PEM water electrolysis hydrogen production system

Abstract

The PEM water electrolysis hydrogen production system comprises a PEM electrolytic bath and a gas-liquid separator, an inlet of the gas-liquid separator is connected with the PEM electrolytic bath, and a water outlet of the gas-liquid separator is connected with a water inlet of the PEM electrolytic bath through a circulating main pipeline. The PEM water electrolysis hydrogen production system further comprises at least one circulating bypass pipeline, at least one deionizing device and at least one first control valve. The circulating bypass pipeline and the circulating main pipeline are connected in parallel, the circulating bypass pipeline is provided with at least one deionizing device and at least one first control valve, the deionizing device is used for removing at least part of ions in circulating water, and the first control valve is used for controlling the circulating water flow of the corresponding circulating bypass pipeline. When the PEM water electrolysis hydrogen production system is applied, the conductivity of circulating water can be reduced without stopping the machine to change water, the hydrogen production efficiency can be improved, and water resources can be saved.

Description

Technical Field

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

[0002] PEM (Proton Exchange Membrane) water electrolysis is a technology that uses a proton exchange membrane as an electrolyte and pure water as a reactant to produce hydrogen. Specifically, PEM water electrolysis is usually carried out in a PEM electrolyzer. Water molecules are first decomposed into oxygen and hydrogen ions under the catalytic action of the anode catalyst. The hydrogen ions then pass through the PEM membrane between the anode and cathode, and then generate hydrogen under the catalytic action of the cathode catalyst. The hydrogen and oxygen produced by the reaction are mixed with water to form a gas-liquid mixture. The gas-liquid mixture then enters the corresponding gas-liquid separator for gas-liquid separation. The separated hydrogen and oxygen enter the subsequent process, and the separated water (hereinafter referred to as "circulating water") is returned to the PEM electrolyzer through a water pump and pipeline for recycling.

[0003] At present, in the process of PEM water electrolysis to produce hydrogen, the conductivity of the circulating water gradually increases as the hydrogen production process proceeds. When the conductivity does not meet the use requirements, the conductivity of the water required for electrolysis is often reduced by replacing it with new water. Changing the water not only requires the system to be shut down, which will reduce the hydrogen production efficiency, but also discards the water with high conductivity, resulting in a waste of water resources.

[0004] Therefore, how to provide a solution to overcome or alleviate the above-mentioned defects is still a technical problem that needs to be solved urgently by those skilled in the art. Utility Model Content

[0005] The purpose of this application is to provide a PEM water electrolysis hydrogen production system, which can reduce the conductivity of circulating water without stopping the system for water replacement, thereby improving hydrogen production efficiency and saving water resources.

[0006] To solve the above technical problems, the present application provides a PEM water electrolysis hydrogen production system, comprising a PEM electrolyzer and a gas-liquid separator, wherein the inlet of the gas-liquid separator is connected to the PEM electrolyzer, and the water outlet of the gas-liquid separator is connected to the water inlet of the PEM electrolyzer via a main circulation line. The PEM water electrolysis hydrogen production system further comprises at least one circulation bypass line, at least one deionization device, and at least one first control valve;

[0007] The circulation bypass line and the circulation main line are connected in parallel, and the circulation bypass line is provided with at least one deionization device and at least one first control valve. The deionization device is used to remove at least part of the ions in the circulating water, and the first control valve is used to control the circulating water flow rate of the corresponding circulation bypass line.

[0008] Optionally, the circulation bypass line is provided with the first control valve upstream of the first deionization device in the flow direction of the circulating water; and / or,

[0009] The first control valve is arranged in the circulation bypass line downstream of the last deionization device in the flow direction of the circulating water; and / or,

[0010] The circulation bypass line is provided with two or more deionization devices in series, and the circulation bypass line is provided with the first control valve between at least two adjacent deionization devices.

[0011] Optionally, the portion of the main circulation line located between the two ends of the bypass circulation line is defined as a parallel pipe section, and the parallel pipe section is provided with a second control valve, which can control the circulating water flow of the parallel pipe section.

[0012] Optionally, the first control valve and / or the second control valve is a ball valve.

[0013] Optionally, the deionization device is an ion exchange resin tank.

