Method for reducing hydrogen content in oxygen of AEM water electrolysis system in emergency shutdown state and shutdown auxiliary system
By using a shutdown assistance system to rapidly reduce the hydrogen content in the oxygen during an emergency shutdown of the AEM water electrolysis system, the problem of elevated hydrogen content in the oxygen was solved, the reliability and safety of the system were improved, and the operation and maintenance costs were reduced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SINOHYKEY TECHNOLOGY (GUANGZHOU) CO LTD
- Filing Date
- 2026-02-11
- Publication Date
- 2026-05-12
AI Technical Summary
In an emergency shutdown, the hydrogen content in the oxygen of an AEM water electrolysis system increases, leading to reduced gas purity, increased purification costs, and a threat to system safety. Existing technologies are unable to effectively address this issue.
A shutdown auxiliary system is adopted, including a shutdown auxiliary power supply, a cold liquid tank, a temperature control system, a pressure control system, and a flow control system, which form an alkaline solution circulation loop. The low-temperature alkaline solution in the cold liquid tank reduces the temperature and pressure of the AEM electrolyzer, enabling it to quickly return to normal temperature and pressure, and expelling any oxygen it carries, thus ensuring system safety.
It can effectively control the hydrogen concentration in oxygen within milliseconds, improve system reliability, reduce operation and maintenance costs, extend the life of core components, reduce human intervention, and adapt to the fluctuations of renewable energy.
Smart Images
Figure CN122013255A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrolysis or electrophoresis technology, and in particular to a method and a shutdown auxiliary system for reducing the hydrogen content in the oxygen of an AEM water electrolysis system during an emergency shutdown. Background Technology
[0002] Compared to traditional alkaline water electrolysis and proton exchange membrane (PEM) water electrolysis technologies, anion exchange membrane (AEM) water electrolysis technology not only allows the use of non-precious metal catalysts but also boasts higher current density and response speed, making it highly promising for adapting to fluctuating power sources such as wind and solar power. However, AEM water electrolysis systems operating under renewable energy sources like wind and solar power must frequently cope with drastic fluctuations in input power. While power electronic control and system integration technologies can mitigate these fluctuations to some extent, extreme weather, grid failures, or sudden equipment malfunctions can still necessitate emergency shutdowns to protect core components. During this process, transient changes in pressure differential, temperature, and ion transport within the electrolyzer disrupt the original gas-liquid equilibrium, particularly exacerbating cross-permeation of gases across the anion exchange membrane, leading to a significant increase in hydrogen concentration on the oxygen side (hydrogen in oxygen). Excessively high levels of hydrogen in oxygen not only reduce gas purity and increase subsequent purification costs but can also form explosive mixtures, seriously threatening system safety.
[0003] Currently, the main technical approaches to addressing the aforementioned issues focus on two main categories: one is to reduce the steady-state permeability of gases through membrane electrode structure optimization (such as enhancing membrane density, designing gradient pore support layers, and introducing hydrogen-blocking coatings); the other is to maintain the chemical potential difference between hydrogen and oxygen during normal operation using dynamic control methods (such as active current density adjustment and pressure balance algorithms). While these methods perform well under normal operating conditions, their processes are complex and their adaptability to non-steady-state processes such as emergency shutdowns is significantly insufficient. For example, although structural improvements to the membrane material can delay gas cross-mixing, they cannot quickly block the already occurring hydrogen-oxygen mixing after a power outage; dynamic control relies on active current regulation, but during an emergency shutdown, the power supply is momentarily interrupted, the control system loses its ability to execute, and pressure imbalance and gas back diffusion become inevitable. Therefore, existing technologies cannot effectively solve the problem of increased hydrogen in oxygen in the electrolyzer of an AEM water electrolysis system during an emergency shutdown. Summary of the Invention
[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method and shutdown auxiliary system for reducing the hydrogen content in the oxygen of an AEM electrolysis water system during emergency shutdown.
[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a method for reducing the hydrogen content in the oxygen of an AEM electrolysis water system during an emergency shutdown, comprising the following steps: S1. In the event of an emergency shutdown of the AEM electrolysis water system, the temperature of the alkaline solution in the AEM electrolyzer is reduced to room temperature via a shutdown auxiliary system. The shutdown auxiliary system includes a shutdown auxiliary power supply, a cold liquid tank, a temperature control system, a pressure control system, and a flow control system. The shutdown auxiliary power supply is electrically connected to the temperature control system, pressure control system, and flow control system. The cold liquid tank, temperature control system, pressure control system, and flow control system are sequentially connected to form an alkaline solution circulation loop. The flow control system is connected to the AEM electrolyzer. S2. When restarting the AEM electrolysis water system, first start the electrical control system, then start the AEM electrolysis cell, then start the anode tail gas system and the cathode tail gas system, then start the anode liquid supply system to start the anode side alkali circulation, and after the flow rate stabilizes, raise the temperature of the anode side alkali to the working temperature.
