Hydrogen separation system for PEM electrolytic bath and process thereof

Abstract

The invention provides a hydrogen separation system for a PEM electrolytic bath and a process thereof, and relates to the technical field of electrolytic baths, the system comprises the PEM electrolytic bath, the PEM electrolytic bath is connected with a gas-liquid separator, the gas-liquid separator is respectively connected with a cooler and a water-sealed tank, the cooler is further connected with the water-sealed tank, and a condensate tank is arranged on a pipeline connecting the cooler and the water-sealed tank. The water-sealed tank is respectively connected with the water injection tank, the nitrogen tank and the U-shaped overflow liquid discharge pipe; a first regulating valve is arranged on a pipeline for connecting the gas-liquid separator and the water-sealed tank; a liquid level meter is arranged on the gas-liquid separator and connected with a liquid level controller, and the liquid level controller is connected with the first adjusting valve. According to the invention, the functions of hydrogen-water preliminary separation, hydrogen cooling, flash evaporation, water sealing, nitrogen humidification and nitrogen replacement are realized; the valve is a pneumatic or electric valve, automatic operation can be achieved through program control, and operability is embodied; the water-sealed tank in the system integrates various process functions such as flash evaporation, water sealing, drainage and nitrogen humidification, so that pipelines and equipment can be reduced, and the system cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolyzers, and in particular to a hydrogen separation system for a PEM electrolyzer and a process thereof. Background Art

[0002] The proton exchange membrane electrolyzer (hereinafter referred to as PEM electrolyzer) is a device that uses pure water as raw material to produce hydrogen or oxygen by electrolyzing water. The anode output of the PEM electrolyzer is mainly a mixture of oxygen and water, and the cathode output is mainly a mixture of hydrogen and water. The electrolyzer supporting system needs to perform preliminary separation of oxygen and water on the anode side and hydrogen and water on the cathode side. For the cathode side, the existing technology mainly performs preliminary separation of hydrogen and water and cools the separated hydrogen; the pressurized hydrogen-containing water is flashed and then discharged. Before operation, the containers and pipelines in the system need to be replaced with high-purity nitrogen, and nitrogen generally requires a certain humidity. The existing technology usually requires an additional nitrogen humidifier to be added to the system. The hydrogen separation system for PEM electrolyzers in the existing technology still has the defects of high cost, low degree of automation, and unstable system operation. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a hydrogen separation system for a PEM electrolyzer and a process thereof. The hydrogen separation process for a PEM electrolyzer includes preliminary hydrogen-water separation, hydrogen cooling, flash evaporation, water sealing, nitrogen humidification, and nitrogen replacement. The hydrogen separation system for a PEM electrolyzer is automatically controlled by an electronic control program, so that the system runs more smoothly and can reduce the cost of the hydrogen separation process system for a PEM electrolyzer.

[0004] The technical solution adopted by the present invention is: A hydrogen separation system for a PEM electrolyzer, comprising a PEM electrolyzer and a master program controller, wherein the PEM electrolyzer is connected to a gas-liquid separator, the gas-liquid separator is respectively connected to a cooler and a water seal tank, the cooler is also connected to the water seal tank, a condensate tank is arranged on a pipeline connecting the cooler and the water seal tank, and the water seal tank is respectively connected to a water injection tank, a nitrogen tank and a U-shaped overflow liquid discharge pipe; A first regulating valve is arranged on the pipeline connecting the gas-liquid separator and the water seal tank; A liquid level meter is arranged on the gas-liquid separator, the liquid level meter is connected to a liquid level controller, the liquid level controller is connected to a first regulating valve, the master program controller is connected to the liquid level controller, and the master program controller is connected to the first regulating valve.

[0005] Preferably, in the hydrogen separation system for the PEM electrolyzer, the gas-liquid separator is connected to the water seal tank via a first pipeline and a second pipeline respectively, the first regulating valve is arranged on the first pipeline, a first cut-off valve and a second cut-off valve are respectively arranged on the first pipeline on both sides of the first regulating valve, and a third cut-off valve is arranged on the second pipeline.