[0014] Optionally, the ion exchange resin in the ion exchange resin tank is in the form of particles with a diameter of 0.4 mm to 0.8 mm.

[0015] Optionally, there are more than two circulation bypass pipes;

[0016] The two or more circulation bypass pipes are arranged in parallel, or the two or more circulation bypass pipes are arranged in sequence on the circulation main pipe along the flow direction of the circulating water.

[0017] Optionally, the PEM water electrolysis hydrogen production system further includes at least one conductivity measuring device;

[0018] At least one conductivity measuring device is provided in the main circulation line, and the conductivity measuring device is used to measure the conductivity of the circulating water in the main circulation line.

[0019] Optionally, the conductivity measuring device is provided on the main circulation line upstream of the first bypass circulation line in the direction of circulating water flow; and / or,

[0020] The conductivity measuring device is arranged in the main circulation line downstream of the last one of the bypass circulation lines in the direction of circulating water flow; and / or,

[0021] There are more than two circulation bypass pipes, which are sequentially arranged on the circulation main pipe along the flow direction of the circulating water. The conductivity measuring device is arranged on the circulation main pipe between at least two adjacent circulation bypass pipes.

[0022] Optionally, the PEM water electrolysis hydrogen production system further includes a heat exchanger and a flow pump;

[0023] The heat exchanger and the flow pump are arranged in the main circulation line, and the heat exchanger is used to cool the circulating water in the main circulation line.

[0024] The PEM water electrolysis hydrogen production system provided in the present application is capable of online purification of the circulating water produced after gas-liquid separation of the PEM water electrolysis hydrogen production product by removing at least part of the ions in the circulating water, reducing the conductivity of the circulating water without stopping the system for water replacement, thereby improving hydrogen production efficiency and saving water resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic structural diagram of a PEM water electrolysis hydrogen production system according to the first embodiment of the present application;

[0026] Figure 2 This is a schematic structural diagram of a PEM water electrolysis hydrogen production system according to a second embodiment of the present application;

[0027] Figure 3 This is a schematic structural diagram of a PEM water electrolysis hydrogen production system according to a third embodiment of the present application;

[0028] Figure 4 This is a structural schematic diagram of the PEM water electrolysis hydrogen production system provided in the fourth embodiment of the present application.

[0029] The reference numerals in the above drawings are described as follows:

[0030] 1-PEM electrolyzer;

[0031] 2-gas-liquid separator;

[0032] 3-circulation main line, 31-parallel pipe section;

[0033] 4-Circulation bypass line;

[0034] 5- Deionization device;

[0035] 6-first control valve;

[0036] 7- Second control valve;

[0037] 8- Conductivity measuring device;

[0038] 91 - heat exchanger, 92 - flow pump, 93 - first temperature measuring device, 94 - second temperature measuring device, 95 - electrolysis power supply. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the present application, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0040] It should be noted that the "upstream" mentioned in this application refers to the "rear" in the direction of the circulating water flow in the corresponding pipeline, and the "downstream" refers to the "front" in the direction of the circulating water flow in the corresponding pipeline.

[0041] The terms "first", "second", etc. mentioned in this application are only used to facilitate the description of two or more structures or components with the same or similar structures and / or functions, and do not mean any special limitation on the order and / or importance.

[0042] In this application, unless otherwise specified or limited, the term "connection" should be understood in a broad sense. For example, it can mean a fixed connection, a detachable connection, or an integral connection; it can mean a mechanical connection or a communication connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean internal communication between two components. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0043] Please refer to Figure 1 , Figure 1 This is a structural schematic diagram of the PEM water electrolysis hydrogen production system provided in the first embodiment of this application.

[0044] In the embodiment provided in the present application, the PEM water electrolysis hydrogen production system includes a PEM electrolyzer 1, a gas-liquid separator 2, at least one circulation bypass line 4, at least one deionization device 5 and at least one first control valve 6. The inlet of the gas-liquid separator 2 is connected to the PEM electrolyzer 1, and the water outlet of the gas-liquid separator 2 is connected to the water inlet of the PEM electrolyzer 1 through the circulation main line 3. The circulation bypass line 4 and the circulation main line 3 are connected in parallel. The circulation bypass line 4 is provided with at least one of the above-mentioned deionization devices 5 and at least one of the above-mentioned first control valves 6. The deionization device 5 is used to remove at least part of the ions in the circulating water, and the first control valve 6 is used to control the circulating water flow rate of the corresponding circulation bypass line 4.

