Hydrogen production system by electrolysis of water

Abstract

The present application relates to the technical field of hydrogen production by water electrolysis, and discloses a hydrogen production by water electrolysis system, which comprises an electrolytic tank, a hydrogen-side separator, a hydrogen-side cooler, a buffer purifier and a water replenishing pump connected in sequence, wherein the inlet of the hydrogen-side separator is connected with the cathode outlet of the electrolytic tank, and ion exchange resin is placed in the buffer purifier; and an oxygen-side separator, a pure water circulating pump, an oxygen-side cooler and an ion exchange resin device connected in sequence, wherein the inlet of the oxygen-side separator is connected with the anode outlet of the electrolytic tank and the outlet of the water replenishing pump, and the outlet of the ion exchange resin device is connected with the water inlet of the electrolytic tank. The hydrogen-side outlet water and the oxygen-side outlet water of the electrolytic tank are separately treated, so that the quality of the pure water circulating water is not affected, and even if the liquid level control of the hydrogen-side separator fails, the hydrogen gas will not directly enter the oxygen-side separator to cause an accident.

Description

Technical Field

[0001] This invention relates to the field of water electrolysis for hydrogen production technology, and more specifically to a water electrolysis system for hydrogen production. Background Technology

[0002] Against the backdrop of energy conservation, emission reduction, and the development of low-carbon industries, large-scale hydrogen production stations combining water electrolysis hydrogen production units with green energy facilities such as photovoltaics and wind power have considerable development prospects. A single water electrolysis hydrogen production system can generally be divided into three units: an electrolyzer, a hydrogen production frame (gas-water separation), and hydrogen purification. The hydrogen purification system is used to purify the separated crude hydrogen, removing saturated water and trace amounts of oxygen.

[0003] For PEM water electrolysis technology, the quality of the circulating water within the system directly affects the lifespan of the electrolyzer. Typically, the inlet water quality requirement for a PEM electrolyzer is below 0.2 μS / cm. To maintain this water quality, ion exchange resin equipment is needed to adsorb impurities. Furthermore, due to the characteristics of the PEM electrolyzer, a pressure difference needs to be established between the hydrogen and oxygen sides during normal operation, with the hydrogen side pressure needing to be slightly higher than the oxygen side pressure.

[0004] The hydrogen-side effluent from the PEM electrolyzer is significantly less than the oxygen-side effluent, but greater than the feed water volume. Due to the structural characteristics of the electrolyzer, it is difficult to thoroughly clean the hydrogen-side water before it leaves the factory, resulting in higher conductivity of the hydrogen-side water during the initial startup phase. If the hydrogen-side water from the electrolyzer is directly returned to the oxygen-side water circulation system (e.g., ...), ... Figure 1 As shown in the diagram, mixing can easily result in high conductivity of the circulating pure water within the system, thus affecting the operation of the electrolyzer. To avoid this, the oxygen-side system of the electrolyzer needs to be equipped with a larger ion exchange resin device to ensure that the specifications can still be met after mixing with the high-conductivity hydrogen-side water from the electrolyzer. Summary of the Invention

[0005] The purpose of this invention is to provide an electrolytic water hydrogen production system that can separate the hydrogen-side and oxygen-side effluent from the electrolyzer for treatment, thereby avoiding any impact on the quality of the pure water circulation. Even if the level control of the hydrogen-side separator fails, it will not directly cause hydrogen to enter the oxygen-side separator and cause an accident.

[0006] To achieve the above objectives, the present invention provides a water electrolysis hydrogen production system, comprising: an electrolyzer; a hydrogen-side separator, a hydrogen-side cooler, a buffer purifier, and a makeup water pump connected in sequence, wherein the inlet of the hydrogen-side separator is connected to the cathode outlet of the electrolyzer, and the buffer purifier contains ion exchange resin; and an oxygen-side separator, a pure water circulation pump, an oxygen-side cooler, and an ion exchange resin device connected in sequence, wherein the inlet of the oxygen-side separator is connected to the anode outlet of the electrolyzer and the outlet of the makeup water pump, and the outlet of the ion exchange resin device is connected to the inlet of the electrolyzer.

[0007] Preferably, the water electrolysis hydrogen production system further includes a three-way regulating valve, which is connected to the pure water circulation pump via a first pipe, to the oxygen-side cooler via a second pipe, and to the water inlet of the electrolyzer via a third pipe.

[0008] Preferably, the water electrolysis hydrogen production system further includes: a hydrogen-side regulating valve located on the pipeline between the hydrogen-side separator and the hydrogen-side cooler; and / or a cooling water regulating valve, the cooling water regulating valve being used to regulate the amount of circulating water entering the oxygen-side cooler.

[0009] Preferably, the water electrolysis hydrogen production system further includes: a flow monitoring device installed at the inlet of the oxygen-side cooler; and a first temperature monitoring device installed at the outlet of the oxygen-side cooler, used to increase the amount of cooling water entering the ion exchange resin device by increasing the cooling water flow through the cooling water regulating valve or the three-way regulating valve when the water temperature detected by the first temperature monitoring device is higher than the preset temperature.

