Electrolytic hydrogen production system and electrolytic hydrogen production method

Abstract

The invention provides an electrolytic hydrogen production system and an electrolytic hydrogen production method, relates to the technical field of electrolytic hydrogen production, and aims to improve the heat exchange efficiency in the electrolytic hydrogen production system and reduce the energy consumption of the electrolytic hydrogen production system. The system comprises a galvanic pile module which comprises a cathode side and an anode side and is used for electrolyzing water vapor to obtain hydrogen and oxygen; the cathode side ejector is located on the cathode side of the electric pile module, a high-speed airflow connector of the cathode side ejector is used for obtaining water vapor, a low-speed airflow connector of the cathode side ejector is used for obtaining hydrogen, and the output end of the cathode side ejector is used for introducing gas into the cathode side of the electric pile module. Hydrogen introduced by the cathode side ejector comprises at least part of hydrogen formed on the cathode side of the galvanic pile module; and / or the concentration analyzer is positioned on the anode side of the electric pile module and is used for analyzing the concentration of oxygen generated on the anode side of the electric pile module; and the variable-frequency fan is positioned on the anode side of the galvanic pile module and is used for introducing purging gas into the anode side of the galvanic pile module according to the concentration of oxygen generated on the anode side.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of hydrogen production by electrolysis, and in particular, to a hydrogen production system by electrolysis and a hydrogen production method by electrolysis. Background Art

[0002] Hydrogen energy is abundant in sources and widely used. It can play an important role in building a clean, low-carbon, safe and efficient energy system, and is of great significance to achieving the dual carbon goals. Most existing hydrogen production technologies rely on disposable energy such as coal and natural gas, and there are still carbon emissions in the hydrogen production process. Therefore, the hydrogen produced is gray hydrogen, which is difficult to meet the requirements of a clean and low-carbon environment. The water electrolysis hydrogen production technology that can be coupled with renewable energy such as wind and solar power can achieve true zero carbon emissions, and therefore is increasingly receiving national attention and support.

[0003] Among the current mainstream water electrolysis hydrogen production technologies, SOEC (Solid Oxide Electrolysis Cell) technology is a technology that produces hydrogen by electrolyzing high-temperature steam. Its operating temperature is as high as 600~900℃. This technology can improve hydrogen production efficiency and reduce electrolysis energy consumption under high temperature conditions. It is the most efficient electrolysis hydrogen production technology.

[0004] In the process of SOEC hydrogen production, a large amount of heat will be generated. The current SOEC hydrogen production method usually collects and utilizes the waste heat in the system through a heat exchanger. Therefore, the heat exchange efficiency of the heat exchanger mainly depends on the performance of the heat exchanger, resulting in low heat exchange efficiency, causing large system heat energy loss, and further reducing the overall efficiency of the system. In addition, the internal hydrogen circulation of the system depends on the external circulation booster device, which needs to operate at room temperature, resulting in further waste of heat and increasing the parasitic power consumption of the system. Summary of the invention

[0005] An electrolytic hydrogen production system and an electrolytic hydrogen production method provided in the embodiments of the present application can improve the heat exchange efficiency in the electrolytic hydrogen production system, reduce the energy consumption of the electrolytic hydrogen production system, improve the efficiency of the electrolytic hydrogen production system, prevent oxidation of the fuel cell module, and extend the service life of the electrolytic hydrogen production system.

[0006] In a first aspect of an embodiment of the present application, a system for producing hydrogen by electrolysis is provided, comprising:

[0007] A stack module, comprising a cathode side and an anode side, the stack module is used to electrolyze water vapor to obtain hydrogen and oxygen, wherein the cathode side is used to introduce water vapor and output hydrogen, and the anode side is used to output oxygen;

[0008] A cathode side ejector is located on the cathode side of the stack module, the high-speed airflow interface of the cathode side ejector is used to obtain water vapor, the low-speed airflow interface of the cathode side ejector is used to obtain hydrogen, and the output end of the cathode side ejector is used to pass gas into the cathode side of the stack module, wherein the hydrogen passed through the cathode side ejector includes at least part of the hydrogen formed on the cathode side of the stack module; and / or,

[0009] A purge module, located on the anode side of the stack module, the purge module comprising a concentration analyzer and a variable frequency fan;

[0010] Wherein, the concentration analyzer is used to analyze the concentration of oxygen generated on the anode side of the stack module;

[0011] The variable frequency fan is used to introduce purge gas into the anode side of the stack module according to the concentration of oxygen generated on the anode side.

[0012] In some embodiments, the electrolysis hydrogen production system further comprises:

[0013] A water supply device for providing deionized water;

[0014] A steam generator, wherein the input end of the steam generator is connected to the output end of the water replenishing device, the output end of the steam generator is connected to the high-speed airflow interface of the cathode side ejector, and the steam generator is used to evaporate the deionized water to obtain water vapor.

[0015] In some embodiments, the electrolysis hydrogen production system further comprises:

[0016] A first heat exchanger, wherein a first cold flow stream inlet end of the first heat exchanger is connected to an output end of the water replenishment device, a first cold flow stream outlet end of the first heat exchanger is connected to an input end of the steam generator, a second cold flow stream inlet end of the first heat exchanger is connected to an output end of the variable frequency fan, a second cold flow stream outlet end of the first heat exchanger is used to transport the purge gas to the anode side of the stack module, a hot flow stream inlet end of the first heat exchanger is used to obtain oxygen generated on the anode side of the stack module, and a hot flow stream outlet end of the first heat exchanger is used to output oxygen, wherein the first heat exchanger is used to realize heat exchange between the purge gas and the oxygen generated on the anode side of the stack module, and the first heat exchanger is used to realize heat exchange between the deionized water and the oxygen generated on the anode side of the stack module, and the concentration analyzer is located at the hot flow stream outlet end of the first heat exchanger;

[0017] A flow controller, the flow controller is used to control the flow rate of the hot stream of the first heat exchanger;

[0018] A first control valve, located between the first heat exchanger and the water replenishing device, the first control valve is used to control the deionized water to be input into the first heat exchanger;

[0019] A second heat exchanger, wherein the cold stream inlet end of the second heat exchanger is connected to the first cold stream outlet end of the first heat exchanger, and the cold stream inlet end of the second heat exchanger is connected to the output end of the water replenishment device, and the cold stream outlet end of the second heat exchanger is connected to the input end of the steam generator, the hot stream inlet end of the second heat exchanger is used to obtain the hydrogen generated on the cathode side of the stack module, and the hot stream outlet end of the second heat exchanger is used to output hydrogen, wherein the second heat exchanger is used to realize heat exchange between deionized water and the hydrogen generated on the cathode side of the stack module;

[0020] A second control valve, located between the second heat exchanger and the water replenishing device, the second control valve is used to control the deionized water to be input into the second heat exchanger;

[0021] A temperature sensor is located at a hot flow outlet of the first heat exchanger, and the temperature sensor is used to obtain a gas temperature at the hot flow outlet of the first heat exchanger;

[0022] The degree of opening and closing of at least one of the first control valve and the second control valve is related to the gas temperature.