[0006] Preferably, in the hydrogen separation system for PEM electrolyzer, the cooler is connected to a downstream device, a pressure transmitter, a first program-controlled valve and a second program-controlled valve are sequentially arranged on a pipeline connecting the downstream device and the cooler, the pressure transmitter and the first program-controlled valve are both connected to a pressure controller, the pressure controller is connected to a master program controller, the second program-controlled valve is connected to a first vent flame arrester, and the first vent flame arrester is connected to a first vent pipeline.

[0007] Preferably, in the hydrogen separation system for PEM electrolyzer, a third programmable valve is provided on the pipeline connecting the cooler and the condensate tank, a fourth programmable valve is provided on the pipeline connecting the condensate tank and the water seal tank, and the third programmable valve and the fourth programmable valve are connected to a master program controller.

[0008] Preferably, in the hydrogen separation system for PEM electrolyzer, a fifth programmable valve is provided on the pipeline connecting the water seal tank and the water injection tank, a sixth programmable valve is provided on the pipeline connecting the water seal tank and the nitrogen tank, and the fifth programmable valve and the sixth programmable valve are connected to the main program controller.

[0009] Preferably, in the hydrogen separation system for PEM electrolyzer, the water seal tank is also connected to a second vent flame arrester, the second vent flame arrester is connected to a second vent pipe, a seventh programmable valve is arranged on the pipeline connecting the water seal tank and the second vent flame arrester, and the seventh programmable valve is connected to the main program controller.

[0010] Preferably, in the hydrogen separation system for PEM electrolyzer, an eighth program-controlled valve is provided on the U-shaped overflow liquid discharge pipe, and the eighth program-controlled valve is connected to the main program controller.

[0011] The present application also provides a hydrogen separation process for a PEM electrolyzer, wherein the hydrogen separation process performs hydrogen separation by using a hydrogen separation system for a PEM electrolyzer, and the hydrogen separation process for a PEM electrolyzer comprises the following steps: Step S1. Install the gas-liquid separator and the water seal tank at the same horizontal plane, open the first regulating valve, the first shut-off valve, the second shut-off valve and the fifth program-controlled valve, inject water into the water seal tank through the water injection tank, and the water in the water seal tank flows into the gas-liquid separator. When the liquid level of the gas-liquid separator reaches the set value, close the fifth program-controlled valve and the water injection is completed; Step S2. The nitrogen entering the water seal tank is brought into contact with the water in the water seal tank to wet the dry nitrogen, thereby completing nitrogen humidification and replacement; Step S3. The cathode outlet of the PEM electrolyzer is a mixed fluid of hydrogen and water. The mixed fluid enters the gas-liquid separator through the pipeline for preliminary gas-liquid separation. The first programmable valve and the second programmable valve are opened to connect the downstream device. After the gas-liquid separation, the high-temperature hydrogen enters the cooler for cooling, and the cooled hydrogen enters the downstream device; the third programmable valve is opened, and the condensed water in the cooler after the gas-liquid separation flows into the condensate tank. When the condensed water in the condensate tank is stored for a certain period of time, the third programmable valve is closed, and the fourth programmable valve is opened to discharge the condensed water into the bottom of the water seal tank; the first regulating valve is opened, and the water in the gas-liquid separator enters the bottom of the water seal tank and flashes. Then, the valve opening of the first regulating valve is adjusted according to the signal sent by the liquid level meter and the liquid level controller, so that the liquid level in the gas-liquid separator is within a certain scale range, so that the system runs more smoothly. When the water in the water seal tank reaches the set value, it is discharged from the system through the U-shaped overflow liquid discharge pipe.