[0006] When an emergency shutdown of the AEM electrolysis water system occurs, the shutdown auxiliary power supply in the shutdown auxiliary system starts quickly to ensure that the current input of the AEM electrolyzer in the AEM electrolysis water system remains unchanged before the shutdown. At the same time, the shutdown auxiliary power supply drives the temperature control system, pressure control system, and flow control system of the alkali circulation in the cold liquid tank to start working.
[0007] A flow control system is used to extract high-temperature alkali solution from the AEM electrolytic cell while simultaneously injecting low-temperature alkali solution from the cold liquid tank into the AEM electrolytic cell. This flow control is linked to the temperature and pressure control systems. When the alkali solution begins to circulate, the temperature control system monitors the temperature of the circulating alkali solution in real time. If the temperature of the circulating alkali solution rises due to the mixing of the high-temperature alkali solution in the AEM electrolytic cell with the low-temperature alkali solution in the cold liquid tank, the temperature control system will correspondingly increase its cooling capacity to ensure that the circulating alkali solution is maintained at a lower temperature, thereby achieving the goal of rapidly cooling the alkali solution in the AEM electrolytic cell.
[0008] Simultaneously, when the alkali solution begins to circulate, the pressure control system monitors the pressure of the circulating alkali solution in real time. When the alkali solution in the AEM electrolyzer is at atmospheric pressure, the pressure control system primarily monitors the pressure of the circulating alkali solution; when the alkali solution in the AEM electrolyzer is at high pressure, the pressure control system uses components such as high-pressure throttling valves to reduce the pressure of the circulating alkali solution, and coordinates with the flow control system and temperature control system to rationally control the state of the circulating alkali solution, thereby achieving the goal of rapidly reducing the pressure of the alkali solution in the AEM electrolyzer.
[0009] Furthermore, when the alkaline solution in the AEM electrolyzer circulates through the temperature, pressure, and flow control systems to the cold liquid tank and returns to ambient temperature and pressure (typically 20-25°C and 1 atmosphere (approximately 101.325 kPa)), the oxygen it carries will accumulate at the top of the cold liquid tank, posing a safety hazard if stored for extended periods. Therefore, a venting unit with an automatic venting component is installed at the top of the cold liquid tank to remove the oxygen carried by the circulating alkaline solution, ensuring the safe and stable operation of the system. When the temperature and pressure of the alkaline solution in the AEM electrolyzer drop to ambient temperature and pressure, the shutdown protection procedure is completed, the auxiliary power supply stops supplying power, and the auxiliary shutdown system ceases operation.
[0010] After the above steps S1, the increase in hydrogen concentration in oxygen in the AEM electrolysis cell after an emergency shutdown of the AEM water electrolysis system can be effectively controlled. At the same time, in conjunction with step S2, when the AEM water electrolysis system is restarted, the electrical control system is first started to provide working current, then the AEM electrolysis cell is started, and then the anode tail gas system and cathode tail gas system are started to monitor the hydrogen content in oxygen and the oxygen content in hydrogen in real time during the operation of the AEM electrolysis cell and to ensure safe operation. Then, the anode liquid supply system is started to start the circulation of alkali solution on the anode side. After the flow rate stabilizes, the temperature of the alkali solution on the anode side is raised to the working temperature.
[0011] At startup, since the temperature has not yet reached the operating temperature, the current applied to the AEM electrolyzer by the electrical control system is the operating current, which will result in a high voltage. As the anode supply system starts up, the temperature of the alkali solution on the anode side begins to rise, and the voltage under the operating current begins to drop. When it drops to a stable level, it indicates that the startup is complete.
[0012] In some embodiments, the cold liquid tank stores an alkaline solution at a temperature below 25°C.
[0013] More preferably, the alkaline solution is a potassium hydroxide (KOH) solution with a concentration of 1M.
[0014] In a second aspect, the present invention provides a shutdown assistance system, comprising: Auxiliary power supply for shutdown, coolant tank, temperature control system, pressure control system, and flow control system; The shutdown auxiliary power supply is electrically connected to the temperature control system, pressure control system, and flow control system; the cold liquid tank, temperature control system, pressure control system, and flow control system are sequentially connected to form an alkaline solution circulation loop; the flow control system is connected to the AEM electrolysis cell in the AEM electrolysis water system.
[0015] When the AEM water electrolysis system encounters an unexpected situation and has to shut down urgently, the shutdown assistance system of this invention can be activated within milliseconds. It uses a cold liquid tank, a temperature control system, a pressure control system, and a flow control system to form an alkaline solution circulation loop. The flow control system extracts the high-temperature alkaline solution from the AEM electrolysis cell and injects the low-temperature alkaline solution from the cold liquid tank into the AEM electrolysis cell, thereby effectively controlling the increase in hydrogen concentration in oxygen in the AEM electrolysis cell after the AEM water electrolysis system has to shut down urgently.
[0016] When the AEM water electrolysis system is shut down in an emergency, the shutdown auxiliary power supply in the shutdown auxiliary system will start quickly to provide power support for the temperature control system, pressure control system and flow control system to ensure the smooth operation of the entire alkali circulation loop; at the same time, it also provides necessary power assistance for the AEM electrolyzer, cathode tail gas system and anode tail gas system in the AEM water electrolysis system.