[0023] In some embodiments, the electrolysis hydrogen production system further comprises:

[0024] A hydrogen supply device, used for providing hydrogen;

[0025] A mixing chamber, the input end of the mixing chamber is connected to the output end of the cathode side ejector, and the input end of the mixing chamber is connected to the output end of the hydrogen supply device, the mixing chamber is used to mix hydrogen and water vapor, and the output end of the mixing chamber is used to input the mixed gas to the cathode side of the stack module;

[0026] A heater is located between the mixing chamber and the cathode side, and is used to heat the mixed gas.

[0027] In some embodiments, the electrolysis hydrogen production system further comprises:

[0028] A third heat exchanger, wherein the cold flow inlet end of the third heat exchanger is connected to the output end of the mixing chamber, the cold flow outlet end of the third heat exchanger is connected to the input end of the heater, the hot flow inlet end of the third heat exchanger is used to obtain the hydrogen generated on the cathode side of the stack module, the hot flow outlet end of the third heat exchanger is used to output hydrogen, and the hot flow outlet end of the third heat exchanger is connected to the low-speed gas interface of the cathode side ejector, wherein the third heat exchanger is used to realize heat exchange between the mixed gas output from the mixing chamber and the hydrogen generated on the cathode side of the stack module.

[0029] In some embodiments, the electrolysis hydrogen production system further comprises:

[0030] A fourth heat exchanger, wherein the hot flow inlet end of the fourth heat exchanger is used to obtain the hydrogen generated on the cathode side of the stack module, the hot flow outlet end of the fourth heat exchanger is connected to the hot flow inlet end of the third heat exchanger, the cold flow inlet end of the fourth heat exchanger is connected to the output end of the variable frequency fan, and the cold flow outlet end of the fourth heat exchanger is used to output the purge gas, wherein the fourth heat exchanger is used to realize heat exchange between the purge gas output by the variable frequency fan and the hydrogen generated on the cathode side of the stack module.

[0031] In some embodiments, the electrolysis hydrogen production system further comprises:

[0032] The third control valve is located between the hot flow outlet of the third heat exchanger and the low-speed gas interface of the cathode side ejector, and the third control valve is used to control the hydrogen flow rate entering the cathode side ejector.

[0033] In some embodiments, the electrolysis hydrogen production system further comprises:

[0034] An anode side ejector, wherein the high-speed gas interface of the anode side ejector is connected to the output end of the variable frequency blower, the low-speed gas interface of the anode side ejector is used to obtain the oxygen generated by the anode side of the stack module, and the output end of the anode side ejector is used to transport oxygen and purge gas to the anode side of the stack module;

[0035] A buffer is located between the output end of the anode side ejector and the anode side of the stack module, and is used to control the pressure of the gas delivered to the anode side of the stack module.

[0036] A second aspect of the embodiment of the present application provides a method for producing hydrogen by electrolysis, comprising:

[0037] By introducing water vapor into the cathode side of the stack module, the stack module electrolyzes the water vapor to generate hydrogen on the cathode side of the stack module and generates oxygen on the anode side of the stack module;

[0038] Transmitting at least part of the hydrogen generated on the cathode side of the stack module to the cathode side of the stack module through a cathode side ejector, wherein the high-speed airflow interface of the cathode side ejector is used to obtain water vapor, the low-speed airflow interface of the cathode side ejector is used to obtain hydrogen, and the output end of the cathode side ejector is used to pass the gas into the cathode side of the stack module;

[0039] Detecting the oxygen concentration on the anode side of the stack module;

[0040] According to the oxygen concentration, a purge gas is introduced into the anode side of the stack module through a variable frequency fan.

[0041] In some embodiments, the step of introducing a purge gas into the anode side of the stack module through a variable frequency blower according to the oxygen concentration includes:

[0042] When the oxygen concentration is less than or equal to a preset concentration, the variable frequency blower is controlled to stop supplying the purge gas to the anode side of the stack module, wherein the gas output rate of the anode side of the stack module is equal to the gas generation rate of the anode side of the stack module;

[0043] When the oxygen concentration is greater than the preset concentration, the rate at which the variable frequency fan introduces the purge gas to the anode side of the fuel cell stack module is controlled according to the oxygen concentration.

[0044] The electrolytic hydrogen production system and electrolytic hydrogen production method provided in the embodiment of the present application electrolyze water vapor to obtain hydrogen and oxygen through the stack module, and by setting a cathode side ejector on the cathode side of the stack module, high-pressure water vapor is used as a driving gas, and the high-temperature hydrogen generated on the cathode side of the stack module is driven by the high-pressure water vapor to flow back to the cathode side of the stack module, so that hydrogen can be used as a reducing protective gas to prevent oxidation on the cathode side of the stack module, and can also avoid the thermal efficiency of the system being affected by the low temperature of hydrogen. At the same time, there is no need to perform additional circulation treatment on the hydrogen, thereby reducing the parasitic power consumption of the electrolytic hydrogen production system. In addition, the oxygen concentration generated on the anode side of the stack module is detected by the concentration analyzer in the purge module, so that the variable frequency fan can control the amount of purge gas delivered to the anode side of the stack module according to the oxygen concentration, so as to prevent oxygen accumulation on the anode side of the stack module. The gas delivery status of the variable frequency fan can be adjusted in real time according to the oxygen concentration in the anode side pipeline. Compared with the traditional mode, since the internal gas circulation can be realized on the anode side of the system, the demand for cold air supply on the anode side of the system is reduced, thereby reducing the power consumption of the variable frequency fan. At the same time, the power consumption demand for air heating on the anode side is reduced, thereby improving the working efficiency of the electrolytic hydrogen production system. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0046] Figure 1 A schematic structural diagram of a hydrogen production system by electrolysis provided in an embodiment of the present application;

[0047] Figure 2 A schematic structural diagram of another electrolysis hydrogen production system provided in an embodiment of the present application;

[0048] Figure 3 A schematic flow chart of a method for producing hydrogen by electrolysis provided in an embodiment of the present application.