[0010] Preferably, the water electrolysis hydrogen production system further includes: a second temperature monitoring device and a conductivity monitoring device, installed at the inlet of the electrolyzer, used to: maintain the water temperature at the inlet of the electrolyzer by controlling the opening of the three-way regulating valve when the conductivity detected by the conductivity monitoring device is less than or equal to a preset conductivity; or increase the preset temperature to maintain the water temperature at the inlet of the electrolyzer when the conductivity detected by the conductivity monitoring device is less than or equal to the preset conductivity and reducing the opening of the three-way regulating valve causes the conductivity to be greater than the preset conductivity.

[0011] Preferably, the water electrolysis hydrogen production system further includes: a first liquid level monitoring device, installed on the hydrogen-side separator, for controlling the hydrogen-side regulating valve to lower the liquid level when the liquid level in the hydrogen-side separator is higher than a first preset liquid level; a second liquid level monitoring device, installed on the oxygen-side separator, for controlling the frequency converter of the water replenishment pump to increase the operating frequency of the water replenishment pump when the liquid level in the oxygen-side separator is higher than a second preset liquid level; and a third liquid level monitoring device, installed on the buffer purifier.

[0012] Preferably, the water electrolysis hydrogen production system further includes: a raw material processing device connected to the buffer purifier, used to provide raw material water to the buffer purifier to maintain the liquid level in the buffer purifier.

[0013] Preferably, the buffer purifier includes: an upper space for mixing raw water with the effluent from the hydrogen-side cooler; and a lower space filled with ion exchange resin for purifying the mixed water provided by the upper space.

[0014] Preferably, the buffer purifier includes: a resin unit for purifying the effluent from the hydrogen-side cooler; and a buffer unit for mixing the raw material water with the purified effluent from the hydrogen-side cooler.

[0015] Preferably, the water electrolysis hydrogen production system further includes: an oxygen-side vent regulating valve and an oxygen-side external supply regulating valve, disposed at the top of the oxygen-side separator; and a hydrogen-side vent regulating valve and a hydrogen-side external supply regulating valve, disposed at the top of the hydrogen-side separator.

[0016] Preferably, the water electrolysis hydrogen production system further includes: a pressure difference monitoring device for hydrogen and oxygen sides, used to control the opening degree of the oxygen-side venting regulating valve or the oxygen-side external supply regulating valve to decrease when the pressure difference between the hydrogen-side separator and the oxygen-side separator is greater than a first preset pressure; and / or a hydrogen-side pressure monitoring device, used to control the opening degree of the hydrogen-side venting regulating valve or the hydrogen-side external supply regulating valve to increase when the pressure of the hydrogen-side separator is greater than a second preset pressure.

[0017] Through the above technical solution, the present invention creatively separates the hydrogen-side wastewater treatment and does not directly integrate it into the system. Instead, the wastewater is cooled to the appropriate operating temperature of the ion exchange resin in the buffer purifier via the hydrogen-side cooler to purify the effluent from the hydrogen-side cooler, thereby avoiding any impact on the quality of the pure water circulation. Even if the liquid level control of the hydrogen-side separator fails, it will not directly cause hydrogen to enter the oxygen-side separator and cause an accident.

[0018] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0020] Figure 1 This is a structural diagram of an existing water electrolysis hydrogen production system;

[0021] Figure 2 This is a structural diagram of a water electrolysis hydrogen production system provided in an embodiment of the present invention;

[0022] Figure 3 This is a structural diagram of a water electrolysis hydrogen production system provided in an embodiment of the present invention; and

[0023] Figure 4 This is a cathode gas separation device provided by an embodiment of the present invention, which can be applied to a water electrolysis hydrogen production system.

[0024] Figure Labels

[0025] A1 - Electrolyzer; B1 - Raw material processing equipment; V1 - Hydrogen-side separator; V2 - Oxygen-side separator; V3 - Buffer purifier; R1 - Ion exchange resin equipment; P1 - Pure water circulation pump; P2 - Make-up water pump; E1 - Oxygen-side cooler; E2 - Hydrogen-side cooler; vv1 - Three-way regulating valve; vv2 - Hydrogen-side regulating valve; vv3 - Cooling water regulating valve; vv4 - Oxygen-side vent regulating valve; vv5 - Oxygen-side external supply regulating valve (hydrogen side); vv6 - Vent regulating valve; vv7 - Hydrogen-side external supply regulating valve; VFD - Frequency converter; LC - Liquid level monitoring; TC - Temperature monitoring; AT - Conductivity monitoring; PC - Pressure monitoring; PDC - Differential pressure monitoring; cl1-cl18: Control loop; 1~18: Piping. Detailed Implementation

[0026] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0027] Before introducing the various embodiments of the present invention, let's first discuss... Figure 1 The existing apparatus shown is briefly described as a PEM hydrogen production and water treatment scheme, which is equivalent to a comparative example of the various embodiments of the present invention.

[0028] like Figure 1 As shown, the water electrolysis hydrogen production system includes an electrolyzer A1, a raw material processing device B1, a hydrogen-side separator V1, an oxygen-side separator V2, a pure water circulation pump P1, a makeup water pump P2, an oxygen-side cooler E1, an ion exchange resin device R1, a three-way regulating valve vv1, a hydrogen-side regulating valve vv2, a cooling water regulating valve vv3, an oxygen-side vent regulating valve vv4, and a hydrogen-side vent regulating valve vv6.

