Waste chlorine gas absorption system

Abstract

The utility model relates to a waste chlorine absorption system and belongs to the technical field of environmental protection. The absorption system comprises a first-stage falling film absorption tower, a second-stage falling film absorption tower, a tail gas absorption tower, an alkali liquor storage tank and a sodium hypochlorite storage tank, and the first-stage falling film absorption tower, the second-stage falling film absorption tower and the tail gas absorption tower are respectively provided with a gas inlet, a gas outlet and an alkali liquor inlet; a gas outlet of the first-stage falling film absorption tower is communicated with a gas inlet of the second-stage falling film absorption tower through a pipeline, the bottom of the first-stage falling film absorption tower is communicated with the sodium hypochlorite storage tank through a pipeline, and the bottom of the second-stage falling film absorption tower is communicated with an alkali liquor inlet of the first-stage falling film absorption tower through a pipeline; and a gas outlet of the secondary falling film absorption tower is communicated with a gas inlet of the tail gas absorption tower through a pipeline. The treated waste chlorine tail gas can reach the emission standard, and the harm of chlorine leakage to the environment and human health is effectively reduced.

Description

Technical Field

[0001] The utility model relates to a waste chlorine absorption system, belonging to the technical field of environmental protection. Background Technique

[0002] Chlorine is a yellow-green strongly irritating gas and a strong oxidant. At high concentrations, it is easy to cause poisoning and safety accidents. At low concentrations, it is easy to cause chronic bronchitis, bronchial asthma or mild pulmonary edema. It is also easy to cause dental erosion, dermatitis and "chlorine acne", etc. The main hazards of chlorine are: ① Flammability and explosiveness: Chlorine does not burn, but can support combustion. It can form explosives when mixed with a variety of flammable gases, and can react violently with a variety of chemical substances; ② Corrosiveness: Chlorine has a corrosive effect on almost metals and non-metals at high temperatures and high humidity. Ordinary carbon steel is corroded by 80% of its original mass within 4 days in a fully chlorinated reaction environment with high temperature and high humidity; ③ High toxicity: After being inhaled, chlorine reacts with water in the human body to form hydrogen chloride and hypochlorous acid, thus producing high toxicity. According to the regulations in GBZ2-2002 "Occupational Exposure Limits for Hazardous Agents in the Workplace", the maximum allowable mass concentration (MAC) of chlorine in the workplace is 1mg / m 3 , which can be converted to a volume fraction of 0.3×10 –6 , when the chlorine mass concentration reaches 1mg / m 3 , it will cause irritation to the upper respiratory tract and eyes.

[0003] When packaging and overhauling and maintaining equipment for handling waste chlorine, a large amount of chlorine will enter the secondary absorption tower of the accident system. If the secondary absorption tower fails to absorb the excessive chlorine in time, it will cause chlorine leakage from the accident tower, posing a certain safety hazard. Chlorine has a relatively high density. When leaking, it mainly concentrates on the ground, forming toxic vapors that diffuse along the ground with the wind and will accumulate in low-lying areas or enclosed spaces, causing serious pollution to the environment. At present, when the absorption tower is handling the leaked chlorine, the absorption efficiency is not high, resulting in chlorine leakage from the absorption tower, posing a certain safety hazard. Content of the Utility Model

[0004] The purpose of the utility model is to provide a waste chlorine absorption system to solve the technical problems existing in the above-mentioned prior art.

[0005] The technical solution provided by the present utility model is as follows: A waste chlorine gas absorption system includes a primary falling film absorption tower, a secondary falling film absorption tower, a tail gas absorption tower, an alkali liquid storage tank, and a sodium hypochlorite storage tank. The primary falling film absorption tower, the secondary falling film absorption tower, and the tail gas absorption tower are all provided with a gas inlet, a gas outlet, and an alkali liquid inlet. The gas outlet of the primary falling film absorption tower is connected to the gas inlet of the secondary falling film absorption tower through a pipeline. The bottom of the primary falling film absorption tower is connected to the sodium hypochlorite storage tank through a pipeline. The bottom of the secondary falling film absorption tower is connected to the alkali liquid inlet of the primary falling film absorption tower through a pipeline. The gas outlet of the secondary falling film absorption tower is connected to the gas inlet of the tail gas absorption tower through a pipeline. The bottom of the tail gas absorption tower is connected to the alkali liquid inlet of the secondary falling film absorption tower through a pipeline. The alkali liquid inlet of the tail gas absorption tower is connected to the alkali liquid storage tank through a pipeline.