[0049] Description of reference numerals:

[0050] 100. Fuel cell stack module; 200. Cathode side ejector; 300. Concentration analyzer; 400. Variable frequency fan. DETAILED DESCRIPTION

[0051] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0053] When used herein, the singular forms "a", "an" and " / the" may also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof. At the same time, in this specification, the term "and / or" includes any and all combinations of the relevant listed items.

[0054] It should be noted that hydrogen energy is abundant in sources and widely used. It can play an important role in building a clean, low-carbon, safe and efficient energy system, and is of great significance to achieving the dual carbon goals. Most existing hydrogen production technologies rely on disposable energy such as coal and natural gas, and there are still carbon emissions in the hydrogen production process. Therefore, the hydrogen produced is gray hydrogen, which is difficult to meet the requirements of a clean and low-carbon environment. The water electrolysis hydrogen production technology that can be coupled with renewable energy such as wind and solar power can achieve true zero carbon emissions, and therefore is increasingly receiving national attention and support.

[0055] Among the current mainstream water electrolysis hydrogen production technologies, SOEC (Solid Oxide Electrolysis Cell) technology is a technology that produces hydrogen by electrolyzing high-temperature steam. Its operating temperature is as high as 600~900℃. This technology can improve hydrogen production efficiency and reduce electrolysis energy consumption under high temperature conditions. It is the most efficient electrolysis hydrogen production technology.

[0056] A large amount of heat is generated during the SOEC hydrogen production process. The current SOEC hydrogen production method usually collects and utilizes the waste heat in the system through a heat exchanger. Therefore, the heat transfer efficiency of the heat exchanger mainly depends on the performance of the heat exchanger, resulting in low heat transfer efficiency, causing large heat energy loss in the system, and further reducing the overall efficiency of the system.

[0057] Due to the special structure of the SOEC stack, during the operation of the system, hydrogen needs to be continuously introduced into the cathode side of the stack as a reducing protective gas to prevent oxidation of the stack; air needs to be introduced into the anode side of the system as a purge gas to prevent oxygen accumulation on the anode side of the stack. Among them, in the existing SOEC system, the hydrogen on the cathode side is generally pressurized and circulated by a hydrogen booster pump. The hydrogen booster pump is sensitive to the hydrogen temperature and requires a lower operating temperature. The circulating low-temperature hydrogen needs to be further heated to the SOEC operating temperature. The system has low thermal efficiency and high energy consumption.

[0058] Therefore, it is an urgent problem to propose an electrolysis hydrogen production system that can recover the heat within the system and reduce the energy consumption of the system.

[0059] like Figure 1 As shown, Figure 1 A schematic structural diagram of an electrolytic hydrogen production system provided in an embodiment of the present application. In the first aspect of an embodiment of the present application, an electrolytic hydrogen production system is provided, comprising: a stack module 100, a cathode side ejector 200 and a purge module, wherein the purge module comprises a concentration analyzer 300 and a variable frequency blower 400. Among them, the stack module 100 comprises a cathode side and an anode side, and the stack module 100 is used to electrolyze water vapor to obtain hydrogen and oxygen, wherein the cathode side is used to pass water vapor and output hydrogen, and the anode side is used to output oxygen; the cathode side ejector 200 is located on the cathode side of the stack module 100, the high-speed airflow interface of the cathode side ejector 200 is used to obtain water vapor, the low-speed airflow interface of the cathode side ejector 200 is used to obtain hydrogen, and the output end of the cathode side ejector 200 is used to pass the gas into the stack module The cathode side of the stack module 100, wherein the hydrogen introduced by the cathode side ejector 200 includes at least part of the hydrogen formed on the cathode side of the stack module 100; the purge module is located on the anode side of the stack module 100, and the purge module includes a concentration analyzer 300 and a variable frequency fan 400; wherein the concentration analyzer 300 is used to analyze the concentration of oxygen generated on the anode side of the stack module 100; the variable frequency fan 400 is used to introduce purge gas to the anode side of the stack module 100 according to the concentration of oxygen generated on the anode side.

[0060] For example, the purge gas may be air, and the water vapor may be high-pressure water vapor to drive the hydrogen gas to reflux.

[0061] It should be noted that, when the hydrogen production by electrolysis system includes the stack module 100, the hydrogen production by electrolysis system provided in the embodiment of the present application may include only the cathode side ejector 200, may include only the purge module, or may include the cathode side ejector 200 and the purge module.

[0062] The electrolytic hydrogen production system provided in the embodiment of the present application electrolyzes water vapor to obtain hydrogen and oxygen through the stack module 100. A cathode side ejector 200 is provided on the cathode side of the stack module 100, and high-pressure water vapor is used as a driving gas. The high-temperature hydrogen generated on the cathode side of the stack module 100 is driven by the high-pressure water vapor to flow back to the cathode side of the stack module 100, so that the hydrogen can be used as a reducing protective gas to prevent oxidation on the cathode side of the stack module 100. It can also prevent the hydrogen temperature from being too low to affect the electrolysis efficiency of the stack module 100. At the same time, there is no need for additional circulation treatment of the hydrogen, thereby reducing the energy consumption of the electrolytic hydrogen production system, extending the service life of the electrolytic hydrogen production system, and simplifying the electrolytic hydrogen production process. In addition, the concentration analyzer 300 in the purge module detects the oxygen concentration inside the anode side circulation pipeline of the stack module 100, so that the variable frequency fan 400 can control the amount of purge gas delivered to the anode side of the stack module 100 according to the oxygen concentration, and prevent oxygen accumulation on the anode side of the stack module 100. The gas delivery state of the variable frequency fan 400 can be adjusted in real time according to the oxygen generation rate, thereby reducing the energy consumption of the variable frequency fan 400, further reducing the energy consumption of the electrolytic hydrogen production system, and improving the working efficiency of the electrolytic hydrogen production system.

[0063] In some feasible embodiments, the electrolysis hydrogen production system also includes: a water replenishing device for providing deionized water; a steam generator, wherein the input end of the steam generator is connected to the output end of the water replenishing device, and the output end of the steam generator is connected to the high-speed airflow interface of the cathode side ejector 200, and the steam generator is used to evaporate deionized water to obtain water vapor.

[0064] The electrolytic hydrogen production system provided in the embodiment of the present application provides deionized water through a water replenishment device, and evaporates the deionized water through a steam generator to obtain water vapor. The water vapor can be supplemented to the fuel cell module 100 to achieve continuous hydrogen production by the electrolytic hydrogen production system.