[0029] The electrolyzer A1 has its hydrogen-side outlet connected to the hydrogen-side separator V1 via pipe 8. The hydrogen-side water separator V1 is connected to the oxygen-side separator V2 via pipe 9, and a hydrogen-side regulating valve vv2 is installed on pipe 9. The oxygen-side outlet of the electrolyzer A1 is connected to the oxygen-side separator V2 via pipe 2. The oxygen-side separator V2 is connected to the pure water circulation pump P1 via pipe 3. The pure water circulation pump P1 is connected to the oxygen-side cooler E1 via pipe 4. The oxygen-side cooler E1 is connected to the three-way regulating valve vv1 via pipe 5. The three-way regulating valve is divided into two paths: the main path is connected to the ion exchange resin equipment R1 via pipe 6a, and the bypass line is pipe 6b. The outlet pipe 7 of the ion exchange resin equipment R1 and the bypass pipe 6b are combined into pipe 1 and connected to the electrolyzer A1. The top of the hydrogen-side separator V1 and the oxygen-side separator V2 are respectively equipped with a hydrogen-side vent regulating valve vv6 and an oxygen-side vent regulating valve vv4.

[0030] The control scheme used in this comparative example includes cl8-cl18: a temperature monitoring device (TC) is installed at the inlet of electrolyzer A1 to indicate changes in the inlet and outlet temperatures of the electrolyzer and control the cooling regulating valve vv3 of the oxygen-side cooler; a conductivity monitoring device (AT) is installed at the inlet of electrolyzer A1 to indicate conductivity monitoring status and control the distribution of the three-way regulating valve vv1; both the hydrogen-side separator and the oxygen-side separator are equipped with level monitoring devices (LC) to indicate the liquid level in the equipment and control the hydrogen-side regulating valve vv2 and the water supply pump P2 respectively. The hydrogen-side pressure and oxygen-side pressure are independently regulated by the hydrogen-side vent regulating valve vv6 and the oxygen-side vent regulating valve vv4, respectively, and the pressure difference is achieved by different set values ​​for the hydrogen and oxygen sides. When the gas produced by the electrolyzer is sent to the purification system, the system pressure is controlled by the purification system pressure.

[0031] The inventor discovered through research Figure 1 The existing device shown has the following three defects.

[0032] (1) In the comparative example, the effluent from the hydrogen-side separator V1 is directly returned to the oxygen-side separator V2, and the quality of the hydrogen-side effluent can directly affect the pure water circulation on the oxygen side. Failure of the liquid level control of the hydrogen-side separator V1 will directly lead to hydrogen entering the oxygen-side separator V2 and causing an accident.

[0033] (2) In the comparative example, the ion exchange resin equipment R1 was not equipped with separate cooling, so its operating temperature was the same as the electrolyzer inlet temperature (approximately 60-75℃), which is not within the ideal operating temperature of the ion exchange resin (25-35℃). A larger packing volume was required to meet the water quality requirements at the electrolyzer inlet. Excessively high water temperature would reduce the adsorption capacity of the ion exchange resin, and if the water temperature was lowered to the temperature required by the ion exchange resin, the ideal operating temperature of the electrolyzer could not be met, thus affecting the operating efficiency.

[0034] (3) In the comparative example, the hydrogen-oxygen pressure difference is achieved by using different set values ​​of two pressure control loops. In practical applications, this will result in low accuracy of pressure difference control due to errors in the pressure monitoring equipment. Because the pressure difference is achieved by different pressure set values ​​on both sides of the hydrogen and oxygen system, the set values ​​need to be frequently adjusted when the system needs to be started or stopped to increase or decrease pressure, which is cumbersome.

[0035] Furthermore, since the hydrogen-side effluent is directly returned to the oxygen-side separator, the flow rate of this return water is affected by the pressure differential. Fluctuations in the return flow rate cause fluctuations in the liquid level of the hydrogen-side separator, ultimately leading to pressure fluctuations. The operational stability of pressure and pressure differential in Comparative Example 1 is relatively poor.

[0036] To address the first deficiency in existing devices, the present invention provides the following embodiments.

[0037] Figure 2This is a structural diagram of a water electrolysis hydrogen production system according to an embodiment of the present invention. The water electrolysis hydrogen production system includes: an electrolyzer A1; a hydrogen-side separator V1, a hydrogen-side cooler E2, a buffer purifier V3, and a makeup water pump P2 connected in sequence, wherein the inlet of the hydrogen-side separator V1 is connected to the cathode outlet of the electrolyzer A1; and an oxygen-side separator V2, a pure water circulation pump P1, an oxygen-side cooler E1, and an ion exchange resin device R1 connected in sequence, wherein the inlet of the oxygen-side separator V2 is connected to the anode outlet of the electrolyzer A1 and the outlet of the makeup water pump P2, and the outlet of the ion exchange resin device R1 is connected to the inlet of the electrolyzer A1.

[0038] The water electrolysis hydrogen production system can be an AEM (anion exchange membrane) water electrolysis hydrogen production system or a PEM (proton exchange membrane) water electrolysis hydrogen production system.