[0045] When in use, the anode side outlet or cathode side outlet of the PEM electrolyzer 1 is connected to the inlet of the gas-liquid separator 2 to feed the gas-liquid mixture formed by the hydrogen or oxygen mixed with water produced by the electrolysis reaction into the gas-liquid separator 2. The gas-liquid separator 2 can perform gas-liquid separation on the gas-liquid mixture, and the hydrogen or oxygen obtained by gas-liquid separation is fed to the subsequent process for treatment. The water obtained by gas-liquid separation is returned to the PEM electrolyzer 1 through the water inlet of the PEM electrolyzer 1 through the circulation main line 3 for recycling, so that the water separated by the gas-liquid separator 2 is called circulating water. Among them, the gas-liquid separator 2 can be a hydrogen separator or an oxygen separator, and there is no specific limitation. When the gas-liquid separator 2 is a hydrogen separator, the inlet of the gas-liquid separator 2 is connected to the cathode side outlet of the PEM electrolyzer 1. When the gas-liquid separator 2 is an oxygen separator, the inlet of the gas-liquid separator 2 is connected to the anode side outlet of the PEM electrolyzer 1.

[0046] As the hydrogen production process progresses, the internal ion concentration of the above-mentioned circulating water gradually increases, causing the conductivity of the circulating water to gradually increase, and even exceeding the preset conductivity threshold and failing to meet the requirements of electrolysis. When the conductivity of the circulating water rises to the conductivity threshold, compared with the technology of reducing the conductivity of the circulating water by stopping the machine to change the water in the related art, the PEM electrolysis water hydrogen production system provided in the above embodiment of the present application can use the deionization device 5 on the circulating bypass line 4 to purify the circulating water to remove at least part of the ions in the circulating water, thereby reducing the conductivity of the circulating water. This process is carried out online without stopping the machine, and is not likely to affect the continuous progress of the hydrogen production process. It can improve the efficiency of hydrogen production, and there is no need to discharge and discard high-conductivity water to replace new water, which can save water resources and reduce the cost of hydrogen production.

[0047] Furthermore, it is readily understood that the first control valve 6 can control the circulating water flow rate in the bypass circulation line 4 to zero to close it, can control the circulating water flow rate in the bypass circulation line 4 to be greater than zero to open it, and can adjust the circulating water flow rate. In this manner, the degree and rate of reduction in the circulating water conductivity can be controlled by controlling the circulating water flow rate in the corresponding bypass circulation line 4 based on the degree to which the conductivity of the circulating water in the main circulation line 3 exceeds the conductivity threshold, thereby enhancing the controllability of the circulating water conductivity reduction process.

[0048] Please refer to Figure 2 and Figure 4 , Figure 2 This is a structural diagram of the PEM water electrolysis hydrogen production system provided in the second embodiment of this application. Figure 3 This is a structural diagram of the PEM water electrolysis hydrogen production system provided in the third embodiment of this application. Figure 4 This is a structural schematic diagram of the PEM water electrolysis hydrogen production system provided in the fourth embodiment of the present application.

[0049] In actual setting, there can be one circulation bypass pipe 4 or more than two, and the specific number is not limited. When there are more than two circulation bypass pipes 4, the more than two circulation bypass pipes 4 can be set in parallel, or can be set in sequence in the circulation main pipe 3 along the flow direction of the circulating water, and the specific arrangement method is not limited; the number of deionization devices 5 in each circulation bypass pipe 4 can be one or more than two.

[0050] Please combine Figure 1 It is understood that in the first embodiment provided in the present application, there is one circulation bypass line 4, and a deionization device 5 is provided on the circulation bypass line 4. The deionization device 5 in the circulation bypass line 4 is used to remove ions from the circulating water, and the structure is relatively simple.