[0065] In some feasible embodiments, the electrolysis hydrogen production system also includes: a first heat exchanger, the first cold flow stream inlet end of the first heat exchanger is connected to the output end of the water replenishment device, the first cold flow stream outlet end of the first heat exchanger is connected to the input end of the steam generator, the second cold flow stream inlet end of the first heat exchanger is connected to the output end of the variable frequency fan 400, the second cold flow stream outlet end of the first heat exchanger is used to transport the purge gas to the anode side of the fuel cell module 100, the hot flow stream inlet end of the first heat exchanger is used to obtain the oxygen generated on the anode side of the fuel cell module 100, and the first heat exchanger The hot fluid outlet end of the heat exchanger is used to output oxygen, wherein the first heat exchanger is used to realize heat exchange between the purge gas and the oxygen generated on the anode side of the stack module 100, and the first heat exchanger is used to realize heat exchange between deionized water and the oxygen generated on the anode side of the stack module 100, and the concentration analyzer is located at the hot fluid outlet end of the first heat exchanger; a flow controller, the flow controller is used to control the hot fluid flow of the first heat exchanger; a first control valve, located between the first heat exchanger and the water replenishment device, the first control valve is used to control the deionized water input to the first heat exchanger.

[0066] The electrolytic hydrogen production system provided in the embodiment of the present application realizes heat exchange between deionized water and oxygen generated on the anode side of the stack module 100 through a first heat exchanger, so that the waste heat in the electrolytic hydrogen production system can be used to preheat the deionized water, thereby improving the energy utilization and heat exchange efficiency in the electrolytic hydrogen production system, further reducing the energy consumption in the evaporation process, and improving the working efficiency of the electrolytic hydrogen production system.

[0067] In some feasible embodiments, the electrolysis hydrogen production system also includes: a second heat exchanger, the cold flow inlet end of the second heat exchanger is connected to the first cold flow outlet end of the first heat exchanger, and the cold flow inlet end of the second heat exchanger is connected to the output end of the water replenishment device, the cold flow outlet end of the second heat exchanger is connected to the input end of the steam generator, the hot flow inlet end of the second heat exchanger is used to obtain the hydrogen generated on the cathode side of the stack module 100, and the hot flow outlet end of the second heat exchanger is used to output hydrogen, wherein the second heat exchanger is used to realize heat exchange between deionized water and the hydrogen generated on the cathode side of the stack module 100; a second control valve, located between the second heat exchanger and the water replenishment device, the second control valve is used to control the input of deionized water to the second heat exchanger; a temperature sensor, located at the hot flow outlet end of the first heat exchanger, the temperature sensor is used to obtain the gas temperature at the hot flow outlet end of the first heat exchanger; wherein the switching degree of at least one of the first control valve and the second control valve is related to the gas temperature.

[0068] For example, when the gas temperature is greater than a preset temperature, the first control valve can be controlled to open so that deionized water enters the first heat exchanger, so that the high-temperature oxygen generated on the anode side of the stack module 100 serves as the hot stream of the first heat exchanger, and the deionized water serves as the cold stream. The high-temperature oxygen is cooled by the deionized water, and the deionized water can be preliminarily heated. When the gas temperature is less than a preset temperature, the first control valve can be controlled to close so that the deionized water directly enters the second heat exchanger through the second control valve.

[0069] The electrolytic hydrogen production system provided in the embodiment of the present application realizes heat exchange between deionized water and hydrogen generated on the cathode side of the stack module 100 through the second heat exchanger, so that the first heat exchanger and the second heat exchanger can be used to preheat the deionized water in sequence through the waste heat in the electrolytic hydrogen production system, which can further increase the temperature of the deionized water, improve the energy utilization rate and heat exchange efficiency in the electrolytic hydrogen production system, further reduce the energy consumption in the evaporation process, and improve the working efficiency of the electrolytic hydrogen production system. By setting a temperature sensor, it is possible to avoid the temperature of the oxygen released by the electrolytic hydrogen production system being too high, causing damage to the oxygen concentration analyzer. At the same time, the opening of the first control valve and the second control valve is controlled according to the gas temperature of the oxygen. When the first control valve is opened, the temperature of the oxygen to be released can be further reduced by heat exchange between the deionized water and the oxygen generated on the anode side of the stack module 100.

[0070] In some feasible embodiments, the electrolysis hydrogen production system also includes: a hydrogen supply device for providing hydrogen; a mixing chamber, the input end of the mixing chamber is connected to the output end of the cathode side ejector 200, and the input end of the mixing chamber is connected to the output end of the hydrogen supply device, the mixing chamber is used to mix hydrogen and water vapor, and the output end of the mixing chamber is used to input the mixed gas to the cathode side of the stack module 100; a heater, located between the mixing chamber and the cathode side, the heater is used to heat the mixed gas.

[0071] Exemplarily, the hydrogen supply device may include a hydrogen storage bottle and a hydrogen generator, etc.

[0072] The electrolytic hydrogen production system provided in the embodiment of the present application can provide hydrogen to the cathode side of the stack module 100 through a hydrogen supply device within a period of time after the electrolytic hydrogen production system starts to be started, thereby further reducing the oxidation risk of the stack module 100. By uniformly mixing hydrogen and water vapor in a mixing chamber, it is possible to avoid the poor uniformity of the mixed gas affecting the electrolysis efficiency of the stack module 100. By setting a heater, the mixed gas can be further heated so that the temperature of the mixed gas is within the electrolysis temperature range of the stack module 100, thereby improving the hydrogen production effect of the electrolytic hydrogen production system.

[0073] In some feasible embodiments, the electrolysis hydrogen production system also includes: a third heat exchanger, the cold flow inlet end of the third heat exchanger is connected to the output end of the mixing chamber, the cold flow outlet end of the third heat exchanger is connected to the input end of the heater, the hot flow inlet end of the third heat exchanger is used to obtain the hydrogen generated on the cathode side of the fuel cell stack module 100, the hot flow outlet end of the third heat exchanger is used to output hydrogen, and the hot flow outlet end of the third heat exchanger is connected to the low-speed gas interface of the cathode side ejector 200, wherein the third heat exchanger is used to realize heat exchange between the mixed gas output from the mixing chamber and the hydrogen generated on the cathode side of the fuel cell stack module 100.

[0074] The electrolytic hydrogen production system provided in the embodiment of the present application realizes heat exchange between the mixed gas and the hydrogen generated on the cathode side of the fuel cell stack module 100 through a third heat exchanger, thereby further improving the utilization efficiency of the waste heat on the cathode side of the fuel cell stack module 100. Before the mixed gas is transported to the cathode side of the fuel cell stack module 100, the mixed gas is further preheated to reduce the energy consumption required for the heater, improve the energy utilization rate and heat exchange efficiency in the electrolytic hydrogen production system, reduce the energy consumption during the heating process, and improve the working efficiency of the electrolytic hydrogen production system.