[0006] Based on the above technical solution, the present utility model can also be improved as follows:

[0007] Further, the gas inlets, gas outlets, and alkali liquid inlets of the primary falling film absorption tower and the secondary falling film absorption tower are respectively arranged at the top, bottom, and upper part of the primary falling film absorption tower and the secondary falling film absorption tower. The gas inlet, gas outlet, and alkali liquid inlet of the tail gas absorption tower are respectively arranged at the bottom, top, and upper part of the tail gas absorption tower.

[0008] Further, sprayers (11) are provided inside the primary falling film absorption tower (2), the secondary falling film absorption tower (3), and the tail gas absorption tower (4).

[0009] Further, liquid distributors (13) are also provided inside the primary falling film absorption tower (2) and the secondary falling film absorption tower (3), and a demister (10) and a gas distributor (12) are also provided inside the tail gas absorption tower (4).

[0010] Further, the demister is a roof-type demister.

[0011] Further, a vacuum pump is provided on the pipeline connecting the alkali liquid storage tank and the tail gas absorption tower.

[0012] Further, the primary falling film absorption tower and the secondary falling film absorption tower are both graphite falling film absorption towers.

[0013] Further, the alkali liquid in the alkali liquid storage tank is an aqueous sodium hydroxide solution with a mass fraction of 35 - 45%.

[0014] The technical solution provided by the present utility model has the following beneficial effects compared with the prior art:

[0015] The utility model adopts two-stage falling film absorption towers and one tail gas absorption tower. The falling film absorption towers are all graphite falling film absorption towers, which have the advantages of small mass transfer resistance, high absorption efficiency, high heat transfer efficiency, long equipment life, easy operation and maintenance, etc., and have great application prospects in the field of chlorine capture;

[0016] The gas distributor in the tail gas absorption tower of the utility model can make the bubbles disperse evenly, enhancing the gas-liquid mass transfer efficiency, and the roof type demister can reduce the liquid loss;

[0017] The content of chlorine gas in the waste gas discharged from the absorption system of the utility model can reach the emission standard, effectively reducing the emission of chlorine gas and reducing the harm caused by chlorine gas to the environment and human health. Description of the Drawings

[0018] Figure 1 It is a structural schematic diagram of the utility model.

[0019] In the figure, 2 is the primary falling film absorption tower; 3 is the secondary falling film absorption tower; 4 is the tail gas absorption tower; 5 is the lye storage tank; 6 is the vacuum pump; 8 is the sodium hypochlorite storage tank; 9 is the tail gas outlet; 10 is the demister; 11 is the sprayer; 12 is the gas distributor; 13 is the liquid distributor. Detailed Embodiment

[0020] The principles and features of the present utility model will be described below in conjunction with examples. The examples given are only for explaining the present utility model and are not intended to limit the scope of the present utility model.

