Tail gas treatment device for lithium hexafluorophosphate

Abstract

A gas inlet pipeline is arranged at the left lower end of a processing tank, a gas outlet pipeline is arranged at the upper end of the processing tank, the gas outlet pipeline is connected with a gas inlet of a condenser a through a compressor, a non-condensable gas outlet is formed in the right side of the upper end of the condenser a, and a condensate outlet is formed in the lower end of the condenser a. The condensate outlet is externally connected with a collecting tank; the left side of the light component removal tower is communicated with a collecting tank through a feeding hole, the lower part is communicated with a reboiler through a connecting hole, the upper part is connected with a reflux condenser through an exhaust pipeline, a hydrogen fluoride extraction pipeline is arranged below the reboiler, and a gas outlet of the reflux condenser is externally connected with a buffer tank; the pressurized distillation kettle comprises a kettle body and a kettle cover, a discharge pipeline is arranged below the kettle body, a material injection pipeline is arranged between the lower end of the left side surface and the buffer tank, a stirring paddle is rotationally arranged in the center of the kettle cover, a discharge pipeline and a pressurized pipeline are arranged on the right side of the upper end, and the stirring paddle is externally connected with a stirring motor; the utility model has the advantages of reasonable structural design and good use effect.

Description

Technical Field

[0001] The utility model belongs to the technical field of chemical tail gas purification, and particularly relates to a tail gas treatment device for lithium hexafluorophosphate. Background Art

[0002] Lithium hexafluorophosphate is an inorganic substance, which is soluble in water and also soluble in organic solvents such as low-concentration methanol, ethanol, acetone, and carbonate esters. It is the most important component of the electrolyte; as the electrolyte of lithium-ion batteries, lithium hexafluorophosphate is mainly used in lithium-ion power batteries, lithium-ion energy storage batteries, and other daily-use batteries. It is an irreplaceable lithium-ion battery electrolyte in the near and medium term. With the continuous boom of the lithium-ion battery industry, the output of lithium hexafluorophosphate products is getting higher and higher; however, a large amount of industrial waste gas is generated during the production of lithium hexafluorophosphate products, and its main components are phosphorus pentafluoride, hydrogen fluoride, and hydrogen chloride, which cause great harm to the environment. Coupled with the increasing attention and stricter requirements of the country for environmental protection, therefore, we need to treat the industrial tail gas before discharging it. However, the treatment of the tail gas of lithium hexafluorophosphate is difficult. At the same time, due to the high content of phosphorus pentafluoride, hydrogen fluoride, and hydrogen chloride in the tail gas, direct treatment will cause certain resource waste; therefore, in order to solve the problems of difficult tail gas treatment, large pollution, high treatment cost, and resource waste, we need to design a tail gas treatment device for lithium hexafluorophosphate with reasonable structure design and good use effect. Summary of the Utility Model

[0003] The purpose of the utility model is to overcome the deficiencies of the prior art and provide a tail gas treatment device for lithium hexafluorophosphate with reasonable structure design and good use effect.

