Lithium-electrode high-purity difluorochloroethane refining device

Abstract

The utility model relates to a lithium-electrode-grade high-purity difluorochloroethane refining device which is characterized in that the upper part in a degassing tower is connected with a gas inlet pipe, the top of the degassing tower is provided with a degassing condenser, the top of the degassing condenser is connected back to a difluorochloroethane coarse material gas hydrochloric acid absorber through a gas return pipe, and the gas return pipe is provided with a gas return valve and an online gas chromatograph; the bottom of the degassing tower is communicated with a degassing reboiler, the degassing reboiler is externally connected with a feeding pipe, the feeding pipe is sequentially provided with a feeding flowmeter and a feeding pump, the feeding pipe is connected with the lower portion of a rectifying tower, the lower portion of the rectifying tower is communicated with a rectifying reboiler, the top of the rectifying tower is connected with a rectifying condenser, and the lower portion of the rectifying condenser is divided into two paths. One path is a return pipe connected with the upper part of the rectifying tower, a return valve is arranged on the return pipe, the other path is a discharge pipe connected with the difluorochloroethane storage tank, and a discharge valve is arranged on the discharge pipe. The device is simple in structure, and can effectively consider refining purity, return gas recovery, exhaust control, energy conservation and cost reduction.

Description

Technical Field

[0001] This utility model relates to the purification technology of difluorochloroethane, specifically a lithium battery-grade high-purity difluorochloroethane purification device. Background Technology

[0002] Dichlorofluoroethane is mainly used to synthesize PVDF, the second largest producer of fluoroplastics. PVDF is primarily used in petrochemicals, electronics, and fluorocarbon coatings, where high purity is not a primary requirement. Since 2021, the rapid development of new energy sources such as lithium batteries and photovoltaics has led to a supply bottleneck for high-performance PVDF products. Specifically, in the lithium battery field, PVDF is mainly used as a cathode binder and separator coating, while in the photovoltaic field, it is primarily used in photovoltaic backsheets. Current mainstream refining technologies mainly involve secondary degassing and multiple distillations for purification, resulting in large overall equipment investment, high energy consumption, and unstable product purity. Summary of the Invention

[0003] This invention provides a lithium-ion battery-grade high-purity dichlorofluoroethane refining device that is simple in structure and effectively balances purification purity, gas recovery, exhaust control, energy saving, and cost reduction.

[0004] The technical solution adopted in this utility model is: a lithium-battery grade high-purity dichlorofluoroethane refining device, comprising a degassing tower and a distillation tower, characterized in that: an inlet pipe is connected to the upper or upper middle part of the degassing tower, a degassing condenser is installed at the top of the degassing tower, the top of the degassing condenser is connected to a dichlorofluoroethane crude gas hydrochloric acid absorber via a return gas pipe, a return gas valve is installed on the return gas pipe, an online gas chromatograph is externally connected to the return gas pipe between the return gas valve and the degassing condenser, and a degassing reboiler is connected to the bottom of the degassing tower, with the degassing reboiler externally connected to... A feed pipe is connected, on which a feed flow meter and a feed pump are installed in sequence. The feed pipe is connected to the lower part of the distillation column, which is connected to a distillation reboiler. The top of the distillation column is connected to a distillation condenser. The lower part of the distillation condenser has two branches: one is a return pipe connected to the upper part of the distillation column, which is equipped with a return valve; the other is a discharge pipe connected to the dichlorofluoroethane storage tank, which is equipped with a discharge valve. The online gas chromatograph, feed flow meter, feed pump, return valve, return valve, and discharge valve are all connected to a controller.

[0005] Flow meters are installed on the air inlet pipe, return pipe, and discharge pipe.

[0006] The online gas chromatograph is a Shandong Ruihong Sp7890pulls.

[0007] Each of the air return valve, material return valve, and material discharge valve is connected in parallel with a straight-through valve, which is connected to the controller.

[0008] The degassing reboiler and the distillation reboiler are steam reboilers.