[0039] In this embodiment, the hydrogen-side wastewater is treated separately and not directly incorporated into the system. Instead, it is cooled to the appropriate operating temperature of the ion exchange resin in the buffer purifier via a hydrogen-side cooler to purify the effluent from the hydrogen-side cooler, thereby avoiding any impact on the quality of the pure water circulating system. Oxygen-side water is sent from the oxygen-side separator to the pure water circulating pump for pressurization and circulation. The circulating pure water is then sent to the electrolyzer via the oxygen-side cooler and the ion exchange resin equipment.

[0040] For the connection method between the oxygen-side separator V2, the pure water circulation pump P1, the oxygen-side cooler E1, and the ion exchange resin equipment R1, refer to existing technologies (e.g., Figure 1 ), or, such as Figure 2 As shown, the water is distributed via a three-way regulating valve, with some of the pure water being purified and the remainder being sent directly to the electrolytic cell via a bypass line.

[0041] In the PEM electrolysis water production hydrogen production integrated system water treatment scheme provided in this embodiment, the hydrogen-side effluent and oxygen-side effluent from the electrolyzer are treated separately to form two cycles. After purification, the hydrogen-side effluent is recycled to the oxygen side to reduce raw material consumption. The oxygen-side effluent from the electrolyzer accounts for the vast majority of the electrolyzer's influent, with only a small portion passing through the hydrogen-side effluent. The water quality at the electrolyzer inlet is mainly ensured by the oxygen-side water treatment equipment.

[0042] In one embodiment, the water electrolysis hydrogen production system further includes: a raw material processing device B1, connected to the buffer purifier V3, for supplying raw water to the buffer purifier V3 to maintain the liquid level within the buffer purifier V3, such as... Figure 2 As shown.

[0043] Among them, the raw material processing equipment B1 can be equipped with reverse osmosis equipment alone, or it can be equipped with polishing resin and other materials alone, or it can be filter materials such as activated carbon, or any combination of the three.

[0044] Specifically, the hydrogen-side cooler E2 is connected to the buffer purifier V3 via pipe 10; the raw material processing equipment B1 is connected to the buffer purifier V3 via pipe 14; and the buffer purifier V3 is connected to the makeup water pump P2 via pipe 11. Figure 2 As shown.

[0045] The buffer purifier V3 includes: an upper space U for mixing raw water with the effluent from the hydrogen-side cooler; and a lower space L filled with ion exchange resin for purifying the mixed water supplied by the upper space U, such as... Figure 4 As shown.

[0046] In this embodiment, the buffer purifier is divided into upper and lower sections. The upper section mixes the hydrogen-side return water and the raw material water, while the lower section is filled with ion exchange resin for further purification. Thus, the hydrogen-side wastewater is treated separately and not directly incorporated into the system to avoid affecting the quality of the pure water circulation. The hydrogen-side wastewater is recycled back to the raw material water system. The oxygen-side effluent from the electrolyzer is used to establish a pure water circulation system.

[0047] In another embodiment, the buffer purifier V3 includes: a resin unit for purifying the effluent from the hydrogen-side cooler; and a buffer unit for mixing the raw material water with the purified effluent from the hydrogen-side cooler.

[0048] To address the second drawback of existing devices (i.e., the need for larger ion exchange resin equipment in the oxygen-side system of the electrolyzer to ensure compliance with specifications after mixing with the high-conductivity hydrogen-side water), the excessive ion exchange resin equipment hinders the miniaturization and skid-mounting of PEM water electrolysis systems. Therefore, a process is needed that can separately treat the effluent from the hydrogen and oxygen sides of the electrolyzer using as little equipment as possible. Thus, based on the above embodiments, the present invention also provides the following preferred embodiments.

[0049] In one embodiment, the water electrolysis hydrogen production system further includes a three-way regulating valve vv1, which is connected to the pure water circulation pump P1 via a first pipe 4, to the oxygen-side cooler E1 via a second pipe 5a, and to the inlet of the electrolyzer A1 via a third pipe 5b. Figure 2 As shown.

[0050] Specifically, such as Figure 2As shown, the oxygen-side wastewater is pressurized by the pure water circulation pump P1 and then distributed by the three-way regulating valve vv1. A portion of this water is cooled by the oxygen-side cooler E1 and then sent to the ion exchange resin equipment R1 for purification. The purified water is then mixed with the bypass water through the three-way regulating valve vv1 and sent to the electrolyzer A1. Thus, the circulating pure water to be purified is first cooled to the appropriate operating temperature of the ion exchange resin (e.g., 25-35°C) by the oxygen-side cooler; simultaneously, the cooled circulating pure water is sent to the ion exchange resin equipment and, after purification, mixed with the material in the bypass line to form effluent at a higher temperature (e.g., 60-75°C), which is then sent to the electrolyzer.

[0051] In this embodiment, an ion exchange resin device is installed within the pure water circulation system of the electrolyzer, along with a three-way regulating valve, a corresponding bypass, and related control circuits to simultaneously control the inlet water temperature and quality of the electrolyzer. Therefore, the actual performance of the ion exchange resin in this embodiment is superior to that in the comparative example, and a larger loading volume is required to meet the water quality requirements at the electrolyzer inlet. The treatment of the oxygen-side effluent ensures that both water quality and temperature meet the requirements simultaneously.