[0012] Preferably, in the hydrogen separation process for PEM electrolyzer, step S2 specifically comprises: Step S21. Open the second program-controlled valve to connect to the first vent pipe, close the fifth program-controlled valve, the seventh program-controlled valve, the eighth program-controlled valve and the first program-controlled valve, and then open the sixth program-controlled valve. The nitrogen in the nitrogen tank is passed into the water seal tank, and the pressure in the system increases. When the pressure transmitter detects that the system pressure reaches the set value, the sixth program-controlled valve is closed, the first program-controlled valve is opened, and the pressure in the system decreases. When it decreases to the set value, the first program-controlled valve is closed; Step S22. Repeat step S21 multiple times to complete the replacement process.

[0013] Preferably, in the hydrogen separation process for the PEM electrolyzer, the setting value of the gas-liquid separator in step S1 is 40-70% of the water storage volume of the gas-liquid separator, and the storage time of the condensed water in the condensate tank in step S3 is 15-30 minutes.

[0014] Advantages of the present invention: The hydrogen separation system and process for PEM electrolyzer of the present invention can realize the functions of preliminary hydrogen-water separation, hydrogen cooling, flash evaporation, water sealing, nitrogen humidification and nitrogen replacement; the valve adopts pneumatic or electric valve, and can realize automatic operation by electric control, which embodies easy operability; the water seal tank in the system integrates multiple process functions such as flash evaporation, water sealing, drainage, nitrogen humidification, etc., which can reduce pipelines and equipment and reduce system costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic structural diagram of the hydrogen separation system for PEM electrolyzer of the present invention.

[0016] Figure 2 It is a circuit connection schematic diagram of the hydrogen separation system for PEM electrolyzer of the present invention. DETAILED DESCRIPTION

[0017] The present invention will be further described below in conjunction with specific drawings and embodiments.

[0018] Example 1 like Figure 1-2 A hydrogen separation system for a PEM electrolyzer, comprising a PEM electrolyzer 1 and a master program controller, wherein the PEM electrolyzer 1 is connected to a gas-liquid separator 2, the gas-liquid separator 2 is respectively connected to a cooler 3 and a water seal tank 16, the cooler 3 is also connected to the water seal tank 16, a condensate tank 10 is arranged on the pipeline connecting the cooler 3 and the water seal tank 16, and the water seal tank 16 is respectively connected to a water injection tank 25, a nitrogen tank 26 and a U-shaped overflow liquid discharge pipe 17; A first regulating valve 20 is provided on the pipeline connecting the gas-liquid separator 2 and the water seal tank 16; The gas-liquid separator 2 is provided with a liquid level meter 14 , the liquid level meter 14 is connected to a liquid level controller 15 , the liquid level controller 15 is connected to a first regulating valve 20 , the master program controller is connected to the liquid level controller 15 , and the master program controller is connected to the first regulating valve 20 .

[0019] The gas-liquid separator 2 is connected to the water seal tank 16 through the first pipeline 27 and the second pipeline 28 respectively. The first regulating valve 20 is arranged on the first pipeline 27. The first shut-off valve 21 and the second shut-off valve 22 are respectively arranged on the first pipeline 27 on both sides of the first regulating valve 20. The third shut-off valve 23 is arranged on the second pipeline 28.

[0020] The cooler 3 is connected to the downstream device 29, and a pressure transmitter 4, a first program-controlled valve 24 and a second program-controlled valve 6 are sequentially arranged on the pipeline connecting the downstream device 29 and the cooler 3. The pressure transmitter 4 and the first program-controlled valve 24 are both connected to a pressure controller 5, and the pressure controller 5 is connected to the main program controller. The second program-controlled valve 6 is connected to a first vent flame arrester 7, and the first vent flame arrester 7 is connected to a first vent pipe 8.

[0021] A third program-controlled valve 9 is arranged on the pipeline connecting the cooler 3 and the condensate tank 10, a fourth program-controlled valve 11 is arranged on the pipeline connecting the condensate tank 10 and the water seal tank 16, and the third program-controlled valve 9 and the fourth program-controlled valve 11 are connected to the overall program controller.

[0022] A fifth program-controlled valve 13 is arranged on the pipeline connecting the water seal tank 16 and the water injection tank 25, a sixth program-controlled valve 19 is arranged on the pipeline connecting the water seal tank 16 and the nitrogen tank 26, and the fifth program-controlled valve 13 and the sixth program-controlled valve 19 are connected to the overall program controller.

