PEM electrolysis water hydrogen production high pressure gas-liquid separation tank and control method thereof

Abstract

This invention discloses a high-pressure gas-liquid separator for PEM electrolysis of water to produce hydrogen and its control method. The separator includes a tank body with an inlet at one upper side and an outlet at the top. A perforated baffle plate is installed inside the tank body near the inlet. A high-pressure gas-liquid mixture enters the tank body through the inlet and undergoes gas-liquid separation under the action of the perforated baffle plate. The gas is discharged directly from the outlet, while the liquid flows downwards through the perforated baffle plate into the bottom of the tank for storage. The gas-liquid separator of this invention features a simple structural design and easier operation. The hydrogen gas still maintains significant pressure when discharged from the outlet, reducing energy consumption for subsequent hydrogen compression and significantly lowering costs. When the liquid level is below the protection level, the protection level solenoid valve closes, preventing complete discharge of liquid from the outlet and achieving a liquid seal effect. This avoids contamination of the hydrogen gas caused by air entering the tank through the outlet after the liquid is completely discharged.

Description

Technical Field

[0001] This invention relates to the field of water electrolysis for hydrogen production technology, specifically to a high-pressure gas-liquid separator for PEM water electrolysis for hydrogen production and its control method. Background Technology

[0002] PEM (Polymer Electrolysis) water electrolysis hydrogen production technology has gained widespread attention due to its advantages such as being pollution-free, producing high-purity hydrogen, having a fast response, and high current density. It can also directly output high-pressure hydrogen, saving energy for hydrogen compressors. During the electrolysis process, protons generated at the anode are transported to the cathode as hydrated hydrogen ions and, under the action of a catalyst, generate hydrogen. This hydrogen carries a large amount of water, requiring gas-liquid separation during subsequent hydrogen purification. However, because the entire hydrogen purification system is under high pressure, the water at the bottom of a typical gas-liquid separator cannot provide the necessary liquid seal. That is, when a certain amount of liquid is stored at the bottom of the separator to be discharged, a large amount of high-pressure hydrogen will be ejected due to the pressure difference, which is not only dangerous but also wasteful. Complete liquid sealing requires a storage tank over 100 meters high.

[0003] Chinese invention patent CN115487621A discloses a novel experimental gas-liquid separation device, particularly for use in water electrolysis hydrogen production equipment. It includes a transparent cylindrical separator shell on both the hydrogen and oxygen sides, a gas-liquid separation diaphragm, and a diaphragm fixing support. The transparent shell design allows for direct study of the flow of alkaline gas mixtures and gas-liquid separation time. The addition of a diaphragm within the gas-liquid separation device increases separation efficiency. The gas-permeable membrane impedes liquid flow, while the liquid-permeable membrane reduces the gas content in the refluxed alkaline solution, thus achieving better separation efficiency. However, the liquid-permeable membrane cannot completely isolate hydrogen gas.

[0004] Chinese invention patent CN117443113A discloses a gas-liquid separation system and method under complex environments. The gas-liquid separation system includes a base, on which a primary separation skid and a secondary separation skid are mounted. The primary separation skid is mounted on the secondary separation skid and the two are connected through a separation hole. The primary separation skid has a first inlet and a second inlet, and the secondary separation skid has a gas outlet and a liquid outlet. A plug-type separator is installed inside the primary separation skid and can slide within it. The first and second inlets intermittently alternately introduce the medium to be separated to complete the separation process. The plug-type separator, which can move intermittently within the primary separation skid, is used for depressurization or cooling. The medium to be separated can achieve primary separation of the gas and liquid phases based on cyclone separation through the through holes, rotating holes, and depressurization holes within the plug-type separator. The secondary separation process is completed by the secondary separation skid, ultimately achieving gas-liquid separation. However, the system structure is relatively complex, and the depressurization of the gas will increase energy consumption for subsequent hydrogen compression. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a high-pressure gas-liquid separator for PEM water electrolysis to produce hydrogen, including a tank body, an air inlet provided on one side of the upper part of the tank body, an exhaust outlet provided at the top of the tank body, and a baffle plate installed in the tank body near the air inlet.

