Method for detecting the gas tightness of a pem electrolyser

Abstract

The application discloses a method for detecting the air tightness of a PEM electrolytic cell, and steps are as follows: (1) preparing a detection device; (2) connecting a first detection pipe with an anode side outlet, connecting a second detection pipe with a cathode side outlet, and sealing an anode pure water inlet by a plug; (3) when detecting the anode side, closing the sixth, second hand valves, opening the first, fourth and fifth hand valves, adjusting a pressure reducing valve until a pressure gauge reaches a required value, closing the first hand valve after the pressure is stable, judging whether the air tightness is up to the standard according to pressure change after pressure maintaining, and opening the second hand valve; (4) when detecting the cathode side, closing the second, fourth and fifth hand valves, opening the first, third and sixth hand valves, adjusting the pressure reducing valve until the pressure gauge reaches the required value, closing the first hand valve after the pressure is stable, judging whether the air tightness is up to the standard according to pressure change after pressure maintaining, and opening the second hand valve. The above method can prevent damage to the electrolytic cell diaphragm caused by too fast air inlet speed of a detection air source and can timely release pressure.

Description

Technical Field

[0001] This invention relates to the field of PEM electrolyzers, and more specifically to a method for detecting the airtightness of PEM electrolyzers. Background Technology

[0002] Before powering on, the PEM water electrolysis hydrogen production electrolyzer must undergo an airtightness test to ensure that the hydrogen and oxygen produced by the electrolyzer do not leak and cause danger. The PEM electrolyzer has a cathode side and an anode side. The cathode side outlet is the hydrogen outlet, the anode side inlet is the pure water inlet, and the anode side outlet is the oxygen and pure water outlet. When the electrolyzer is powered on, pure water enters through the anode side inlet. The oxygen produced after the reaction flows out through the anode side outlet along with the unreacted pure water, while the hydrogen produced on the cathode side is discharged through the cathode side outlet. During the airtightness test, the electrolyzer is neither powered nor circulated with water; only the airtightness of the anode and cathode under the working gas pressure is tested. Current methods for testing the airtightness of PEM electrolyzers do not consider the potential damage to the electrolyzer diaphragm caused by excessively fast gas intake, nor do they consider the safety hazards caused by excessively high pressure during testing. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method for detecting the airtightness of a PEM electrolyzer that can prevent damage to the diaphragm of the electrolyzer caused by excessively fast gas intake and can release pressure in a timely manner.

[0004] To solve the above problems, the technical solution adopted by the present invention is as follows: a method for detecting the airtightness of a PEM electrolytic cell, the method steps of which are as follows: (1) Prepare the detection device. The detection device includes: a detection gas source and a buffer tank. The outlet of the detection gas source is connected to the inlet of the buffer tank through a gas supply pipe. One end of the vent pipe is open, and the other end of the vent pipe is connected to the gas supply pipe. The buffer tank is equipped with four outlets, namely the first outlet, the second outlet, the third outlet, and the fourth outlet. The first outlet is connected to one end of the first pipe, and the other end of the first pipe is connected to the vent pipe. The second outlet is connected to one end of the second pipe, and the other end of the second pipe is connected to the vent pipe. The third outlet is connected to one end of the third pipe, and the other end of the third pipe is connected to the first detection pipe, the second outlet, and the third outlet. One end of the second detection tube is connected, and a pressure gauge is connected to the fourth outlet. A pressure reducing valve and a first hand valve are connected in series along the flow direction on the gas supply pipe. A second hand valve is connected in series on the vent pipe. Closing the second hand valve does not affect the venting of the first and second pipelines. The connection between the vent pipe and the gas supply pipe is located between the first hand valve and the buffer tank. A third hand valve and a high-pressure safety valve are connected in series along the flow direction on the first pipeline. A fourth hand valve and a low-pressure safety valve are connected in series along the flow direction on the second pipeline. A fifth hand valve is connected in series on the first detection tube, and a sixth hand valve is connected in series on the second detection tube. A plug for sealing the pure water inlet of the electrolytic cell anode is also provided. (2) Connect the other end of the first detection tube to the anode side outlet of the electrolytic cell, and connect the other end of the second detection tube to the cathode side outlet of the electrolytic cell. Seal the anode pure water inlet of the electrolytic cell with a plug. (3) When the anode side air tightness test begins, close the sixth hand valve, disconnect the second test tube, close the second hand valve, and open the first hand valve, fourth hand valve, and fifth hand valve in sequence. Then slowly adjust the pressure reducing valve until the pressure displayed on the pressure gauge reaches the required value. When the pressure stabilizes, close the first hand valve and maintain the pressure for the specified time. Determine whether the anode side air tightness meets the standard based on the pressure change. Then open the second hand valve to empty the pressure in the pipeline. The anode side air tightness test of the electrolytic cell is completed. (4) When the cathode side air tightness test begins, close the second, fourth and fifth hand valves, and open the first, third and sixth hand valves in sequence. Then slowly adjust the pressure reducing valve until the pressure displayed on the pressure gauge reaches the required value. After the pressure stabilizes, close the first hand valve and maintain the pressure for the specified time. Determine whether the cathode side air tightness meets the standard based on the pressure change. Then open the second hand valve to release the pressure in the pipeline. The cathode side air tightness test of the electrolytic cell is completed.

