Water electrolysis hydrogen production system based on proton exchange membrane electrolytic cell

Abstract

The device is mainly used in the technical field of electrolytic hydrogen production. The invention discloses a water electrolysis hydrogen production system based on a proton exchange membrane electrolytic cell. The water electrolysis hydrogen production system comprises an electrolysis unit, a water circulation unit and a gas-liquid separation unit, the electrolysis unit is used for carrying out electrolysis treatment on the liquid water to obtain hydrogen, oxygen and gas-liquid mixed water; the gas-liquid separation unit comprises a primary separation module and a secondary separation module; the primary separation module is used for carrying out separation treatment on the gas-liquid mixed state water to obtain separated liquid water; the second-stage separation module is used for performing gas release treatment on the separated liquid water to obtain the liquid water after gas release; and the water circulation unit is used for transmitting liquid water after gas release to the electrolysis unit. According to the technical scheme, the release speed of the gas dissolved in the liquid water can be increased, the content of the gas in the liquid water is reduced, and therefore the safety risk of the water electrolysis hydrogen production system in the hydrogen production process is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of electrolytic hydrogen production, and in particular to a water electrolysis hydrogen production system based on a proton exchange membrane electrolyzer. Background Art

[0002] At present, the new energy industry represented by hydrogen energy has received great attention and strong support from national and local governments. Hydrogen energy has the characteristics of wide sources, energy saving and environmental protection, high efficiency and cleanliness, and high thermal efficiency. It has a strong substitution effect on traditional fossil energy, so it is considered to be an important solution for achieving the transformation of energy to green and low-carbon. When the existing water electrolysis hydrogen production system is working, an electrochemical reaction occurs through the proton exchange membrane electrolyzer, thereby electrolyzing water into hydrogen and oxygen. However, some hydrogen and oxygen gases are dissolved in the unelectrolyzed liquid discharged from the proton exchange membrane electrolyzer. Since the existing water electrolysis hydrogen production system cannot separate the gas and liquid to the greatest extent, and at the same time needs to recycle the liquid on both sides of the proton exchange membrane electrolyzer for recycling, the gas dissolved in the liquid escapes in the same gas phase space, which is easy to form an explosive environment. It can be seen that the existing water electrolysis hydrogen production system has huge safety hazards. Summary of the invention

[0003] The present invention provides a water electrolysis hydrogen production system based on a proton exchange membrane electrolyzer, which can accelerate the release rate of gas dissolved in liquid water and reduce the gas content in liquid water, thereby reducing the safety risk of the water electrolysis hydrogen production system in the hydrogen production process.

[0004] The present invention provides a water electrolysis hydrogen production system based on a proton exchange membrane electrolyzer, the system comprising an electrolysis unit, a water circulation unit and a gas-liquid separation unit; The electrolysis unit is used to electrolyze liquid water to obtain hydrogen, oxygen and gas-liquid mixed water; The gas-liquid separation unit includes a primary separation module and a secondary separation module; The primary separation module is used to separate the gas-liquid mixed water to obtain separated liquid water; The secondary separation module is used to perform gas release treatment on the liquid water after the separation treatment to obtain liquid water after gas release; The water circulation unit is used to reduce the conductivity of the liquid water after the gas is released and then transmit it to the electrolysis unit.

[0005] Optionally, the gas-liquid separation unit includes a first gas-liquid separation sub-unit and a second gas-liquid separation sub-unit; The electrolysis unit is also used to output hydrogen and liquid water after electrolysis through a first end of the electrolysis unit, and to output oxygen and liquid water after electrolysis through a second end of the electrolysis unit; The first gas-liquid separation unit includes a first primary separation module and a first secondary separation module; The first stage separation module is used to separate the hydrogen to obtain liquid water in the hydrogen; The first and second separation modules are used to perform gas release treatment on the liquid water in the hydrogen and the liquid water after the electrolysis treatment to obtain liquid water after the gas is released; The second gas-liquid separation unit includes a second primary separation module and a second secondary separation module; The second-stage separation module is used to separate the oxygen to obtain liquid water in the oxygen; The second secondary separation module is used to perform gas release treatment on the liquid water in the oxygen and the liquid water after the electrolysis treatment to obtain liquid water after gas release; The water circulation unit is also used to collect liquid water released from the gas output by the first secondary separation module and the second secondary separation module and transmit it to the electrolysis unit.

[0006] Optionally, the first gas-liquid separation subunit includes a first regulating valve module, and the second gas-liquid separation subunit includes a second regulating valve module; The first regulating valve module is used to regulate the gas pressure in the first gas-liquid separation subunit; The second regulating valve module is used to control the air pressure in the second gas-liquid separation subunit according to a preset air pressure value.

[0007] Optionally, the first primary separation module includes a first primary separator, a first heat exchanger and a first demister; The first end of the first primary separator is used to input hydrogen and liquid water after electrolysis, the second end of the first primary separator is connected to the input end of the first heat exchanger, the third end of the first primary separator is connected to the third end of the first demister, and the fourth end of the first primary separator is used to output liquid water in the hydrogen and liquid water after electrolysis; The output end of the first heat exchanger is connected to the first end of the first demister, and the first heat exchanger is used to obtain hydrogen through the input end of the first heat exchanger, and output the obtained hydrogen through the output end of the first heat exchanger after condensing the hydrogen; The first demister is used to separate the hydrogen after condensation treatment to obtain liquid water in the hydrogen and the separated hydrogen, and output the separated hydrogen through the second end of the first demister and output the liquid water in the hydrogen through the third end of the first demister.