[0009] The steam reboiler is equipped with a steam heating tube, which is connected to a steam inlet and outlet.

[0010] The lower part of the distillation condenser has two outlets via a U-shaped bend. The bottom of the U-shaped bend is connected to the discharge pipe, and the two branches are connected to the distillation condenser and the return pipe, respectively.

[0011] An exhaust pipe is connected to the top of the distillation column, and an exhaust valve is installed on the exhaust pipe. The exhaust valve is connected to a controller.

[0012] The beneficial effects of this invention are as follows: After being deacidified by a hydrochloric acid absorber and an alkaline scrubbing tower, the crude difluorochloroethane gas is sent to a degassing tower. Inside the degassing tower, it is heated by a degassing reboiler, and the light difluoroethane component is effectively separated by a degassing condenser and returned to the hydrochloric acid absorber for recovery via a return gas pipe. The heavier components, difluorochloroethane and difluorotrichloroethane, are sent to a distillation tower for rectification via a feed pipe in the degassing reboiler. An online gas chromatograph is installed on the return gas pipe to monitor the content of the light difluoroethane component collected from the top of the degassing tower in real time, in conjunction with the feed flow meter on the feed pipe and the opening of the return gas valve. Strict control of return gas ensures efficient degassing within the degassing tower, guaranteeing the purity of heavy components delivered through the feed pipe. After the heavy components are distilled, dichlorofluoroethane is collected in the distillation reboiler. The dichlorofluoroethane is then sent to the distillation condenser for condensation and returned to the distillation via the return pipe to improve distillation efficiency and purity. Once the distillation purity is met, it is collected by the discharge pipe to the dichlorofluoroethane storage tank. The overall structure is simple, and the equipment and process are streamlined, which helps to save energy and reduce costs. At the same time, the degassing control of return gas and the distillation condensation reflux purification effectively ensure the purification of dichlorofluoroethane. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of this utility model.

[0014] In the diagram: 1. Inlet pipe; 2. Degassing tower; 3. Degassing condenser; 4. Return pipe; 5. Dichlorofluoroethane crude gas hydrochloric acid absorber; 6. Return valve; 7. Online gas chromatograph; 8. Degassing reboiler; 9. Feed pipe; 10. Feed flow meter; 11. Feed pump; 12. Distillation tower; 13. Distillation reboiler; 14. Distillation condenser; 15. U-bend; 16. Return pipe; 17. Return valve; 18. Return flow meter; 19. Discharge pipe; 20. Discharge valve; 21. Dichlorofluoroethane storage tank; 22. Exhaust pipe; 23. Exhaust valve; 24. Detailed Implementation

[0015] The following description, in conjunction with the accompanying drawings and embodiments, provides further details.

[0016] Figure 1The image shows a lithium-ion battery grade high-purity dichlorofluoroethane refining apparatus, comprising an inlet pipe 1, a degassing tower 2, a degassing condenser 3, a return pipe 4, a return valve 6, an online gas chromatograph 7, a degassing reboiler 8, a feed pipe 9, a feed flow meter 10, a feed pump 11, a distillation tower 12, a distillation reboiler 13, a distillation condenser 14, a U-shaped bend 15, a return pipe 16, a return valve 17, a return flow meter 18, a discharge pipe 19, a discharge valve 20, a discharge flow meter 21, a dichlorofluoroethane storage tank 22, an exhaust pipe 23, and an exhaust valve 24. The upper or upper-middle part of the degassing tower 2 is connected to the inlet pipe 1, which is connected to the intermediate gas after acid and alkali washing of the crude difluorochloroethane. A degassing condenser 3 is installed at the top of the degassing tower 2. The top of the degassing condenser 3 is connected to the difluorochloroethane crude gas hydrochloric acid absorber 5 via the return gas pipe 4. A return gas valve 6 is installed on the return gas pipe 4. An online gas chromatograph 7 is connected to the return gas pipe 4 between the return gas valve 6 and the degassing condenser 3. A degassing reboiler 8 is connected to the bottom of the degassing tower 2. A feed pipe 9 is connected to the degassing reboiler 8. A feed flow meter 10 and a feed pump 11 are installed sequentially on the feed pipe 9. The feed pipe 9 is connected to the distillation column. The lower part of the distillation column 12 is connected to the distillation reboiler 13. The top of the distillation column 12 is connected to the distillation condenser 14. The lower part of the distillation condenser 14 is connected to two branches via a U-shaped bend 15. One branch is connected to the return pipe 16 at the top of the distillation column. The return pipe 16 is equipped with a return valve 17 and a return flow meter 18. The other branch is connected to the discharge pipe 19 at the bottom of the U-shaped bend 15 to the dichlorofluoroethane storage tank 22. The discharge pipe 19 is equipped with a discharge valve 20 and a discharge flow meter 21. The online gas chromatograph, feed flow meter, feed pump, valves and flow meters are all connected to the controller.