[0005] Furthermore, in the aforementioned method for detecting the airtightness of a PEM electrolyzer, the detection gas source is a nitrogen cylinder group.

[0006] Furthermore, in the aforementioned method for detecting the airtightness of a PEM electrolyzer, the set pressure of the high-pressure safety valve is 1.1 times the working pressure on the cathode side of the electrolyzer, and the set pressure of the low-pressure safety valve is 1.1 times the working pressure on the anode side of the electrolyzer.

[0007] Furthermore, in the aforementioned method for detecting the airtightness of a PEM electrolyzer, the inlet of the buffer tank is located in the lower middle part of the buffer tank, and each outlet of the buffer tank is located at the top of the buffer tank.

[0008] The advantages of this invention are as follows: The detection device used in the method for detecting the airtightness of a PEM electrolyzer has a compact structure and is easy to operate. By installing a pressure reducing valve at the outlet of the detection gas source, the inlet pressure of the electrolyzer can be adjusted. The pressure-reduced gas source first passes through a buffer tank, which buffers the gas and prevents excessively fast flow rates from impacting the electrolyzer diaphragm. Furthermore, during the anode and cathode airtightness test, there is a risk that manual pressure adjustment may be too rapid, causing the pressure to exceed the design pressure of the electrolyzer. To avoid this risk and potential damage to the electrolyzer, a safety valve is added. Simultaneously, to meet the testing requirements of different pressure levels for the anode and cathode, high-pressure safety valves and low-pressure safety valves are used respectively, and manual valves are provided for switching between them. Attached Figure Description

[0009] Figure 1This is a schematic diagram of the detection device described in this invention. Detailed Implementation