[0008] Optionally, the second primary separation module includes a second primary separator, a second heat exchanger and a second demister; The first end of the second primary separator is used to input oxygen and liquid water after electrolysis, the second end of the second primary separator is connected to the input end of the second heat exchanger, the third end of the second primary separator is connected to the third end of the second demister, the fourth end of the second primary separator is used to transfer the liquid water in the oxygen and the liquid water after electrolysis to the electrolysis unit and the second secondary separation module, and the fifth end of the second primary separator is used to obtain liquid water after the gas output by the water circulation unit is released; The output end of the second heat exchanger is connected to the second end of the second demister, and the second heat exchanger is used to obtain oxygen through the input end of the second heat exchanger, and condense the obtained oxygen and output it through the output end of the second heat exchanger; The second demister is used to separate the oxygen after condensation to obtain liquid water in the oxygen and the separated oxygen, and output the separated oxygen through the second end of the second demister and output the liquid water in the oxygen through the third end of the second demister.

[0009] Optionally, the water circulation unit includes a circulating water tank, a resin tank, a first water pump, and a second water pump; The circulating water tank is used to store liquid water after the gas is released, and the liquid water stored in the circulating water tank is transferred to the resin tank through the first water pump; The resin tank is used to perform deionization treatment on liquid water, and output the deionized liquid water through the second water pump.

[0010] Optionally, the first secondary separation module includes a first secondary separator, the second secondary separation module includes a second secondary separator, and the first secondary separator and the second secondary separator are both liquid containers; The input end of the first secondary separator and the input end of the second secondary separator are both provided with pressure reducing valves, and the output end of the first secondary separator and the output end of the second secondary separator are both connected to the circulating water tank through an overflow pipe.

[0011] Optionally, the first secondary separator includes a first input end, a first output end, a second input end, and a second output end; The first input end of the first secondary separator is used to input the liquid water in the hydrogen and the liquid water after electrolysis; The first output end of the first secondary separator is used to output liquid water after the gas is released; The second input end of the first and second separators is used to input inert gas; The second output end of the first secondary separator is used to output the gas in the first secondary separator.

[0012] Optionally, the system comprises a control unit, the control unit comprising a plurality of sensors; Each of the sensors is used to detect the electrolysis unit, the water circulation unit or the gas-liquid separation unit to obtain a process parameter value; The control unit is used to determine whether the process parameter value is within a first preset value range. If not, the electrolysis unit, the water circulation unit and the gas-liquid separation unit are controlled to stop working. If so, when the process parameter value is not within a second preset value range, the electrolysis unit, the water circulation unit or the gas-liquid separation unit is controlled to adjust until the process parameter value is within the second preset value range.

[0013] Optionally, the electrolysis unit comprises: A proton exchange membrane electrolysis module is used to electrolyze liquid water to obtain hydrogen, oxygen and gas-liquid mixed water; The voltage control module is used to detect the cell voltage and the cell current voltage of the proton exchange membrane electrolysis module. When any cell voltage detected is higher than a preset voltage value or the cell current voltage detected is higher than a preset current voltage value, the proton exchange membrane electrolysis module is controlled to stop working.

[0014] The present invention has at least the following beneficial effects: In the technical solution of the present application, after the electrolysis unit electrolyzes liquid water to obtain hydrogen, oxygen and gas-liquid mixed water, gas-liquid separation is first performed in the primary separation module, mainly to separate the liquid water in the gas. The liquid water in the primary separation module passes through the secondary separation module to release the gas dissolved in the water. This solution adopts the secondary separation technology, which can accelerate the release rate of the gas dissolved in the liquid water and release the gas dissolved in the water as much as possible. Finally, the liquid water after the gas is released is transmitted to the electrolysis unit for repeated use for electrolysis through the water circulation unit, which saves water resources. Since the gas in the recycled water has escaped, the gas content in the liquid water is reduced, and the hydrogen and oxygen escaped from the recycled liquid water are prevented from merging in the electrolysis unit to form an explosive gas environment, thereby reducing the safety risk of the electrolysis water hydrogen production system in the hydrogen production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0016] Figure 1 It is a first structural schematic diagram of a water electrolysis hydrogen production system based on a proton exchange membrane electrolyzer; Figure 2 is a second structural schematic diagram of a water electrolysis hydrogen production system based on a proton exchange membrane electrolyzer; Figure 3 is a third structural schematic diagram of a water electrolysis hydrogen production system based on a proton exchange membrane electrolyzer; Among them, 1. proton exchange membrane electrolyzer; 2. hydrogen primary separator; 3. hydrogen gas path heat exchanger; 4. hydrogen demister; 5. hydrogen regulating valve; 6. hydrogen oxygen analyzer; 8. oxygen primary separator; 9. oxygen gas path heat exchanger; 10. oxygen demister; 11. oxygen regulating valve; 12. oxygen hydrogen analyzer; 14. circulating pump; 15. oxygen side water path heat exchanger; 16. oxygen side pressure reducing valve; 17. hydrogen side pressure reducing valve; 18. hydrogen secondary separator; 19. oxygen secondary separator; 20. circulating water tank; 21. make-up water pump; 22. make-up water heat exchanger; 23. resin tank; 24. high-pressure pump. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0018] It should be noted that, depending on the properties of the electrolyte, there are three main technologies for hydrogen production by water electrolysis: alkaline solution (ALK), proton exchange membrane (PEM) and solid oxide (SOEC) water electrolysis technology. Compared with other membranes, proton exchange membrane has the advantages of stable chemical properties, high proton conductivity, and non-porous gas isolation. It can also be integrated with electrodes to reduce the additional resistance and power loss caused by the distance between the two electrodes. This technology can improve the purity of hydrogen production while obtaining high current density and rapid responsiveness, and is suitable for renewable energy power generation systems with greater volatility.

