A device for removing dissolved chlorine from a solution

Abstract

The utility model discloses a device for removing dissolved chlorine in solution, which comprises a TMAC solution pipeline connected with the outlet of a dechlorination tower, a TMAH solution pipeline arranged on one side of the TMAC solution pipeline for adjusting the pH of the TMAC solution pipeline, a pipeline mixer inlet connected with the outlet of the TMAC solution pipeline, a main pipeline connected with the outlet of the pipeline mixer, a pH meter arranged on the main pipeline, a plurality of branch pipelines connected with the other end of the main pipeline, and an activated carbon adsorption tower arranged on each of the branch pipelines, and the plurality of branch pipelines are connected with a refined TMAC storage tank through a discharge pipeline.

Description

Technical Field

[0001] This utility model relates to the field of chlor-alkali chemical industry and chlorine-related electrolytic production technology, and in particular to a device for removing dissolved chlorine from a solution. Background Technology

[0002] In chlorine-related electrolytic processes, dechlorination towers typically use vacuum dechlorination to remove the dilute solution effluent from the electrolytic cell. However, this only removes most of the chloride ions; a small amount of free chlorine remains. This requires adjusting the solution pH to alkaline and then adding a reducing agent (such as sodium sulfite) for removal. However, in some electrolytic processes, such as the production of tetramethylammonium hydroxide (TMAH), the flow rate of the dechlorinated feedstock tetramethylammonium chloride (TMAC) is relatively low (approximately 0.1-0.2 m³ / s). 3 / h), resulting in an addition of approximately 0.001m of sodium sulfite. 3 If the amount added is below a certain level, excessive amounts will increase the sulfate ion content in the electrolytic raw material TMAC. Furthermore, the finished product TMAH requires the content of metal ions to be below 5 ppb. Sulfite will inevitably introduce new metal cations, seriously affecting product quality. If the amount added is insufficient, free chlorine cannot be completely removed, leading to the failure of the subsequent purification tower resin. Impurities such as metal ions will precipitate into the electrolyzer, affecting not only the operating status of the electrolyzer and the service life of the ion exchange membrane, but also the product quality. Summary of the Invention

[0003] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a device for removing dissolved chlorine from a solution, which can remove free chlorine from a dilute TMAC solution, reduce production costs, and improve process stability and product quality.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is: a device for removing dissolved chlorine from a solution, including a TMAC solution pipeline connected to the outlet of a dechlorination tower, a TMAH solution pipeline for adjusting its pH on one side of the TMAC solution pipeline, the outlet of the TMAC solution pipeline connected to the inlet of a pipeline mixer, the outlet of the pipeline mixer connected to one end of a main pipeline, a pH meter installed on the main pipeline, the other end of the main pipeline connected to multiple branch pipelines, each branch pipeline equipped with an activated carbon adsorption tower, and the multiple branch pipelines connected to a refined TMAC storage tank through a discharge pipeline.

[0005] Preferably, the TMAH solution pipeline is provided with a first check valve and a manual valve in sequence.

[0006] Preferably, a pneumatic control valve and a flow meter are sequentially installed on the TMAC solution pipeline.

[0007] Preferably, the other end of the main pipeline is connected to three branch pipelines, and the three branch pipelines are respectively equipped with a first activated carbon adsorption tower, a second activated carbon adsorption tower and a third activated carbon adsorption tower.

[0008] Preferably, a first connecting pipeline is provided between the outlet of the first activated carbon adsorption tower and the inlet of the second activated carbon adsorption tower, a second connecting pipeline is provided between the outlet of the second activated carbon adsorption tower and the inlet of the third activated carbon adsorption tower, and a third connecting pipeline is provided between the outlet of the third activated carbon adsorption tower and the first activated carbon adsorption tower.

[0009] Preferably, valves are installed at the inlet and outlet pipelines of the first, second, and third activated carbon adsorption towers.

[0010] Preferably, valves are provided at the locations of the first connecting pipeline, the second connecting pipeline, and the third connecting pipeline.

[0011] Preferably, the discharge pipeline is equipped with valves in the areas where the outlets of the second and third activated carbon adsorption towers are located.