[0075] In some feasible embodiments, the electrolysis hydrogen production system also includes: a fourth heat exchanger, wherein the hot flow inlet end of the fourth heat exchanger is used to obtain the hydrogen generated on the cathode side of the fuel cell stack module 100. Since the cold air flow rate required on the anode side of the present method is relatively small, the fourth heat exchanger directly uses the high-temperature exhaust gas at the anode side outlet of the fuel cell stack module to directly heat the incoming air to the operating temperature range, thereby avoiding the use of an anode side heater, saving system hardware costs and processing parasitic power consumption. The hot flow outlet end of the fourth heat exchanger is connected to the hot flow inlet end of the third heat exchanger, and the cold flow inlet end of the fourth heat exchanger is connected to the output end of the variable frequency fan 400. The cold flow outlet end of the fourth heat exchanger is used to output purge gas, wherein the fourth heat exchanger is used to realize heat exchange between the purge gas output by the variable frequency fan 400 and the hydrogen generated on the cathode side of the fuel cell stack module 100.

[0076] The electrolytic hydrogen production system provided in the embodiment of the present application realizes heat exchange between the purge gas output by the variable frequency fan 400 and the hydrogen produced on the cathode side of the stack module 100 through the fourth heat exchanger, thereby further improving the utilization efficiency of the waste heat on the anode side of the stack module 100, preheating the purge gas to avoid the purge gas temperature being too low, which would lead to insufficient electrolysis temperature of the stack module 100, and further improving the electrolysis efficiency of the stack module 100, improving the hydrogen production effect of the electrolytic hydrogen production system, improving the energy utilization rate and heat exchange efficiency in the electrolytic hydrogen production system, reducing the energy consumption during the heating process, and improving the working efficiency of the electrolytic hydrogen production system.

[0077] In some feasible embodiments, the electrolysis hydrogen production system also includes: a third control valve, located between the hot flow outlet end of the third heat exchanger and the low-speed gas interface of the cathode side ejector 200, and the third control valve is used to control the hydrogen flow rate entering the cathode side ejector 200.

[0078] The electrolytic hydrogen production system provided in the embodiment of the present application can adjust the hydrogen circulation flow rate in real time according to the electrolysis power demand to match the optimal working state of the stack module 100. At the same time, it can avoid that the hydrogen flow rate entering the cathode side ejector 200 is too small, resulting in insufficient hydrogen in the gas entering the cathode side, causing oxidation of the stack module 100, thereby protecting the stack module 100 and extending the service life of the electrolytic hydrogen production system.

[0079] In some feasible embodiments, the electrolysis hydrogen production system also includes: an anode side ejector, the high-speed gas interface of the anode side ejector is connected to the output end of the variable frequency fan 400, the low-speed gas interface of the anode side ejector is used to obtain the oxygen generated on the anode side of the stack module 100, and the output end of the anode side ejector is used to transport oxygen and purge gas to the anode side of the stack module 100; a buffer, located between the output end of the anode side ejector and the anode side of the stack module 100, and the buffer is used to control the pressure of the gas transported to the anode side of the stack module 100.

[0080] The electrolytic hydrogen production system provided in the embodiment of the present application can mix the oxygen output from the anode side of the stack module 100 with the purge gas output from the variable frequency blower through the anode side ejector, and drive the oxygen through the purge gas to deliver the mixed gas to the anode side of the stack module 100, so as to realize the gas circulation on the anode side of the system, reduce the amount of cold air introduced on the anode side, and then reduce the heat loss of the air on the anode side, and reduce the parasitic power consumption of the air heating on the anode side. The high-temperature oxygen on the anode side of the stack module 100 can be used to preheat the purge gas, so as to further reduce the energy consumption of the purge gas heating, improve the energy utilization rate and heat exchange efficiency in the electrolytic hydrogen production system, and improve the working efficiency of the electrolytic hydrogen production system.

[0081] Figure 2 A schematic flow chart of another electrolysis hydrogen production system provided in an embodiment of the present application. Figure 2 As shown, the electrolysis hydrogen production system includes a stack module 100, an ejector 1, an ejector 2, a variable frequency fan, a heater, a water replenishment device, a hydrogen supply device, an oxygen concentration analyzer, an evaporator, a heat exchanger 1, a heat exchanger 2, a heat exchanger 3, a heat exchanger 4, a mixing chamber, a buffer, a resistance element, a flow meter, a temperature transmitter, a control valve 1, a control valve 2, a control valve 3, a control valve 4, a control valve 5, and a control module.

[0082] The stack module 100 is the core component of the SOEC hydrogen production system, and is responsible for the electrolysis of water vapor to produce hydrogen and oxygen. The raw gas introduced into the cathode side of the stack module 100 is water vapor and hydrogen, and the outlet gas is high-temperature hydrogen containing moisture; the gas introduced into the anode side is air to purge the oxygen produced on the anode side.

[0083] The evaporator is used to generate steam required for electrolysis of the stack module 100. The deionization required by the steam generator is provided by the water replenishment device. The outlet of the steam generator is connected to the cathode side ejector 200 and the mixing chamber.

[0084] The water replenishment device can adjust the flow of deionized water and thus the flow of steam. The outlet of the water replenishment device is connected to heat exchanger 1 and heat exchanger 2 respectively through control valve 1 and control valve 2. When control valve 1 is opened, deionized water first passes through heat exchanger 1 for primary heating, then passes through heat exchanger 2 for secondary heating, and finally passes through the evaporator for further heating to superheated steam. When control valve 2 is opened, deionized water passes through heat exchanger 4 for primary heating, and the heated deionized water enters the evaporator for further heating to steam.

[0085] The cathode side ejector 200 is used to partially reflux the hydrogen generated on the cathode side of the stack module 100 as cathode side reducing gas. The high-pressure driving airflow of the cathode side ejector 200 is the steam at the evaporator outlet, and the high-pressure steam drives the hydrogen to reflux.

[0086] The mixing chamber is used to mix steam and reducing hydrogen. After the mixed gas is further heated to the SOEC working temperature, it is passed into the cathode of the stack module 100. The mixing chamber is provided with two inlets, one of which is connected to the cathode side ejector 200, and the other is connected to the hydrogen supply device. The outlet of the mixing chamber is connected to the heat exchanger 3 and the heater in sequence.