[0052] In one embodiment, the water electrolysis hydrogen production system further includes: a hydrogen-side regulating valve vv2, located on the pipeline between the hydrogen-side separator V1 and the hydrogen-side cooler E2; and / or a cooling water regulating valve vv3, the cooling water regulating valve vv3 being used to regulate the amount of circulating water entering the oxygen-side cooler E1, such as... Figure 2 As shown.

[0053] Specifically, hydrogen-side separator V1 is connected to hydrogen-side cooler E2 via pipe 9, and hydrogen-side regulating valve vv2 is installed on pipe 9; hydrogen-side cooler E2 is connected to buffer purifier V3 via pipe 10. Hydrogen-side effluent from the hydrogen-side separator is depressurized by the hydrogen-side regulating valve and then cooled by the hydrogen-side cooler to the appropriate operating temperature of the ion exchange resin in the buffer purifier. After cooling, the hydrogen-side effluent mixes with purified feed water from the feed processing equipment in the buffer purifier. The mixed hydrogen-side effluent is then purified by the ion exchange resin bed at the bottom of the buffer purifier and sent to the oxygen-side separator via the outlet makeup water pump. Cooling water regulating valve vv3 is installed on the cooling water pipeline of oxygen-side cooler E1, such as... Figure 2 As shown.

[0054] After being separated by the hydrogen-side water separator, the hydrogen-side effluent is depressurized and sent to the buffer purifier. The buffer purifier collects both hydrogen-side wastewater and raw material pure water, and its bottom is equipped with an ion exchange resin section to adsorb impurities in the hydrogen-side wastewater. Oxygen-side wastewater from the electrolyzer is circulated within the system via a pure water circulation pump. The ion exchange resin equipment and its pre-cooler are located on the internal circulation pipeline, which has a bypass to regulate the throughput of the ion exchange resin equipment and is controlled by the electrolyzer inlet temperature and conductivity. The pre-cooler is temperature-controlled, adjusting the cooling water flow to meet the temperature requirements of the ion exchange resin equipment.

[0055] In one embodiment, the water electrolysis hydrogen production system further includes: a flow monitoring device FC, installed at the inlet of the oxygen-side cooler E1; and a first temperature monitoring device (e.g., a temperature monitoring device TC), installed at the outlet of the oxygen-side cooler E1, used to increase the amount of cooling water entering the ion exchange resin device R1 by increasing the cooling water flow through the cooling water regulating valve vv3 or the three-way regulating valve vv1 when the water temperature detected by the first temperature monitoring device is higher than a preset temperature. Figure 3 As shown.

[0056] Specifically, a flow monitoring device FC is installed at the inlet of the oxygen-side cooler E1 on the main pipeline at the outlet of the three-way regulating valve vv1, and a temperature monitoring device TC is installed at the outlet. Figure 3 As shown.

[0057] The oxygen-side cooler cooling water control cl4 includes: the cooling water regulating valve vv3 of the oxygen-side cooler E1 and the outlet temperature monitoring device TC of the oxygen-side cooler E1. When the outlet temperature of the oxygen-side cooler E1 is too high (i.e., higher than the preset temperature), the cooling water regulating valve vv3 is activated to increase the circulating water volume and thus lower the temperature.

[0058] In one embodiment, the water electrolysis hydrogen production system further includes: a first liquid level monitoring device (e.g., a liquid level monitoring device LC), installed on the hydrogen-side separator V1, for controlling the hydrogen-side regulating valve vv2 to lower the liquid level when the liquid level in the hydrogen-side separator V1 is higher than a first preset liquid level; a second liquid level monitoring device (e.g., a liquid level monitoring device LC), installed on the oxygen-side separator V2, for controlling the frequency converter VFD of the water replenishment pump P2 to increase the operating frequency of the water replenishment pump P2 when the liquid level in the oxygen-side separator V2 is higher than a second preset liquid level; and a third liquid level monitoring device (e.g., a liquid level monitoring device LC), installed on the buffer purifier V3, such as... Figure 3 As shown.

[0059] The hydrogen-side separator level control cl2 includes: a level monitoring device LC on the hydrogen-side separator V1 and a hydrogen-side regulating valve vv2. When the level in the hydrogen-side separator V1 is high, the hydrogen-side regulating valve vv2 is opened to lower the level.

[0060] The oxygen-side separator level control cl3 includes: a level monitoring device LC on the oxygen-side separator V2, a frequency converter VFD for the makeup water pump, and the makeup water pump P2. When the level in the oxygen-side separator V2 is high, the frequency converter VFD is activated to increase the operating frequency of the makeup water pump P2, thereby lowering the level.

[0061] The buffer purifier level control cl5 includes: a level monitoring device LC on the buffer purifier V3 and a raw material processing device B1. When the level in the buffer purifier V3 is high, the raw material processing device B1 reduces its water output frequency, thereby lowering the level.