[0019] However, there are a series of problems when the existing proton exchange membrane water electrolysis system works: The conductivity of deionized water increases during the electrolysis process, and the water with high conductivity is directly discharged, resulting in low utilization efficiency of deionized water and waste of resources; The liquid level of the liquid storage tank is controlled by an instrument detection valve. The instrument valve is expensive. If the instrument valve fails, the system cannot be controlled and may easily lead to dangerous conditions. Proton exchange membrane electrolyzers are easily affected by voltage. If the voltage is too high, the proton exchange membrane may be broken down, causing a short circuit between the anode and cathode. If the voltage is too low, it cannot meet the gas production requirements. The electrolyzer has a very high pressure difference requirement. The liquid level fluctuation of the separator can easily affect the pressure difference on both sides, thus creating the risk of hydrogen and oxygen mixing to form explosive gas. When the water electrolysis hydrogen production system is started or stopped or encounters abnormal working conditions, human intervention is required, which poses a safety hazard; Cooling water at a temperature of about 40°C is used to exchange heat for hydrogen, which does not completely separate the gaseous water in the gas, and the concentration of hydrogen after separation does not meet the requirements.

[0020] It should be noted that the gas-liquid two-phase flow produced by the proton exchange membrane electrolyzer contains some dissolved gas. Since it is impossible to separate the gas and liquid to the greatest extent, the equipment of the water electrolysis hydrogen production system is prone to explosion when working in a gas-liquid mixed environment. It can be seen that the existing water electrolysis hydrogen production system has huge safety hazards.

[0021] In order to solve the above problems, the technical solution of the present application can accelerate the release rate of the gas dissolved in the liquid water, reduce the gas content in the liquid water, and thus reduce the safety risk of the water electrolysis hydrogen production system during the hydrogen production process. The following is an embodiment of the technical solution of the present application.

[0022] Please refer to Figure 1 , Figure 1 It is the first structural schematic diagram of a water electrolysis hydrogen production system based on a proton exchange membrane electrolyzer.

[0023] This embodiment provides a water electrolysis hydrogen production system based on a proton exchange membrane electrolyzer, including an electrolysis unit, a water circulation unit, and a gas-liquid separation unit.

[0024] The electrolysis unit is used to electrolyze liquid water to obtain hydrogen, oxygen and gas-liquid mixed water.

[0025] The gas-liquid separation unit includes a primary separation module and a secondary separation module.

[0026] The primary separation module is used to separate the gas-liquid mixed water to obtain separated liquid water.

[0027] The secondary separation module is used to perform gas release treatment on the liquid water after separation treatment to obtain liquid water after gas release.

[0028] The water circulation unit is used to transfer the liquid water after the gas is released to the electrolysis unit.

[0029] It can be understood that the technical solution of the present application transmits liquid water between the electrolysis unit, the water circulation unit and the gas-liquid separation unit through a pipeline, and the oxygen and hydrogen obtained by electrolysis in the liquid water are introduced into a preset gas storage device through a pipeline, and the liquid water is continuously recycled between the electrolysis unit, the water circulation unit and the gas-liquid separation unit until the volume of the liquid water is less than the preset water volume, and new liquid water is added to the water electrolysis hydrogen production system based on the proton exchange membrane electrolyzer.

[0030] In some embodiments, the electrolysis unit is an electrolysis cell, and optionally, the electrolysis unit is a proton exchange membrane electrolysis cell.

[0031] It is understandable that in the technical solution of the present application, after the electrolysis unit electrolyzes the liquid water to obtain hydrogen, oxygen and gas-liquid mixed water, it first performs gas-liquid separation in the primary separation module, mainly to separate the liquid water in the gas. The liquid water in the primary separation module passes through the secondary separation module to release the gas dissolved in the water. This solution adopts the secondary separation technology, which can accelerate the release rate of the gas dissolved in the liquid water and release the gas dissolved in the water as much as possible. Finally, the liquid water after the gas is released is transmitted to the electrolysis unit for repeated use for electrolysis through the water circulation unit, which saves water resources while reducing the gas content in the liquid water because the gas in the recycled water has escaped, and avoids the hydrogen and oxygen escaped from the recycled liquid water to merge in the electrolysis unit to form an explosive gas environment, thereby reducing the safety risk of the electrolysis water hydrogen production system in the hydrogen production process.

[0032] Optionally, the first-stage separation module is configured to operate in a high-pressure state, and the second-stage separation module is configured to operate in a normal-pressure state.

[0033] It is understandable that the solubility of gas at different pressures is different. Some gas can be separated in the high-pressure gas-liquid separator, but some gas must still be dissolved in the water. When external conditions change (such as temperature, pressure, etc.), the gas dissolved in the water will escape. The escaped hydrogen and oxygen will merge in the electrolytic cell to form an explosive gas environment, which brings certain risks. This embodiment adopts a two-stage separation technology, namely high-pressure gas-liquid separation and low-pressure gas-liquid separation, to release the gas dissolved in the water as much as possible to avoid gas explosion.

[0034] Please refer to Figure 2 , Figure 2 This is a second structural schematic diagram of a water electrolysis hydrogen production system based on a proton exchange membrane electrolyzer.

[0035] In some embodiments, the gas-liquid separation unit includes a first gas-liquid separation sub-unit and a second gas-liquid separation sub-unit.

[0036] The electrolysis unit is also used to output hydrogen and liquid water after electrolysis through a first end of the electrolysis unit, and to output oxygen and liquid water after electrolysis through a second end of the electrolysis unit.

[0037] The first gas-liquid separation unit includes a first primary separation module and a first secondary separation module.

[0038] The first stage separation module is used to separate the hydrogen to obtain liquid water in the hydrogen.

[0039] The first and second level separation modules are used to perform gas release treatment on the liquid water in the hydrogen and the liquid water after electrolysis treatment to obtain liquid water after gas release.

[0040] The second gas-liquid separation unit includes a second primary separation module and a second secondary separation module.

[0041] The second first-stage separation module is used to separate oxygen to obtain liquid water from oxygen.

[0042] The second secondary separation module is used for performing gas release treatment on the liquid water in the oxygen and the liquid water after the electrolysis treatment to obtain liquid water after the gas is released.

[0043] The water circulation unit is also used to collect liquid water released from the gas output by the first and second separation modules and the second and second separation modules and transmit it to the electrolysis unit.

