Method for conveying carbon B residual liquid

Abstract

The invention relates to the technical field of chemical production, in particular to a carbon B residual liquid conveying method which comprises a waste liquid tank used for storing carbon B residual liquid and communicated with a tank bottom root valve through a pipeline, and the tank bottom root valve is communicated with a first pump inlet valve and a second pump inlet valve through pipelines. The first pump inlet valve is communicated with the first filter through a pipeline, the first filter is communicated with the first machine pump through a pipeline, the first machine pump is communicated with the first pump outlet one-way valve set through a pipeline, and a first pump outlet pressure gauge is arranged on the pipeline between the first machine pump and the first pump outlet one-way valve set. And the second pump inlet valve is communicated with the second filter through a pipeline. Aiming at the characteristic that B carbon residual liquid is easy to block, on-line cleaning and replacement work of a single-pump system is achieved under the condition that B carbon conveying is not interrupted, comprehensive cleaning and replacement work after the whole system is stopped can be achieved, and the reliability of equipment and facilities in the production process is ensured.

Description

Technical Field

[0001] This invention relates to the field of chemical production technology, and specifically to a method for conveying ethylene carbon residue. Background Technology

[0002] Ethylene carbonate is a transparent, colorless liquid (>35℃), a crystalline solid at room temperature. It has low viscosity and low volatility, good chemical stability, and is relatively resistant to reaction with other substances. It also has low toxicity and irritation, and is not easily flammable at room temperature.

[0003] Ethylene carbonate is a good solvent for polyacrylonitrile and polyvinyl chloride. It can be used as a spinning solution in textiles, as a solvent for removing acidic gases, and as an additive in concrete. In the pharmaceutical industry, it can be used as a component and raw material. It can also be used as a foaming agent for plastics and a stabilizer for synthetic lubricants. In the battery industry, it can be used as an excellent solvent for lithium battery electrolytes. It is an environmentally friendly chemical raw material and plays an indispensable role in the new energy field. With the rapid development of the lithium battery industry, the total market volume of ethylene carbonate continues to rise.

[0004] Currently, the industrial production of ethylene carbonate primarily utilizes the addition reaction of carbon dioxide and ethylene oxide under the catalysis of a catalyst. During the production process, due to the high temperatures involved in the reaction and separation, side reactions can occur, forming polymers. To ensure consistent product quality, this polymer-containing ethylene carbonate residue requires periodic special treatment.

[0005] In the process of handling ethylene carbonate residue containing polymers, the material needs to be transported. However, the material has a high viscosity and is not easy to handle. In particular, it is prone to clogging pipelines and equipment when the equipment is not in use, which seriously affects the stability of production operations. Therefore, a method for transporting ethylene carbonate residue is proposed to solve this production difficulty. Summary of the Invention

[0006] In view of the problems in the prior art, the present invention provides a method for conveying ethylene carbon residue to solve the problems in the technical background.

[0007] The technical solution adopted by this invention to solve its technical problem is a method for conveying ethylene carbon residue, comprising the following equipment and their connections: a waste liquid tank for storing ethylene carbon residue and connected to a bottom root valve via a pipeline; the bottom root valve is connected to a first pump inlet valve and a second pump inlet valve via pipelines. The first pump inlet valve is connected to a first filter via a pipeline; the first filter is connected to a first pump via a pipeline; the first pump is connected to a first check valve group at the pump outlet via a pipeline; the first check valve group at the pump outlet is connected to a first pump outlet valve via a pipeline; a first pump outlet pressure gauge is installed on the pipeline between the first pump and the first check valve group at the pump outlet; the second pump inlet valve is connected to a second filter via a pipeline; the second filter is connected to a second pump via a pipeline; the second pump is connected to a second check valve group at the pump outlet via a pipeline; the second check valve group at the pump outlet is connected to a second pump outlet valve via a pipeline; a second pump outlet pressure gauge is installed on the pipeline between the second pump and the second check valve group at the pump outlet; the first pump outlet valve is connected to the second pump inlet valve via a pipeline. The pump outlet valves are connected. One pipeline between the first and second pump outlet valves is connected to the minimum reflux valve, and the other pipeline is connected to the external supply control valve. The minimum reflux valve is connected to the waste liquid tank. The external supply control valve is connected to the drainage treatment facility. The common medium nitrogen is connected to the nitrogen four-valve group via a pipeline. The common medium steam is connected to the steam four-valve group via a pipeline. The steam four-valve group is connected to the pipeline after the valve at the bottom of the tank, the pipeline before the first pump outlet valve, and the pipeline before the second pump outlet valve via a pipeline. The first filter is connected to the first drainage three-valve group via a pipeline. The second filter is connected to the second drainage three-valve group via a pipeline. The first and second drainage three-valve groups are connected to the underground collection tank via a pipeline.

