Preparation system of bis (fluorosulfonyl) imide

Abstract

The utility model provides a preparation system of bis (fluorosulfonyl) imide. In the preparation system of the imidodisulfuryl fluoride, after the imidodisulfuryl fluoride is generated by reaction in a reaction container, mixed gas containing hydrogen fluoride and hydrogen chloride enters a separation system, and mixed liquid containing the imidodisulfuryl fluoride and hydrogen chloride enters another separation system; the hydrogen fluoride separated by the two separation systems is recovered into a recovery container. Therefore, the hydrogen fluoride can be recycled as much as possible, and the recycling energy consumption and related cost of the hydrogen fluoride can be reduced, so that the tail gas treatment cost is relatively low.

Description

Technical Field

[0001] The present application relates to the field of preparation of bisfluorosulfonyl imide, and in particular to a preparation system of bisfluorosulfonyl imide. Background Art

[0002] In the existing lithium battery industry, lithium salt electrolyte is an important component of lithium batteries. Among them, lithium bis(fluorosulfonyl)imide has very good application prospects due to its good performance in thermal stability, decomposition resistance and electrical conductivity. Bis(fluorosulfonyl)imide is an important raw material of lithium bis(fluorosulfonyl)imide, which affects the yield and purity of lithium bis(fluorosulfonyl)imide. In a typical scheme, bis(fluorosulfonyl)imide is generated by fluorination reaction using hydrogen fluoride. It is usually necessary to provide excessive hydrogen fluoride to improve the conversion rate, which makes the tail gas recovery and treatment inconvenient.

[0003] For example, in the Chinese invention patent application with publication number CN115974013 A and titled “Method for preparing bisfluorosulfonyl imide and method for preparing bisfluorosulfonyl imide salt”, although the concept of improving the raw material conversion rate is proposed, the recycling of hydrogen fluoride is lacking, resulting in a low recycling rate of hydrogen fluoride in the entire reaction process, thereby making the recycling energy consumption large and the cost high. Utility Model Content

[0004] This application is made in view of the above-mentioned state of the prior art. The purpose of this application is to provide a system for preparing bisfluorosulfonyl imide, which is used in the reaction process of generating bisfluorosulfonyl imide and hydrogen chloride by fluorination reaction, fully recovering hydrogen fluoride, thereby improving the recovery rate of hydrogen fluoride, reducing the reaction process of generating bisfluorosulfonyl imide and the energy consumption and related costs of recycling hydrogen fluoride.

[0005] In order to achieve the above objectives, this application adopts the following technical solutions.

[0006] The present application provides a system for preparing bisfluorosulfonyl imide, comprising: a reaction container, which is used for reacting chloride with hydrogen fluoride to generate bisfluorosulfonyl imide; a recovery container, which is used for recovering hydrogen fluoride; a first separation system, whose inlet is connected to the first outlet of the reaction container, and whose outlet is connected to the recovery container, and is used for separating a first mixed gas containing hydrogen fluoride and hydrogen chloride; and a second separation system, whose inlet is connected to the second outlet of the reaction container, and whose outlet is connected to the recovery container, and is used for separating a mixed liquid containing bisfluorosulfonyl imide and hydrogen fluoride.

[0007] In an optional scheme, it also includes a flow sensor and a first control valve, the first control valve is opened and closed based on the parameters detected by the flow sensor, the recovery container and the reaction container are controlled to be connected via the first control valve, and the flow sensor is used to sense the flow rate of the fluid flowing between the recovery container and the reaction container; and / or the reaction pressure P1 of the reaction container is 2.0MPaG≥P1≥1.8MPaG.

[0008] In another optional scheme, the second separation system includes: a flash evaporation system, which is connected to the second outlet, and the mixed liquid enters the flash evaporation system to produce a second mixed gas containing hydrogen fluoride; and a condensation system, which is connected to the flash evaporation system and the recovery container respectively, so that the second mixed gas enters the condensation system for separation.

[0009] In another optional solution, the flash system includes a flash tank, which has at least an inlet connected to the reaction vessel and a third outlet connected to the condensation system, and the mixed liquid is input from the inlet of the flash tank.

[0010] In another optional solution, the flash system further includes a vaporizer, the flash tank has a fourth outlet for outputting the intermediate, and the inlet and outlet of the vaporizer are respectively connected to the fourth outlet and the condensation system.