[0017] In a preferred embodiment of the shutdown assistance system of the present invention, the cold liquid tank includes an evacuation unit for discharging oxygen carried to the cold liquid tank by the alkali solution circulation.
[0018] The cold liquid tank in the shutdown auxiliary system is used to store a certain amount of alkali solution. When the AEM water electrolysis system shuts down in an emergency, it provides a recyclable alkali solution to quickly cool and depressurize the alkali solution in the AEM electrolyzer. This part of the alkali solution is stored separately in the cold liquid tank and is not mixed with the alkali solution circulated and consumed during the normal operation of the AEM water electrolysis system. It is only used during an emergency shutdown.
[0019] In a preferred embodiment of the shutdown assistance system of the present invention, the temperature control system includes: Temperature detection unit, used to detect the temperature of circulating alkaline solution; Temperature cooling unit is used to reduce the temperature of circulating alkali solution.
[0020] The temperature control system in the shutdown auxiliary system is mainly used for temperature detection and regulation of the circulating alkali solution. When the temperature of the circulating alkali solution rises, it is cooled down in time, thereby rapidly cooling down the alkali solution in the AEM electrolyzer. On the one hand, this ensures that the alkali solution in the AEM electrolyzer can quickly return to room temperature standby state in the event of an unexpected shutdown, reducing corrosion of the electrolyzer and related pipelines at operating temperatures. On the other hand, rapid cooling can shorten the intervention time of the shutdown auxiliary system, extend the service life of the shutdown auxiliary system, and reduce the capacity of the shutdown auxiliary power supply to reduce costs.
[0021] In a preferred embodiment of the shutdown assistance system of the present invention, the pressure control system includes: Pressure detection unit is used to detect the pressure of circulating alkali solution; Pressure regulating valve, used to reduce the pressure of circulating alkali solution.
[0022] More preferably, the pressure regulating valve is a high-pressure throttle valve.
[0023] The pressure control system in the shutdown auxiliary system is mainly used for detecting and regulating the pressure of the circulating alkali solution. In case of an emergency shutdown, it quickly restores the alkali solution in the AEM electrolyzer from a high-pressure state to an atmospheric pressure state. If the anolyte in the AEM electrolyzer is pressurized during operation, the pressure control system will perform pressure matching in the circulating alkali solution, ensuring that the pressure of the alkali solution in the cooling tank is consistent with the pressure in the AEM electrolyzer, and gradually reducing the pressure during circulation.
[0024] In a preferred embodiment of the shutdown assistance system of the present invention, the flow control system includes: A flow detection unit is used to detect the flow rate of the circulating alkali solution; The flow regulation unit is used to regulate the flow rate of the circulating alkali solution.
[0025] The flow control system in the shutdown auxiliary system is mainly used for detecting and regulating the flow rate of circulating alkali solution. In case of emergency shutdown, it starts circulating alkali solution and works with the temperature control system and pressure control system to quickly adjust the temperature and pressure of alkali solution in the AEM electrolytic cell to normal temperature and pressure.
[0026] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a method for reducing the hydrogen content in oxygen within an AEM (Aqueous Electrolytic Metal) water electrolysis system during emergency shutdowns. When AEM water electrolysis systems inevitably face the risk of emergency shutdowns due to fluctuating power sources such as wind and solar power, this method, compared to traditional methods relying on membrane material optimization or dynamic current regulation, maintains safety and protection capabilities even under extreme conditions such as power outages and communication interruptions. This significantly improves the reliability of the AEM water electrolysis system, making it more commercially viable in renewable energy fluctuation scenarios. Simultaneously, because the hydrogen concentration in oxygen is effectively controlled after shutdown, the load on the subsequent hydrogen purification system is significantly reduced, decreasing additional energy consumption, lowering operation and maintenance costs, and extending the lifespan of core components (such as membrane electrodes), thus reducing the overall operation and maintenance costs of the AEM electrolyzer system.
[0027] The shutdown assistance system of this invention can be started within milliseconds. It utilizes a cold liquid tank, a temperature control system, a pressure control system, and a flow control system to form an alkaline solution circulation loop. The flow control system extracts high-temperature alkaline solution from the AEM electrolyzer and injects low-temperature alkaline solution from the cold liquid tank into the AEM electrolyzer, thereby effectively controlling the increase in hydrogen concentration in the oxygen within the AEM electrolyzer after an emergency shutdown. Traditional AEM electrolyzer systems often require manual intervention for gas replacement or pre-restart purification after an emergency shutdown, which not only increases operational complexity but may also affect hydrogen production efficiency and economics. The shutdown assistance system of this invention enables fully automated emergency handling, reducing the need for manual intervention. Attached Figure Description
[0028] Figure 1 This is a schematic diagram of the shutdown assistance system and the AEM water electrolysis system of the present invention; Figure 2 The graphs show the changes in voltage across the AEM electrolyzer and the hydrogen content in the oxygen of the anode tail gas system in Test Examples 1-4 of this invention.