[0010] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0011] The method for detecting the airtightness of a PEM electrolyzer is as follows: (1) Prepare the detection device, such as Figure 1As shown, the detection device includes: a detection gas source 1 and a buffer tank 2. In this embodiment, the detection gas source 1 is a nitrogen cylinder group. In actual applications, the detection gas source 1 can also be other inert gas cylinder groups. The outlet of the detection gas source 1 is connected to the inlet of the buffer tank 2 through a gas supply pipe 3. One end of the vent pipe 4 is open, and the other end of the vent pipe 4 is connected to the gas supply pipe 3. The buffer tank 2 is provided with four outlets, namely the first outlet, the second outlet, the third outlet, and the fourth outlet. The first outlet is connected to one end of the first pipe 5, and the other end of the first pipe 5 is connected to the vent pipe 4. The second outlet is connected to one end of the second pipe 6. The other end is connected to the vent pipe 4. The third outlet is connected to one end of the third pipe 7. The other end of the third pipe 7 is connected to one end of the first detection pipe 8 and the second detection pipe 9, respectively. The other end of the first detection pipe 8 is used to connect to the anode side outlet of the electrolytic cell 10, and the other end of the second detection pipe 9 is used to connect to the cathode side outlet of the electrolytic cell 10. A pressure gauge 11 is connected to the fourth outlet. The pressure gauge 11 is used to display the pressure in the buffer tank 2 and the tank. A pressure reducing valve 12 and a first hand valve 13 are connected in series along the flow direction on the gas supply pipe 3. A second hand valve 14 is connected in series on the vent pipe 4. When the second hand valve 14 is closed, it does not affect the first pipe. 5. The exhaust pipe 6 and the second pipe are connected to the gas supply pipe 3 between the first hand valve 13 and the buffer tank 2. The third hand valve 15 and the high pressure safety valve 16 are connected in series along the flow direction on the first pipe 5. The fourth hand valve 17 and the low pressure safety valve 18 are connected in series along the flow direction on the second pipe 6. The fifth hand valve 19 is connected in series on the first detection pipe 8. The sixth hand valve 20 is connected in series on the second detection pipe 9. A plug for sealing the pure water inlet of the anode of the electrolytic cell 10 is also provided. (2) Connect the other end of the first detection pipe 8 to the anode side outlet of the electrolytic cell 10. Connect the other end of the second detection pipe 9 to the cathode side outlet of the electrolytic cell 10. Use a plug to seal the pure water inlet of the anode of the electrolytic cell 10; (3) When the anode side air tightness test begins, close the sixth hand valve 20, disconnect the second test tube 9, the high pressure safety valve 16 and the third hand valve 15 can be left open, close the second hand valve 14, open the first hand valve 13, the fourth hand valve 17 and the fifth hand valve 19 in sequence, and then slowly adjust the pressure reducing valve 12 until the pressure displayed by the pressure gauge 11 reaches the required value. When the pressure is stable, close the first hand valve 13, maintain the pressure for the specified time, judge whether the anode side air tightness meets the standard based on the pressure change, and then open the second hand valve 14 to empty the pressure in the pipeline. The anode side air tightness test of the electrolytic cell is completed.(4) When starting the cathode-side airtightness test, close the second hand valve 14, the fourth hand valve 17, and the fifth hand valve 19, and open the first hand valve 13, the third hand valve 15, and the sixth hand valve 20 in sequence. Then, slowly adjust the pressure reducing valve 12 until the pressure displayed on the pressure gauge 11 reaches the required value. After the pressure stabilizes, close the first hand valve 13 and maintain the pressure for the specified time. Determine whether the cathode-side airtightness meets the standard based on the pressure change. Then, open the second hand valve 14 to release the pressure in the pipeline. The cathode-side airtightness test of the electrolytic cell is now complete.

[0012] The inlet pressure of the electrolytic cell 10 can be adjusted by installing a pressure reducing valve 12 at the outlet of the nitrogen cylinder group. The nitrogen gas after pressure reduction first passes through a buffer tank, which can buffer the gas and prevent excessive flow rate from impacting the diaphragm of the electrolytic cell.

[0013] PEM electrolyzers typically produce hydrogen at a high pressure of 3-4 MPa at the cathode, while oxygen is produced at atmospheric pressure at the anode. The circulating water pressure is generally less than 0.5 MPa. To meet the different pressure levels required for cathode and anode testing, the testing system is equipped with a high-pressure safety valve 16 and a low-pressure safety valve 18. These two safety valves can be switched manually. The safety valves effectively prevent damage to the electrolyzer's interior caused by excessive pressure during airtightness testing.

[0014] In this embodiment, the set pressure of the high-pressure safety valve 16 is 1.1 times the working pressure on the cathode side of the electrolytic cell, and the set pressure of the low-pressure safety valve 18 is 1.1 times the working pressure on the anode side of the electrolytic cell.

[0015] For better cushioning, the inlet of buffer tank 2 is located in the lower middle part of buffer tank 2, and each outlet of buffer tank 2 is located at the top of buffer tank 2.