[0011] In another optional scheme, it also includes a first pressure sensor and a second control valve, the second control valve is opened and closed based on the parameters detected by the first pressure sensor, the flash tank and the condensation system are controlled to be connected via the second control valve, and the first pressure sensor is used to sense the flash pressure in the flash tank; and / or, it also includes a first temperature sensor and a third control valve, the third control valve is opened and closed based on the parameters detected by the first temperature sensor, the first temperature sensor is used to sense the temperature of the vaporizer, and the third control valve can control the opening and closing of the heating fluid inlet of the vaporizer.

[0012] In another optional solution, the condensation system includes at least two condensers connected in series, and the at least two condensers are used to separate hydrogen fluoride and non-condensable gas in the second mixed gas.

[0013] In another optional scheme, the first separation system at least includes a distillation tower, a tower top condenser and a tower bottom reboiler, the reaction vessel, the distillation tower, the tower bottom reboiler and the recovery container are connected in sequence, the first mixed gas is separated into hydrogen fluoride via the distillation tower and the tower bottom reboiler, the tower top condenser is installed on the top of the distillation tower and is connected to the distillation tower, and liquid hydrogen chloride is obtained via the tower top condenser.

[0014] In another optional scheme, it also includes a liquid level sensor and a fourth control valve, the fourth control valve is opened and closed based on the parameters detected by the liquid level sensor, the distillation tower and the recovery container are controlled to be connected via the fourth control valve, and the liquid level sensor is used to sense the liquid level of the liquid in the bottom of the distillation tower; and / or, it also includes a second pressure sensor and a fifth control valve, the fifth control valve is opened and closed based on the parameters detected by the second pressure sensor, the second pressure sensor is used to sense the pressure at the top of the distillation tower, and the fifth control valve can control the opening and closing of the condenser tail gas outlet of the top condenser; and / or, it also includes a second temperature sensor and a sixth control valve, the sixth control valve is opened and closed based on the parameters detected by the second temperature sensor, the second temperature sensor is used to sense the temperature of the bottom of the distillation tower, and the sixth control valve can control the opening and closing of the heating fluid inlet of the bottom reboiler.

[0015] In another optional solution, the first separation system includes at least two condensers connected in series, and the at least two condensers are used to separate hydrogen chloride and hydrogen fluoride in the first mixed gas.

[0016] By adopting the above technical solution, the present application provides a system for preparing bisfluorosulfonyl imide. In the system for preparing bisfluorosulfonyl imide, a reaction vessel, a recovery vessel, a first separation system and a second separation system are integrated together. The reaction vessel is used for reacting chloride with hydrogen fluoride to generate bisfluorosulfonyl imide. The first separation system is connected to the reaction vessel so that the mixed gas containing hydrogen fluoride and hydrogen chloride from the reaction vessel can enter the first separation system for separation. The second separation system is connected to the reaction vessel so that the mixed liquid containing bisfluorosulfonyl imide and hydrogen fluoride from the reaction vessel can enter the second separation system for separation. The recovery container is connected to both separation systems for recovering hydrogen fluoride from the separation system.

[0017] In this way, after the reaction in the reaction container generates bisfluorosulfonyl imide, the mixed gas containing hydrogen fluoride and hydrogen chloride enters the first separation system for separation, and the mixed liquid containing bisfluorosulfonyl imide and hydrogen fluoride enters the second separation system for separation, and the hydrogen fluoride separated by the two separation systems is recovered into the recovery container. Thus, hydrogen fluoride can be recovered as much as possible, thereby reducing the energy consumption and cost of recycling hydrogen fluoride, making the cost of tail gas treatment low, and being conducive to obtaining a bisfluorosulfonyl imide product liquid with higher purity, providing super-quality raw materials for the production of lithium bisfluorosulfonyl imide. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram showing the topological structure of a system for preparing bisfluorosulfonyl imide according to the first embodiment of the present application.

[0019] Figure 2 Schematic diagram showing the topological structure of a system for preparing bisfluorosulfonyl imide according to the second embodiment of the present application.