[0004] The purpose of the present utility model is achieved as follows: An exhaust gas treatment device for lithium hexafluorophosphate includes a gas pretreatment system, a hydrogen fluoride purification device, and a pressurized distillation kettle. The gas pretreatment system includes a processing tank and a condenser a. The processing tank is generally cylindrical, with a bracket fixedly provided below it. The lower end of the left side is connected to an intake pipe, and the middle of the upper surface is connected to an outlet pipe. A gas flow meter and a solenoid valve are provided on the intake pipe. The outlet pipe is connected to the intake port of the condenser a through a compressor. The right side of the upper end of the condenser a is provided with a non-condensable gas outlet, and the lower end is provided with a condensate outlet. The condensate outlet is externally connected to a collection tank. The hydrogen fluoride purification device includes a de-lighting tower and a reboiler. Packing and grid plates are provided at both the upper and lower ends inside the de-lighting tower. The middle of the left side is provided with a feed port, the lower part is provided with a connection port, and the upper part is provided with an exhaust pipe. The feed port is interconnected with the collection tank, the connection port is interconnected with the reboiler, and the lower part of the reboiler is externally connected to a storage tank through a hydrogen fluoride extraction pipe. The exhaust pipe is externally connected to a reflux condenser, and the gas outlet of the reflux condenser and the non-condensable gas outlet of the condenser a are both externally connected to a buffer tank through a gas guide pipe. The pressurized distillation kettle includes a kettle body and a kettle cover. A jacket is provided on the outer surface of the kettle body, a discharge pipe is provided below it, and a feeding pipe is provided at the lower end of the left side. The feeding pipe is interconnected with the upper end of the buffer tank. A stirring paddle is rotatably provided at the center of the upper end of the kettle cover, and a discharge pipe and a pressurizing pipe are provided on the right side of the upper end. The upper end of the stirring paddle is externally connected to a stirring motor, and the lower end is located inside the kettle body. The discharge pipe is externally connected to a connection absorption device, and a phosphorus pentafluoride measuring device is installed on the discharge pipe. The pressurizing pipe is externally connected to a pressurizing device.

[0005] Further, the processing tank is made of stainless steel material or steel lined with tetrafluoro material.

[0006] Further, a gas pressure gauge and a control valve are installed on the connecting pipe between the compressor and the intake port of the condenser a.

[0007] Further, a hydrogen fluoride content measuring device is installed on the hydrogen fluoride extraction pipe.

[0008] Further, a thermometer, a radar level gauge, and a pressure gauge are sequentially installed on the left side of the upper end of the kettle cover.

[0009] Advantages of the present utility model: By providing a processing tank, a compressor and a condenser a, the present utility model can separate crude hydrogen fluoride and other incondensable gases according to the different boiling points of gases during use. By providing a de-light tower, the purification treatment of crude hydrogen fluoride can be completed by using the de-light tower, which is convenient for its continuous use in the production of lithium hexafluorophosphate. By providing a kettle body, a kettle cover, a stirring motor, a stirring paddle and a pressurizing pipeline, with this structure, after the mixed gas of phosphorus pentafluoride and hydrogen chloride is injected into the kettle body, the pressurizing and distilling effect of the pressurizing distillation kettle can be used to liquefy hydrogen chloride gas and keep phosphorus pentafluoride gas in a gas state, so as to realize the separation operation of hydrogen chloride gas and phosphorus pentafluoride gas. Generally, the present utility model has the advantages of reasonable structural design and good use effect. Brief Description of the Drawings

[0010] Figure 1 is a schematic structural diagram of the present utility model.

[0011] Figure 2 is a sectional view of the front view of the pressurizing distillation kettle in the present utility model.

[0012] In the figure: 1. Gas pretreatment system 11. Processing tank 12. Condenser a 13. Support 14. Intake pipeline 15. Outlet pipeline 16. Compressor 17. Incondensable gas outlet 18. Condensate outlet 2. Hydrogen fluoride purification device 21. De-light tower 22. Reboiler 23. Feed inlet 24. Connection port 25. Exhaust pipeline 26. Hydrogen fluoride extraction pipeline 27. Reflux condenser 28. Buffer tank 3. Pressurizing distillation kettle 31. Kettle body 32. Kettle cover 33. Discharge pipeline 34. Injection pipeline 35. Stirring paddle 36. Discharge pipeline 37. Pressurizing pipeline 4. Collection tank. Specific Embodiments

[0013] The following further describes the present utility model with reference to the drawings.