[0023] The water seal tank 16 is also connected to a second venting flame arrester 30, which is connected to a second venting pipeline 31. A seventh program-controlled valve 12 is arranged on the pipeline connecting the water seal tank 16 and the second venting flame arrester 30, and the seventh program-controlled valve 12 is connected to a general program controller.

[0024] The U-shaped overflow liquid discharge pipe 17 is provided with an eighth program-controlled valve 18 , and the eighth program-controlled valve 18 is connected to the main program controller.

[0025] Example 2 like Figure 1-2 A hydrogen separation process for a PEM electrolyzer is disclosed. The hydrogen separation process is performed by a hydrogen separation system for a PEM electrolyzer. The hydrogen separation process for a PEM electrolyzer comprises the following steps: Step S1. The installation heights of the gas-liquid separator 2 and the water seal tank 16 are on the same horizontal plane, the first regulating valve 20, the first shut-off valve 21, the second shut-off valve 22 and the fifth program-controlled valve 13 are opened, water is injected into the water seal tank 16 through the water injection tank 25, and the water in the water seal tank 16 flows into the gas-liquid separator 2. When the liquid level of the gas-liquid separator 2 reaches the set value, the fifth program-controlled valve 13 is closed and the water injection is completed; the set value of the gas-liquid separator 2 is 40-70% of the water storage volume of the gas-liquid separator 2. The purpose of water injection is to allow the gas-liquid separator 2 and the water seal tank 16 to have a certain water level height. For the gas-liquid separator 2, it is mainly to prevent the gas-liquid separator 2 from being empty when the system is initially running, and hydrogen enters the water seal tank 16 from the bottom. For the liquid level of the water seal tank 16, it mainly plays a water seal role and reflects safety.

[0026] Step S2. Before the hydrogen-containing pipeline is put into use, inert gas replacement should be performed. Generally, high-purity nitrogen is used, and a certain humidity is required. The nitrogen entering the water seal tank 16 is brought into contact with the water in the water seal tank 16 to wet the dry nitrogen, thereby completing nitrogen humidification and nitrogen replacement; Step S3. The cathode outlet of the PEM electrolyzer 1 is a mixed fluid of hydrogen and water. The mixed fluid enters the gas-liquid separator 2 through a pipeline for preliminary gas-liquid separation. The first program-controlled valve 24 and the second program-controlled valve 6 are opened to connect to the downstream device 29. After the gas-liquid separation, the high-temperature hydrogen enters the cooler 3 for cooling and enters the downstream device 29; the third program-controlled valve 9 is opened, and the condensed water in the cooler 3 after the gas-liquid separation flows into the condensate tank 10. When the condensed water in the condensate tank 10 is stored for 15-30 minutes, the third program-controlled valve 9 is closed, and the fourth program-controlled valve 11 is opened to discharge the condensed water into the bottom of the water seal tank 16; the water seal tank 16 is provided with a second venting pipeline 31, and the pressure is normal pressure, so the gas-liquid separator 2 is higher than the pressure of the water seal tank 16, the first regulating valve 20 is opened, the water of the gas-liquid separator 2 enters the bottom of the water seal tank 16 and flashes, and the trace hydrogen dissolved in the water turns back into gas due to the pressure reduction. Since it enters from the bottom of the water seal tank 16, a certain height of water level in the tank can play the role of water seal, and then the valve opening of the first regulating valve 20 is adjusted by the signal sent by the liquid level meter 14 and the liquid level controller 15, so that the liquid level in the gas-liquid separator 2 is within a certain scale range, so that the system runs more smoothly. When the water in the water seal tank 16 reaches the set value, the water set value of the water seal tank 16 is the liquid level height of the U-shaped overflow liquid discharge pipe 17, and the system is discharged through the U-shaped overflow liquid discharge pipe 17.