[0012] Preferably, a second check valve is provided on the main pipeline.

[0013] Preferably, the pH meter is located in the area between the second check valve and the outlet of the pipeline mixer.

[0014] The beneficial effects of this utility model are as follows: This utility model adopts activated carbon adsorption without adding other chemical reducing agents, thus preventing other impurity ions from entering the system, which reduces production costs and improves process stability and product quality. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a device for removing dissolved chlorine from a solution. Detailed Implementation

[0016] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0017] like Figure 1 As shown, an apparatus for removing dissolved chlorine from a solution includes a TMAC solution pipeline 2 connected to the outlet of a dechlorination tower 1. A TMAC solution pipeline 3 for adjusting the pH of the TMAC solution pipeline 2 is provided on one side. The outlet of the TMAC solution pipeline 2 is connected to the inlet of a pipeline mixer 4. The outlet of the pipeline mixer 4 is connected to one end of a main pipeline 5. A pH meter 5.1 is installed on the main pipeline 5. The other end of the main pipeline 5 is connected to multiple branch pipelines. Each branch pipeline is equipped with an activated carbon adsorption tower. The multiple branch pipelines are connected to a purified TMAC storage tank 7 via a discharge pipeline 6.

[0018] Preferably, a first check valve 3.1 and a manual valve 3.2 are sequentially provided on the TMAH solution pipeline 3. In this embodiment, the first check valve 3.1 can prevent material backflow, and the manual valve 3.2 can adjust the flow rate of the TMAH solution pipeline 3, so that a certain amount of TMAH solution is added into the TMAC solution pipeline 2 for pH adjustment.

[0019] Preferably, a pneumatic control valve 2.1 and a flow meter 2.2 are sequentially installed on the TMAC solution pipeline 2.

[0020] Preferably, the other end of the main pipeline 5 is connected to three branch pipelines, and the three branch pipelines are respectively equipped with a first activated carbon adsorption tower 8, a second activated carbon adsorption tower 9 and a third activated carbon adsorption tower 10.

[0021] Preferably, a first connecting pipeline 11 is provided between the outlet of the first activated carbon adsorption tower 8 and the inlet of the second activated carbon adsorption tower 9, a second connecting pipeline 12 is provided between the outlet of the second activated carbon adsorption tower 9 and the inlet of the third activated carbon adsorption tower 10, and a third connecting pipeline 13 is provided between the outlet of the third activated carbon adsorption tower 10 and the first activated carbon adsorption tower 8.

[0022] Preferably, valves are provided at the inlet and outlet pipelines of the first activated carbon adsorption tower 8, the second activated carbon adsorption tower 9, and the third activated carbon adsorption tower 10.

[0023] Preferably, valves are provided at the locations of the first connecting pipeline 11, the second connecting pipeline 12, and the third connecting pipeline 13.

[0024] Preferably, the discharge pipeline 6 is equipped with valves in the area where the outlet of the second activated carbon adsorption tower 9 and the outlet of the third activated carbon adsorption tower 10 are located.

[0025] Preferably, a second check valve 14 is provided on the main pipeline 5.

[0026] Preferably, the pH meter 5.1 is located in the area between the second check valve 14 and the outlet of the pipeline mixer 4. In this embodiment, the second check valve 14 can prevent material backflow, and the pipeline mixer 4 is a container with an internal agitator.

[0027] In this embodiment, each time the three activated carbon adsorption towers are used, only two of them are turned on and put into use, while the other is kept as a backup.

[0028] For example, when the first activated carbon adsorption tower 8 and the second activated carbon adsorption tower 9 are put into use, the material enters the first activated carbon adsorption tower 8 from the main line 5 through the branch line, and then exits from the bottom outlet of the first activated carbon adsorption tower 8, enters the second activated carbon adsorption tower 9 through the first connecting line 11, and finally exits from the bottom outlet of the second activated carbon adsorption tower 9, and enters the refined TMAC storage tank 7 through the discharge line 6.