[0014] Embodiment: As Figure 1 , Figure 2As shown in the figure, a tail gas treatment device for lithium hexafluorophosphate includes a gas pretreatment system 1, a hydrogen fluoride purification device 2, and a pressurized distillation kettle 3. The gas pretreatment system 1 includes a processing tank 11 and a condenser a12. The processing tank 11 is integrally cylindrical, with a support 13 fixedly provided below it. The lower end of the left side is connected to an intake pipe 14, and the middle of the upper surface is connected to an outlet pipe 15. A gas flow meter and a solenoid valve are provided on the intake pipe 14. The outlet pipe 15 is connected to the intake port of the condenser a12 through a compressor 16. An incondensable gas outlet 17 is provided on the right side of the upper end of the condenser a12, and a condensate outlet 18 is provided at the lower end. The condensate outlet 18 is externally connected to a collection tank 4. The hydrogen fluoride purification device 2 includes a de-light tower 21 and a reboiler 22. Packing and grid plates are provided at both the upper and lower ends inside the de-light tower 21. A feed inlet 23 is provided in the middle of the left side, a connection port 24 is provided below, and an exhaust passage 25 is provided above. The feed inlet 23 is interconnected with the collection tank 4. The connection port 24 is interconnected with the reboiler 22, and the lower part of the reboiler 22 is externally connected to a storage tank through a hydrogen fluoride extraction pipe 26. The exhaust passage 25 is externally connected to a reflux condenser 27, and the gas outlet of the reflux condenser 27 and the incondensable gas outlet 17 of the condenser a12 are both externally connected to a buffer tank 28 through a gas pipe. The pressurized distillation kettle 3 includes a kettle body 31 and a kettle cover 32. A jacket is provided on the outer surface of the kettle body 31, a discharge pipe 33 is provided below, and a charging pipe 34 is provided at the lower end of the left side. The charging pipe 34 is interconnected with the upper end of the buffer tank 28. A stirring paddle 35 is rotatably provided at the center of the upper end of the kettle cover 32, and a discharge pipe 36 and a pressurizing pipe 37 are provided on the right side of the upper end. The upper end of the stirring paddle 35 is externally connected to a stirring motor, and the lower end is located inside the kettle body 31. The discharge pipe 36 is externally connected to a connection absorption device, and a phosphorus pentafluoride measuring device is installed on the discharge pipe 36. The pressurizing pipe 37 is externally connected to a pressurizing device.

[0015] The processing tank 11 is made of stainless steel material or steel lined with tetrafluoro material; a gas pressure gauge and a control valve are installed on the connecting pipe between the compressor 16 and the intake port of the condenser a12; a hydrogen fluoride content measuring device is installed on the hydrogen fluoride extraction pipe 26; a thermometer, a radar level gauge, and a pressure gauge are sequentially installed on the left side of the upper end of the kettle cover 32.

[0016] When the utility model is in use, first, the tail gas generated in the production process of lithium hexafluorophosphate is injected into the interior of the processing tank 11 through the air inlet pipe 14. After that, under the action of the compressor 16, the mixed tail gas is compressed and then injected into the interior of the condenser a12 through the air inlet. At this time, taking advantage of the different boiling points of gases, the mixed tail gas is separated inside the condenser a12. Among them, the crude hydrogen fluoride enters the collection tank 4 through the condensate outlet 18, and other non-condensable gases are injected into the buffer tank 28 through the non-condensable gas outlet 17. Then, the crude hydrogen fluoride entering the interior of the collection tank 4 can be added into the interior of the light component removal tower 21 through the feed inlet 23, and the light component removal tower 21 is used to purify the crude hydrogen fluoride. Finally, the purified hydrogen fluoride can pass through the connection port 24 and, after being processed again by the reboiler 22, is injected into the storage tank through the hydrogen fluoride extraction pipe 26 for storage and subsequent reuse in the production of lithium hexafluorophosphate. The other small amounts of gases generated during the purification process are injected into the reflux condenser 27 through the exhaust pipe 25 and are separated again under the condensation action of the reflux condenser 27. Among them, the liquid enters the interior of the light component removal tower 21 again through the liquid channel, and the non-condensable gas is injected into the interior of the buffer tank 28 through the gas phase channel. After the above operations are completed, the non-condensable gas entering the interior of the buffer tank 28 can enter the pressurized distillation kettle 3 through the injection pipe 34. At this time, by using the method of pressurized low-temperature distillation, the hydrogen chloride gas in the non-condensable gas can be liquefied, and the phosphorus pentafluoride gas remains gasified, thus realizing the separation operation of hydrogen chloride gas and phosphorus pentafluoride gas. Finally, the liquefied hydrogen chloride can flow out through the discharging pipe 33 and be stored for standby, and the phosphorus pentafluoride gas enters the absorption device through the discharge channel 36 for absorption and purification treatment; with this structure, the utility model can process the tail gas generated during the production of lithium hexafluorophosphate, thereby separating and recovering hydrogen fluoride, phosphorus pentafluoride, and hydrogen chloride in the tail gas, improving the tail gas treatment effect and treatment convenience, and also avoiding waste of resources through recycling; generally, the utility model has the advantages of reasonable structural design and good use effect.