[0029] Explanation of reference numerals in the attached figures: 101. AEM electrolytic cell; 102. Anode tail gas system; 103. Anode liquid supply system; 104. Electrical control system; 105. Cathode liquid supply system; 106. Cathode tail gas system; 200. Shutdown Auxiliary System; 201. Shutdown Auxiliary Power Supply; 202. Cold Liquid Tank; 203. Temperature Control System; 204. Pressure Control System; 205. Flow Control System; 206. Cold Liquid Tank Drainage Unit. Detailed Implementation
[0030] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.
[0031] Unless otherwise specified, all other materials and reagents used in the examples are commercially available.
[0032] Example 1 1) A shutdown assistance system (such as...) Figure 1 As shown), it includes: an auxiliary power supply 201, a cold liquid tank 202, a temperature control system 203, a pressure control system 204, a flow control system 205, and a cold liquid tank venting unit 206; the auxiliary power supply 201 is electrically connected to the temperature control system 203, the pressure control system 204, and the flow control system 205; the cold liquid tank 202, the temperature control system 203, the pressure control system 204, and the flow control system 205 are sequentially connected to form an alkaline solution circulation loop; the flow control system 205 is connected to the AEM electrolysis water system (such as...). Figure 1 Connect the AEM electrolytic cell 101 shown in the diagram. Connect the PLC control system to... Figure 1 The components of the shutdown assistance system shown are connected in sequence.
[0033] 2) A method for reducing the hydrogen content in the oxygen of an AEM water electrolysis system during an emergency shutdown, comprising the following steps: In the initial state, the AEM electrolysis cell 101 in the AEM water electrolysis system operates under normal conditions (single anode liquid inlet), and the anode tail gas system 102, anode liquid supply system 103 and electrical control system 104 operate normally; the cathode liquid supply system 105 is in standby state due to the single anode liquid inlet, and the cathode tail gas system 106 operates normally.
[0034] In the event of an emergency shutdown, the electrical control system 104 in the AEM water electrolysis system stops working, as do the AEM electrolysis cell 101, the anode tail gas system 102, the anode liquid supply system 103, and the cathode tail gas system 106.
[0035] When the shutdown auxiliary system 200 is activated, the shutdown auxiliary power supply 201 starts working, providing power to the anode tail gas system 102, the cathode tail gas system 106, and the AEM electrolytic cell 101. The current applied to the AEM electrolytic cell 101 is the same as the current applied to both ends of the AEM electrolytic cell 101 by the electrical control system 104 before the emergency shutdown. Simultaneously, the shutdown auxiliary power supply 201 provides power to the temperature control system 203, pressure control system 204, and flow control system 205 of the alkali circulation system to ensure their stable operation.
[0036] When the temperature and pressure of the circulating alkali solution drop to ambient temperature and pressure, the temperature control system 203, pressure control system 204, and flow control system 205 of the alkali solution circulation system cease operation. The venting unit 206 of the cold liquid tank discharges the accumulated gas at the top of the cold liquid tank 202 into the system. The shutdown auxiliary power supply 201 stops providing power to the AEM electrolytic cell 101; the anode tail gas system 102 and the cathode tail gas system 106 cease operation. At this point, the shutdown auxiliary system 200 completes its operation, and the shutdown is complete.
[0037] Upon restart, the electrical control system 104 in the AEM electrolysis system is first activated to provide operating current to the AEM electrolyzer 101. Then, the anode tail gas system 102 and the cathode tail gas system 106 are activated to monitor the hydrogen content in oxygen and oxygen in hydrogen during the operation of the AEM electrolyzer 101 in real time to ensure safe operation. Next, the anode supply system 103 is activated to start the circulation of alkali solution on the anode side. After the flow rate stabilizes, the temperature of the alkali solution on the anode side is increased to the operating temperature and then maintained at the operating temperature.
[0038] 3) The above method for reducing the hydrogen content in the oxygen of the AEM electrolysis water system under emergency shutdown conditions was used for testing, with the specific conditions as follows: Initially, the AEM electrolytic cell 101 maintains a single anode inlet, i.e., the anode supply system 103 is activated, while the cathode supply system 105 remains closed. The anode inlet flow rate is 100 mL / min, and the anode inlet temperature is 60°C. The electrical control system 104 operates normally, applying a working current across the AEM electrolytic cell 101 to ensure it is maintained at 1 A / cm. 2 The working status is as follows: Start the anode tail gas system 102 and the cathode tail gas system 106, and monitor the oxygen and hydrogen content and the oxygen content in the tail gas generated during the operation of the AEM electrolyzer 101 in real time.
[0039] Shut down the electrical control system 104, simultaneously turn on the shutdown auxiliary power supply 201, and apply the same operating current to both ends of the AEM electrolytic cell 101, ensuring it is maintained at 1 A / cm. 2 The operating status. The shutdown auxiliary power supply 201 provides power for the alkaline solution circulation of the shutdown auxiliary system 200, and also provides power for the anode tail gas system 102 and the cathode tail gas system 106 in the AEM water electrolysis system.