[0062] In one embodiment, the water electrolysis hydrogen production system further includes: a second temperature monitoring device (e.g., temperature monitoring device TC) and a conductivity monitoring device AT, disposed at the inlet of the electrolyzer A1, for: maintaining the water temperature at the inlet of the electrolyzer A1 as monitored by the second temperature monitoring device (e.g., temperature monitoring device TC) when the conductivity monitored by the conductivity monitoring device AT is less than or equal to a preset conductivity; or increasing the preset temperature to maintain the water temperature at the inlet of the electrolyzer A1 when the conductivity monitored by the conductivity monitoring device AT is less than or equal to the preset conductivity and reducing the opening of the three-way regulating valve vv1 causes the conductivity to be greater than the preset conductivity. Figure 3 As shown.

[0063] Specifically, the inlet of electrolyzer A1 is equipped with a temperature measuring device TC and a conductivity measuring device AT. The electrolyzer inlet water quality and temperature control cl1 includes: the temperature monitoring device TC and conductivity monitoring device AT at the electrolyzer inlet, the flow monitoring device FC at the oxygen-side cooler inlet, and a three-way regulating valve vv1. When the conductivity meets the requirements, the inlet water temperature of the electrolyzer is regulated by adjusting the opening of the three-way regulating valve vv1; when the water temperature is too high, the water flow to the main resin path is increased to lower the temperature after mixing.

[0064] When the electrolyzer inlet water quality and temperature control cl1 achieves temperature control, and reducing the opening of the three-way regulating valve vv1 results in the electrolyzer inlet conductivity failing to meet requirements, necessitating an increase in the ion exchange resin equipment's processing capacity, the system will raise the set temperature of the oxygen-side cooler cooling water control cl4 to ensure the electrolyzer inlet water temperature. In other words, when the electrolyzer inlet conductivity and inlet temperature cannot be simultaneously satisfied, it is necessary to appropriately increase the inlet temperature setting of the ion exchange resin equipment.

[0065] In order to address the third defect of the existing device, the present invention provides the following preferred embodiments based on the above embodiments.

[0066] In one embodiment, the water electrolysis hydrogen production system further includes: an oxygen-side vent regulating valve vv4 and an oxygen-side external supply regulating valve vv5, disposed at the top of the oxygen-side separator V2; and a hydrogen-side vent regulating valve vv6 and a hydrogen-side external supply regulating valve vv7, disposed at the top of the hydrogen-side separator V1, as shown below. Figure 2 As shown.

[0067] The water electrolysis hydrogen production system further includes: a hydrogen-oxygen pressure difference monitoring device (PDC), used to control the opening of the oxygen-side venting regulating valve vv4 or the oxygen-side external supply regulating valve vv5 to decrease when the pressure difference between the hydrogen-side separator V1 and the oxygen-side separator V2 is greater than a first preset pressure; and / or a hydrogen-side pressure monitoring device (PC), used to control the opening of the hydrogen-side venting regulating valve vv6 or the hydrogen-side external supply regulating valve vv7 to increase when the pressure in the hydrogen-side separator V1 is greater than a second preset pressure. Figure 2-3 As shown.

[0068] Among them, the differential pressure monitoring device (PDC) on both sides of hydrogen and oxygen can be a remote differential pressure gauge.

[0069] The oxygen-side differential pressure control cl6 includes: an oxygen-side venting regulating valve vv4, an oxygen-side external supply regulating valve vv5, and a hydrogen-oxygen differential pressure monitoring device (PDC). When the hydrogen-oxygen differential pressure becomes too large, the system will selectively close the oxygen-side venting regulating valve vv4 or the oxygen-side external supply regulating valve vv5 to a certain degree, based on the settings. The valve selection is determined by the destination of the oxygen, a byproduct of PEM water electrolysis. That is, if the oxygen is destined for venting, the control loop will adjust the oxygen-side venting regulating valve vv4.

[0070] The hydrogen-side pressure control system CL7 includes: a hydrogen-side venting regulating valve VV6, a hydrogen-side external supply regulating valve VV7, and a hydrogen-side pressure monitoring device PC. When the hydrogen-side pressure is high, the system selects and controls either the hydrogen-side venting regulating valve VV6 or the hydrogen-side external supply regulating valve VV7 to open to a certain degree, based on the settings. The valve selection is determined by the destination of the hydrogen in the PEM electrolyzed water product. That is, if the hydrogen destination is venting, the control loop adjusts the hydrogen-side venting regulating valve VV6.

[0071] During normal operation of the PEM electrolyzer, a pressure difference needs to be established across the hydrogen and oxygen sides. Excessive pressure difference can damage the electrolyzer. In this embodiment, the hydrogen and oxygen sides of the electrolyzer are controlled by pressure and pressure difference, respectively. This ensures stable pressure control on both sides while maintaining sensitive pressure difference control. Therefore, the supporting system needs to be equipped with facilities to ensure stable pressure difference, preventing excessively high pressure differences across the electrolyzer during start-up, shutdown, and other changing operating conditions.

[0072] Specifically, the system differential pressure is regulated by adjusting two regulating valves at the top of the oxygen-side separator, and the control is selected based on the destination of the by-product oxygen from the electrolyzer. That is, when the oxygen is destined for venting, the differential pressure signal directly controls the oxygen vent regulating valve. The overall system pressure is controlled by two regulating valves at the outlet of the hydrogen-side separator, and the control is selected based on the destination of the hydrogen produced from the electrolyzer. That is, when the hydrogen is destined for venting, the differential pressure signal directly controls the hydrogen vent regulating valve.