[0027] Step S2 is specifically as follows: Step S21. Open the second program-controlled valve 6 to connect to the first vent pipe 8, close the fifth program-controlled valve 13, the seventh program-controlled valve 12, the eighth program-controlled valve 18 and the first program-controlled valve 24, and then open the sixth program-controlled valve 19, the nitrogen in the nitrogen tank 26 is passed into the water seal tank 16, the pressure in the system increases, when the pressure transmitter 4 detects that the system pressure reaches the set value, close the sixth program-controlled valve 19, open the first program-controlled valve 24, the pressure in the system decreases, and when it decreases to the set value, close the first program-controlled valve 24; Step S22. Repeat step S21 multiple times, 3-5 times, to complete the replacement process.

[0028] The hydrogen separation system for PEM electrolyzer of the present invention and the process thereof can realize the functions of preliminary hydrogen-water separation, hydrogen cooling, flash evaporation, water sealing, nitrogen humidification and nitrogen replacement; the valve adopts pneumatic or electric valve, and can realize automatic operation by electric control, which embodies easy operability; the water seal tank in the system integrates multiple process functions such as flash evaporation, water sealing, drainage, nitrogen humidification, etc., which can reduce pipelines and equipment and reduce system costs.

[0029] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A hydrogen separation system for a PEM electrolyzer, characterized in that: The invention comprises a PEM electrolyzer (1) and a master program controller, wherein the PEM electrolyzer (1) is connected to a gas-liquid separator (2), the gas-liquid separator (2) is respectively connected to a cooler (3) and a water seal tank (16), the cooler (3) is also connected to the water seal tank (16), a condensate tank (10) is arranged on the pipeline connecting the cooler (3) and the water seal tank (16), and the water seal tank (16) is respectively connected to a water injection tank (25), a nitrogen tank (26) and a U-shaped overflow liquid discharge pipe (17); A first regulating valve (20) is provided on the pipeline connecting the gas-liquid separator (2) and the water seal tank (16); A liquid level meter (14) is provided on the gas-liquid separator (2), the liquid level meter (14) is connected to a liquid level controller (15), the liquid level controller (15) is connected to a first regulating valve (20), the master program controller is connected to the liquid level controller (15), and the master program controller is connected to the first regulating valve (20).

2. The hydrogen separation system for PEM electrolyzer according to claim 1, characterized in that: The gas-liquid separator (2) is connected to the water seal tank (16) via a first pipeline (27) and a second pipeline (28), respectively; the first regulating valve (20) is arranged on the first pipeline (27); a first shut-off valve (21) and a second shut-off valve (22) are respectively arranged on the first pipeline (27) on both sides of the first regulating valve (20); and a third shut-off valve (23) is arranged on the second pipeline (28).

3. The hydrogen separation system for PEM electrolyzer according to claim 1, characterized in that: The cooler (3) is connected to a downstream device (29). A pressure transmitter (4), a first program-controlled valve (24) and a second program-controlled valve (6) are arranged in sequence on the pipeline connecting the downstream device (29) and the cooler (3). The pressure transmitter (4) and the first program-controlled valve (24) are both connected to a pressure controller (5). The pressure controller (5) is connected to a master program controller. The second program-controlled valve (6) is connected to a first venting flame arrester (7). The first venting flame arrester (7) is connected to a first venting pipeline (8).

4. The hydrogen separation system for PEM electrolyzer according to claim 1, characterized in that: A third program-controlled valve (9) is provided on the pipeline connecting the cooler (3) and the condensate tank (10), and a fourth program-controlled valve (11) is provided on the pipeline connecting the condensate tank (10) and the water seal tank (16). Both the third program-controlled valve (9) and the fourth program-controlled valve (11) are connected to a master program controller.

5. The hydrogen separation system for PEM electrolyzer according to claim 1, characterized in that: A fifth programmable valve (13) is arranged on the pipeline connecting the water seal tank (16) and the water injection tank (25), and a sixth programmable valve (19) is arranged on the pipeline connecting the water seal tank (16) and the nitrogen tank (26). Both the fifth programmable valve (13) and the sixth programmable valve (19) are connected to a master program controller.