[0044] In some embodiments, the electrolysis unit further includes an electrolysis tank, a circulation pump, and a third heat exchanger.

[0045] The circulation pump is used to transfer the liquid water after the gas is released to the third heat exchanger.

[0046] The third heat exchanger is used to adjust the temperature of the liquid water after the gas is released to a preset temperature.

[0047] The electrolyzer is used to electrolyze liquid water after the gas is released at a preset temperature to obtain hydrogen, oxygen and gas-liquid mixed water.

[0048] It is understandable that the liquid water after the gas is released is transferred to the third heat exchanger for cooling by the circulating pump, so as to reduce the temperature of the liquid water after the gas is released to the optimal operating temperature of the electrolyzer. The electrolyzer undergoes an electrolysis reaction under the action of direct current, and the hydrogen obtained by electrolysis is discharged from the cathode side of the electrolyzer with a small amount of liquid water, and is further sent to the first primary separation module for gas-liquid separation; oxygen is discharged from the anode side of the electrolyzer with unreacted liquid water, and is further sent to the second primary separation module for gas-liquid separation.

[0049] In some embodiments, the electrolytic cell is a proton exchange membrane electrolytic cell, and the electrolytic unit also includes an electrolytic cell temperature control module, which is used to monitor the temperature of the electrolytic cell. When it is detected that the temperature of the electrolytic cell is not within a preset value range, the temperature or flow rate at the input end of the electrolytic cell is adjusted until the temperature of the electrolytic cell is within the preset value range.

[0050] It is understandable that overheating of the PEM electrolyzer will affect the performance and life of the PEM, so part of the water in the PEM electrolyzer is used as the electrolysis raw material, and part is used to take away the heat generated by the electrolysis of the PEM electrolyzer. In order to ensure that the temperature of the PEM electrolyzer is within the set range, a temperature detector is set at the outlet of the PEM electrolyzer. When abnormal temperature is detected, it will automatically adjust according to the control program, such as adjusting the cooling water flow of the electrolysis unit.

[0051] In some embodiments, the first gas-liquid separation subunit includes a first regulating valve module, and the second gas-liquid separation subunit includes a second regulating valve module.

[0052] The first regulating valve module is used to regulate the gas pressure in the first gas-liquid separation subunit.

[0053] The second regulating valve module is used to control the air pressure in the second gas-liquid separation subunit according to a preset air pressure value.

[0054] In some embodiments, the first regulating valve module includes a first regulating valve, and the second regulating valve module includes a second regulating valve and a vent valve.

[0055] It can be understood that the second regulating valve and the vent valve are arranged in the pipeline. The second regulating valve ensures the discharge pressure of oxygen in the second gas-liquid separation subunit, which also enables the proton exchange membrane electrolyzer to produce hydrogen at the optimal pressure. At the same time, when the device has abnormal operating conditions, the vent valve will be opened in time to ensure the safety of the device.

[0056] It is understandable that the pressure difference between the hydrogen and oxygen sides of the existing alkali tank hydrogen production system is within the range of 3Kpa to 5Kpa. The pressure difference is adjusted by the control valve of the oxygen outlet, which requires very precise pressure difference control, otherwise it is easy to cause hydrogen and oxygen to cross; at the same time, because its allowable pressure difference range is too small, the liquid level of the hydrogen and oxygen liquid separator has a great influence on the pressure difference. At present, the liquid level is monitored by adding a liquid level gauge to prevent the pressure difference from changing due to excessive liquid level fluctuations. The increase of the liquid level gauge also increases the cost. In this embodiment, the pressure difference on the hydrogen and oxygen side can reach 5 bar, and the pressure on both sides of the hydrogen and oxygen can be adjusted by using a regulating valve to meet the pressure difference requirements of the proton exchange membrane electrolyzer, thereby reducing the use of the liquid level gauge and reducing the cost; it also avoids the frequent action of the valve due to liquid level fluctuations, and prolongs the life of the valve.

[0057] In some embodiments, the first primary separation module includes a first primary separator, a first heat exchanger, and a first demister.

[0058] The first end of the first stage separator is used to input hydrogen and liquid water after electrolysis treatment, the second end of the first stage separator is connected to the input end of the first heat exchanger, the third end of the first stage separator is connected to the third end of the first demister, and the fourth end of the first stage separator is used to output liquid water in hydrogen and liquid water after electrolysis treatment.

[0059] The output end of the first heat exchanger is connected to the first end of the first demister. The first heat exchanger is used to obtain hydrogen through the input end of the first heat exchanger, and output the obtained hydrogen through the output end of the first heat exchanger after condensation.

[0060] The first demister is used to separate the hydrogen after condensation treatment to obtain liquid water in the hydrogen and the separated hydrogen, and output the separated hydrogen through the second end of the first demister and output the liquid water in the hydrogen through the third end of the first demister.

[0061] In some embodiments, the second primary separation module includes a second primary separator, a second heat exchanger, and a second demister.

[0062] The first end of the second first-stage separator is used to input oxygen and liquid water after electrolysis treatment, the second end of the second first-stage separator is connected to the input end of the second heat exchanger, the third end of the second first-stage separator is connected to the third end of the second demister, the fourth end of the second first-stage separator is used to transmit the liquid water in the oxygen and the liquid water after electrolysis treatment to the electrolysis unit and the second second-stage separation module, and the fifth end of the second first-stage separator is used to obtain liquid water after the gas released from the water circulation unit.

[0063] The output end of the second heat exchanger is connected to the second end of the second demister. The second heat exchanger is used to obtain oxygen through the input end of the second heat exchanger, and condense the obtained oxygen before outputting it through the output end of the second heat exchanger.

[0064] The second demister is used to separate the oxygen after condensation treatment to obtain liquid water in the oxygen and the separated oxygen, and output the separated oxygen through the second end of the second demister and output the liquid water in the oxygen through the third end of the second demister.