[0021] Such as Figure 1As shown in the figure, a waste chlorine gas absorption system includes a primary falling film absorption tower 2, a secondary falling film absorption tower 3, a tail gas absorption tower 4, an alkali solution storage tank 5, and a sodium hypochlorite storage tank 8. The primary falling film absorption tower 2, the secondary falling film absorption tower 3, and the tail gas absorption tower 4 are each provided with a gas inlet, a gas outlet, and an alkali solution inlet. The gas outlet of the primary falling film absorption tower 2 is connected to the gas inlet of the secondary falling film absorption tower 3 through a pipeline. The bottom of the primary falling film absorption tower 2 is connected to the sodium hypochlorite storage tank 8 through a pipeline. The bottom of the secondary falling film absorption tower 3 is connected to the alkali solution inlet of the primary falling film absorption tower 2 through a pipeline. The gas outlet of the secondary falling film absorption tower 3 is connected to the gas inlet of the tail gas absorption tower 4 through a pipeline. The bottom of the tail gas absorption tower 4 is connected to the alkali solution inlet of the secondary falling film absorption tower 3 through a pipeline. The alkali solution inlet of the tail gas absorption tower 4 is connected to the alkali solution storage tank 5 through a pipeline, and a vacuum pump 6 is provided on the pipeline connecting the alkali solution storage tank 5 and the tail gas absorption tower 4. The gas inlets, gas outlets, and alkali solution inlets of the primary falling film absorption tower 2 and the secondary falling film absorption tower 3 are respectively arranged at the top, bottom, and upper part of the primary falling film absorption tower 2 and the secondary falling film absorption tower 3. The gas inlet, gas outlet, and alkali solution inlet of the tail gas absorption tower 4 are respectively arranged at the bottom, top, and upper part of the tail gas absorption tower 4. Inside the primary falling film absorption tower 2 and the secondary falling film absorption tower 3, sprayers 11 and liquid distributors 13 are provided from top to bottom. Inside the tail gas absorption tower 4, a ridge type demister, a sprayer 11, and a gas distributor 12 are arranged in sequence from top to bottom. The primary falling film absorption tower 2 and the secondary falling film absorption tower 3 are both graphite falling film absorption towers, and the alkali solution in the alkali solution storage tank 5 is a sodium hydroxide aqueous solution with a mass fraction of 40%.

[0022] When the waste chlorine gas is absorbed by the present utility model, the waste chlorine gas enters the first falling film absorption tower 2 through the top gas inlet of the first falling film absorption tower 2. At the same time, the sodium hypochlorite-containing alkaline solution from the bottom of the second falling film absorption tower 3 also enters the first falling film absorption tower 2 through the alkaline solution inlet of the first falling film absorption tower 2. Through the sprayer 11 of the first falling film absorption tower 2, it performs co-current absorption with the waste chlorine gas, and then through the liquid distributor 13 of the first falling film absorption tower 2, sodium hypochlorite is obtained. The sodium hypochlorite flows into the sodium hypochlorite storage tank 8 from the bottom of the first falling film absorption tower 2 for temporary storage or external sale; the waste chlorine gas not absorbed by the first falling film absorption tower 2 is transported to the inside of the second falling film absorption tower 3 through the gas outlet at the lower part of the first falling film absorption tower 2 through a pipeline connected to the top gas inlet of the second falling film absorption tower 3. At the same time, the sodium hypochlorite-containing alkaline solution from the bottom of the tail gas absorption tower 4 also enters the second falling film absorption tower 3 through the alkaline solution inlet of the second falling film absorption tower 3. Through the sprayer 11 of the second falling film absorption tower 3, it performs co-current absorption with the waste chlorine gas, and then through the liquid distributor 13 of the second falling film absorption tower 3, an alkaline solution containing hypochlorous acid is obtained, which is input into the first falling film absorption tower 2 through a pipeline connected to the alkaline solution inlet of the first falling film absorption tower 2 at the bottom of the second falling film absorption tower 3 as the chlorine absorption liquid of the first falling film absorption tower 2; the waste chlorine gas not absorbed by the second falling film absorption tower 3 is transported to the tail gas absorption tower 4 through a pipeline connected to the gas inlet at the lower part of the tail gas absorption tower 4 through the gas outlet at the lower part of the second falling film absorption tower 3. At the same time, the sodium hydroxide aqueous solution in the alkaline solution storage tank 5 is also transported into the tail gas absorption tower 4 through the vacuum pump 6 and then through the alkaline solution inlet at the upper part of the tail gas absorption tower 4. The sodium hydroxide aqueous solution is sprayed down through the demister 10 and the sprayer 11 of the tail gas absorption tower 4 to perform counter-current absorption with the waste chlorine gas, and an alkaline solution containing hypochlorous acid is obtained, which is input into the second falling film absorption tower 3 through a pipeline connected to the alkaline solution inlet of the second falling film absorption tower 3 at the bottom of the tail gas absorption tower 4 as the chlorine absorption liquid of the second falling film absorption tower 3. Finally, the tail gas of the waste chlorine gas after absorption is discharged from the tail gas outlet 9 at the top of the tail gas absorption tower 4.