[0006] High-pressure gas-liquid mixture enters the tank through the inlet. Under the action of the baffle plate, gas-liquid separation occurs. The gas is discharged directly from the outlet, while the liquid flows down through the baffle plate into the bottom of the tank for storage.

[0007] Preferably, a discharge level solenoid valve is installed in the middle of the tank body, which divides the tank body into two chambers, including a first chamber and a second chamber.

[0008] Preferably, the tank is equipped with two liquid level monitoring points: one is the discharge liquid level and is located in the first chamber, and the other is the protection liquid level and is located in the second chamber.

[0009] Preferably, the first chamber is located above the discharge level solenoid valve, the baffle plate is located inside the first chamber, and the first chamber is connected to the air inlet and the exhaust port.

[0010] Preferably, the second chamber is located below the discharge level solenoid valve, and a drain port is provided at the bottom of the tank, which is connected to the second chamber.

[0011] Preferably, the drain outlet is connected to the inlet of the diaphragm drainage pump via a pipeline.

[0012] Preferably, it also includes dual liquid level sensors for monitoring the maximum and minimum liquid levels in the tank, and the dual liquid level sensors are electrically connected to the controller.

[0013] Preferably, the controller is a PLC controller.

[0014] Preferably, the controller is electrically connected to the discharge level solenoid valve, the protection level solenoid valve, and the diaphragm drain pump, and the controller realizes the opening and closing of the discharge level solenoid valve, the protection level solenoid valve, and the diaphragm drain pump.

[0015] A control method for a high-pressure gas-liquid separator used in PEM water electrolysis for hydrogen production, the specific steps of which are as follows:

[0016] The system is started, and the gas-liquid mixture enters the tank through the air inlet;

[0017] The gas-liquid mixture undergoes gas-liquid separation under the action of the baffle plate. The gas is discharged from the exhaust port, and the liquid flows into the bottom of the tank. The discharge level solenoid valve is in the open state, and the protection level solenoid valve is in the closed state to store the liquid.

[0018] Determine if the maximum liquid level of the dual liquid level sensor is at the discharge level. If not, return to the previous step; if yes, proceed to the next step.

[0019] After the discharge level solenoid valve is adjusted to the closed state, the protection level solenoid valve and the diaphragm drain pump are adjusted to the open state to discharge liquid from the drain port.

[0020] Determine whether the minimum liquid level of the dual liquid level sensor is at the protection liquid level or whether the maximum liquid level is at the maximum range liquid level. If not, return to the previous step; if yes, proceed to the next step.

[0021] After the protective liquid level solenoid valve and diaphragm drain pump are first adjusted to the closed state, the discharge liquid level solenoid valve is then immediately adjusted to the open state to store liquid.

[0022] If the gas-liquid mixture continues to enter the tank, the system continues to check whether the maximum liquid level of the dual liquid level sensors is at the discharge level. If the gas-liquid mixture stops entering the tank, the system stops.

[0023] The technical effects and advantages of this invention are as follows:

[0024] 1. In the gas-liquid separator of the present invention, the structure of the tank is simple and the operation is simpler. The hydrogen gas still has a large pressure when it is discharged from the exhaust port, which reduces the energy consumption of subsequent hydrogen compression and can greatly reduce the cost.

[0025] 2. In this invention, when the liquid level is lower than the protection liquid level, the protection liquid level solenoid valve is closed, and the liquid will not be completely discharged from the drain port, which achieves the effect of liquid sealing and also avoids the pollution of hydrogen caused by air entering the tank from the drain port after the liquid is completely discharged.

[0026] 3. This control method is used for the gas-liquid separation of high-pressure hydrogen in the PEM water electrolysis hydrogen production process. It can effectively solve the safety and waste problems caused by the large-scale escape of high-pressure hydrogen during gas-liquid separation and recovery in the PEM water electrolysis hydrogen production process. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the high-pressure gas-liquid separator for PEM water electrolysis to produce hydrogen provided in the embodiments of this application;

[0028] Figure 2 This is a flowchart of the control method for the high-pressure gas-liquid separator used in PEM water electrolysis for hydrogen production, provided in an embodiment of this application.