[0029] When the second activated carbon adsorption tower 9 and the third activated carbon adsorption tower 10 are put into use, the material enters the second activated carbon adsorption tower 9 from the main line 5 through the branch line, and then exits from the bottom outlet of the second activated carbon adsorption tower 9, and enters the third activated carbon adsorption tower 10 through the second connecting line 12. Finally, it exits from the bottom outlet of the third activated carbon adsorption tower 10 and enters the refined TMAC storage tank 7 through the discharge line 6.

[0030] When the third activated carbon adsorption tower 10 and the first activated carbon adsorption tower 8 are put into use, the material enters the third activated carbon adsorption tower 10 from the main pipeline 5 through the branch pipeline, and then exits from the bottom outlet of the third activated carbon adsorption tower 10. After exiting from the third activated carbon adsorption tower 10, it enters the first activated carbon adsorption tower 8 through the third connecting pipeline 13. Finally, after exiting from the bottom outlet of the first activated carbon adsorption tower 8, it enters the refined TMAC storage tank 7 through the discharge pipeline 6.

[0031] In the above process, when two of the activated carbon adsorption towers are in use, the other activated carbon adsorption tower is on standby, so the multiple valves involved are opened and closed as needed.

[0032] The working principle of this embodiment is as follows:

[0033] The dechlorinated, diluted TMAC solution from dechlorination tower 1 enters TMAC solution pipeline 2. Then, a certain amount of TMAH is introduced into TMAC solution pipeline 2 from TMAH solution pipeline 3. After mixing in pipeline mixer 4, the solution is adjusted to alkalinity (pH controlled between 9-13). During this process, the feed flow rate of pipeline mixer 4 is controlled by pneumatic control valve 2.1, while flow meter 2.2 monitors the flow rate in real time. The material exiting pipeline mixer 4 enters main pipeline 5, then enters the activated carbon adsorption tower through branch pipelines, and finally enters the refined TMAC storage tank 7 through discharge pipeline 6. In this embodiment, the concentration entering the activated carbon adsorption tower is controlled to approximately 35% and the flow rate to be 0.9-1 m³ / h by adjusting the corresponding valve opening and flow rate. 3 / h (raw material concentration is approximately 45%-50%).

[0034] During the activation process, activated carbon forms various functional groups on its surface. The interactions between these functional groups and chloride ions include van der Waals forces (or electrostatic attraction), a phenomenon known as physisorption. In the physisorption stage, the pores and capillaries on the surface and inside the activated carbon rapidly adsorb free chlorine from the solution. Furthermore, activated carbon can also react with free chlorine through chemisorption, a reaction that helps reduce the free chlorine content of water.

[0035] The reaction equation is as follows: HCIO + C* → CO* + Cl- + H+

[0036] Where C* represents activated carbon free radicals and CO* represents surface oxides.

[0037] In this embodiment, two of the three activated carbon towers operate in series, with one tower switched off for standby. Every hour, the outlet of the first tower is inspected to observe its color. If the solution is transparent, the activated carbon tower continues operation; conversely, if the outlet liquid is black or yellowish-green, it indicates excessive local reaction in the activated carbon tower, causing the activated carbon particles to become powdery, and the tower must be switched to standby immediately. Regeneration steps: 1. The switched-off, failed tower is regenerated at a pure water inlet flow rate of 1.5 m³ / h. 3 / h+31% high-purity acid 0.3m 3 1. Perform acid washing at a rate of / h, with the acid washing time controlled at 30 minutes. 2. Close the acid addition valve, maintain the pure water flow rate, and continue washing for 6-7 hours. Measure the outlet pH value. 3. The outlet pH should be neutral. 4. Close the pure water and activated carbon outlet valves, and use the regeneration tower as a backup tower to complete the entire activated carbon adsorption tower regeneration process.

[0038] The device in this embodiment does not use sodium sulfite to remove free chlorine, which reduces the consumption of sodium sulfite and avoids the need to add a denitrification device due to high sulfate content in the TMAC solution. Furthermore, the activated carbon tower regeneration process is simple, and the activated carbon is used for 3 months at a time. Based on the current operating load of the device, the regeneration cycle is about once a month, and each regeneration consumes about 0.17 tons of high-purity acid.