[0008] The equipment process flow includes the following steps:

[0009] S1, the ethylene carbon residue stored in the waste liquid tank is transported to the pump inlet through the height difference, and one of the first or second pumps is started to pressurize the ethylene carbon residue; when the pump outlet pressure gauge shows that the pressure is normal, the corresponding pump outlet valve is opened, and the external flow rate is controlled by the external delivery control valve; when it is necessary to temporarily stop the external delivery, the external delivery control valve is closed and the minimum return valve is opened to meet the minimum flow rate required for the pump to operate;

[0010] S2, the first pump and the second pump serve as backups for each other. When the inlet filter of the running pump becomes clogged, the backup pump is switched to operate. The pump that is switched out uses nitrogen and steam to repeatedly purge, boil, and purge the pipeline to achieve the purpose of online pump cleaning.

[0011] S3. After the ethylene carbon residue is transported, in order to ensure smooth operation next time, nitrogen and steam are used to purge, clean and dry the entire system from front to back to ensure that the system is in good working order.

[0012] Specifically, the nitrogen four-valve assembly for the common medium nitrogen is configured with a double gate valve, a check valve, and a drain valve, which can prevent material backflow when switching common media and meet the internal pressure relief requirements of the valve assembly when the common medium is not in use.

[0013] Specifically, the four-valve assembly for the common medium steam is configured with double gate valves and an intermediate check valve and drain valve. This can prevent material backflow when switching common media and meet the internal pressure relief requirements of the valve assembly when it is not in use. It can also realize the function of warming up the pipes and draining liquid before steam is put into use.

[0014] Specifically, the common medium nitrogen and steam should be connected to the tank bottom root valve, the first pump outlet valve, and the second pump outlet valve at the shortest possible distance (MIN) to facilitate more thorough purging of the pipeline and avoid residual materials.

[0015] Specifically, the outlets of the first and second pumps are respectively equipped with a first check valve group and a second check valve group. The valve group is configured with a bypass of the check valve and the shut-off valve so as to realize the hot standby of the standby pump (the first pump and the second pump are each other's backups).

[0016] Specifically, the minimum reflux valve and the external supply control valve can be configured as automatic control valves, thereby improving the automation of the system.

[0017] Specifically, the bottom of the first filter and the second filter are respectively equipped with a first three-valve assembly for drainage and a second three-valve assembly for drainage. The three-valve assembly for drainage is configured with a double gate valve and an intermediate drain valve. In addition to fulfilling the normal drainage function, it can also be used for unblocking pipes in special circumstances (such as pipe blockage).

[0018] The common medium, nitrogen or steam, is used in conjunction with the three-valve drain assembly via a nitrogen four-valve group or a steam four-valve group to perform purging, cleaning, and drying operations on the first pump system and the second pump system, either individually or together.

[0019] The beneficial effects of this invention are as follows: In view of the characteristic that ethylene carbon residue is prone to clogging, this application realizes online cleaning and replacement of a single pump system without interruption of ethylene carbon delivery, and can also realize comprehensive cleaning and replacement after the entire system is shut down, thus ensuring the reliability of equipment and facilities in the production process.