[0029] In the diagram: 1. Air inlet; 2. Exhaust outlet; 3. Dual liquid level sensor; 4. Discharge liquid level solenoid valve; 5. Protective liquid level solenoid valve; 6. Drain outlet; 7. Controller; 8. Baffle plate; 9. Diaphragm drain pump; 10. Tank. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and design various embodiments with various modifications suitable for a particular purpose.

[0031] Please see Figure 1 As shown in the figure, this embodiment provides a high-pressure gas-liquid separator for PEM water electrolysis to produce hydrogen, including a tank body 10. An air inlet 1 is provided on one side of the upper part of the tank body 10, and an exhaust port 2 is provided at the top of the tank body 10. A baffle plate 8 is installed inside the tank body 10 near the air inlet 1. The high-pressure gas-liquid mixture enters the tank body 10 from the air inlet 1 and undergoes gas-liquid separation under the action of the baffle plate 8. The gas is discharged directly from the exhaust port 2, and the liquid flows down into the bottom of the tank body 10 through the baffle plate 8 for storage. The gas-liquid separation is achieved through the baffle plate 8. The tank body 10 has a simple structural design and is easier to operate.

[0032] Compared with existing technologies that use diaphragms or depressurize the gas, hydrogen still has a large pressure when it is discharged from exhaust port 2, which reduces the energy consumption of subsequent hydrogen compression and can greatly reduce costs.

[0033] Furthermore, multiple perforated baffle plates 8 can be provided, and the multiple perforated baffle plates 8 are arranged at intervals to form tortuous channels. The gas-liquid mixture passes through the tortuous channels and comes into contact with the multiple perforated baffle plates 8, so that the water vapor can be fully condensed.

[0034] Understandably, in order to improve condensation efficiency, a serpentine pipe can also be welded onto the perforated baffle plate 8. The pipe is connected to a heat exchanger, and the heat exchanger cools down the perforated baffle plate 8, thereby improving the efficiency of water vapor condensation.

[0035] In this embodiment, a discharge level solenoid valve 4 is installed in the middle of the tank body 10. The discharge level solenoid valve 4 divides the tank body 10 into two chambers, including a first chamber and a second chamber. The chamber above the discharge level solenoid valve 4 is the first chamber. The baffle plate 8 is located in the first chamber. The first chamber is connected to the air inlet 1 and the exhaust port 2.

[0036] The chamber below the discharge level solenoid valve 4 is the second chamber. A drain port 6 is provided at the bottom of the tank 10. The drain port 6 is connected to the second chamber. A protective level solenoid valve 5 is installed on the drain port 6. After the protective level solenoid valve 5 is opened, the liquid stored at the bottom of the tank 10 is discharged in time.

[0037] Furthermore, the drain port 6 is connected to the inlet of the diaphragm drain pump 9 through a pipeline, and the outlet of the diaphragm drain pump 9 is connected to the return water storage tank through a pipeline. When draining, starting the diaphragm drain pump 9 can improve the efficiency of draining, and the diaphragm drain pump 9 can also play a sealing role to prevent air from entering the tank 10 from the drain port 6.

[0038] In this embodiment, two liquid level monitoring points are provided inside the tank 10. One liquid level monitoring point is located in the first chamber, where the liquid level is the discharge liquid level, and the discharge liquid level is located between the discharge liquid level solenoid valve 4 and the baffle porous plate 8.

[0039] Another liquid level monitoring point is located in the second chamber. The liquid level here is the protection liquid level. The protection liquid level is located between the discharge liquid level solenoid valve 4 and the discharge port 6, and there is a certain distance between the protection liquid level and the discharge port 6. When the liquid level is lower than the protection liquid level, the protection liquid level solenoid valve 5 is closed, and the liquid will not be completely discharged from the discharge port 6, which plays a liquid seal role. It also prevents air from entering the tank 10 from the discharge port 6 after the liquid is completely discharged, thus preventing the backflow of air after the liquid below the protection liquid level is discharged.