[0017] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that it is still possible to modify the specific implementation manners of the present invention or make equivalent replacements. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall be covered by the scope of the claims of the present invention.

Claims

1. A tail gas treatment device for lithium hexafluorophosphate, comprising a gas pretreatment system (1), a hydrogen fluoride purification device (2) and a pressurized distillation kettle (3), characterized in that: The gas pretreatment system (1) comprises a processing tank (11) and a condenser a (12); the processing tank (11) is cylindrical in shape as a whole, a bracket (13) is fixedly provided below the processing tank (11), the lower end of the left side surface is connected to an air inlet pipe (14), and the middle part of the upper surface is connected to an air outlet pipe (15), a gas flow meter and a solenoid valve are provided on the air inlet pipe (14), the air outlet pipe (15) is connected to the air inlet of the condenser a (12) through a compressor (16), a non-condensable gas outlet (17) is provided on the right side of the upper end of the condenser a (12), and a condensate outlet (18) is provided at the lower end, and the condensate outlet (18) is externally connected to a collection tank (4); The hydrogen fluoride purification device (2) comprises a light-removal tower (21) and a reboiler (22), wherein the upper and lower ends of the light-removal tower (21) are both provided with fillers and grid plates, a feed port (23) is provided in the middle of the left side, a connection port (24) is provided at the bottom, and an exhaust channel (25) is provided at the top, the feed port (23) and the collecting tank (4) are communicated with each other, the connection port (24) and the reboiler (22) are communicated with each other, and the bottom of the reboiler (22) is connected to an external storage tank through a hydrogen fluoride extraction pipeline (26), the exhaust channel (25) is externally connected to a reflux condenser (27), and the gas outlet of the reflux condenser (27) and the non-condensable gas outlet (17) of the condenser a (12) are both externally connected to a buffer tank (28) through an air guide pipe; The pressurized distillation kettle (3) comprises a kettle body (31) and a kettle cover (32). The outer surface of the kettle body (31) is provided with an interlayer, a discharge pipe (33) is provided below, and an injection pipe (34) is provided at the lower end of the left side surface, and the injection pipe (34) is communicated with the upper end of the buffer tank (28). A stirring paddle (35) is rotatably provided at the center of the upper end of the kettle cover (32), and a discharge pipe (36) and a pressurizing pipe (37) are provided on the right side of the upper end. The upper end of the stirring paddle (35) is externally connected to a stirring motor, and the lower end is located in the kettle body (31). The discharge pipe (36) is externally connected to an absorption device, and a phosphorus pentafluoride measuring device is installed on the discharge pipe (36). The pressurizing pipe (37) is externally connected to a pressurizing device.

2. A tail gas treatment device for lithium hexafluorophosphate as claimed in claim 1, characterized in that: The processing tank (11) is made of stainless steel or steel-lined polytetrafluoroethylene.

3. A tail gas treatment device for lithium hexafluorophosphate as claimed in claim 1, characterized in that: A gas pressure gauge and a control valve are installed on the connecting pipe between the compressor (16) and the air inlet of the condenser a (12).

4. A tail gas treatment device for lithium hexafluorophosphate as claimed in claim 1, characterized in that: The hydrogen fluoride production pipeline (26) is equipped with a hydrogen fluoride content measuring device.

5. A tail gas treatment device for lithium hexafluorophosphate as claimed in claim 1, characterized in that: A thermometer, a radar level gauge and a pressure gauge are sequentially mounted on the left side of the upper end of the kettle cover (32).

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