[0020] This invention solves the technical problem of difficult ethylene carbon residue transportation caused by its high viscosity and tendency to clog pipes and equipment. By installing nitrogen and steam purging and replacement systems on the pump inlet and outlet pipelines, it achieves online cleaning of individual pumps and comprehensive cleaning of the entire system, ensuring the continuity of the ethylene carbon residue transportation process and the reliability of the equipment. The distance between the waste liquid tank and the bottom valve is set to the shortest possible value, reducing the amount of liquid remaining at the blind end. The design of the nitrogen four-valve group and the steam four-valve group effectively prevents material backflow and meets pressure relief requirements. The shortest possible distance between the nitrogen and steam inlet points improves purging efficiency. The bypass design of the pump outlet check valve group enables the hot standby function of the backup pump. The automatic control of the minimum reflux valve and the external control valve improves the system's automation level. The design of the three-valve group for drainage meets the needs of normal drainage and pipeline unblocking under special circumstances. The combined use of nitrogen or steam with the three-valve group for drainage enables purging, cleaning, and drying of the single-pump system or the entire system. Through the application of the above technical solutions, the stability of the ethylene carbon residue transportation process is ensured, equipment service life is extended, maintenance costs are reduced, and production efficiency is improved. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings and examples.

[0022] Figure 1 This is an overall schematic diagram of the present invention;

[0023] In the diagram: 1. Waste liquid tank; 2. Tank bottom root valve; 3A. First pump inlet valve; 4A. First filter; 4A-1. First drain three-valve assembly; 5A. First pump; 6A. First pump outlet pressure gauge; 7A. Pump outlet first check valve assembly; 8A. First pump outlet valve; 3B. Second pump inlet valve; 4B. Second filter; 4B-1. Second drain three-valve assembly; 5B. Second pump; 6B. Second pump outlet pressure gauge; 7B. Pump outlet second check valve assembly; 8B. Second pump outlet valve; 9. Minimum reflux valve; 10. External supply control valve; 11. Drainage treatment facility; 12. Underground collection tank; 13. Nitrogen four-valve assembly; 14. Steam four-valve assembly; 15-1. First purge three-valve assembly; 15-2. Second purge three-valve assembly; 15-3. Third purge three-valve assembly. Detailed Implementation

[0024] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0025] Example 1

[0026] As one embodiment of the present invention, such as Figure 1 As shown, the present invention provides a method for conveying ethylene carbon residue, comprising the following equipment and their connection relationships:

[0027] Equipment: Waste liquid tank 1, tank bottom root valve 2, first pump inlet valve 3A, first filter 4A, first drain three-valve group 4A-1, pump 5A, first pump outlet pressure gauge 6A, pump outlet first check valve group 7A, first pump outlet valve 8A, second pump inlet valve 3B, second filter 4B, second drain three-valve group 4B-1, second pump 5B, second pump outlet pressure gauge 6B, pump outlet second check valve group 7B, second pump outlet valve 8B, minimum reflux valve 9, external control valve 10, drain treatment facility 11, underground collection tank 12, nitrogen four-valve group 13, steam four-valve group 14, first purge three-valve group 15-1, second purge three-valve group 15-2, third purge three-valve group 15-3.

[0028] Connection Relationship: The waste liquid tank 1 is connected to the bottom root valve 2 via a pipeline. The bottom root valve 2 is connected to the first pump inlet valve 3A and the second pump inlet valve 3B via pipelines. The first pump inlet valve 3A is connected to the first filter 4A via a pipeline. The first filter 4A is connected to the first pump 5A via a pipeline. The first pump 5A is connected to the first one-way valve group 7A at the pump outlet via a pipeline. The first one-way valve group 7A at the pump outlet is connected to the first pump outlet valve 8A via a pipeline. The second pump inlet valve 3B is connected to the second filter 4B via a pipeline. The second filter 4B is connected to the second pump 5B via a pipeline. The second pump 5B is connected to the second one-way valve group 7B at the pump outlet via a pipeline. The second one-way valve group 7B at the pump outlet is connected to the second pump outlet valve 8B via a pipeline. The first pump outlet valve 8A and the second pump outlet valve 8B are connected via pipelines. One pipeline of the second pump outlet valve 8B is connected to the minimum reflux valve 9 via a pipeline, and the other pipeline of the second pump outlet valve 8B is connected to the external supply control valve 10 via a pipeline. The minimum reflux valve 9 is connected to the waste liquid tank 1 via a pipeline. The external supply control valve 10 is connected to the drainage treatment facility 11 via a pipeline. The nitrogen four-valve group 13 is connected to the common medium nitrogen pipeline via a pipeline. The common medium nitrogen pipeline is connected to the steam four-valve group 14 via a pipeline. The steam four-valve group 14 is connected to the pipeline after the bottom root valve 2 of the tank, the pipeline before the first pump outlet valve 8A, and the pipeline before the second pump outlet valve 8B via a pipeline. The first filter 4A is connected to the first drainage three-valve group 4A-1 via a pipeline. The second filter 4B is connected to the second drainage three-valve group 4B-1 via a pipeline. The first drainage three-valve group 4A-1 and the second drainage three-valve group 4B-1 are connected to the underground collection tank 12 via a pipeline.