[0023] The waste chlorine gas (chlorine concentration 40000 ppm) performs primary co-current absorption with the alkaline solution containing hypochlorous acid from the bottom of the second falling film absorption tower 3 at the top gas inlet of the first falling film absorption tower 2 to obtain a sodium hypochlorite product. The obtained sodium hypochlorite flows into the sodium hypochlorite storage tank 8 from the bottom of the first falling film absorption tower 2 for temporary storage or external sale; the waste chlorine gas absorbed by the first falling film absorption tower 2 enters the top of the second falling film absorption tower 3 to perform co-current absorption with the alkaline solution from the tail gas absorption tower 4. The generated alkaline solution containing sodium hypochlorite is used as the absorption liquid of the first falling film absorption tower 2. The unabsorbed waste chlorine gas enters the lower part of the tail gas absorption tower 4. The 40% by mass sodium hydroxide aqueous solution from the alkaline solution storage tank 5 is sprayed into the upper part of the tail gas absorption tower 4 for counter-current absorption. Finally, the chlorine content in the discharged tail gas is less than 50 ppm, meeting the standard for chlorine discharge.

[0024] The above are only the preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A waste chlorine gas absorption system, characterized in that, It includes a primary falling film absorption tower (2), a secondary falling film absorption tower (3), a tail gas absorption tower (4), an alkali solution storage tank (5), and a sodium hypochlorite storage tank (8). The primary falling film absorption tower (2), the secondary falling film absorption tower (3), and the tail gas absorption tower (4) are all provided with a gas inlet, a gas outlet, and an alkali solution inlet. The gas outlet of the primary falling film absorption tower (2) is connected to the gas inlet of the secondary falling film absorption tower (3) through a pipeline. The bottom of the primary falling film absorption tower (2) is connected to the sodium hypochlorite storage tank (8) through a pipeline. The bottom of the secondary falling film absorption tower (3) is connected to the alkali solution inlet of the primary falling film absorption tower (2) through a pipeline. The gas outlet of the secondary falling film absorption tower (3) is connected to the gas inlet of the tail gas absorption tower (4) through a pipeline. The bottom of the tail gas absorption tower (4) is connected to the alkali solution inlet of the secondary falling film absorption tower (3) through a pipeline. The alkali solution inlet of the tail gas absorption tower (4) is connected to the alkali solution storage tank (5) through a pipeline.

2. The chlorine waste gas absorption system according to claim 1, characterized in that, The gas inlets, gas outlets, and alkali solution inlets of the primary falling film absorption tower (2) and the secondary falling film absorption tower (3) are respectively arranged at the top, bottom, and upper part of the primary falling film absorption tower (2) and the secondary falling film absorption tower (3). The gas inlet, gas outlet, and alkali solution inlet of the tail gas absorption tower (4) are respectively arranged at the bottom, top, and upper part of the tail gas absorption tower (4).

3. The waste chlorine gas absorption system according to claim 1, wherein, Sprayers (11) are provided inside the primary falling film absorption tower (2), the secondary falling film absorption tower (3), and the tail gas absorption tower (4).

4. The waste chlorine gas absorption system according to claim 3, characterized in that, Liquid distributors (13) are further provided inside the primary falling film absorption tower (2) and the secondary falling film absorption tower (3). A demister (10) and a gas distributor (12) are further provided inside the tail gas absorption tower (4).

5. The waste chlorine gas absorption system according to claim 4, characterized in that, The demister (10) is a roof-type demister.

6. The waste chlorine gas absorption system according to claim 1, characterized in that A vacuum pump (6) is provided on the pipeline connecting the alkali solution storage tank (5) and the tail gas absorption tower (4).

7. The waste chlorine gas absorption system according to claim 1, characterized in that, Both the primary falling film absorption tower (2) and the secondary falling film absorption tower (3) are graphite falling film absorption towers.

8. The waste chlorine gas absorption system according to claim 1, wherein, The alkali solution in the alkali solution storage tank (5) is an aqueous sodium hydroxide solution with a mass fraction of 35 - 45%.

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