[0020] Description of Reference Numerals

[0021] 1 reaction vessel;

[0022] 2 first separation system; 21 rectification tower; 22 tower top condenser; 23 tower bottom reboiler; 24 first condenser; 25 second condenser;

[0023] 3 flash system; 31 flash tank; 32 vaporizer;

[0024] 4 condensation system; 41 third condenser; 42 fourth condenser;

[0025] 5. Recycling containers;

[0026] FC flow sensor; PC1 first pressure sensor; PC2 second pressure sensor; TC1 first temperature sensor; TC2 second temperature sensor; LC liquid level sensor; V1 first control valve; V2 second control valve; V3 third control valve; V4 fourth control valve; V5 fifth control valve; V6 sixth control valve; PU pump. DETAILED DESCRIPTION

[0027] The exemplary embodiments of the present application are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present application, and are not intended to exhaust all feasible methods of the present application, nor to limit the scope of the present application.

[0028] In this application, unless otherwise specified, the communication between two objects (including but not limited to between systems, between containers, and between a system and a container) means that the inlet of one object is connected to the outlet of another object, and the communication may or may use some pipelines or conduits. In the figure, the arrows on the lines representing the pipelines or conduits show the flow direction of the fluid in the pipelines or conduits. In addition, "communication" includes always connected and controlled communication, and always connected means that the pipeline or conduit between the two objects can always be in a connected state, and controlled communication means that the pipeline or conduit between the two objects can be controlled to be in a connected state or a non-connected state.

[0029] In the present application, unless otherwise specified, the "opening and closing" of the control valve includes the control valve being fully opened, the control valve being fully closed, and the opening of the control valve being controllably adjusted.

[0030] The following describes a system for preparing bis(fluorosulfonyl)imide according to the first embodiment of the present application in conjunction with the accompanying drawings.

[0031] (System for preparing bis(fluorosulfonyl)imide according to the first embodiment of the present application)

[0032] like Figure 1 As shown, the preparation system of bisfluorosulfonyl imide according to the first embodiment of the present application includes a reaction vessel 1, a first separation system 2, a second separation system (including a flash system 3, a condensation system 4) and a recovery container 5. The reaction vessel 1 is connected to both the first separation system 2 and the second separation system, so that the first mixed gas containing hydrogen fluoride and hydrogen chloride in the reaction vessel 1 can enter the first separation system 2, and the mixed liquid containing bisfluorosulfonyl imide and hydrogen fluoride in the reaction vessel 1 can enter the second separation system. Specifically, the mixed liquid enters the flash system 3 of the second separation system, and the condensation system 4 is connected to the flash system 3, so that the second mixed gas containing hydrogen fluoride and non-condensable gas from the flash system 3 can enter the condensation system 4. The recovery container 5 is connected to both the first separation system 2 and the condensation system 4 of the second separation system, and is used to recover hydrogen fluoride from the first separation system 2 and the condensation system 4 of the second separation system. The recovery container 5 is also connected to the reaction vessel 1, so that the recovered hydrogen fluoride can be transported to the reaction vessel 1 for fluorination reaction to achieve reuse.

[0033] In the present embodiment, reaction vessel 1 is a reactor capable of adjusting reaction pressure. In the reactor, a chemical reaction in which chloride (e.g., chloroimide) reacts with hydrogen fluoride to generate bis(fluorosulfonyl)imide and hydrogen chloride can be carried out, and the reaction pressure P1 of the chemical reaction satisfies 2.0MPaG≥P1≥1.8MPaG, where MPaG is a gauge pressure. Thus, a fluorination reaction with a higher reaction pressure can be carried out in reaction vessel 1 to generate bis(fluorosulfonyl)imide and hydrogen chloride. It is understood that reaction vessel 1 can also be other containers capable of achieving safe and smooth progress of the above-mentioned chemical reaction, such as a reactor, a generator, a synthesis tower, etc. Further, reaction vessel 1 has a first outlet communicated with the inlet of the first separation system 2 and a second outlet communicated with the inlet of the second separation system.