[0051] Please combine Figure 2 It is understood that in the second embodiment provided in the present application, there is one circulation bypass line 4, and three deionization devices 5 are arranged in series on the circulation bypass line 4. The three deionization devices 5 of the circulation bypass line 4 are used in sequence to remove ions from the circulating water, which can enhance the ion removal effect of the circulating water.

[0052] Please combine Figure 3 It is understood that in the third embodiment provided in the present application, there are two circulation bypass lines 4, and the two circulation bypass lines 4 are arranged in parallel. Each circulation bypass line 4 is provided with a deionization device 5, so that the two circulation bypass lines 4 can be used to divert the circulating water of the circulation main line 3, and the deionization devices 5 of the two circulation bypass lines 4 can be used to remove ions from the diverted circulating water respectively, or only one of the circulation bypass lines 4 can be used to divert the circulating water of the circulation main line 3, and the deionization device 5 of the circulation bypass line 4 can be used to remove ions from the diverted circulating water, which has high flexibility.

[0053] Please combine Figure 4 It is understood that in the fourth embodiment provided in the present application, there are three circulation bypass pipes 4, and the three circulation bypass pipes 4 are arranged in sequence on the circulation main pipe 3 along the flow direction of the circulating water. Each circulation bypass pipe 4 is provided with a deionization device 5. The deionization devices 5 of the three circulation bypass pipes 4 can be used in sequence to remove ions from the circulating water, or only the deionization devices 5 of one or two of the circulation bypass pipes 4 can be used to remove ions from the circulating water, which has high flexibility.

[0054] In actual configuration, the position and number of the first control valves 6 on the circulation bypass line 4 are not limited.

[0055] For example, the circulation bypass line 4 may be provided with a first control valve 6 upstream of the first deionization device 5 in the direction of circulating water flow to control the opening or closing of the circulation bypass line 4, or adjust the flow rate of circulating water entering the circulation bypass line 4, so as to control the degree and rate of reduction of the conductivity of the circulating water; the circulation bypass line 4 may also be provided with a first control valve 6 downstream of the last deionization device 5 in the direction of circulating water flow to adjust the flow rate of the circulating water purified by the circulation bypass line 4 to the circulation main line 3, thereby adjusting the time for the deionization device 5 to purify the circulating water, and adjusting the degree and rate of reduction of the conductivity of the circulating water; when the circulation bypass line 4 is provided with more than two deionization devices 5 in series, the circulation bypass line 4 may also be provided with a first control valve 6 between at least two adjacent deionization devices 5 to accurately control the flow rate of circulating water flowing into or out of the corresponding deionization device 5, thereby adjusting the time for the corresponding deionization device 5 to purify the circulating water, and thus controlling the degree and rate of reduction of the conductivity of the circulating water.

[0056] The portion of the main circulation line 3 between the two ends of the bypass circulation line 4 is defined as a parallel pipe section 31. A second control valve 7 is provided in the parallel pipe section 31, which controls the circulating water flow rate in the parallel pipe section 31. Thus, the second control valve 7 can be used to control the opening or closing of the parallel pipe section 31, or to adjust the circulating water flow rate in the parallel pipe section 31.

[0057] Of course, the first control valve 6 and the second control valve 7 can be controlled in coordination to adjust the circulating water flow rate of the corresponding pipeline to adjust the degree and rate of reduction of the circulating water conductivity.

[0058] The following describes the principle of coordinated control of the first control valve 6 and the second control valve 7 by taking the example of a deionization device 5 and a deionization device 5 provided in the circulation bypass pipe 4 as examples:

[0059] like Figure 1 、 Figure 3 and Figure 4As shown, when each circulation bypass line 4 is provided with a deionization device 5, the deionization device 5 is both the first deionization device 5 in the circulation bypass line 4 in the circulation water flow direction and the last deionization device 5 in the circulation bypass line 4 in the circulation water flow direction. A first control valve 6 can be respectively provided upstream and downstream of the deionization device 5 in each circulation bypass line 4. When the conductivity of the circulating water sent out by the gas-liquid separator 2 is high, the second control valve 7 and the two first control valves 6 of the circulation bypass pipe 4 can be opened at the same time, and the proportion of the circulating water volume passing through the circulation bypass pipe 4 to the circulating water volume sent out by the gas-liquid separator 2 can be controlled to a specific value, such as 20%, according to the design of the pipeline resistance and the valve opening design. In this way, the conductivity of the circulating water can be reduced at a set rate and this state can be maintained for a long time. Of course, after the first control valve 6 is opened for a period of time so that the circulating water fills the deionization device 5, the two first control valves 6 can be closed for a preset time to control the time for the deionization device 5 to purify the circulating water, so as to fully purify the circulating water. When the conductivity of the circulating water sent out by the gas-liquid separator 2 is too high, the conductivity of the circulating water needs to be quickly reduced. The two first control valves 6 of the circulation bypass pipe 4 can be controlled to be open and the second control valve 7 can be closed so that all the circulating water is purified by the deionization device 5 in the circulation bypass pipe 4, thereby quickly reducing the conductivity.

[0060] like Figure 2 As shown, when the circulation bypass line 4 is provided with more than two deionization devices 5, a first control valve 6 can be provided on the circulation bypass line 4 upstream of the first deionization device 5, between two adjacent deionization devices 5, and downstream of the last deionization device 5 along the direction of the circulating water flow. When the conductivity of the circulating water sent out by the gas-liquid separator 2 is high, the second control valve 7 and all the first control valves 6 on the circulation bypass line 4 can be opened simultaneously, and the valves can be maintained in an open state. Alternatively, each first control valve 6 can be opened in sequence at preset intervals to control the time for each deionization device 5 to purify the circulating water. Alternatively, all the first control valves 6 can be opened simultaneously, and after the circulating water fills all the deionization devices 5, the upstream and downstream first control valves 6 can be closed to control the time for each deionization device 5 to purify the circulating water. In this way, the control method is flexible and changeable. When the conductivity of the circulating water sent out by the gas-liquid separator 2 is too high, all the first control valves 6 can be controlled to open and the second control valve 7 can be closed. The three deionization devices 5 can purify the circulating water in sequence, achieving triple purification, high ion removal efficiency, and can quickly reduce the conductivity.

[0061] like Figure 3As shown, when two circulation bypass pipes 4 are arranged in parallel, if the conductivity of the circulating water sent out by the gas-liquid separator 2 is high, only the first control valve 6 of one circulation bypass pipe 4 can be controlled to open, so that only the deionization device 5 of one circulation bypass pipe 4 is used to purify the circulating water; if the conductivity of the circulating water sent out by the gas-liquid separator 2 is too high, the first control valves 6 of both circulation bypass pipes 4 can be controlled to open, so that the two circulation bypass pipes 4 are used to purify the circulating water at the same time, so as to improve the purification efficiency, thereby quickly reducing the conductivity of the circulating water.

[0062] like Figure 4 As shown, when more than two circulation bypass pipes 4 are sequentially arranged along the flow direction of the circulating water in the circulation main pipe 3, if the conductivity of the circulating water sent out by the gas-liquid separator 2 is high, the first control valve 6 of any one or any two circulation bypass pipes 4 can be controlled to open, so as to use the deionization device 5 of any one circulation bypass pipe 4 to purify the circulating water, or the deionization devices 5 of any two circulation bypass pipes 4 can be used in sequence to purify the circulating water. If the conductivity of the circulating water sent out by the gas-liquid separator 2 is too high, the first control valves 6 of all the circulation bypass pipes 4 can be controlled to open, so as to use the deionization devices 5 of three circulation bypass pipes 4 in sequence to purify the circulating water, so as to enhance the purification effect and quickly reduce the conductivity of the circulating water.

[0063] Of course, when the conductivity of the circulating water reaches the standard, all the first control valves 6 can be closed and all the second control valves 7 can be opened to shield all the deionization devices 5 and place them for rest or maintenance.

[0064] In addition, in Figure 3 and Figure 4 In the embodiment shown, the provision of more than two circulation bypass lines 4 also enables, when the deionization device 5 of one of the circulation bypass lines 4 is damaged, the other circulation bypass lines 4 where the deionization device 5 is not damaged to be switched in time for purification work, so as to ensure the continuous purification work of the circulating water.