[0073] In this embodiment, remote differential pressure gauges are installed on both the hydrogen and oxygen sides of the electrolyzer to control the vent valve on the oxygen side of the electrolyzer to ensure stable system differential pressure. A remote pressure gauge is installed on the hydrogen side of the electrolyzer to control the vent valve on the hydrogen side or the downstream regulating valve to ensure system pressure. Both the system pressure and differential pressure control loops are equipped with valve control selection to suit different product disposal conditions.

[0074] In summary, the water treatment control scheme of the PEM electrolysis water production hydrogen production integrated system includes: electrolyzer inlet water quality and temperature control cl1; hydrogen-side separator level control cl2; oxygen-side separator level control cl3; oxygen-side cooler cooling water control cl4; buffer purifier level control cl5; oxygen-side differential pressure control cl6; and hydrogen-side pressure control cl7.

[0075] This invention provides a water treatment solution for an integrated PEM electrolysis system for hydrogen production, ensuring various process parameters during normal operation of the PEM electrolyzer, including the pressure difference and pressure on both sides of the electrolyzer, the temperature at the inlet and outlet of the electrolyzer, and the water quality at the inlet of the electrolyzer.

[0076] The following is an overall introduction to the integrated water electrolysis hydrogen production system provided by this invention, such as... Figure 2-3 As shown.

[0077] The cathode outlet of electrolyzer A1 is connected to hydrogen-side separator V1 and subsequent hydrogen-water treatment system via pipe 8; the anode outlet of electrolyzer A1 is connected to oxygen separator V2 and subsequent oxygen-side water treatment system via pipe 2.

[0078] The subsequent hydrogen-side water treatment system includes: a hydrogen-side cooler E2, a buffer purifier V3, a makeup water pump P2, a raw material processing device B1, and a hydrogen-side regulating valve vv2. Specifically: the hydrogen-side separator V1 is connected to the hydrogen-side cooler E2 via pipe 9, and the hydrogen-side regulating valve vv2 is located on pipe 9; the hydrogen-side cooler E2 is connected to the buffer purifier V3 via pipe 10; the raw material water is connected to the raw material processing device B1 via pipe 13; the raw material processing device B1 is connected to the buffer purifier V3 via pipe 14; the buffer purifier V3 is connected to the makeup water pump P2 via pipe 11; and the makeup water pump P2 is connected to the oxygen-side separator V2 via pipe 12.

[0079] The subsequent oxygen-side water treatment system includes: a pure water circulation pump P1, a three-way regulating valve vv1, an oxygen-side cooler E1, and an ion exchange resin unit R1. Specifically: the oxygen-side separator V2 is connected to the pure water circulation pump (P1) via pipe 3; the pure water circulation pump P1 is connected to the three-way regulating valve (vv1) via pipe 4; the three-way regulating valve vv1 is connected to the oxygen-side cooler E1 via pipe 5a; the oxygen-side cooler E1 is connected to both the oxygen-side cooler E1 and the ion exchange resin unit R1 via pipe 6; the ion exchange resin unit R1 is connected to pipe 1 via pipe 7 and the bypass pipe 5b of the three-way regulating valve vv1, and pipe 1 ultimately connects to the electrolyzer A1.

[0080] Oxygen-side separator V2 is vented through pipe 15, and an oxygen-side vent regulating valve vv4 is installed on pipe 15. The top of the oxygen-side separator is sent to the downstream purification unit through pipe 16, and an oxygen-side external supply regulating valve vv5 is installed on pipe 16. Hydrogen-side separator V1 is vented through pipe 17, and a hydrogen-side vent regulating valve vv6 is installed on pipe 17. The top of the hydrogen-side separator is sent to the downstream purification unit through pipe 18, and a hydrogen-side external supply regulating valve vv7 is installed on pipe 18.

[0081] This invention provides a PEM electrolyzer system and its control scheme, integrating the electrolyzer, ion exchange resin equipment, and raw material purification system. It is capable of handling impurities carried by the raw materials during operation, impurities accumulated during operation, and impurities introduced into the equipment at the initial stage of operation. This process and control scheme separately treats the hydrogen-side and oxygen-side effluent from the electrolyzer, enabling control of the influent temperature while ensuring stable water quality. To ensure controllable pressure difference across the hydrogen and oxygen sides of the electrolyzer, corresponding instrument valves and control schemes are added. This invention provides a complete process system and corresponding control scheme that can simultaneously ensure the operating efficiency of the ion exchange resin, the stability of the pressure difference across the electrolyzer, and the controllable operating temperature of the electrolyzer.

[0082] The main advantages of this invention are: (1) Hydrogen-side effluent and oxygen-side effluent are each equipped with corresponding water treatment systems. Hydrogen and oxygen wastewater are treated separately, and the hydrogen separator and oxygen separator do not affect each other. Hydrogen-side wastewater is sent to a separate buffer purifier to mix with the raw water and is purified by ion exchange resin in the buffer purifier. (2) The temperature of the oxygen-side circulating pure water is adjusted by regulating the flow rate of the resin line. The resin line is equipped with a cooler to ensure that the water temperature meets the operating temperature requirements of the ion exchange resin. (3) Differential pressure control is mainly achieved by controlling the oxygen-side separator outlet vent regulating valve through remote differential pressure gauges on both sides. The system pressure is controlled by the hydrogen-side separator outlet regulating valve. The differential pressure adjustment range is wide.