[0029] During normal operation, under condition 1: The ethylene residue stored in waste tank 1 is pressurized by the first pump 5A through the bottom valve 2, the first pump inlet valve 3A, and the first filter 4A. Then, it is sent out through the first pump outlet check valve group 7A and the first pump outlet valve 8A. One path returns to waste tank 1 through the minimum reflux valve 9, and the other path is sent to the drainage treatment facility 11 through the outflow control valve. At this time, the second pump inlet valve 3B, the second filter 4B, the second pump 5B, the second pump outlet check valve group 7B, and the second pump outlet valve 8B are in standby mode. Similarly, in operating condition two: when the ethylene residue stored in waste liquid tank 1 is pressurized by the second pump 5B through the bottom valve 2, the second pump inlet valve 3B, and the second filter 4B, and then sent out through the second pump outlet check valve group 7B and the second pump outlet valve 8B, one path returns to waste liquid tank 1 through the minimum return valve 9, and the other path is sent to the drainage treatment facility 11 through the outward control valve; at this time, the first pump inlet valve 3A, the first filter 4A, the first pump 5A, the first pump outlet check valve group 7A, and the first pump outlet valve 8A are in standby state;

[0030] If an abnormality occurs during the delivery of ethylene carbon residue, it is necessary to switch from operating condition one to operating condition two or vice versa. After switching from operating condition one to operating condition two, close the first pump outlet valve 8A, stop the first pump 5A, close the first pump inlet valve 3A, open the first drain three-valve group 4A-1, open the second purge three-valve group 15-2, open the pump outlet check valve 7A, and open the nitrogen four-valve group 13. Use nitrogen to purge the ethylene carbon residue between the first pump outlet valve 8A and the first pump inlet valve 3A. The liquid is transferred to the underground collection tank 12. After approximately 30 minutes, the nitrogen four-valve group 13 is closed, and the steam four-valve group 14 is opened. Steam is used to clean the pipelines and equipment between the first pump outlet valve 8A and the first pump inlet valve 3A. After approximately 30 minutes, the steam four-valve group 14 is closed, and the nitrogen four-valve group 13 is opened. Steam is used to dry the pipelines and equipment between the first pump outlet valve 8A and the first pump inlet valve 3A. After approximately 30 minutes, this step is completed, and the equipment and pipelines involved in Condition 1 are treated. The work required after switching from Condition 2 to Condition 1 is similar and will not be described in detail. After the above work is completed, the standby standby transport facility for ethylene carbon residue is ready for use.

[0031] Example 2

[0032] As one embodiment of the present invention, such as Figure 1 As shown, the present invention provides a method for conveying ethylene carbon residue, comprising the following equipment and their connection relationships:

[0033] Equipment: Waste liquid tank 1, tank bottom root valve 2, first pump inlet valve 3A, first filter 4A, first drain three-valve group 4A-1, pump 5A, first pump outlet pressure gauge 6A, pump outlet first check valve group 7A, first pump outlet valve 8A, second pump inlet valve 3B, second filter 4B, second drain three-valve group 4B-1, second pump 5B, second pump outlet pressure gauge 6B, pump outlet second check valve group 7B, second pump outlet valve 8B, minimum reflux valve 9, external control valve 10, drain treatment facility 11, underground collection tank 12, nitrogen four-valve group 13, steam four-valve group 14, first purge three-valve group 15-1, second purge three-valve group 15-2, third purge three-valve group 15-3.