[0065] It can be seen that the arrangement of the first control valve 6 and the second control valve 7 enables the circulating water purification process to be flexibly controlled, thereby improving the efficiency and effect of the circulating water purification.

[0066] In actual configuration, the structural forms of the first control valve 6 and the second control valve 7 are not limited.

[0067] In the embodiment provided in the present application, the first control valve 6 and the second control valve 7 are both ball valves, which can be opened and closed quickly, thereby realizing rapid adjustment of the circulating water flow in the corresponding pipeline, and have a compact structure and low cost.

[0068] In actual configuration, the structure of the deionization device 5 is not limited, as long as it can remove at least part of the ions in the circulating water.

[0069] In the embodiment provided herein, the deionization device 5 is an ion exchange resin tank. This not only ensures the purification effect of the circulating water, but can even purify the circulating water into ultrapure water to ensure the efficiency and product purity of hydrogen production by PEM electrolysis of water. In addition, the exchange capacity of the used resin can be restored through a chemical regeneration process, enabling the reuse of the ion exchange resin and reducing the purification cost of the circulating water.

[0070] When used specifically, the type and particle size of the ion exchange resin in the ion exchange resin tank are not limited and can be customized according to the type of ions that need to be removed in the circulating water. For example, a general-purpose ultrapure water ion exchange resin can be used, which can be a composite resin that can include styrene and acrylic (ester) materials and can be made into particles with a diameter of 0.4mm~0.8mm to improve the ion adsorption effect and can adsorb Fe 3+ 、Al 3+ , Pb 2+ , Ca 2+ Mg 2+ , K + 、Na + 、H + Isocations and SO4 2- 、NO3 － 、Cl － 、HCO3 － OH － The range of ions that can be adsorbed is wide. After adsorption, the conductivity of the circulating water can be greatly reduced, and the resistivity can reach above 18MΩ.cm.

[0071] In the embodiment provided in the present application, when the first control valve 6 of the circulation bypass line 4 is opened and the circulation runs for half an hour, the conductivity of the circulating water in the PEM water electrolysis hydrogen production system can be reduced to below 0.2uS / cm.

[0072] In the embodiment provided in the present application, the PEM water electrolysis hydrogen production system further includes at least one conductivity measuring device 8 ; at least one conductivity measuring device 8 is provided in the main circulation line 3 , and the conductivity measuring device 8 is used to measure the conductivity of the circulating water in the main circulation line 3 .

[0073] In this way, the conductivity measuring device 8 can be used to measure the conductivity of the circulating water in the main circulation line 3 in real time, so as to obtain the conductivity information of the circulating water and the purification effect of the deionization device 5 on the circulating water in real time, thereby facilitating the control of the opening of each first control valve 6 and the second control valve 7.

[0074] In actual setting, the location of the conductivity measuring device 8 is not limited.

[0075] As an optional solution, a conductivity measuring device 8 may be provided on the main circulation line 3 upstream of the first circulation bypass line 4 in the direction of circulating water flow. In this way, the conductivity of the circulating water delivered by the gas-liquid separator 2 can be measured in a timely manner, so as to timely control the operation of the circulation bypass line 4 when the conductivity is high.

[0076] As an alternative, Figures 1 to 4 As shown, the main circulation line 3 can be provided with a conductivity measuring device 8 downstream of the last circulation bypass line 4 in the flow direction of the circulating water. In this way, the conductivity of the circulating water returning to the PEM electrolyzer 1 can be measured in a timely manner, and the effect of the deionization device 5 of the circulation bypass line 4 in purifying the circulating water can also be intuitively reflected.

[0077] As another optional solution, when there are more than two circulation bypass pipes 4 and the two or more circulation bypass pipes 4 are arranged in sequence in the circulation main pipe 3 along the flow direction of the circulating water, the circulation main pipe 3 may be provided with a conductivity measuring device 8 between at least two adjacent circulation bypass pipes 4. For example, a conductivity measuring device 8 may be provided between every two adjacent circulation bypass pipes 4. During use, the first circulation bypass pipe 4 can be opened along the flow direction of the circulating water to purify the circulating water. According to the conductivity measured by the conductivity measuring device 8 between the first circulation bypass pipe 4 and the second circulation bypass pipe 4, it is judged whether the conductivity of the circulating water after purification by the first circulation bypass pipe 4 meets the requirements. If it meets the requirements, there is no need to open the subsequent circulation bypass pipe 4. If it does not meet the requirements, the second circulation bypass pipe 4 can be opened, and so on, until it is judged whether the conductivity measured by the last conductivity measuring device 8 meets the requirements. The circulation bypass pipe 4 can be selectively opened according to the real-time circulation water purification effect to accurately control the conductivity of the circulating water. It can also save the use time of the conductivity measuring device 8 and improve the efficiency of the circulation water purification.