[0087] The hydrogen supply device is used to provide reducing hydrogen to the cathode side of the stack module 100. The hydrogen supply device can be a hydrogen storage bottle, a hydrogen generator, etc.

[0088] The variable frequency fan 400 is used to provide purge air for the anode of the stack module 100. The outlet of the variable frequency fan 400 is connected to the heat exchanger 1, the heat exchanger 4, the anode side ejector, the buffer in sequence, and finally flows into the stack module 100.

[0089] The hot flow stream of the heat exchanger 1 is the high-temperature gas at the anode side outlet of the stack module 100, and the cold flow stream is provided with an air heat exchange coil and a water heat exchange coil, and the two sets of coils are independent of each other.

[0090] A flow controller, an oxygen concentration analyzer, and a temperature sensor are provided at the hot flow outlet of the heat exchanger 1. The flow controller is used to control the flow of the hot flow of the heat exchanger 1. The oxygen concentration analyzer is used to monitor the oxygen concentration of the gas at the outlet of the anode side of the stack module 100 in real time.

[0091] The hot stream of heat exchanger 4 is the high-temperature gas at the cathode side outlet of the stack module 100, and the cold stream is the hot air stream outlet of heat exchanger 1. When the variable frequency fan 400 is started, the input air is heated by heat exchanger 1, and then transported to heat exchanger 2 for further heating to the working temperature before entering the stack module 100; the high-temperature gas at the cathode side outlet is cooled by the first stage of heat exchange, and then passed through heat exchanger 3 and heat exchanger 2 in sequence to cool to room temperature.

[0092] The hot flow inlet of heat exchanger 3 is connected to the hot flow outlet of heat exchanger 4, and the hot flow outlet is connected to the hot flow inlet of heat exchanger 2; the cold flow inlet of heat exchanger 3 is connected to the mixing chamber outlet, and the cold flow outlet is connected to the heater inlet; the mixed gas at the mixing chamber outlet and the cathode side outlet gas undergo heat exchange here.

[0093] The hot stream inlet of heat exchanger 2 is connected to the hot stream outlet of heat exchanger 3. The hydrogen produced by the system is cooled to room temperature after heat exchange and transported to the user end or further purified. The cold stream inlet of heat exchanger 2 is connected to heat exchanger 1 and water replenishment device through control valve 1 and control valve 2 respectively.

[0094] The buffer is used to reduce the pressure fluctuation of the anode inlet gas of the stack module 100 and protect the stack. The inlet and outlet of the buffer are respectively provided with a resistance element and a pressure transmitter. The pressure transmitter monitors the gas pressure at the buffer outlet in real time, and feeds back the monitoring signal to the control module to automatically adjust the pressure of the resistance element so that the anode inlet gas pressure meets the use requirements of the stack module 100.

[0095] The anode side ejector is used to mix the anode side outlet gas of the stack module 100 with the outlet air of the variable frequency blower 400, and send it to the anode inlet of the stack. The high-pressure driving airflow of the anode side ejector is the outlet air of the variable frequency blower 400, and the anode outlet gas is driven to flow back through the high-pressure air.

[0096] Figure 3 A schematic flow chart of a method for producing hydrogen by electrolysis provided in an embodiment of the present application. Figure 3 As shown, in a second aspect of the embodiment of the present application, a method for producing hydrogen by electrolysis is provided, comprising:

[0097] Step S110 , by introducing water vapor into the cathode side of the fuel cell stack module 100 , the fuel cell stack module 100 electrolyzes the water vapor to generate hydrogen on the cathode side of the fuel cell stack module 100 , and generates oxygen on the anode side of the fuel cell stack module 100 .

[0098] Step S120, transmitting at least part of the hydrogen generated on the cathode side of the stack module 100 to the cathode side of the stack module 100 through the cathode side ejector 200, wherein the high-speed airflow interface of the cathode side ejector 200 is used to obtain water vapor, the low-speed airflow interface of the cathode side ejector 200 is used to obtain hydrogen, and the output end of the cathode side ejector 200 is used to pass the gas into the cathode side of the stack module 100.

[0099] Step S130 , detecting the oxygen concentration on the anode side of the fuel cell stack module 100 .

[0100] Step S140 , according to the oxygen concentration, a purge gas is introduced into the anode side of the fuel cell stack module 100 through the variable frequency blower 400 .

[0101] The electrolytic hydrogen production method provided in the embodiment of the present application electrolyzes water vapor to obtain hydrogen and oxygen through the stack module 100, and sets a cathode side ejector 200 on the cathode side of the stack module 100, uses high-pressure water vapor as a driving gas, and drives the high-temperature hydrogen generated on the cathode side of the stack module 100 to flow back to the cathode side of the stack module 100 through the high-pressure water vapor, so that the hydrogen can be used as a reducing protective gas to prevent oxidation on the cathode side of the stack module 100, and can also avoid the hydrogen temperature being too low to affect the thermal efficiency of the system, and at the same time, there is no need to perform additional circulation treatment on the hydrogen, thereby reducing the energy consumption of the electrolytic hydrogen production system. In addition, the oxygen concentration generated on the anode side of the stack module 100 is detected by the concentration analyzer 300, so that the variable frequency fan 400 can control the amount of purge gas delivered to the anode side of the stack module 100 according to the oxygen concentration, so as to prevent oxygen accumulation on the anode side of the stack module 100. The gas delivery state of the variable frequency fan 400 can be adjusted in real time according to the oxygen concentration inside the anode side pipeline, reducing the amount of purge air introduced, thereby reducing the energy consumption of the variable frequency fan 400 and the heating power consumption of the cold air, reducing the heat loss on the anode side, and improving the working efficiency of the electrolytic hydrogen production system.

[0102] In some feasible embodiments, a purge gas is introduced into the anode side of the fuel cell stack module 100 through the variable frequency fan 400 according to the oxygen concentration, including: when the oxygen concentration is less than or equal to a preset concentration, the variable frequency fan 400 is controlled to stop introducing the purge gas into the anode side of the fuel cell stack module 100, wherein the gas output rate of the anode side of the fuel cell stack module 100 is equal to the gas generation rate of the anode side of the fuel cell stack module 100; when the oxygen concentration is greater than a preset concentration, the rate at which the variable frequency fan 400 introduces the purge gas into the anode side of the fuel cell stack module 100 is controlled according to the oxygen concentration.

[0103] The electrolytic hydrogen production method provided in the embodiment of the present application can further save the energy consumption of the variable frequency fan 400 and the heating power consumption of the anode side purge air by controlling whether the variable frequency fan 400 blows air and the blowing rate according to the oxygen concentration, reduce the heat loss on the anode side of the system, reduce the energy consumption of the electrolytic hydrogen production system, and improve the working efficiency of the electrolytic hydrogen production system.