[0034] Connection Relationship: The waste liquid tank 1 is connected to the bottom root valve 2 via a pipeline. The bottom root valve 2 is connected to the first pump inlet valve 3A and the second pump inlet valve 3B via pipelines. The first pump inlet valve 3A is connected to the first filter 4A via a pipeline. The first filter 4A is connected to the first pump 5A via a pipeline. The first pump 5A is connected to the first one-way valve group 7A at the pump outlet via a pipeline. The first one-way valve group 7A at the pump outlet is connected to the first pump outlet valve 8A via a pipeline. The second pump inlet valve 3B is connected to the second filter 4B via a pipeline. The second filter 4B is connected to the second pump 5B via a pipeline. The second pump 5B is connected to the second one-way valve group 7B at the pump outlet via a pipeline. The second one-way valve group 7B at the pump outlet is connected to the second pump outlet valve 8B via a pipeline. The first pump outlet valve 8A and the second pump outlet valve 8B are connected via pipelines. One pipeline of the second pump outlet valve 8B is connected to the minimum reflux valve 9 via a pipeline, and the other pipeline of the second pump outlet valve 8B is connected to the external supply control valve 10 via a pipeline. The minimum reflux valve 9 is connected to the waste liquid tank 1 via a pipeline. The external supply control valve 10 is connected to the drainage treatment facility 11 via a pipeline. The nitrogen four-valve group 13 is connected to the common medium nitrogen pipeline via a pipeline. The common medium nitrogen pipeline is connected to the steam four-valve group 14 via a pipeline. The steam four-valve group 14 is connected to the pipeline after the bottom root valve 2 of the tank, the pipeline before the first pump outlet valve 8A, and the pipeline before the second pump outlet valve 8B via a pipeline. The first filter 4A is connected to the first drainage three-valve group 4A-1 via a pipeline. The second filter 4B is connected to the second drainage three-valve group 4B-1 via a pipeline. The first drainage three-valve group 4A-1 and the second drainage three-valve group 4B-1 are connected to the underground collection tank 12 via a pipeline.

[0035] During normal operation, under condition 1: The ethylene residue stored in waste tank 1 is pressurized by the first pump 5A through the bottom valve 2, the first pump inlet valve 3A, and the first filter 4A. Then, it is sent out through the first pump outlet check valve group 7A and the first pump outlet valve 8A. One path returns to waste tank 1 through the minimum reflux valve 9, and the other path is sent to the drainage treatment facility 11 through the outflow control valve. At this time, the second pump inlet valve 3B, the second filter 4B, the second pump 5B, the second pump outlet check valve group 7B, and the second pump outlet valve 8B are in standby mode. Similarly, in operating condition two: when the ethylene residue stored in waste liquid tank 1 is pressurized by the second pump 5B through the bottom valve 2, the second pump inlet valve 3B, and the second filter 4B, and then sent out through the second pump outlet check valve group 7B and the second pump outlet valve 8B, one path returns to waste liquid tank 1 through the minimum return valve 9, and the other path is sent to the drainage treatment facility 11 through the outward control valve; at this time, the first pump inlet valve 3A, the first filter 4A, the first pump 5A, the first pump outlet check valve group 7A, and the first pump outlet valve 8A are in standby state;

[0036] When the demand for external delivery of ethylene carbon residue in waste tank 1 is suspended, stop the first pump 5A or the second pump 5B, close the bottom valve 2, and open the flow from the bottom valve 2 to the drainage treatment facility 11. This involves opening the first pump inlet valve 3A, the second pump inlet valve 3B, the first pump outlet valve 8A, the second pump outlet valve 8B, the external delivery control valve 10, and the nitrogen four-valve group 13. Nitrogen gas is then used to purge the ethylene carbon residue between the bottom valve 2 and the drainage treatment facility 11 to the drainage treatment facility. In the facility, open the minimum reflux valve 9 to purge the pipeline between the minimum reflux valve 9 and the waste liquid tank 1; after 30 minutes, close the minimum reflux valve 9, close the nitrogen four-valve group 13, and open the steam four-valve group 14 to use steam to boil away the ethylene carbon residue between the bottom valve 2 of the tank and the drainage treatment facility 11; after 30 minutes, close the steam four-valve group 13 and open the steam four-valve group 14 to use steam to dry the facilities and pipelines between the bottom valve 2 of the tank and the drainage treatment facility 11. After completing the above work, the ethylene carbon residue conveying facility is ready for use.