[0040] It also includes a dual liquid level sensor 3, which is used to monitor the maximum and minimum liquid levels in the tank 10. The dual liquid level sensor 3 is electrically connected to the controller 7, which can realize accurate monitoring of the liquid level in the tank 10. The controller 7 is a PLC controller, which can load control instructions into memory at any time for storage and execution.

[0041] In this embodiment, the controller 7 is also electrically connected to the discharge level solenoid valve 4, the protection level solenoid valve 5, and the diaphragm drain pump 9. The controller 7 enables the opening and closing of the discharge level solenoid valve 4, the protection level solenoid valve 5, and the diaphragm drain pump 9, which is easily achieved in the prior art and will not be described in detail here.

[0042] High-pressure gas-liquid mixture enters tank 10 through inlet 1. Under the action of baffle plate 8, gas-liquid separation occurs. The gas is discharged directly from outlet 2, while the liquid condenses after passing through baffle plate 8 and flows downwards into the bottom of tank 10 for storage. Controller 7 determines the real-time liquid level based on feedback from dual liquid level sensors 3 and controls the opening and closing of discharge level solenoid valve 4, protection level solenoid valve 5, and diaphragm drain pump 9. When the maximum liquid level detected by dual liquid level sensor 4 is greater than or equal to the discharge level... The controller 7 first adjusts the discharge level solenoid valve 4 to the closed state, and then adjusts the protection level solenoid valve 5 and the diaphragm drain pump 9 to the open state to discharge liquid. When the dual level sensor 4 detects that the minimum liquid level is less than or equal to the protection level or the maximum liquid level rises to the maximum range level, the controller 7 first adjusts the protection level solenoid valve 5 and the diaphragm drain pump 9 to the closed state, and then adjusts the discharge level solenoid valve 4 to the open state to store liquid. This completes one cycle of liquid storage and discharge, and repeats this cycle until the system stops operating.

[0043] In this invention, the tank contains two solenoid valves and a dual liquid level sensor. The controller can automatically adjust the opening and closing status of the solenoid valves according to the actual liquid level. When the maximum liquid level of the dual liquid level sensor 3 reaches the discharge liquid level, the discharge liquid level solenoid valve 4 will automatically close to isolate the high-pressure hydrogen from the separated water. Then, the protective liquid level solenoid valve 5 at the tail end of the tank 10 will open. The water below the discharge liquid level solenoid valve 4 (in the second chamber) will be discharged into the hydrogen return water storage tank under the action of gravity or diaphragm drainage pump 9. When the minimum liquid level of the dual liquid level sensor 3 is at the protective liquid level or the maximum liquid level is at the maximum range liquid level, the controller will automatically close the protective liquid level solenoid valve 5 and diaphragm drainage pump 9 first, and then open the discharge liquid level solenoid valve 4 to store the liquid. This prevents air backflow after the liquid below the protective liquid level is drained, and prevents the liquid above the discharge liquid level solenoid valve 4 from overflowing the baffle plate 8. This completes one gas-liquid separation, storage, and discharge process. It not only recovers the water carried by the hydrogen, but also prevents the escape of high-pressure hydrogen, which is both safe and avoids waste.

[0044] In another embodiment, see Figure 2 As shown, a control method for a high-pressure gas-liquid separator used in PEM water electrolysis for hydrogen production is also provided, with the specific steps as follows:

[0045] S1. Start the system. The gas-liquid mixture enters the tank 10 from the air inlet 1.

[0046] S2. The gas-liquid mixture undergoes gas-liquid separation under the action of the baffle porous plate 8. The gas is discharged from the exhaust port 2, and the liquid flows into the bottom of the tank. The discharge level solenoid valve 4 is in the open state, and the protection level solenoid valve 5 is in the closed state to store the liquid.

[0047] S3. Determine whether the maximum liquid level of the dual liquid level sensor 3 is at the discharge liquid level. If not, return to step S2. If yes, proceed to the next step.

[0048] S4. After the discharge level solenoid valve 4 is adjusted to the closed state, the protection level solenoid valve 5 is adjusted to the open state, and the liquid is discharged from the discharge port 6.

[0049] S5. Determine whether the minimum liquid level of the dual liquid level sensor 3 is at the protection liquid level or whether the maximum liquid level is at the maximum range liquid level. If not, return to step S4. If yes, proceed to the next step.