[0065] In some embodiments, the water circulation unit includes a circulation water tank, a resin tank, and a first water pump and a second water pump.

[0066] The circulating water tank is used to store liquid water after the gas is released, and to transfer the liquid water stored in the circulating water tank to the resin tank through the first water pump.

[0067] The resin tank is used to deionize the liquid water and output the deionized liquid water through the second water pump.

[0068] It is understandable that in the electrolysis water hydrogen production system based on the proton exchange membrane electrolyzer of the present embodiment, long-term operation will inevitably lead to an increase in the conductivity of deionized water, that is, an increase in conductive ions, and the proton exchange membrane is very sensitive to ions. Long-term exposure to water with high conductivity will shorten the life of the proton exchange membrane electrolyzer. In order to avoid this situation, the prior art is to directly discharge water with unqualified conductivity and re-inject water with qualified conductivity, which leads to a waste of water resources, which is acceptable in areas with abundant water resources, but unacceptable in areas with scarce water resources. In this embodiment, the conductivity of the deionized water refined by the resin tank can be lower than 0.5μS / cm, which fully meets the requirements of the proton exchange membrane electrolyzer, thereby reducing the conductivity and facilitating the reuse of liquid water.

[0069] In some embodiments, the first secondary separation module includes a first secondary separator, the second secondary separation module includes a second secondary separator, and the first secondary separator and the second secondary separator are both liquid containers.

[0070] The input ends of the first and second level separators and the input ends of the second level separators are both provided with pressure reducing valves, and the output ends of the first and second level separators and the output ends of the second level separators are both connected to the circulating water tank through an overflow pipe.

[0071] It is understandable that the current alkali tank electrolysis water system controls the liquid level of the container through instrument monitoring and valve action coordination, and the use of instruments and valves leads to increased costs. This embodiment maintains a constant liquid level through an overflow pipe, reduces the use of valves and instruments, reduces costs, and avoids safety risks caused by instrument or valve failure.

[0072] In some embodiments, the first two-stage separator includes a first input end, a first output end, and a second input end, a second output end.

[0073] The first input end of the first and second level separators is used to input liquid water in hydrogen and liquid water after electrolysis treatment.

[0074] The first output end of the first and second separators is used to output liquid water after the gas is released.

[0075] The second input end of the first and second separators is used to input inert gas.

[0076] The second output end of the first and second separators is used to output the gas in the first and second separators.

[0077] It is understandable that in order to avoid the accumulation of hydrogen in the gas phase space of the first and second separators to form an explosive gas mixture and increase safety hazards, a stream of nitrogen is introduced from the side of the first and second separators to dilute the hydrogen concentration to below the lower explosion limit, and at the same time, a vent pipe is installed to discharge the gas inside the first and second separators to a safe area, and liquid water is discharged from the bottom of the first and second separators. By diluting and discharging hydrogen, the generation of an explosive gas environment is avoided.

[0078] In some embodiments, a system includes a control unit including a plurality of sensors.

[0079] Each sensor is used to detect the electrolysis unit, the water circulation unit or the gas-liquid separation unit to obtain the process parameter value.

[0080] The control unit is used to determine whether the process parameter value is within the first preset value range. If not, the electrolysis unit, the water circulation unit and the gas-liquid separation unit are controlled to stop working. If so, when the process parameter value is not within the second preset value range, the electrolysis unit, the water circulation unit or the gas-liquid separation unit is controlled to adjust until the process parameter value is within the second preset value range.

[0081] It is understandable that after the operator presses the start button, the system automatically detects whether the conditions for hydrogen production are met according to the logic control program. For example, before hydrogen production, the oxygen content of the gas in the equipment needs to be detected. If the content is too high, nitrogen needs to be supplemented. If the content is below the set value, nitrogen supplementation is stopped. In addition to detecting the oxygen content, some other indicators are also detected. The equipment can continue to operate only after all indicators meet the standards. Instruments such as level gauges, thermometers, pressure gauges, and flow meters are installed in various parts of the equipment to detect process parameters. At the same time, a second preset value range is set for normal production. When the process parameter value is not within the second preset value range, the electrolysis unit, water circulation unit or gas-liquid separation unit is controlled to adjust until the process parameter value is within the second preset value range. When it exceeds the first preset value range, the system will power off and the control electrolysis unit, water circulation unit and gas-liquid separation unit will stop working.

[0082] In some embodiments, the electrolysis unit comprises: The proton exchange membrane electrolysis module is used to electrolyze liquid water to obtain hydrogen, oxygen and gas-liquid mixed water.

[0083] The voltage control module is used to detect the cell voltage and the cell current voltage of the proton exchange membrane electrolysis module. When any cell voltage detected is higher than a preset voltage value or the cell current voltage detected is higher than a preset current voltage value, the proton exchange membrane electrolysis module is controlled to stop working.

[0084] It is understandable that due to the excessively high voltage applied to both sides of the proton exchange membrane electrolyzer, the proton exchange membrane may be broken down, resulting in a short circuit between the anode and cathode, causing hydrogen and oxygen to cross-link and pose a safety risk, while also causing great damage to the electrolyzer itself; if the voltage is too low, the gas production requirement cannot be met. Therefore, this embodiment monitors the voltage of the electrolysis chamber and the voltage and current of the electrolyzer. When an abnormality occurs, the system will power off and trip to protect the proton exchange membrane electrolyzer.

[0085] Please refer to Figure 3 , Figure 3 This is the third structural schematic diagram of the water electrolysis hydrogen production system based on the proton exchange membrane electrolyzer.

[0086] In this embodiment, the gas-liquid separation unit includes a first gas-liquid separation subunit and a second gas-liquid separation subunit; the first gas-liquid separation unit includes a first primary separation module and a first secondary separation module; the second gas-liquid separation unit includes a second primary separation module and a second secondary separation module.

