochloric acid high-level tank (2), a hydrochloric acid gas first absorption tower (3), a hydrochloric acid gas second absorption tower (4), a hydrochloric acid gas third absorption tower (5), a hydrochloric acid gas fourth absorption tower (6), a hydrochloric acid gas fifth absorption tower (7) and an electric demister (8); The hydrochloric acid gas first absorption tower (3), the hydrochloric acid gas second absorption tower (4), the hydrochloric acid gas third absorption tower (5), the hydrochloric acid gas fourth absorption tower (6) and the hydrochloric acid gas fifth absorption tower (7) are all connected to an outlet pipe (9) at the bottom and to an inlet pipe (10) at the top; the outlet pipe (9) is connected to the corresponding inlet pipe (10) via a circulation pump (11); the inlet pipe (10) connected to the hydrochloric acid gas second absorption tower (4) is connected to a branch pipe (12); the branch pipe (12) is connected to a dilute hydrochloric acid high-level tank (2); the dilute hydrochloric acid high-level tank (2) is connected to a falling film absorber (1) via a flow guide pipe (13); the chlorosulfonic acid tail gas washed by the sulfuric acid gas washing tower enters the falling film absorber (1); the gas outlet of the falling film absorber (1) is connected to the falling film absorber (1); The exhaust pipe (14) is connected to the hydrochloric acid gas first absorption tower (3), and the liquid outlet of the falling film absorber (1) is connected to the hydrochloric acid gas first absorption tower (3) through the discharge pipe (15); the hydrochloric acid gas first absorption tower (3), the hydrochloric acid gas second absorption tower (4), the hydrochloric acid gas third absorption tower (5), the hydrochloric acid gas fourth absorption tower (6), the hydrochloric acid gas fifth absorption tower (7) and the electric precipitator (8) are arranged in sequence and are connected in sequence through the tail gas conveying pipe (16); the hydrochloric acid gas fifth absorption tower (7) is connected to a water injection pipe (17); the bottoms of the hydrochloric acid gas fifth absorption tower (7), the hydrochloric acid gas fourth absorption tower (6), the hydrochloric acid gas third absorption tower (5) and the hydrochloric acid gas second absorption tower (4) are connected in sequence through a liquid replenishment pipe (18); and the electric precipitator (8) is connected to a discharge port (19).

2. A chlorosulfonic acid tail gas treatment device according to claim 1, characterized in that: The upper part of the dilute hydrochloric acid high-level tank (2) is connected to the hydrochloric acid gas secondary absorption tower (4) through a reflux pipe (20).

3. A chlorosulfonic acid tail gas treatment device according to claim 1, characterized in that: A rotor flowmeter (21) is installed on the flow guide pipe (13).

4. A chlorosulfonic acid tail gas treatment device according to claim 1, characterized in that: At least two falling film absorbers (1) are provided.

5. A chlorosulfonic acid tail gas treatment device according to claim 1, characterized in that: The bottom of the hydrochloric acid gas absorption tower (3) is connected to a hydrochloric acid intermediate tank (23) through an acidity meter (22).

6. A chlorosulfonic acid tail gas treatment device according to claim 1, characterized in that: The electric demister (8) is connected to a recovery pipe (24); the recovery pipe (24) is used to be connected to a sulfuric acid gas washing tower.

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