[0083] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0084] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0085] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A water electrolysis hydrogen production system, characterized in that, The water electrolysis hydrogen production system includes: Electrolytic cell; A hydrogen-side separator, a hydrogen-side cooler, a buffer purifier, and a water supply pump are connected in sequence, wherein the inlet of the hydrogen-side separator is connected to the cathode outlet of the electrolyzer; and An oxygen-side separator, a pure water circulating pump, an oxygen-side cooler, and an ion exchange resin device are connected in sequence. The inlet of the oxygen-side separator is connected to the anode outlet of the electrolytic cell and the outlet of the makeup water pump, and the outlet of the ion exchange resin device is connected to the inlet of the electrolytic cell.

2. The water electrolysis hydrogen production system according to claim 1, characterized in that, The water electrolysis hydrogen production system also includes: A three-way regulating valve is connected to the pure water circulation pump via a first pipe, to the oxygen-side cooler via a second pipe, and to the inlet of the electrolytic cell via a third pipe.

3. The water electrolysis hydrogen production system according to claim 2, characterized in that, The water electrolysis hydrogen production system also includes: A hydrogen-side regulating valve is located on the pipeline between the hydrogen-side separator and the hydrogen-side cooler; and / or A cooling water regulating valve is used to regulate the amount of circulating water entering the oxygen-side cooler.

4. The water electrolysis hydrogen production system according to claim 3, characterized in that, The water electrolysis hydrogen production system also includes: A flow monitoring device is installed at the inlet of the oxygen-side cooler; and A first temperature monitoring device is installed at the outlet of the oxygen-side cooler. When the water temperature monitored by the first temperature monitoring device is higher than the preset temperature, the device increases the cooling water flow rate by increasing the cooling water flow rate or by increasing the water flow rate into the ion exchange resin equipment through the cooling water regulating valve or the three-way regulating valve.

5. The water electrolysis hydrogen production system according to claim 4, characterized in that, The water electrolysis hydrogen production system also includes: The second temperature monitoring device and conductivity monitoring device are installed at the inlet of the electrolytic cell and are used to: maintain the water temperature at the inlet of the electrolytic cell by controlling the opening of the three-way regulating valve when the conductivity detected by the conductivity monitoring device is less than or equal to a preset conductivity; or increase the preset temperature to maintain the water temperature at the inlet of the electrolytic cell when the conductivity detected by the conductivity monitoring device is less than or equal to the preset conductivity and reducing the opening of the three-way regulating valve causes the conductivity to be greater than the preset conductivity.

6. The water electrolysis hydrogen production system according to claim 3, characterized in that, The water electrolysis hydrogen production system also includes: A first liquid level monitoring device is installed on the hydrogen-side separator and is used to control the hydrogen-side regulating valve to lower the liquid level when the liquid level in the hydrogen-side separator is higher than a first preset liquid level. A second liquid level monitoring device, installed on the oxygen-side separator, is used to control the frequency converter of the water supply pump to increase the operating frequency of the water supply pump when the liquid level in the oxygen-side separator is higher than a second preset liquid level; and The third liquid level monitoring device is installed on the buffer purifier.

7. The water electrolysis hydrogen production system according to claim 1, characterized in that, The water electrolysis hydrogen production system also includes: A raw material processing device, connected to the buffer purifier, is used to supply raw water to the buffer purifier to maintain the liquid level inside the buffer purifier.

8. The water electrolysis hydrogen production system according to claim 7, characterized in that, The buffer purifier includes: The upper space is used for mixing the feed water with the effluent from the hydrogen-side cooler; and The lower space is filled with ion exchange resin for purifying the mixed water supplied by the upper space.

9. The water electrolysis hydrogen production system according to claim 7, characterized in that, The buffer purifier includes: A resin unit for purifying the effluent from the hydrogen-side cooler; and A buffer unit is used to mix the raw water with the purified effluent from the hydrogen-side cooler.

10. The water electrolysis hydrogen production system according to claim 1, characterized in that, The water electrolysis hydrogen production system also includes: An oxygen-side vent regulating valve and an oxygen-side external supply regulating valve are located at the top of the oxygen-side separator; and The hydrogen-side vent regulating valve and the hydrogen-side external supply regulating valve are located at the top of the hydrogen-side separator.

11. The water electrolysis hydrogen production system according to claim 10, characterized in that, The water electrolysis hydrogen production system also includes: A pressure difference monitoring device between the hydrogen and oxygen sides is used to control the opening degree of the oxygen-side venting regulating valve or the oxygen-side external supply regulating valve to decrease when the pressure difference between the hydrogen-side separator and the oxygen-side separator is greater than a first preset pressure; and / or A hydrogen-side pressure monitoring device is used to control the opening degree of the hydrogen-side venting regulating valve or the hydrogen-side external supply regulating valve to increase when the pressure of the hydrogen-side separator is greater than a second preset pressure.

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