[0037] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for conveying residual ethylene carbonate, characterized in that, This includes the following devices and their connections: Equipment: Waste liquid tank (1), bottom valve (2), first pump inlet valve (3A), first filter (4A), first drain three-valve group (4A-1), pump (5A), first pump outlet pressure gauge (6A), pump outlet first check valve group (7A), first pump outlet valve (8A), second pump inlet valve (3B), second filter (4B), second drain three-valve group (4B-1), second pump (5B), second pump outlet pressure gauge (6B), pump outlet second check valve group (7B), second pump outlet valve (8B), minimum reflux valve (9), external control valve (10), drain treatment facility (11), underground collection tank (12), nitrogen four-valve group (13), steam four-valve group (14), first purge three-valve group (15-1), second purge three-valve group (15-2), third purge three-valve group (15-3). Connection relationship: The waste liquid tank (1) is connected to the bottom root valve (2) of the tank via a pipeline. The bottom root valve (2) of the tank is connected to the first pump inlet valve (3A) and the second pump inlet valve (3B) via pipelines. The first pump inlet valve (3A) is connected to the first filter (4A) via a pipeline. The first filter (4A) is connected to the first pump (5A) via a pipeline. The first pump (5A) is connected to the first one-way valve group (7A) at the pump outlet via a pipeline. A) The second pump inlet valve (3B) is connected to the first pump outlet valve (8A) via a pipeline. The second pump inlet valve (3B) is connected to the second filter (4B) via a pipeline. The second filter (4B) is connected to the second pump (5B) via a pipeline. The second pump (5B) is connected to the second pump outlet check valve assembly (7B) via a pipeline. The second pump outlet check valve assembly (7B) is connected to the second pump outlet valve (8B) via a pipeline. The first pump outlet valve (8A) and the second pump outlet valve (8B) are connected via a pipeline. One pipeline of the second pump outlet valve (8B) is connected to the minimum reflux valve (9) via a pipeline, and the other pipeline of the second pump outlet valve (8B) is connected to the external supply control valve (10) via a pipeline. The minimum reflux valve (9) is connected to the waste liquid tank (1) via a pipeline. The external supply control valve (10) is connected to the drainage treatment facility (11) via a pipeline. The nitrogen four-valve group (13) is connected to the common medium nitrogen pipeline via a pipeline. The common medium nitrogen pipeline is connected to the steam four-valve group (14) via a pipeline. The steam four-valve group (14) is connected to the pipeline after the bottom root valve (2), the pipeline before the first pump outlet valve (8A), and the pipeline before the second pump outlet valve (8B) via pipelines. The first filter (4A) is connected to the first drain three-valve group (4A-1) via pipelines. The second filter (4B) is connected to the second drain three-valve group (4B-1) via pipelines. The first drain three-valve group (4A-1) and the second drain three-valve group (4B-1) are connected to the underground collection tank (12) via pipelines.

2. The method for conveying ethylene carbon residue according to claim 1, characterized in that, The distance between the waste liquid tank (1) and the root valve (2) at the bottom of the tank is set to the shortest.

3. The method for conveying ethylene carbon residue according to claim 2, characterized in that, Both the nitrogen four-valve group (13) and the steam four-valve group (14) are equipped with double gate valves, check valves and drain valves.

4. A method for conveying ethylene carbon residue according to claim 3, characterized in that, The first check valve group (7A) and the second check valve group (7B) at the pump outlet are equipped with check valves and shut-off valves for bypass.

5. A method for conveying ethylene carbon residue according to claim 4, characterized in that, The minimum return valve (9) and the external control valve (10) are configured as automatic control valves.

6. A method for conveying ethylene carbon residue according to claim 5, characterized in that, The first three-valve group for drainage (4A-1) and the second three-valve group for drainage (4B-1) are equipped with double gate valves and intermediate drain valves.

7. A method for conveying ethylene carbon residue according to claim 6, characterized in that, The nitrogen four-valve group (13) and the steam four-valve group (14) are respectively connected to the common medium nitrogen pipeline and the common medium steam pipeline through pipelines. The common medium nitrogen pipeline and the common medium steam pipeline are respectively connected to the nitrogen four-valve group (13) and the steam four-valve group (14) in conjunction with the first drain three-valve group (4A-1) and the second drain three-valve group (4B-1) to realize the purging, cleaning and drying of the first pump (5A) system or the second pump (5B) system.

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