[0017] In this embodiment, the online gas chromatograph is a Shandong Ruihong Sp7890pulls.

[0018] In this embodiment, the degassing reboiler and the distillation reboiler are steam reboilers. The steam reboiler is equipped with a steam heating tube, which is connected to a steam inlet and outlet.

[0019] In this embodiment, an exhaust pipe 23 is connected to the top of the distillation column 12, and an exhaust valve 24 is installed on the exhaust pipe. The exhaust valve is connected to a controller.

Claims

1. A lithium-ion battery-grade high-purity dichlorofluoroethane refining apparatus, comprising a degassing column and a distillation column, characterized in that: The degassing tower is connected to an inlet pipe at its upper or upper-middle part. A degassing condenser is installed at the top of the degassing tower. The top of the degassing condenser is connected to the dichlorofluoroethane crude gas hydrochloric acid absorber via a return gas pipe. A return gas valve is installed on the return gas pipe. An online gas chromatograph is connected to the return gas pipe between the return gas valve and the degassing condenser. A degassing reboiler is connected to the bottom of the degassing tower. A feed pipe is connected to the degassing reboiler. A feed flow meter and a feed pump are installed sequentially on the feed pipe. The feed pipe is connected to the lower part of the distillation tower. A distillation reboiler is connected to the lower part of the distillation tower. A distillation condenser is connected to the top of the distillation tower. Two separate paths branch off from the lower part of the distillation condenser. One path is a return gas pipe connected to the upper part of the distillation tower, with a return gas valve installed on the return gas pipe. The other path is a discharge pipe connected to the dichlorofluoroethane storage tank, with a discharge valve installed on the discharge pipe. The online gas chromatograph, feed flow meter, feed pump, return gas valve, return gas valve, and discharge valve are all connected to a controller.

2. The lithium-ion grade high-purity dichlorofluoroethane refining apparatus according to claim 1, characterized in that: Flow meters are installed on the air inlet pipe, return pipe, and discharge pipe.

3. The lithium-ion grade high-purity dichlorofluoroethane refining apparatus according to claim 1, characterized in that: Each of the air return valve, material return valve, and material discharge valve is connected in parallel with a straight-through valve, which is connected to the controller.

4. The lithium-ion grade high-purity dichlorofluoroethane refining apparatus according to claim 1, characterized in that: The degassing reboiler and the distillation reboiler are steam reboilers.

5. The lithium-ion grade high-purity dichlorofluoroethane refining apparatus according to claim 4, characterized in that: The steam reboiler is equipped with a steam heating tube, which is connected to a steam inlet and outlet.

6. The lithium-ion grade high-purity dichlorofluoroethane refining apparatus according to claim 1, characterized in that: The lower part of the distillation condenser has two outlets via a U-shaped bend. The bottom of the U-shaped bend is connected to the discharge pipe, and the two branches are connected to the distillation condenser and the return pipe, respectively.

7. The lithium-ion grade high-purity dichlorofluoroethane refining apparatus according to claim 1, characterized in that: An exhaust pipe is connected to the top of the distillation column, and an exhaust valve is installed on the exhaust pipe. The exhaust valve is connected to a controller.

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