[0078] Of course, the above three schemes can be combined arbitrarily. For example, when there are more than two circulation bypass pipes 4 and more than two circulation bypass pipes 4 are arranged in sequence in the circulation main pipe 3 along the circulation water flow direction, the circulation main pipe 3 can be provided with a conductivity measuring device 8 upstream of the first circulation bypass pipe 4 in the circulation water flow direction, between each two adjacent circulation bypass pipes 4 and downstream of the last circulation bypass pipe 4, so that the conductivity measured by each conductivity measuring device 8 along the circulation water flow direction can be used in sequence to determine whether to open the next circulation bypass pipe 4, so as to accurately control the conductivity of the circulating water and the opening or closing of each circulation bypass pipe 4.

[0079] In the examples provided in this application, Figures 1 to 4 As shown, the PEM water electrolysis hydrogen production system further includes a heat exchanger 91 and a flow pump 92 ; the heat exchanger 91 and the flow pump 92 are arranged in the main circulation line 3 , and the heat exchanger 91 is used to cool the circulating water in the main circulation line 3 .

[0080] It can be understood that the heat medium inlet and heat medium outlet of the heat exchanger 91 can be connected to the circulation main line 3. Specifically, the heat medium inlet can be connected to the water outlet of the gas-liquid separator 2 through the circulation main line 3, and the heat medium outlet can be connected to the first circulation bypass line 4 through the circulation main line 3. The circulating water can enter the heat exchanger 91 through the heat medium inlet and perform heat exchange with the cooling medium, such as coolant, introduced into the heat exchanger 91 to achieve cooling of the circulating water. The cooled circulating water can flow out of the heat exchanger 91 through the heat medium outlet; the flow pump 92 is used to pump the circulating water in the circulation main line 3 so that the circulating water flows back to the PEM electrolyzer 1. The flow pump 92 can also be connected to an external water source to replenish the electrolyte for the PEM electrolyzer 1 when the electrolyte is consumed and needs to be replenished.

[0081] In actual setting, the order in which the heat exchanger 91, the flow pump 92 and the circulation bypass line 4 are arranged on the circulation main line 3 is not limited. For example, Figures 1 to 4 As shown, the heat exchanger 91 can be arranged upstream of all the circulation bypass pipes 4 to send the cooled circulating water into the circulation bypass pipes 4 for purification, and the flow pump 92 can be arranged downstream of all the circulation bypass pipes 4, so that the purified circulating water can be efficiently sent to the PEM electrolyzer 1.

[0082] In the examples provided in this application, Figures 1 to 4 As shown, the PEM water electrolysis hydrogen production system also includes an electrolysis power supply 95, a first temperature measuring device 93 and a second temperature measuring device 94. The electrolysis power supply 95 can be connected to the PEM electrolyzer 1 to provide power to the PEM electrolyzer 1. The first temperature measuring device 93 can be arranged between the PEM electrolyzer 1 and the gas-liquid separator 2 on the main circulation line 3 to measure the post-cell temperature of the PEM electrolyzer 1. The second temperature measuring device 94 can be arranged between the conductivity measuring device 8 on the main circulation line 3 and the PEM electrolyzer 1 to measure the pre-cell temperature of the PEM electrolyzer 1.

[0083] It is worth noting that the PEM water electrolysis hydrogen production system provided in the present application may also include a controller; the controller and all conductivity measuring devices 8, first control valves 6 and second control valves 7 can be connected to achieve automatic and real-time control of the opening or closing or opening degree of each first control valve 6 and each second control valve 7 according to the conductivity measured by the conductivity measuring device 8.