[0104] For example, in Figure 2 In the electrolysis hydrogen production system shown, the steam required for electrolysis of the stack module 100 is produced by an evaporator. The deionized water output by the water replenishment device is heated by a heat exchanger and then passed into the evaporator for further heating to superheated steam. The superheated steam is mixed with the reducing hydrogen required on the cathode side of the stack module, and then further heated to the working temperature of the stack module 100 by a heat exchanger 3 and a heater, and then passed into the stack module 100 for electrolysis.

[0105] A temperature transmitter is provided at the cathode inlet of the stack module 100 to monitor the cathode inlet gas temperature in real time and feed it back to the control module. When the monitored temperature T0 < the set value T1, the heater power is increased; when the monitored temperature T0 > the set value T1, the heater power is reduced.

[0106] During the system startup phase, the reducing hydrogen required by the stack module 100 is provided by a hydrogen supply device, which can be a hydrogen bottle, a hydrogen generator, etc. The hydrogen output by the hydrogen supply device is evenly mixed with the superheated steam generated by the evaporator in the mixing chamber. A flow controller is provided at the outlet of the hydrogen supply device to control the hydrogen flow.

[0107] After the system runs stably, the hydrogen supply device is turned off, the control valve 5 is opened, and part of the hydrogen generated by the system is returned to the ejector 2 through the ejector 2 as reducing hydrogen. After the hydrogen and steam are mixed in the ejector 2, they enter the mixing chamber for further mixing, and then are further heated to the SOEC working temperature through the heat exchanger 3 and the heater, and then passed into the stack module 100 for electrolysis. A flow meter is provided on the hydrogen inlet side of the ejector 2 to monitor the inlet flow of hydrogen in real time and feed it back to the control module. The control module adjusts the opening of the control valve 5 to adjust the hydrogen flow rate.

[0108] The air required for electrolysis of the stack module 100 is provided by the variable frequency fan 400. Air is continuously introduced during the system startup phase, and the air flow is controlled by the variable frequency fan 400. During the system startup phase, the flow controller is opened to the maximum state, and the outlet air of the variable frequency fan 400 is heated by heat exchangers 1 and 2, and then passed into the SOEC stack, and then discharged into the atmosphere through heat exchanger 1 and the flow controller. A flow controller and an oxygen concentration analyzer are provided at the outlet of the hot stream of heat exchanger 1. After the system runs stably, the control valve 3 is opened, and the hydrogen concentration analyzer monitors the heat exchanger 1 in real time. During this process, the concentration analyzer monitors the concentration C0 of oxygen in the outlet gas of heat exchanger 1 in real time.

[0109] When the oxygen concentration C0 ≤ the set value C1, the variable frequency fan 400 is automatically turned off by the control module, and the flow value of the flow controller 1 is adjusted to be equal to the oxygen production rate V0 on the anode side of the stack. At this time, the control valve 1 is opened and the control valve 2 is closed, and the water replenishment device outputs deionized water as a cold stream to pass into the heat exchanger 1 for primary heating. A part of the outlet gas on the anode side of the stack module 100 is discharged into the atmosphere after passing through the heat exchanger 1 for heat exchange and cooling. The flow of this part of the gas is controlled by the flow controller; the other part of the gas continues to circulate back to the anode side inlet of the stack module 100 to realize the anode side gas circulation.

[0110] When the oxygen concentration C0> the set value C1, the variable frequency fan 400 is automatically turned on through the control module. The ventilation volume of the variable frequency fan gradually increases from 0 until the oxygen concentration C0< the set value C1. During this period, the hot flow outlet temperature sensor of the heat exchanger 1 monitors the hot flow outlet temperature in real time. When the monitored temperature Ta0< the set temperature Ta1, the opening of the control valve 1 is reduced and the opening of the control valve 2 is increased, thereby reducing the flow of deionized water flowing into the heat exchanger 1 and increasing the heat exchange on the air side; when the monitored temperature Ta0=the set temperature Ta1, the opening of the control valve 1 and the control valve 2 are kept unchanged; when the monitored temperature Ta0>the set temperature Ta1, the opening of the control valve 1 is increased and the opening of the control valve 2 is reduced, thereby increasing the flow of deionized water flowing into the heat exchanger 1, improving the thermal efficiency of the system, and protecting the oxygen concentration analyzer and the flow controller 1 at the same time.

[0111] The air output by the variable frequency fan 400 is passed into the heat exchanger 1 as a cold stream for primary heating, and the heated gas is passed into the high-speed airflow interface of the ejector 1. A part of the gas at the anode side outlet of the stack module 100 is passed into the heat exchanger 1 for heat exchange and cooling, and then discharged into the atmosphere. The flow rate of this part of the gas is controlled by the flow controller; the other part of the gas is passed into the low-speed fluid interface of the ejector 1, and is pressurized and returned to the buffer for pressure stabilization. The gas after pressure stabilization is then transported to the anode of the stack.

[0112] The buffer inlet is equipped with a resistance element, and the outlet is equipped with a pressure transmitter. The pressure transmitter monitors the buffer outlet gas pressure signal in real time and feeds it back to the control module. When the pressure transmitter monitors the buffer outlet pressure P0> the set value P1, the control module adjusts the resistance value of the resistance element to reduce the gas pressure.

[0113] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", "ideal embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0114] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features of the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0115] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A hydrogen production system by electrolysis, characterized in that: include: A stack module, comprising a cathode side and an anode side, the stack module is used to electrolyze water vapor to obtain hydrogen and oxygen, wherein the cathode side is used to introduce water vapor and output hydrogen, and the anode side is used to output oxygen; A cathode side ejector is located on the cathode side of the stack module, the high-speed airflow interface of the cathode side ejector is used to obtain water vapor, the low-speed airflow interface of the cathode side ejector is used to obtain hydrogen, and the output end of the cathode side ejector is used to pass gas into the cathode side of the stack module, wherein the hydrogen passed through the cathode side ejector includes at least part of the hydrogen formed on the cathode side of the stack module; and / or, A purge module, located on the anode side of the stack module, the purge module comprising a concentration analyzer and a variable frequency fan; Wherein, the concentration analyzer is used to analyze the concentration of oxygen generated on the anode side of the stack module; The variable frequency fan is used to introduce purge gas into the anode side of the stack module according to the concentration of oxygen generated on the anode side.