[0034] In this embodiment, if Figure 1As shown, the inlet of the first separation system 2 is connected to the first outlet of the reaction vessel 1, so that the first mixed gas containing hydrogen fluoride and hydrogen chloride from the reaction vessel 1 can enter the first separation system 2 for separation. The first separation system 2 includes a distillation tower 21, a tower top condenser 22 and a tower bottom reboiler 23. The distillation tower 21 is always connected to the reaction vessel 1, so that the first mixed gas produced by the chemical reaction in the reaction vessel 1 can enter the distillation tower 21 for distillation separation. The interior of the distillation tower 21 is provided with necessary structures for implementing distillation operations (such as tower plates for separating the mixture, etc.). The tower top condenser 22 is installed at the top of the distillation tower 21 and is always connected to the top of the distillation tower 21. Liquid hydrogen chloride is obtained through the tower top condenser 22 (using, for example, a refrigerant fluid at -40°C), and then the liquid hydrogen chloride is treated accordingly. The bottom reboiler 23 is installed at the bottom of the distillation tower 21 and is always connected to the bottom of the distillation tower 21. Part of the liquid material at the bottom of the distillation tower 21 (according to the required proportion) can be re-vaporized through the bottom reboiler 23, thereby purifying the liquid hydrogen fluoride. In addition, the bottom of the distillation tower 21 is also controlled to be connected to the recovery container 5, so that the liquid hydrogen fluoride after distillation and purification by the first separation system 2 can be recovered into the recovery container 5.

[0035] In this embodiment, if Figure 1As shown, the inlet of the second separation system is connected to the second outlet of the reaction vessel 1. Specifically, in the second separation system, the flash system 3 is connected to the second outlet of the reaction vessel 1, so that the mixed liquid containing bisfluorosulfonyl imide and hydrogen fluoride from the reaction vessel 1 can enter the flash system 3. The flash system 3 includes a flash tank 31 and a vaporizer 32. The flash pressure P2 in the flash tank 31 can be adjusted, and the flash pressure P2 in the flash tank 31 satisfies 0.3MPaG≥P2≥-0.098MPaG. The inlet of the flash tank 31 is always connected to the reaction vessel 1, and the mixed liquid entering the flash tank 31 can obtain an intermediate containing bisfluorosulfonyl imide and hydrogen fluoride and a first gas to be recovered containing hydrogen fluoride by flash evaporation. Further, the third outlet at the top of the flash tank 31 is controlled to be connected to the condensation system 4 and the fourth outlet at the bottom of the flash tank 31 is always connected to the inlet of the vaporizer 32, so that the intermediate will enter the vaporizer 32 and the first gas to be recovered will be mixed with the second gas to be recovered from the vaporizer 32 as the second mixed gas. The inlet and outlet of the vaporizer 32 are always connected to the flash tank 31 and the condensation system 4 respectively. After the intermediate from the flash tank 31 enters the vaporizer 32, the bisfluorosulfonyl imide and the second gas to be recovered containing hydrogen fluoride are separated by vaporization. The bisfluorosulfonyl imide will be transported to the outside of the entire preparation system for treatment, and the second gas to be recovered and the first gas to be recovered are mixed together as the second mixed gas and enter the condensation system 4 for further separation. Using the flash system 3, not only can the mixed gas in the reaction solution be recovered, but also the hydrogen fluoride and hydrogen chloride content in the intermediate product can be low and the content of bisfluorosulfonyl imide can be high, which is helpful to improve the yield and purity of lithium bisfluorosulfonyl imide. It can be understood that in other optional solutions, the first gas to be recovered from the flash tank 31 and the second gas to be recovered from the vaporizer 32 may not be mixed, but may be delivered to the condensation system 4 independently of each other.

[0036] In this embodiment, if Figure 1 As shown, the condensation system 4 is connected to the flash system 3, so that the second mixed gas containing hydrogen fluoride from the flash system 3 can enter the condensation system 4. The condensation system 4 includes a third condenser 41 and a fourth condenser 42 connected in series, and the two condensers are used to perform graded condensation on the second mixed gas. The third condenser 41 is always connected to the vaporizer 32, and the fourth condenser 42 is always connected to the recovery container 5, so that the hydrogen fluoride separated will be recovered into the recovery container 5 and the separated non-condensable gas will be treated accordingly.

[0037] In this embodiment, if Figure 1As shown, the recovery container 5 is controlled to be connected with the first separation system 2 and the recovery container 5 is always connected with the condensation system 4, so as to recover the hydrogen fluoride from the first separation system 2 and the condensation system 4. In addition, the recovery container 5 is also controlled to be connected with the reaction container 1, so that the hydrogen fluoride recovered into the recovery container 5 can enter the reaction container 1 for reuse.