[0040] At this time, due to the shutdown of the electrical control system 104, the anode supply system 103 and the cathode supply system 105 remain closed. Based on the state before shutdown, the temperature of the anode alkali solution in the AEM electrolytic cell 101 is 60°C, and the pressure is atmospheric pressure. At this time, the alkali solution circulation flow control system 205 sets the circulation flow rate to 100 mL / min. When the anode alkali solution in the AEM electrolytic cell 101 circulates to the cold liquid tank 202, it mixes with the ambient temperature alkali solution (25°C), causing the circulating alkali solution temperature to rise. When the circulating alkali solution flows through the temperature control system 203, the air cooling in the temperature control system 203 activates, causing the circulating alkali solution temperature to drop rapidly.
[0041] Because the alkali solution pressure was at atmospheric pressure before shutdown, the pressure control system 204 maintained real-time pressure monitoring without performing any pressure relief. When the circulating alkali solution temperature dropped back to 25°C, it indicated that the alkali solution temperature in the AEM electrolytic cell 101 had returned to normal temperature and pressure. At this point, the venting unit 206 above the cold liquid tank 202 was opened to release any residual gas from the cold liquid tank 202. The shutdown auxiliary power supply 201 was then stopped from supplying power to the AEM electrolytic cell 101 and all other systems, completing the shutdown process.
[0042] The electrical control system 104 is activated to apply operating current to the AEM electrolytic cell 101 and maintain it at 1 A / cm. 2 Operating current density. Next, the anode tail gas system 102 and cathode tail gas system 106 are quickly started to monitor the oxygen-hydrogen and hydrogen-oxygen ratios in the AEM electrolyzer 101 during operation. Then, the anode supply system 103 is started, with the alkali flow rate set to 100 mL / min, and the temperature raised to the operating temperature of 60°C. During the heating process, the voltage across the AEM electrolyzer 101 and the oxygen-hydrogen ratio in the anode tail gas are monitored in real time. Once the voltage and oxygen-hydrogen ratio stabilize, the startup process is complete.
[0043] Comparative Example 1 1) A method for reducing the hydrogen content in oxygen in an AEM water electrolysis system during an emergency shutdown, comprising the following steps: In the initial state, the AEM electrolysis cell 101 in the AEM water electrolysis system operates under normal conditions (single anode liquid inlet), and the anode tail gas system 102, anode liquid supply system 103 and electrical control system 104 operate normally; the cathode liquid supply system 105 is in standby state due to the single anode liquid inlet, and the cathode tail gas system 106 operates normally.
[0044] In an emergency shutdown, the electrical control system 104 ceases operation, as do the AEM electrolytic cell 101, the anode tail gas system 102, the anode liquid supply system 103, and the cathode tail gas system 106. Without the intervention of the shutdown auxiliary system, the operating current of the AEM electrolytic cell 101 instantly drops to 0A. Furthermore, due to the lack of alkali circulation operation from the shutdown auxiliary system, the alkali in the AEM electrolytic cell 101 cools naturally, slowly decreasing from its operating temperature to room temperature.
[0045] Upon restart, the electrical control system 104 in the AEM electrolysis system is first activated to provide operating current to the AEM electrolyzer 101. Then, the anode tail gas system 102 and the cathode tail gas system 106 are activated to monitor the hydrogen content in oxygen and oxygen in hydrogen during the operation of the AEM electrolyzer 101 in real time to ensure safe operation. Next, the anode supply system 103 is activated to start the circulation of alkali solution on the anode side. After the flow rate stabilizes, the temperature of the alkali solution on the anode side is increased to the operating temperature and then maintained at the operating temperature.
[0046] 2) The above method for reducing the hydrogen content in the oxygen of the AEM electrolysis water system under emergency shutdown conditions was used for testing, with the specific conditions as follows: Initially, the AEM electrolytic cell 101 maintains a single anode inlet, i.e., the anode supply system 103 is activated, while the cathode supply system 105 remains closed. The anode inlet flow rate is 100 mL / min, and the anode inlet temperature is 60°C. The electrical control system 104 operates normally, applying a working current across the AEM electrolytic cell 101 to ensure it is maintained at 1 A / cm. 2 The working status is as follows: Start the anode tail gas system 102 and the cathode tail gas system 106, and monitor the oxygen and hydrogen content and the oxygen content in the tail gas generated during the operation of the AEM electrolyzer 101 in real time.
[0047] The electrical control system 104 is shut down, ceasing its application of operating current to the AEM electrolyzer 101, and the anode alkali supply system 103 and cathode tail gas system 106 are also stopped. However, to detect the impact of the shutdown process on hydrogen in oxygen, power is supplied only to the anode tail gas system 102 for data collection.