2. The electrolysis hydrogen production system according to claim 1, characterized in that: Also includes: A water supply device for providing deionized water; A steam generator, wherein the input end of the steam generator is connected to the output end of the water replenishing device, the output end of the steam generator is connected to the high-speed airflow interface of the cathode side ejector, and the steam generator is used to evaporate the deionized water to obtain water vapor.

3. The electrolysis hydrogen production system according to claim 2, characterized in that: Also includes: A first heat exchanger, wherein a first cold flow stream inlet end of the first heat exchanger is connected to an output end of the water replenishment device, a first cold flow stream outlet end of the first heat exchanger is connected to an input end of the steam generator, a second cold flow stream inlet end of the first heat exchanger is connected to an output end of the variable frequency fan, a second cold flow stream outlet end of the first heat exchanger is used to transport the purge gas to the anode side of the stack module, a hot flow stream inlet end of the first heat exchanger is used to obtain oxygen generated on the anode side of the stack module, and a hot flow stream outlet end of the first heat exchanger is used to output oxygen, wherein the first heat exchanger is used to realize heat exchange between the purge gas and the oxygen generated on the anode side of the stack module, and the first heat exchanger is used to realize heat exchange between the deionized water and the oxygen generated on the anode side of the stack module, and the concentration analyzer is located at the hot flow stream outlet end of the first heat exchanger; A flow controller, the flow controller is used to control the flow rate of the hot stream of the first heat exchanger; A first control valve, located between the first heat exchanger and the water replenishing device, the first control valve is used to control the deionized water to be input into the first heat exchanger; A second heat exchanger, wherein the cold stream inlet end of the second heat exchanger is connected to the first cold stream outlet end of the first heat exchanger, and the cold stream inlet end of the second heat exchanger is connected to the output end of the water replenishment device, and the cold stream outlet end of the second heat exchanger is connected to the input end of the steam generator, the hot stream inlet end of the second heat exchanger is used to obtain the hydrogen generated on the cathode side of the stack module, and the hot stream outlet end of the second heat exchanger is used to output hydrogen, wherein the second heat exchanger is used to realize heat exchange between deionized water and the hydrogen generated on the cathode side of the stack module; A second control valve, located between the second heat exchanger and the water replenishing device, the second control valve is used to control the deionized water to be input into the second heat exchanger; A temperature sensor is located at a hot flow outlet of the first heat exchanger, and the temperature sensor is used to obtain a gas temperature at the hot flow outlet of the first heat exchanger; The degree of opening and closing of at least one of the first control valve and the second control valve is related to the gas temperature.

4. The electrolysis hydrogen production system according to claim 1, characterized in that: Also includes: A hydrogen supply device, used for providing hydrogen; A mixing chamber, the input end of the mixing chamber is connected to the output end of the cathode side ejector, and the input end of the mixing chamber is connected to the output end of the hydrogen supply device, the mixing chamber is used to mix hydrogen and water vapor, and the output end of the mixing chamber is used to input the mixed gas to the cathode side of the stack module; A heater is located between the mixing chamber and the cathode side, and is used to heat the mixed gas.

5. The electrolysis hydrogen production system according to claim 4, characterized in that: Also includes: A third heat exchanger, wherein the cold flow inlet end of the third heat exchanger is connected to the output end of the mixing chamber, the cold flow outlet end of the third heat exchanger is connected to the input end of the heater, the hot flow inlet end of the third heat exchanger is used to obtain the hydrogen generated on the cathode side of the stack module, the hot flow outlet end of the third heat exchanger is used to output hydrogen, and the hot flow outlet end of the third heat exchanger is connected to the low-speed gas interface of the cathode side ejector, wherein the third heat exchanger is used to realize heat exchange between the mixed gas output from the mixing chamber and the hydrogen generated on the cathode side of the stack module.

6. The electrolysis hydrogen production system according to claim 5, characterized in that: Also includes: A fourth heat exchanger, wherein the hot flow inlet end of the fourth heat exchanger is used to obtain the hydrogen generated on the cathode side of the stack module, the hot flow outlet end of the fourth heat exchanger is connected to the hot flow inlet end of the third heat exchanger, the cold flow inlet end of the fourth heat exchanger is connected to the output end of the variable frequency fan, and the cold flow outlet end of the fourth heat exchanger is used to output the purge gas, wherein the fourth heat exchanger is used to realize heat exchange between the purge gas output by the variable frequency fan and the hydrogen generated on the cathode side of the stack module.

7. The electrolysis hydrogen production system according to claim 5, characterized in that: Also includes: The third control valve is located between the hot flow outlet of the third heat exchanger and the low-speed gas interface of the cathode side ejector, and the third control valve is used to control the hydrogen flow rate entering the cathode side ejector.

8. The electrolysis hydrogen production system according to claim 1, characterized in that: Also includes: An anode side ejector, wherein the high-speed gas interface of the anode side ejector is connected to the output end of the variable frequency blower, the low-speed gas interface of the anode side ejector is used to obtain the oxygen generated by the anode side of the stack module, and the output end of the anode side ejector is used to transport oxygen and purge gas to the anode side of the stack module; A buffer is located between the output end of the anode side ejector and the anode side of the stack module, and is used to control the pressure of the gas delivered to the anode side of the stack module.

9. A method for producing hydrogen by electrolysis, characterized in that: include: By introducing water vapor into the cathode side of the stack module, the stack module electrolyzes the water vapor to generate hydrogen on the cathode side of the stack module and generates oxygen on the anode side of the stack module; Transmitting at least part of the hydrogen generated on the cathode side of the stack module to the cathode side of the stack module through a cathode side ejector, wherein the high-speed airflow interface of the cathode side ejector is used to obtain water vapor, the low-speed airflow interface of the cathode side ejector is used to obtain hydrogen, and the output end of the cathode side ejector is used to pass the gas into the cathode side of the stack module; Detecting the oxygen concentration on the anode side of the stack module; According to the oxygen concentration, a purge gas is introduced into the anode side of the stack module through a variable frequency fan.

10. The method for producing hydrogen by electrolysis according to claim 9, characterized in that: The step of introducing a purge gas into the anode side of the stack module through a variable frequency fan according to the oxygen concentration includes: When the oxygen concentration is less than or equal to a preset concentration, the variable frequency blower is controlled to stop supplying the purge gas to the anode side of the stack module, wherein the gas output rate of the anode side of the stack module is equal to the gas generation rate of the anode side of the stack module; When the oxygen concentration is greater than the preset concentration, the rate at which the variable frequency fan introduces the purge gas to the anode side of the fuel cell stack module is controlled according to the oxygen concentration.

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