[0038] By using the above-mentioned preparation system, the fluorination reaction of chloroimide and hydrogen fluoride is realized under relatively high pressure conditions, and the raw materials of such high-pressure reaction are in liquid state to carry out liquid reaction, thereby improving the reaction rate and raw material conversion rate. After the above-mentioned high-pressure reaction, the mixed gas containing hydrogen fluoride and hydrogen chloride enters the first separation system 2, and the mixed liquid containing bisfluorosulfonyl imide and hydrogen fluoride enters the flash system 3. Thus, the mixed gas can be directly separated at high pressure in the first separation system 2 without pressurization or cooling operation, thereby realizing the recovery of hydrogen fluoride in the mixed gas. In addition, the hydrogen fluoride in the mixed liquid separated in the flash system 3 is further separated via the condensation system 4 to be recovered in the recovery container 5. Therefore, the above-mentioned preparation system can recover hydrogen fluoride as much as possible, which not only greatly reduces the raw material cost of the fluorination reaction, but also helps to reduce the cost of tail gas treatment.

[0039] In addition, in this embodiment, the preparation system also includes a plurality of sensors of different types and a plurality of control valves to achieve corresponding control of the preparation system so as to accurately adjust various parameters in the preparation system.

[0040] Specifically, the preparation system includes a flow sensor FC and a first control valve V1. The first control valve V1 and the flow sensor FC can be electrically connected or signal connected, so that the first control valve V1 is opened and closed based on the parameters detected by the flow sensor FC. The recovery container 5 and the reaction container 1 are controlled to be connected via the first control valve V1, and the flow sensor FC is used to sense the flow rate of the fluid flowing between the recovery container 5 and the reaction container 1, that is, the flow rate of the fluid flowing from the recovery container 5 to the reaction container 1. In addition, a pump PU is also provided between the recovery container 5 and the reaction container 1. The pump PU can pressurize the hydrogen fluoride from the recovery container 5 and then transport it to the reaction container 1 for chemical reaction. In this way, the hydrogen fluoride feed amount of the reaction container 1 is accurately controlled by the flow sensor FC and the first control valve V1 to achieve stable feeding.

[0041] Further, the preparation system further includes a first pressure sensor PC1 and a second control valve V2, and the second control valve V2 and the first pressure sensor PC1 can be electrically connected or signal connected, so that the second control valve V2 is opened and closed based on the parameters detected by the first pressure sensor PC1, and the flash tank 31 is controlled to communicate with the condensation system 4 via the second control valve V2, and the first pressure sensor PC1 is used to sense the flash pressure in the flash tank 31. In this way, the gas outlet of the flash tank 31 is accurately controlled by the first pressure sensor PC1 and the second control valve V2 to ensure the stability of the composition of the obtained gas phase. It can be understood that the electrical connection or signal connection can be indirectly achieved through the controller, thereby realizing the control described above.

[0042] Furthermore, the preparation system further includes a first temperature sensor TC1 and a third control valve V3, the third control valve V3 and the first temperature sensor TC1 can be electrically connected or signal connected, so that the third control valve V3 is opened and closed based on the parameters detected by the first temperature sensor TC1, the first temperature sensor TC1 is used to sense the temperature of the vaporizer 32, and the third control valve V3 can control the opening and closing of the heating fluid inlet of the vaporizer 32. In this way, the temperature of the vaporizer 32 is precisely controlled by adjusting the heating fluid (heat medium) to ensure that the hydrogen fluoride in the product liquid is recovered as much as possible.

[0043] Furthermore, the preparation system also includes a liquid level sensor LC and a fourth control valve V4. The fourth control valve V4 and the liquid level sensor LC can be electrically connected or signal connected, so that the fourth control valve V4 is opened and closed based on the parameters detected by the liquid level sensor LC, and the distillation tower 21 and the recovery container 5 are controlled to be connected via the fourth control valve V4, and the liquid level sensor LC is used to sense the liquid level of the liquid in the distillation tower 21.

[0044] Further, the preparation system further includes a second pressure sensor PC2 and a fifth control valve V5, the fifth control valve V5 and the second pressure sensor PC2 can be electrically connected or signal connected, so that the fifth control valve V5 is opened and closed based on the parameters detected by the second pressure sensor PC2, the second pressure sensor PC2 is used to sense the pressure at the top of the distillation tower 21, and the fifth control valve V5 can control the opening and closing of the condenser tail gas outlet of the tower top condenser 22. In this way, the pressure at the top of the distillation tower 21 is precisely controlled by the condenser tail gas pipe to achieve stable pressure at the top of the distillation tower 21, and ensure the stable operation of the distillation tower 21 and the quality of the separated hydrogen chloride.