6. The hydrogen separation system for PEM electrolyzer according to claim 1, characterized in that: The water seal tank (16) is also connected to a second venting flame arrester (30), and the second venting flame arrester (30) is connected to a second venting pipeline (31). A seventh programmable valve (12) is arranged on the pipeline connecting the water seal tank (16) and the second venting flame arrester (30), and the seventh programmable valve (12) is connected to a master program controller.

7. The hydrogen separation system for PEM electrolyzer according to claim 1, characterized in that: An eighth program-controlled valve (18) is provided on the U-shaped overflow liquid discharge pipe (17), and the eighth program-controlled valve (18) is connected to the main program controller.

8. A hydrogen separation process for a PEM electrolyzer, characterized in that: The hydrogen separation process is carried out by using the hydrogen separation system for a PEM electrolyzer according to any one of claims 1 to 7, and the hydrogen separation process for a PEM electrolyzer comprises the following steps: Step S1. Install the gas-liquid separator (2) and the water seal tank (16) at the same horizontal plane, open the first regulating valve (20), the first shut-off valve (21), the second shut-off valve (22) and the fifth programmable valve (13), inject water into the water seal tank (16) through the water injection tank (25), and the water in the water seal tank (16) flows into the gas-liquid separator (2). When the liquid level of the gas-liquid separator (2) reaches the set value, close the fifth programmable valve (13), and the water injection is completed; Step S2. The nitrogen entering the water seal tank (16) is brought into contact with the water in the water seal tank (16) to wet the dry nitrogen, thereby completing nitrogen humidification and replacement; Step S3. The cathode outlet of the PEM electrolyzer (1) is a mixed fluid of hydrogen and water. The mixed fluid enters the gas-liquid separator (2) through a pipeline for preliminary gas-liquid separation. The first program-controlled valve (24) and the second program-controlled valve (6) are opened to connect to the downstream device (29). After the gas-liquid separation, the high-temperature hydrogen enters the cooler (3) for cooling. The cooled hydrogen enters the downstream device (29). The third program-controlled valve (9) is opened. After the gas-liquid separation, the condensed water in the cooler (3) flows into the condensate tank (10). When the condensed water in the condensate tank (10) is stored for a certain period of time, the third program-controlled valve (9) is closed. The third programmable valve (9) is opened, and the fourth programmable valve (11) is opened to discharge the condensed water into the bottom of the water seal tank (16); the first regulating valve (20) is opened, and the water in the gas-liquid separator (2) enters the bottom of the water seal tank (16) and flashes, and then the valve opening of the first regulating valve (20) is adjusted by the signal sent by the liquid level meter (14) and the liquid level controller (15), so that the liquid level in the gas-liquid separator (2) is within a certain scale range, so that the system runs more smoothly. When the water in the water seal tank (16) reaches the set value, it is discharged from the system through the U-shaped overflow liquid discharge pipe (17).

9. The hydrogen separation process for PEM electrolyzer according to claim 8, characterized in that: Step S2 specifically includes: Step S21. Open the second program-controlled valve (6) to connect to the first venting pipeline (8), close the fifth program-controlled valve (13), the seventh program-controlled valve (12), the eighth program-controlled valve (18) and the first program-controlled valve (24), then open the sixth program-controlled valve (19), and let the nitrogen in the nitrogen tank (26) flow into the water seal tank (16), so that the pressure in the system increases. When the pressure transmitter (4) detects that the system pressure reaches the set value, close the sixth program-controlled valve (19), open the first program-controlled valve (24), and reduce the pressure in the system. When the pressure drops to the set value, close the first program-controlled valve (24); Step S22. Repeat step S21 multiple times to complete the humidification and replacement process.

10. The hydrogen separation process for PEM electrolyzer according to claim 8, characterized in that: In step S1, the setting value of the gas-liquid separator (2) is 40-70% of the water storage volume of the gas-liquid separator (2), and in step S3, the storage time of the condensed water in the condensate tank (10) is 15-30 minutes.

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