[0048] The electrical control system 104 is activated to apply operating current to the AEM electrolytic cell 101 and maintain it at 1 A / cm. 2Operating current density. Next, the anode tail gas system 102 and cathode tail gas system 106 are quickly started to monitor the oxygen-hydrogen and hydrogen-oxygen ratios in the AEM electrolyzer 101 during operation. Then, the anode supply system 103 is started, with the alkali flow rate set to 100 mL / min, and the temperature raised to the operating temperature of 60°C. During the heating process, the voltage across the AEM electrolyzer 101 and the oxygen-hydrogen ratio in the anode tail gas are monitored in real time. Once the voltage and oxygen-hydrogen ratio stabilize, the startup process is complete.
[0049] Comparative Example 2 1) A method for reducing the hydrogen content in oxygen in an AEM water electrolysis system during an emergency shutdown, comprising the following steps: In the initial state, the AEM electrolysis cell 101 in the AEM water electrolysis system operates under normal conditions (single anode liquid inlet), and the anode tail gas system 102, anode liquid supply system 103 and electrical control system 104 operate normally; the cathode liquid supply system 105 is in standby state due to the single anode liquid inlet, and the cathode tail gas system 106 operates normally.
[0050] In the event of an emergency shutdown, the electrical control system 104 in the AEM water electrolysis system stops working, as do the AEM electrolysis cell 101, the anode tail gas system 102, the anode liquid supply system 103, and the cathode tail gas system 106.
[0051] When the shutdown auxiliary system 200 is activated, the shutdown auxiliary power supply 201 starts working, providing power to the anode tail gas system 102, the cathode tail gas system 106, and the AEM electrolytic cell 101. The current applied to the AEM electrolytic cell 101 is the same as the current applied to both ends of the AEM electrolytic cell 101 by the electrical control system 104 before the emergency shutdown. Simultaneously, the shutdown auxiliary power supply 201 provides power to the temperature control system 203, pressure control system 204, and flow control system 205 of the alkali circulation system to ensure their stable operation.
[0052] When the temperature and pressure of the circulating alkali solution drop to ambient temperature and pressure, the temperature control system 203, pressure control system 204, and flow control system 205 of the alkali solution circulation system cease operation. The venting unit 206 of the cold liquid tank discharges the accumulated gas at the top of the cold liquid tank 202 into the system. The shutdown auxiliary power supply 201 stops providing power to the AEM electrolytic cell 101; the anode tail gas system 102 and the cathode tail gas system 106 cease operation. At this point, the shutdown auxiliary system 200 completes its operation, and the shutdown is complete.
[0053] Upon restart, the electrical control system 104 of the AEM water electrolysis system is first activated, but no operating current is applied to the AEM electrolysis cell 101. Next, the anode supply system 103 is activated to ensure a normal supply of alkali solution to the AEM electrolysis cell 101 and to raise the alkali solution temperature to the operating temperature. Then, the anode tail gas system 102 and the cathode tail gas system 106 are activated to monitor the hydrogen content in oxygen and the oxygen content in hydrogen during the operation of the AEM electrolysis cell 101 in real time to ensure safe operation. Once the alkali solution temperature in the AEM electrolysis cell 101 reaches the operating temperature, an operating current is applied to the AEM electrolysis cell 101 to begin testing, completing the startup process.
[0054] 2) The above method for reducing the hydrogen content in the oxygen of the AEM electrolysis water system under emergency shutdown conditions was used for testing, with the specific conditions as follows: Initially, the AEM electrolytic cell 101 maintains a single anode inlet, i.e., the anode supply system 103 is activated, while the cathode supply system 105 remains closed. The anode inlet flow rate is 100 mL / min, and the anode inlet temperature is 60°C. The electrical control system 104 operates normally, applying a working current across the AEM electrolytic cell 101 to ensure it is maintained at 1 A / cm. 2 The working status is as follows: Start the anode tail gas system 102 and the cathode tail gas system 106, and monitor the oxygen and hydrogen content and the oxygen content in the tail gas generated during the operation of the AEM electrolyzer 101 in real time.
[0055] Shut down the electrical control system 104, simultaneously turn on the shutdown auxiliary power supply 201, and apply the same operating current to both ends of the AEM electrolytic cell 101, ensuring it is maintained at 1 A / cm. 2 The operating status. The shutdown auxiliary power supply 201 provides power for the alkaline solution circulation of the shutdown auxiliary system 200, and also provides power for the anode tail gas system 102 and the cathode tail gas system 106 in the AEM water electrolysis system.
[0056] At this time, due to the shutdown of the electrical control system 104, the anode supply system 103 and the cathode supply system 105 remain closed. Based on the state before shutdown, the temperature of the anode alkali solution in the AEM electrolytic cell 101 is 60°C, and the pressure is atmospheric pressure. At this time, the alkali solution circulation flow control system 205 sets the circulation flow rate to 100 mL / min. When the anode alkali solution in the AEM electrolytic cell 101 circulates to the cold liquid tank 202, it mixes with the ambient temperature alkali solution (25°C), causing the circulating alkali solution temperature to rise. When the circulating alkali solution flows through the temperature control system 203, the air cooling in the temperature control system 203 activates, causing the circulating alkali solution temperature to drop rapidly.