[0045] Further, the preparation system further includes a second temperature sensor TC2 and a sixth control valve V6, the sixth control valve V6 and the second temperature sensor TC2 can be electrically connected or signal connected, so that the sixth control valve V6 is opened and closed based on the parameters detected by the second temperature sensor TC2, the second temperature sensor TC2 is used to sense the temperature of the bottom of the distillation tower 21, and the sixth control valve V6 can control the opening and closing of the heating fluid inlet of the tower bottom reboiler 23. In this way, the temperature of the bottom of the distillation tower 21 is precisely controlled by the reboiler heating fluid (heat medium) to achieve the temperature stability of the bottom of the distillation tower 21, to ensure the stable operation of the distillation tower 21 and the purity of the separated hydrogen fluoride.

[0046] The following describes a system for preparing bisfluorosulfonyl imide according to a second embodiment of the present application.

[0047] (System for preparing bis(fluorosulfonyl)imide according to the second embodiment of the present application)

[0048] like Figure 2 As shown, the structure of the preparation system of bisfluorosulfonyl imide according to the second embodiment of the present application is substantially the same as the structure of the preparation system of bisfluorosulfonyl imide according to the first embodiment of the present application, and the differences between the two are mainly described below.

[0049] In this embodiment, unlike the first embodiment, the first separation system 2 includes a first condenser 24 and a second condenser 25. The first condenser 24 is always connected to the reaction vessel 1, the second condenser 25 is always connected to the first condenser 24 in series and is always connected to the recovery container 5, and the first separation system 2 is used to separate hydrogen fluoride and hydrogen chloride in the first mixed gas, thereby achieving the same effect as in the first embodiment. In addition, in this embodiment, the sensors and control valves corresponding to the first separation system 2 in the first embodiment are also omitted.

[0050] It should be understood that the above embodiments are merely exemplary and are not intended to limit the present application. Those skilled in the art may make various modifications and changes to the above embodiments under the guidance of the present application without departing from the scope of the present application. Further, the following supplementary explanations are provided.

[0051] i. Although the above solution illustrates that the first separation system 2 includes two condensers 24, 25, and the condensation system 4 of the second separation system includes two condensers 41, 42, the present application is not limited thereto. The number and connection mode of the condensers in the first separation system 2 and the condensation system 4 of the second separation system can be set as needed.

[0052] ii. In the variations of the first embodiment and the second embodiment above, the reaction container 1 and the recovery container 5 may not be connected, and the hydrogen fluoride in the recovery container 5 may be used for other purposes and processed.

[0053] iii. In the variants of the above embodiments of the present application, the second separation system may be other systems capable of separating bis(fluorosulfonyl)imide and hydrogen fluoride, for example, the flash system may adopt other types of distillation systems. It is understood that various other components may be provided as needed on the basis of the above variants to achieve the required functions, so as to realize other variants. Here, the structures of other variants are not described in detail.

[0054] iv. In the technical solution of the present application, a high-pressure fluorination reaction is used to generate bis(fluorosulfonyl)imide and hydrogen chloride, and a high reaction conversion rate is achieved while fully recovering and reusing hydrogen fluoride at a relatively low cost. Hydrogen fluoride is recycled in the system, reducing the amount of hydrogen fluoride entering the tail gas treatment system, thereby reducing the probability of causing equipment corrosion, seal failure, hydrogen fluoride leakage and other problems, thereby controlling these problems as much as possible in the preparation system and reducing the cost of downstream equipment. In addition, in the present preparation system, the entire process is carried out continuously, and a variety of sensors and interlocking of different control valves are used to accurately control the process, which is conducive to the automation of the entire preparation system and is easy to operate and manage.

Claims

1. A system for preparing bis(fluorosulfonyl)imide, characterized in that: include: A reaction vessel for reacting chloride with hydrogen fluoride to form bisfluorosulfonyl imide; A recovery container for recovering hydrogen fluoride; a first separation system, whose inlet is connected to the first outlet of the reaction container and whose outlet is connected to the recovery container, for separating a first mixed gas containing hydrogen fluoride and hydrogen chloride; and The second separation system has an inlet connected to the second outlet of the reaction container and an outlet connected to the recovery container, and is used for separating the mixed liquid containing bis(fluorosulfonyl)imide and hydrogen fluoride.