[0039] After one month of operation, data analysis was conducted on the activated carbon's performance. The results are as follows: The voltage of the ion-exchange membrane in the electrolytic cell remained stable at around 3.5V per cell with minimal fluctuations, and the overall cell voltage exhibited a normal fluctuation trend. The metal content in the product was within the controllable range of the process parameters. In summary, the data indicates that by changing the method of using activated carbon adsorption for dechlorination, free chlorine in the dechlorinated TMAC solution can be effectively removed. Simultaneously, it saves on reducing agent consumption, prevents the introduction of new anionic and cation impurities, improves the service life of the ion-exchange membrane in the electrolytic cell, and stabilizes the metal ion content in the TMAH product. This modification was successful.

[0040] The above embodiments are merely preferred technical solutions of this utility model and should not be considered as limitations on this utility model. The protection scope of this utility model should be the technical solution described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the protection scope of this utility model.

Claims

1. An apparatus for removing dissolved chlorine from a solution, comprising a TMAC solution pipeline (2) connected to the outlet of a dechlorination tower (1), characterized in that: The TMAC solution pipeline (2) is provided with a TMAH solution pipeline (3) for adjusting its pH on one side. The outlet of the TMAC solution pipeline (2) is connected to the inlet of the pipeline mixer (4). The outlet of the pipeline mixer (4) is connected to one end of the main pipeline (5). A pH meter (5.1) is provided on the main pipeline (5). The other end of the main pipeline (5) is connected to multiple branch pipelines. Each branch pipeline is equipped with an activated carbon adsorption tower. The multiple branch pipelines are connected to the refined TMAC storage tank (7) through the discharge pipeline (6).

2. The apparatus for removing dissolved chlorine from a solution according to claim 1, characterized in that: The TMAH solution pipeline (3) is equipped with a first check valve (3.1) and a manual valve (3.2) in sequence.

3. The apparatus for removing dissolved chlorine from a solution according to claim 1, characterized in that: The TMAC solution pipeline (2) is equipped with a pneumatic control valve (2.1) and a flow meter (2.2) in sequence.

4. The apparatus for removing dissolved chlorine from a solution according to claim 1, characterized in that: The other end of the main pipeline (5) is connected to three branch pipelines, and the three branch pipelines are respectively equipped with a first activated carbon adsorption tower (8), a second activated carbon adsorption tower (9) and a third activated carbon adsorption tower (10).

5. The apparatus for removing dissolved chlorine from a solution according to claim 4, characterized in that: A first connecting pipeline (11) is provided between the outlet of the first activated carbon adsorption tower (8) and the inlet of the second activated carbon adsorption tower (9), a second connecting pipeline (12) is provided between the outlet of the second activated carbon adsorption tower (9) and the inlet of the third activated carbon adsorption tower (10), and a third connecting pipeline (13) is provided between the outlet of the third activated carbon adsorption tower (10) and the first activated carbon adsorption tower (8).

6. The apparatus for removing dissolved chlorine from a solution according to claim 5, characterized in that: Valves are installed at the inlet and outlet pipelines of the first activated carbon adsorption tower (8), the second activated carbon adsorption tower (9), and the third activated carbon adsorption tower (10).

7. The apparatus for removing dissolved chlorine from a solution according to claim 6, characterized in that: Valves are provided at the locations of the first connecting pipeline (11), the second connecting pipeline (12), and the third connecting pipeline (13).

8. The apparatus for removing dissolved chlorine from a solution according to claim 7, characterized in that: The discharge pipeline (6) is equipped with valves in the area where the outlet of the second activated carbon adsorption tower (9) and the outlet of the third activated carbon adsorption tower (10) are located.

9. The apparatus for removing dissolved chlorine from a solution according to claim 1, characterized in that: A second check valve (14) is provided on the main pipeline (5).

10. The apparatus for removing dissolved chlorine from a solution according to claim 9, characterized in that: The pH meter (5.1) is located in the area between the second check valve (14) and the outlet of the pipeline mixer (4).

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