[0087] The electrolysis unit includes a proton exchange membrane electrolyzer 1 , a circulation pump 14 and an oxygen-side water heat exchanger 15 .

[0088] The first primary separation module includes a hydrogen primary separator 2 , a hydrogen gas path heat exchanger 3 , and a hydrogen demister 4 ; the first regulating valve module includes a hydrogen regulating valve 5 and a hydrogen oxygen analyzer 6 .

[0089] The first and second-stage separation module includes a hydrogen-side pressure reducing valve 17 and a hydrogen second-stage separator 18 .

[0090] The second primary separation module includes an oxygen primary separator 8 , an oxygen gas path heat exchanger 9 , and an oxygen demister 10 ; the second regulating valve module includes an oxygen regulating valve 11 and an oxygen-hydrogen analyzer 12 .

[0091] The second secondary separation module includes an oxygen pressure reducing valve 16 and an oxygen secondary separator 19 .

[0092] The water circulation unit includes a circulating water tank 20 , a water supply pump 21 , a water supply heat exchanger 22 , a resin tank 23 and a high-pressure pump 24 .

[0093] The deionized water in the primary oxygen separator 8 is transported to the proton exchange membrane electrolyzer 1 as a raw material for electrolysis by a circulating pump 14. The proton exchange membrane electrolyzer 1 undergoes an electrolysis reaction under the action of direct current, and hydrogen entrained with a small amount of liquid water is discharged from the cathode side through the pipeline at a, and is further sent to the primary hydrogen separator 2 for gas-liquid separation; oxygen entrained with unreacted liquid water is discharged from the anode side through the pipeline at i, and is further sent to the primary oxygen separator 8 for gas-liquid separation.

[0094] Overheating of the proton exchange membrane electrolyzer 1 will affect the performance and life of the proton exchange membrane. Therefore, part of the water in the proton exchange membrane electrolyzer 1 is used as an electrolysis raw material, and part is used to take away the heat generated by the electrolysis of the proton exchange membrane electrolyzer 1. In order to ensure that the temperature of the proton exchange membrane electrolyzer 1 is within the set range, a temperature detector is set at the outlet of the proton exchange membrane electrolyzer 1. When an abnormal temperature is detected, it will automatically adjust according to the control program, such as adjusting the cooling water flow rate l in the oxygen system. The proton exchange membrane electrolyzer is equipped with a small chamber voltage detection and an abnormal current and voltage detection of the electrolyzer. Once an abnormality is detected, the system will automatically adjust. If it exceeds a certain limit of the set value, it will automatically power off and shut down.

[0095] The main function of the oxygen separation system is to collect the unreacted deionized water on the anode side and pressurize and circulate it back to the proton exchange membrane electrolyzer system. The oxygen entering the primary oxygen separator 8 is initially separated under high pressure and sent to the oxygen gas path heat exchanger 9 to condense gaseous water. The oxygen is filtered out of liquid water by the oxygen demister 10 and then discharged. The filtered liquid water returns to the primary oxygen separator 8 from the pipeline at g. In order to test the product quality, an oxygen hydrogen analyzer 12 is installed in the oxygen outlet pipeline n to detect the hydrogen content in oxygen. If the monitoring is unqualified, an alarm signal is generated and the power is cut off and the machine is shut down. The deionized water of the oxygen primary separator 8 is pressurized from the pipeline at w to the oxygen side water heat exchanger 15 through the circulating pump 14 to cool the deionized water. At this time, the temperature of the deionized water is the optimal operating temperature of the proton exchange membrane electrolyzer 1. The deionized water is divided here. A part of the high-pressure deionized water is sent from the pipeline at m to the proton exchange membrane electrolyzer 1, and the other part of the high-pressure deionized water is sent from the pipeline at o to the oxygen secondary separator 19 for secondary separation through the oxygen side pressure reducing valve. A small amount of oxygen dissolved in the water is released under low pressure conditions. The deionized water enters the circulating water tank 20 from the pipeline at p for conductivity reduction treatment.

[0096] Temperature detection instruments are arranged before and after the oxygen side water heat exchanger 15 in the oxygen separation system. Once the temperature is higher or lower than the optimal operating temperature of the proton exchange membrane electrolyzer 1, the flow rate l at the cold end of the oxygen side water heat exchanger 15 will be adjusted to restore the temperature of the deionized water delivered to the proton exchange membrane electrolyzer 1 to the normal range, and the proton exchange membrane electrolyzer has the highest working efficiency; a liquid level gauge is installed on the oxygen primary separator 8 to ensure that the liquid level is at a reasonable position. If the liquid level is too high, the valve for replenishing water to the oxygen primary separator 1 is closed, and the flow rate of the water replenishment pipeline u is reduced. After the electrolysis is consumed and the oxygen side pressure reducing valve 16 is opened, a part of the water is discharged to the oxygen secondary separator 19 to lower the liquid level, and the excess water is transported to the deionized water system; if the liquid level is too low, the water replenishment valve is opened to increase the flow rate to replenish water to the oxygen primary separator 1 through the pipeline at u, and the drain valve of the oxygen secondary separator 19 is closed until the liquid level of the oxygen primary separation tank 8 returns to the set point. The branch for replenishing water to the proton exchange membrane electrolyzer is equipped with a flow detection instrument. If the flow is too low, the speed of the circulating pump 14 is increased to ensure that the flow to the proton exchange membrane electrolyzer is constant, so that the heat generated by the reaction of the proton exchange membrane electrolyzer can be taken away and the temperature of the proton exchange membrane electrolyzer can be reduced; the oxygen discharge pipeline is provided with a regulating valve 11 and a vent valve. The regulating valve 11 ensures the discharge pressure at the oxygen end, which also enables the proton exchange membrane electrolyzer to produce hydrogen at the optimal pressure. At the same time, when the device has an abnormal operating condition, the vent valve will be opened in time to ensure the safety of the device.