[0084] This document uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only intended to help understand the device and its core concept of this application. It should be noted that for those skilled in the art, without departing from the principles of this application, various improvements and modifications can be made to this application, and such improvements and modifications also fall within the scope of protection of the claims of this application.

Claims

1. A PEM water electrolysis hydrogen production system, comprising a PEM electrolyzer (1) and a gas-liquid separator (2), wherein the inlet of the gas-liquid separator (2) is connected to the PEM electrolyzer (1), and the water outlet of the gas-liquid separator (2) is connected to the water inlet of the PEM electrolyzer (1) through a main circulation line (3), characterized in that: The PEM water electrolysis hydrogen production system further includes at least one circulation bypass pipeline (4), at least one deionization device (5) and at least one first control valve (6); The circulation bypass line (4) and the circulation main line (3) are connected in parallel. The circulation bypass line (4) is provided with at least one deionization device (5) and at least one first control valve (6). The deionization device (5) is used to remove at least part of the ions in the circulating water. The first control valve (6) is used to control the circulating water flow rate of the corresponding circulation bypass line (4).

2. The PEM water electrolysis hydrogen production system according to claim 1, characterized in that: The circulation bypass line (4) is provided with the first control valve (6) upstream of the first deionization device (5) in the flow direction of the circulating water; and / or, The circulation bypass line (4) is provided with the first control valve (6) downstream of the last deionization device (5) in the flow direction of the circulating water; and / or, The circulation bypass line (4) is provided with two or more deionization devices (5) in series, and the circulation bypass line (4) is provided with the first control valve (6) between at least two adjacent deionization devices (5).

3. The PEM water electrolysis hydrogen production system according to claim 1 or 2, characterized in that: The portion of the main circulation line (3) located between the two ends of the bypass circulation line (4) is defined as a parallel pipe section (31). The parallel pipe section (31) is provided with a second control valve (7). The second control valve (7) is capable of controlling the circulating water flow of the parallel pipe section (31).

4. The PEM water electrolysis hydrogen production system according to claim 3, characterized in that: The first control valve (6) and / or the second control valve (7) are ball valves.

5. The PEM water electrolysis hydrogen production system according to claim 1 or 2, characterized in that: The deionization device (5) is an ion exchange resin tank.

6. The PEM water electrolysis hydrogen production system according to claim 5, characterized in that: The ion exchange resin in the ion exchange resin tank is in the form of particles with a diameter of 0.4 mm to 0.8 mm.

7. The PEM water electrolysis hydrogen production system according to claim 1 or 2, characterized in that: There are more than two circulating bypass pipes (4); The two or more circulation bypass pipes (4) are arranged in parallel, or the two or more circulation bypass pipes (4) are arranged in sequence on the circulation main pipe (3) along the flow direction of the circulating water.

8. The PEM water electrolysis hydrogen production system according to claim 1 or 2, characterized in that: The PEM water electrolysis hydrogen production system further includes at least one conductivity measuring device (8); At least one conductivity measuring device (8) is provided in the main circulation line (3), and the conductivity measuring device (8) is used to measure the conductivity of the circulating water in the main circulation line (3).

9. The PEM water electrolysis hydrogen production system according to claim 8, characterized in that: The conductivity measuring device (8) is provided on the circulation main line (3) upstream of the first circulation bypass line (4) in the direction of circulation water flow; and / or, The conductivity measuring device (8) is provided on the circulation main line (3) downstream of the last circulation bypass line (4) in the direction of circulation water flow; and / or, There are more than two circulation bypass pipes (4), and the two or more circulation bypass pipes (4) are sequentially arranged on the circulation main pipe (3) along the flow direction of the circulating water. The circulation main pipe (3) is provided with the conductivity measuring device (8) between at least two adjacent circulation bypass pipes (4).

10. The PEM water electrolysis hydrogen production system according to claim 1 or 2, characterized in that: The PEM water electrolysis hydrogen production system further includes a heat exchanger (91) and a flow pump (92); The heat exchanger (91) and the flow pump (92) are provided in the main circulation line (3), and the heat exchanger (91) is used to cool the circulating water in the main circulation line (3).

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