[0016] During the anode and cathode airtightness test, there is a risk that manual pressure adjustment may be too rapid, causing the pressure to exceed the design pressure of the electrolytic cell. To avoid this risk and damage to the electrolytic cell, a safety valve has been added. Furthermore, to meet the testing requirements of different pressure levels for the anode and cathode, a high-pressure safety valve 16 and a low-pressure safety valve 18 are used, each with a manual valve for switching.

Claims

1. A method for detecting the airtightness of a PEM electrolytic cell, characterized in that: The steps are as follows: (1) Prepare the detection device. The detection device includes: a detection gas source and a buffer tank. The outlet of the detection gas source is connected to the inlet of the buffer tank through a gas supply pipe. One end of the vent pipe is open, and the other end of the vent pipe is connected to the gas supply pipe. The buffer tank is equipped with four outlets, namely the first outlet, the second outlet, the third outlet, and the fourth outlet. The first outlet is connected to one end of the first pipe, and the other end of the first pipe is connected to the vent pipe. The second outlet is connected to one end of the second pipe, and the other end of the second pipe is connected to the vent pipe. The third outlet is connected to one end of the third pipe, and the other end of the third pipe is connected to the first detection pipe, the second outlet, and the third outlet. One end of the second detection tube is connected, and a pressure gauge is connected to the fourth outlet. A pressure reducing valve and a first hand valve are connected in series along the flow direction on the gas supply pipe. A second hand valve is connected in series on the vent pipe. Closing the second hand valve does not affect the venting of the first and second pipelines. The connection between the vent pipe and the gas supply pipe is located between the first hand valve and the buffer tank. A third hand valve and a high-pressure safety valve are connected in series along the flow direction on the first pipeline. A fourth hand valve and a low-pressure safety valve are connected in series along the flow direction on the second pipeline. A fifth hand valve is connected in series on the first detection tube, and a sixth hand valve is connected in series on the second detection tube. A plug for sealing the pure water inlet of the electrolytic cell anode is also provided. (2) Connect the other end of the first detection tube to the anode side outlet of the electrolytic cell, and connect the other end of the second detection tube to the cathode side outlet of the electrolytic cell. Seal the anode pure water inlet of the electrolytic cell with a plug. (3) When the anode side air tightness test begins, close the sixth hand valve, disconnect the second test tube, close the second hand valve, and open the first hand valve, fourth hand valve, and fifth hand valve in sequence. Then slowly adjust the pressure reducing valve until the pressure displayed on the pressure gauge reaches the required value. When the pressure stabilizes, close the first hand valve and maintain the pressure for the specified time. Determine whether the anode side air tightness meets the standard based on the pressure change. Then open the second hand valve to empty the pressure in the pipeline. The anode side air tightness test of the electrolytic cell is completed. (4) When the cathode side air tightness test begins, close the second, fourth and fifth hand valves, and open the first, third and sixth hand valves in sequence. Then slowly adjust the pressure reducing valve until the pressure displayed on the pressure gauge reaches the required value. After the pressure stabilizes, close the first hand valve and maintain the pressure for the specified time. Determine whether the cathode side air tightness meets the standard based on the pressure change. Then open the second hand valve to release the pressure in the pipeline. The cathode side air tightness test of the electrolytic cell is completed.

2. The method for detecting the airtightness of a PEM electrolyzer according to claim 1, characterized in that: The gas source for testing is a nitrogen cylinder group.

3. The method for detecting the airtightness of a PEM electrolyzer according to claim 1 or 2, characterized in that: The set pressure of the high-pressure safety valve is 1.1 times the working pressure on the cathode side of the electrolytic cell, and the set pressure of the low-pressure safety valve is 1.1 times the working pressure on the anode side of the electrolytic cell.

4. The method for detecting the airtightness of a PEM electrolyzer according to claim 1 or 2, characterized in that: The inlet of the buffer tank is located in the lower middle part of the buffer tank, and the outlets of the buffer tank are located at the top of the buffer tank.

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