[0097] The main function of the hydrogen primary separator 2 is to perform gas-liquid separation of hydrogen and liquid deionized water at the cathode outlet of the proton exchange membrane electrolyzer through the pipeline at a under high pressure, mainly to separate the liquid water in the gas and allow the liquid water to settle in the hydrogen primary separator 2. The separated hydrogen and gaseous water are drawn out from the top of the hydrogen primary separator 2 through the pipeline at c, and condensed by the hydrogen gas path heat exchanger 3. The cold end of the hydrogen gas path heat exchanger 3 uses chilled water at a temperature of 8°C to be transported through the pipeline at b, maximizing the condensation of gaseous water into liquid water for subsequent separation. The cooled hydrogen passes through the wire mesh of the hydrogen demister 4, filters out the liquid water, and is sent to the downstream after being stabilized by the regulating valve 5. The condensed deionized water is drawn out from the lower position of the hydrogen demister 4 and refluxes to the hydrogen primary separator 2. The hydrogen primary separator 2 is equipped with a liquid level gauge. When the liquid level is higher than the set value, the program controls the opening of the hydrogen side pressure reducing valve 17, and the deionized water enters the hydrogen secondary separator 18 close to normal pressure to restore the hydrogen primary separator 2 to a normal liquid level. At the same time, the deionized water entering the hydrogen secondary separator 18 further releases the dissolved hydrogen. In order to avoid the accumulation of hydrogen in the gas phase space of the hydrogen secondary separator 18 to form an explosive gas mixture and increase safety hazards, a stream of nitrogen is introduced from the side of the hydrogen secondary separator 18 to dilute the hydrogen concentration to below the lower explosion limit, and a vent pipe is installed to discharge the gas to a safe area. The remaining deionized water is discharged from the bottom of the hydrogen secondary separator 18 to the circulating water tank 20.

[0098] Like the oxygen separation system, the hydrogen separation system is also equipped with an online analysis system to avoid unqualified products. When the oxygen analyzer 6 detects that the oxygen content exceeds the set value, it will shut down and cut off the power to prompt the user to detect the system.

[0099] The deionized water from the oxygen secondary separator 19 and the hydrogen secondary separator 18 will be collected in the circulating water tank 20 of the deionized water system. The secondary separator uses an overflow pipe to control the liquid level. When the liquid level reaches the set value, it can be discharged to the circulating water tank 20 by itself, without the need to monitor the liquid level through an instrument, avoiding the safety risks caused by instrument failure; reducing the use of instrument valves also reduces costs. A water replenishment pump 21 is set downstream of the circulating water tank 20. After reaching a suitable temperature through the water replenishment heat exchanger 22, it is sent to the resin tank 23 for refining. The resin tank is filled with resin particles. The conductivity of the deionized water discharged from the resin tank can be lower than 0.5μS / cm, maintaining the conductivity within the acceptable range of the proton exchange membrane electrolyzer, which avoids the waste of water resources caused by the direct discharge of deionized water. The refined deionized water is injected into the oxygen primary separator 8 through the high-pressure pump 24 in the pipeline at z. The circulating water tank 20 is mixed with deionized water from the oxygen secondary separator 19 and the hydrogen secondary separator 18, so trace amounts of hydrogen or oxygen dissolved in the water may be released here to form an explosive gas mixture. Therefore, a nitrogen pipeline is also provided in the circulating water tank 20 to dilute the gas in the circulating water tank and empty it at the same time.

[0100] In this embodiment, after the electrolysis unit electrolyzes the liquid water to obtain hydrogen, oxygen and gas-liquid mixed water, gas-liquid separation is first performed in the primary separation module, mainly to separate the liquid water in the gas. The liquid water in the primary separation module passes through the secondary separation module to release the gas dissolved in the water. This scheme adopts the secondary separation technology, which can accelerate the release rate of the gas dissolved in the liquid water and release the gas dissolved in the water as much as possible. Finally, the liquid water after the gas is released is transmitted to the electrolysis unit for repeated use and electrolysis through the water circulation unit. While saving water resources, the gas in the recycled water has escaped, reducing the gas content in the liquid water, avoiding the hydrogen and oxygen escaping from the recycled liquid water to merge in the electrolysis unit to form an explosive gas environment, thereby reducing the safety risk of the electrolysis water hydrogen production system in the hydrogen production process.

[0101] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0102] It should be understood that in the present application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0103] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0104] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0105] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0106] Although the description of the present application has been quite detailed and specifically describes several described embodiments, it is not intended to be limited to any of these details or embodiments or any particular embodiment, but should be regarded as providing a broad possible interpretation of these claims by reference to the attached claims, taking into account the prior art, so as to effectively cover the intended scope of the present application. In addition, the above description of the present application is based on the embodiments foreseeable by the inventor, and its purpose is to provide a useful description, and those non-substantial changes to the present application that have not yet been foreseen may still represent equivalent changes to the present application.

Claims

1. A water electrolysis hydrogen production system based on a proton exchange membrane electrolyzer, characterized in that: The system includes an electrolysis unit, a water circulation unit and a gas-liquid separation unit; The electrolysis unit is used to electrolyze liquid water to obtain hydrogen, oxygen and gas-liquid mixed water; The gas-liquid separation unit includes a primary separation module and a secondary separation module; The primary separation module is used to separate the gas-liquid mixed water to obtain separated liquid water; The secondary separation module is used to perform gas release treatment on the liquid water after the separation treatment to obtain liquid water after gas release; The water circulation unit is used to transfer the liquid water released from the gas to the electrolysis unit.