[0057] Because the alkali solution pressure was at atmospheric pressure before shutdown, the pressure control system 204 maintained real-time pressure monitoring without performing any pressure relief. When the circulating alkali solution temperature dropped back to 25°C, it indicated that the alkali solution temperature in the AEM electrolytic cell 101 had returned to normal temperature and pressure. At this point, the venting unit 206 above the cold liquid tank 202 was opened to release any residual gas from the cold liquid tank 202. The shutdown auxiliary power supply 201 was then stopped from supplying power to the AEM electrolytic cell 101 and all other systems, completing the shutdown process.
[0058] The electrical control system 104 is started, but no operating current is supplied to the AEM electrolytic cell 101. Next, the anode supply system 103 is started to ensure a normal supply of alkali solution to the AEM electrolytic cell 101 and to raise the alkali solution temperature to the operating temperature. Then, the anode tail gas system 102 and the cathode tail gas system 106 are started to monitor the hydrogen content in oxygen and the oxygen content in hydrogen in real time, ensuring the system operates within a safe range. Once the alkali solution temperature in the AEM electrolytic cell 101 reaches the operating temperature, an operating current is applied to the AEM electrolytic cell 101 to begin testing, completing the startup process.
[0059] Comparative Example 3 1) A method for reducing the hydrogen content in oxygen in an AEM water electrolysis system during an emergency shutdown, comprising the following steps: In the initial state, the AEM electrolysis cell 101 in the AEM water electrolysis system operates under normal conditions (single anode liquid inlet), and the anode tail gas system 102, anode liquid supply system 103 and electrical control system 104 operate normally; the cathode liquid supply system 105 is in standby state due to the single anode liquid inlet, and the cathode tail gas system 106 operates normally.
[0060] In an emergency shutdown, the electrical control system 104 ceases operation, as do the AEM electrolytic cell 101, the anode tail gas system 102, the anode liquid supply system 103, and the cathode tail gas system 106. Without the intervention of the shutdown auxiliary system, the operating current of the AEM electrolytic cell 101 instantly drops to 0A. Furthermore, due to the lack of alkali circulation operation from the shutdown auxiliary system, the alkali in the AEM electrolytic cell 101 cools naturally, slowly decreasing from its operating temperature to room temperature.
[0061] Upon restart, the electrical control system 104 of the AEM water electrolysis system is first activated, but no operating current is applied to the AEM electrolysis cell 101. Next, the anode supply system 103 is activated to ensure a normal supply of alkali solution to the AEM electrolysis cell 101 and to raise the alkali solution temperature to the operating temperature. Then, the anode tail gas system 102 and the cathode tail gas system 106 are activated to monitor the hydrogen content in oxygen and the oxygen content in hydrogen during the operation of the AEM electrolysis cell 101 in real time to ensure safe operation. Once the alkali solution temperature in the AEM electrolysis cell 101 reaches the operating temperature, an operating current is applied to the AEM electrolysis cell 101 to begin testing, completing the startup process.
[0062] 2) The above method for reducing the hydrogen content in the oxygen of the AEM electrolysis water system under emergency shutdown conditions was used for testing, with the specific conditions as follows: Initially, the AEM electrolytic cell 101 maintains a single anode inlet, i.e., the anode supply system 103 is activated, while the cathode supply system 105 remains closed. The anode inlet flow rate is 100 mL / min, and the anode inlet temperature is 60°C. The electrical control system 104 operates normally, applying a working current across the AEM electrolytic cell 101 to ensure it is maintained at 1 A / cm. 2 The working status is as follows: Start the anode tail gas system 102 and the cathode tail gas system 106, and monitor the oxygen and hydrogen content and the oxygen content in the tail gas generated during the operation of the AEM electrolyzer 101 in real time.
[0063] The electrical control system 104 is shut down, ceasing its application of operating current to the AEM electrolyzer 101, and the anode alkali supply system 103 and cathode tail gas system 106 are also stopped. However, to detect the impact of the shutdown process on hydrogen in oxygen, power is supplied only to the anode tail gas system 102 for data collection.
[0064] The electrical control system 104 is started, but no operating current is supplied to the AEM electrolytic cell 101. Next, the anode supply system 103 is started to ensure a normal supply of alkali solution to the AEM electrolytic cell 101 and to raise the alkali solution temperature to the operating temperature. Then, the anode tail gas system 102 and the cathode tail gas system 106 are started to monitor the hydrogen content in oxygen and the oxygen content in hydrogen in real time, ensuring the system operates within a safe range. Once the alkali solution temperature in the AEM electrolytic cell 101 reaches the operating temperature, an operating current is applied to the AEM electrolytic cell 101 to begin testing, completing the startup process.
[0065] Test results are as follows Figure 2 As shown, Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 correspond to... Figure 2 Test Case 1, Test Case 2, Test Case 3, and Test Case 4.