[0050] S6. After the protection level solenoid valve 5 and the diaphragm drain pump 9 are first adjusted to the closed state, the discharge level solenoid valve 4 is then immediately adjusted to the open state to store liquid.

[0051] S7. If the gas-liquid mixture continues to enter the tank 10, return to step S3. If the gas-liquid mixture stops entering the tank 10, stop the system.

[0052] This control method is used for the gas-liquid separation of high-pressure hydrogen in the PEM water electrolysis hydrogen production process. It can effectively solve the safety and waste problems caused by the large amount of high-pressure hydrogen escaping during the gas-liquid separation and recovery process in the PEM water electrolysis hydrogen production process.

[0053] Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art and related fields based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described and explained in the present invention, unless otherwise specified or limited, shall be implemented according to conventional means in the art.

Claims

1. A high-pressure gas-liquid separator for PEM water electrolysis to produce hydrogen, comprising a tank body, characterized in that, An air inlet is provided on one side of the upper part of the tank body, and an exhaust outlet is provided at the top of the tank body. A baffle plate is installed inside the tank body near the air inlet. High-pressure gas-liquid mixture enters the tank from the inlet. Under the action of the baffle plate, gas-liquid separation occurs. Gas is discharged directly from the outlet, while liquid flows down through the baffle plate into the bottom of the tank for storage. A discharge level solenoid valve is installed in the middle of the tank body, which divides the tank body into two chambers, including a first chamber and a second chamber. The tank is equipped with two liquid level monitoring points: one is the discharge liquid level and is located in the first chamber, and the other is the protection liquid level and is located in the second chamber. It also includes dual level sensors for monitoring the maximum and minimum liquid levels in the tank, and the dual level sensors are electrically connected to the controller; The first chamber is located above the discharge level solenoid valve, and the baffle plate is located inside the first chamber. The first chamber is connected to the air inlet and the exhaust outlet. The second chamber is located below the discharge level solenoid valve. A drain port is provided at the bottom of the tank, which is connected to the second chamber. A protective level solenoid valve is installed on the drain port. The drain outlet is connected to the inlet of the diaphragm drainage pump via a pipeline.

2. The high-pressure gas-liquid separator for PEM electrolysis of water to produce hydrogen according to claim 1, characterized in that, The controller is a PLC controller.

3. The high-pressure gas-liquid separator for PEM electrolysis of water to produce hydrogen according to claim 1, characterized in that, The controller is electrically connected to the discharge level solenoid valve, the protection level solenoid valve, and the diaphragm drain pump, and the controller enables the opening and closing of the discharge level solenoid valve, the protection level solenoid valve, and the diaphragm drain pump.

4. A control method for a high-pressure gas-liquid separator for PEM water electrolysis to produce hydrogen according to any one of claims 1-3, characterized in that, The specific steps are as follows: The system is started, and the gas-liquid mixture enters the tank through the air inlet; The gas-liquid mixture undergoes gas-liquid separation under the action of the baffle plate. The gas is discharged from the exhaust port, and the liquid flows into the bottom of the tank. The discharge level solenoid valve is in the open state, and the protection level solenoid valve is in the closed state to store the liquid. Determine if the maximum liquid level of the dual liquid level sensor is at the discharge level. If not, return to the previous step; if yes, proceed to the next step. After the discharge level solenoid valve is adjusted to the closed state, the protection level solenoid valve and the diaphragm drain pump are adjusted to the open state to discharge liquid from the drain port. Determine whether the minimum liquid level of the dual liquid level sensor is at the protection liquid level or whether the maximum liquid level is at the maximum range liquid level. If not, return to the previous step; if yes, proceed to the next step. After the protective liquid level solenoid valve and diaphragm drain pump are first adjusted to the closed state, the discharge liquid level solenoid valve is then immediately adjusted to the open state to store liquid. If the gas-liquid mixture continues to enter the tank, the system continues to check whether the maximum liquid level of the dual liquid level sensors is at the discharge level. If the gas-liquid mixture stops entering the tank, the system stops.

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