2. A water electrolysis hydrogen production system based on a proton exchange membrane electrolyzer according to claim 1, characterized in that: The gas-liquid separation unit comprises a first gas-liquid separation sub-unit and a second gas-liquid separation sub-unit; The electrolysis unit is also used to output hydrogen and liquid water after electrolysis through a first end of the electrolysis unit, and to output oxygen and liquid water after electrolysis through a second end of the electrolysis unit; The first gas-liquid separation unit includes a first primary separation module and a first secondary separation module; The first stage separation module is used to separate the hydrogen to obtain liquid water in the hydrogen; The first and second separation modules are used to perform gas release treatment on the liquid water in the hydrogen and the liquid water after the electrolysis treatment to obtain liquid water after the gas is released; The second gas-liquid separation unit includes a second primary separation module and a second secondary separation module; The second-stage separation module is used to separate the oxygen to obtain liquid water in the oxygen; The second secondary separation module is used to perform gas release treatment on the liquid water in the oxygen and the liquid water after the electrolysis treatment to obtain liquid water after gas release; The water circulation unit is also used to collect liquid water released from the gas output by the first secondary separation module and the second secondary separation module and transmit it to the electrolysis unit.

3. A water electrolysis hydrogen production system based on a proton exchange membrane electrolyzer according to claim 2, characterized in that: The first gas-liquid separation subunit includes a first regulating valve module, and the second gas-liquid separation subunit includes a second regulating valve module; The first regulating valve module is used to regulate the gas pressure in the first gas-liquid separation subunit; The second regulating valve module is used to control the air pressure in the second gas-liquid separation subunit according to a preset air pressure value.

4. A water electrolysis hydrogen production system based on a proton exchange membrane electrolyzer according to claim 2, characterized in that: The first primary separation module includes a first primary separator, a first heat exchanger and a first demister; The first end of the first primary separator is used to input hydrogen and liquid water after electrolysis, the second end of the first primary separator is connected to the input end of the first heat exchanger, the third end of the first primary separator is connected to the third end of the first demister, and the fourth end of the first primary separator is used to output liquid water in the hydrogen and liquid water after electrolysis; The output end of the first heat exchanger is connected to the first end of the first demister, and the first heat exchanger is used to obtain hydrogen through the input end of the first heat exchanger, and output the obtained hydrogen through the output end of the first heat exchanger after condensing the hydrogen; The first demister is used to separate the hydrogen after condensation treatment to obtain liquid water in the hydrogen and the separated hydrogen, and output the separated hydrogen through the second end of the first demister and output the liquid water in the hydrogen through the third end of the first demister.

5. A water electrolysis hydrogen production system based on a proton exchange membrane electrolyzer according to claim 2, characterized in that: The second primary separation module includes a second primary separator, a second heat exchanger and a second demister; The first end of the second primary separator is used to input oxygen and liquid water after electrolysis, the second end of the second primary separator is connected to the input end of the second heat exchanger, the third end of the second primary separator is connected to the third end of the second demister, the fourth end of the second primary separator is used to transfer the liquid water in the oxygen and the liquid water after electrolysis to the electrolysis unit and the second secondary separation module, and the fifth end of the second primary separator is used to obtain liquid water after the gas output by the water circulation unit is released; The output end of the second heat exchanger is connected to the second end of the second demister, and the second heat exchanger is used to obtain oxygen through the input end of the second heat exchanger, and condense the obtained oxygen and output it through the output end of the second heat exchanger; The second demister is used to separate the oxygen after condensation to obtain liquid water in the oxygen and the separated oxygen, and output the separated oxygen through the second end of the second demister and output the liquid water in the oxygen through the third end of the second demister.

6. A water electrolysis hydrogen production system based on a proton exchange membrane electrolyzer according to claim 2, characterized in that: The water circulation unit comprises a circulating water tank, a resin tank, a first water pump and a second water pump; The circulating water tank is used to store liquid water after the gas is released, and the liquid water stored in the circulating water tank is transferred to the resin tank through the first water pump; The resin tank is used to perform deionization treatment on liquid water, and output the deionized liquid water through the second water pump.

7. A water electrolysis hydrogen production system based on a proton exchange membrane electrolyzer according to claim 6, characterized in that: The first secondary separation module includes a first secondary separator, the second secondary separation module includes a second secondary separator, and the first secondary separator and the second secondary separator are both liquid containers; The input end of the first secondary separator and the input end of the second secondary separator are both provided with pressure reducing valves, and the output end of the first secondary separator and the output end of the second secondary separator are both connected to the circulating water tank through an overflow pipe.

8. A water electrolysis hydrogen production system based on a proton exchange membrane electrolyzer according to claim 7, characterized in that: The first secondary separator comprises a first input end, a first output end, a second input end, and a second output end; The first input end of the first secondary separator is used to input the liquid water in the hydrogen and the liquid water after electrolysis; The first output end of the first secondary separator is used to output liquid water after the gas is released; The second input end of the first and second separators is used to input an inert gas; The second output end of the first secondary separator is used to output the gas in the first secondary separator.

9. A water electrolysis hydrogen production system based on a proton exchange membrane electrolyzer according to any one of claims 1 to 8, characterized in that: The system includes a control unit, the control unit including a plurality of sensors; Each of the sensors is used to detect the electrolysis unit, the water circulation unit or the gas-liquid separation unit to obtain a process parameter value; The control unit is used to determine whether the process parameter value is within a first preset value range. If not, the electrolysis unit, the water circulation unit and the gas-liquid separation unit are controlled to stop working. If so, when the process parameter value is not within a second preset value range, the electrolysis unit, the water circulation unit or the gas-liquid separation unit is controlled to adjust until the process parameter value is within the second preset value range.

10. A water electrolysis hydrogen production system based on a proton exchange membrane electrolyzer according to claim 9, characterized in that: The electrolysis unit comprises: A proton exchange membrane electrolysis module is used to electrolyze liquid water to obtain hydrogen, oxygen and gas-liquid mixed water; The voltage control module is used to detect the cell voltage and the cell current voltage of the proton exchange membrane electrolysis module. When any cell voltage detected is higher than a preset voltage value or the cell current voltage detected is higher than a preset current voltage value, the proton exchange membrane electrolysis module is controlled to stop working.

Images