[0066] The results of Test Example 1 show that the initial hydrogen concentration in oxygen was 3200 ppm, and after restarting, the hydrogen concentration remained close to 3516 ppm, a difference of 316 ppm, which is within the test error range. Initial state: 1 A / cm 2 At the current density, the voltage across AEM electrolytic cell 101 is 1.831V. After shutdown and restart, the voltage drops to 1.819V, a decrease of 12mV.
[0067] The results of Test Example 2 show that the initial hydrogen concentration in oxygen was 3988 ppm, which increased to 5788 ppm after startup, an increase of 1800 ppm. Initially, the hydrogen concentration was 1 A / cm². 2 At the current density, the voltage across AEM electrolytic cell 101 is 1.841V. After shutdown and restart, the voltage drops to 1.826V, a decrease of 15mV.
[0068] The results of Test Example 3 show that the initial hydrogen concentration in oxygen was 3192 ppm, which increased to 5472 ppm after startup, an increase of 2280 ppm. Initially, the hydrogen concentration was 1 A / cm². 2 At the current density, the voltage across AEM electrolytic cell 101 is 1.834V. After shutdown and restart, the voltage drops to 1.818V, a decrease of 16mV.
[0069] The results of Test Example 4 show that the initial hydrogen concentration in oxygen was 3112 ppm. After startup, the hydrogen concentration in oxygen rapidly increased to 9010 ppm, then quickly decreased to 6932 ppm, with an increase of 3820 ppm. Initially, 1 A / cm² 2 At the current density, the voltage across AEM electrolytic cell 101 is 1.831V. After shutdown and restart, the voltage drops to 1.828V, a decrease of 3mV.
[0070] The results of Test Examples 1-4 demonstrate that the method of reducing the hydrogen content in the oxygen of the AEM electrolysis water system under emergency shutdown conditions can effectively solve the problem of increased hydrogen content in the oxygen during restart due to unexpected emergency shutdowns. Furthermore, in Comparative Example 4, the electrolysis voltage recovery of the AEM electrolyzer before and after startup was only 3mV, while in Example 1, the electrolysis voltage recovery was 12mV. This indicates that the method of reducing the hydrogen content in the oxygen of the AEM electrolysis water system under emergency shutdown conditions helps to ensure that the hydrogen content in the oxygen does not increase while also contributing to the performance recovery of the AEM electrolyzer.
[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.
Claims
1. A method for reducing the hydrogen content in the oxygen of an AEM electrolysis water system during an emergency shutdown, characterized in that, Includes the following steps: S1. In the event of an emergency shutdown of the AEM electrolysis water system, the temperature of the alkaline solution in the AEM electrolyzer is reduced to room temperature via a shutdown auxiliary system. The shutdown auxiliary system includes a shutdown auxiliary power supply, a cold liquid tank, a temperature control system, a pressure control system, and a flow control system. The shutdown auxiliary power supply is electrically connected to the temperature control system, pressure control system, and flow control system. The cold liquid tank, temperature control system, pressure control system, and flow control system are sequentially connected to form an alkaline solution circulation loop. The flow control system is connected to the AEM electrolyzer. S2. When restarting the AEM electrolysis water system, first start the electrical control system, then start the AEM electrolysis cell, then start the anode tail gas system and the cathode tail gas system, then start the anode liquid supply system to start the anode side alkali circulation, and after the flow rate stabilizes, raise the temperature of the anode side alkali to the working temperature.
2. The method as described in claim 1, characterized in that, The cold liquid tank contains an alkaline solution with a temperature below 25°C.
3. The method according to claim 1, wherein the alkaline solution is a potassium hydroxide solution.
4. A shutdown assistance system, characterized in that, include: Auxiliary power supply for shutdown, coolant tank, temperature control system, pressure control system, and flow control system; The shutdown auxiliary power supply is electrically connected to the temperature control system, pressure control system, and flow control system; the cold liquid tank, temperature control system, pressure control system, and flow control system are sequentially connected to form an alkaline solution circulation loop; the flow control system is connected to the AEM electrolysis cell in the AEM electrolysis water system.
5. The shutdown assistance system as described in claim 4, characterized in that, The cold liquid tank includes a venting unit for discharging oxygen carried into the cold liquid tank by the alkali solution circulation.
6. The shutdown assistance system as described in claim 4, characterized in that, The temperature control system includes: a temperature detection unit for detecting the temperature of the circulating alkaline solution; Temperature cooling unit is used to reduce the temperature of circulating alkali solution.
7. The shutdown assistance system as described in claim 4, characterized in that, The pressure control system includes: a pressure detection unit for detecting the pressure of the circulating alkali solution; Pressure regulating valve, used to reduce the pressure of circulating alkali solution.
8. The shutdown assistance system as described in claim 7, characterized in that, The pressure regulating valve is a high-pressure throttle valve.
9. The shutdown assistance system as described in claim 4, characterized in that, The flow control system includes: a flow detection unit for detecting the flow rate of the circulating alkaline solution; The flow regulation unit is used to regulate the flow rate of the circulating alkali solution.