2. The system for preparing bis(fluorosulfonyl)imide according to claim 1, characterized in that: It also includes a flow sensor and a first control valve, wherein the first control valve is opened and closed based on a parameter detected by the flow sensor, the recovery container and the reaction container are controlled to be connected via the first control valve, and the flow sensor is used to sense the flow of the fluid flowing between the recovery container and the reaction container; and / or, The reaction pressure P1 of the reaction container is 2.0 MPaG ≥ P1 ≥ 1.8 MPaG.

3. The system for preparing bis(fluorosulfonyl)imide according to claim 1, characterized in that: The second separation system comprises: a flash evaporation system, connected to the second outlet, wherein the mixed liquid enters the flash evaporation system and generates a second mixed gas containing hydrogen fluoride; and The condensation system is connected to the flash evaporation system and the recovery container respectively, so that the second mixed gas enters the condensation system for separation.

4. The system for preparing bis(fluorosulfonyl)imide according to claim 3, characterized in that: The flash system comprises a flash tank, which has at least an inlet connected to the reaction container and a third outlet connected to the condensation system, and the mixed liquid is input from the inlet of the flash tank.

5. The system for preparing bis(fluorosulfonyl)imide according to claim 4, characterized in that: The flash system further comprises a vaporizer, the flash tank comprises a fourth outlet for outputting the intermediate, and the inlet and the outlet of the vaporizer are respectively connected to the fourth outlet and the condensation system.

6. The system for preparing bis(fluorosulfonyl)imide according to claim 5, characterized in that: It also includes a first pressure sensor and a second control valve, the second control valve is opened and closed based on the parameter detected by the first pressure sensor, the flash tank is controlled to be connected with the condensation system via the second control valve, and the first pressure sensor is used to sense the flash pressure in the flash tank; and / or, It also includes a first temperature sensor and a third control valve, the third control valve is opened and closed based on the parameters detected by the first temperature sensor, the first temperature sensor is used to sense the temperature of the vaporizer, and the third control valve can control the opening and closing of the heating fluid inlet of the vaporizer.

7. The system for preparing bis(fluorosulfonyl)imide according to claim 3, characterized in that: The condensation system comprises at least two condensers connected in series, and the at least two condensers are used to separate hydrogen fluoride and non-condensable gas in the second mixed gas.

8. The system for preparing bisfluorosulfonyl imide according to any one of claims 1 to 7, characterized in that: The first separation system at least comprises a distillation tower, a tower top condenser and a tower bottom reboiler, and the reaction vessel, the distillation tower, the tower bottom reboiler and the recovery vessel are connected in sequence. The first mixed gas is passed through the distillation tower and the tower bottom reboiler to separate hydrogen fluoride, the tower top condenser is installed on the top of the distillation tower and communicated with the distillation tower, and liquid hydrogen chloride is obtained through the tower top condenser.

9. The system for preparing bis(fluorosulfonyl)imide according to claim 8, characterized in that: It also includes a liquid level sensor and a fourth control valve, the fourth control valve is opened and closed based on the parameters detected by the liquid level sensor, the distillation tower and the recovery container are controlled to be connected via the fourth control valve, and the liquid level sensor is used to sense the liquid level of the liquid in the bottom of the distillation tower; and / or, It also includes a second pressure sensor and a fifth control valve, wherein the fifth control valve is opened and closed based on a parameter detected by the second pressure sensor, the second pressure sensor is used to sense the pressure at the top of the distillation tower, and the fifth control valve can control the opening and closing of the condenser tail gas outlet of the tower top condenser; and / or, It also includes a second temperature sensor and a sixth control valve, wherein the sixth control valve is opened and closed based on the parameters detected by the second temperature sensor, the second temperature sensor is used to sense the temperature at the bottom of the distillation tower, and the sixth control valve can control the opening and closing of the heating fluid inlet of the tower bottom reboiler.

10. The system for preparing bisfluorosulfonyl imide according to any one of claims 1 to 7, characterized in that: The first separation system includes at least two condensers connected in series, and the at least two condensers are used to separate hydrogen chloride and hydrogen fluoride in the first mixed gas.

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