Water electrolysis hydrogen production system for improving purity of hydrogen in oxygen

Abstract

The utility model provides a water electrolysis hydrogen production system capable of improving the purity of hydrogen in oxygen. The water electrolysis hydrogen production system capable of improving the purity of hydrogen in oxygen comprises a PEM electrolytic bath, an oxygen separator, a hydrogen separator and a heat exchanger, the PEM electrolytic cell is used for decomposing an accessed water source to obtain hydrogen and oxygen; the oxygen separator is used for receiving the oxygen through a first pipeline and discharging the oxygen after separation; the hydrogen separator is used for receiving the hydrogen through a second pipeline and discharging the hydrogen after separation; the heat exchanger is connected to the first pipeline in series, and water separated from the hydrogen separator exchanges heat with the first pipeline and then is supplemented into the oxygen separator. Water in the hydrogen splitter is supplemented into the oxygen separator through the heat exchanger, and the technical problem that in the prior art, the solubility of hydrogen in pure water supplemented into the oxygen separator by the hydrogen separator cannot be effectively reduced, the purity of hydrogen in oxygen cannot be improved, and normal operation of the system cannot be guaranteed is solved.

Description

Technical fields:

[0001] This invention belongs to the field of hydrogen production by water electrolysis, specifically a hydrogen production system by water electrolysis that improves the purity of hydrogen in oxygen. Background technology:

[0002] Regarding waste heat recovery in water electrolysis hydrogen production systems, some technologies primarily recover heat from the oxygen separator or a combination of oxygen and hydrogen separators to heat the pure water electrolyte, thereby improving electrolysis efficiency. Other methods utilize the heat generated during electrolysis for plant heating or other purposes that convert low-quality heat into high-quality heat. Regarding improving gas purity in water electrolysis hydrogen production systems, one approach is to reduce the water content in the hydrogen, thus increasing the dew point. Another method is to allow air to flow into the buffer tank; once the pressure in the buffer tank matches that of the oxygen scrubber separator, the solenoid valve is opened to allow air to enter the oxygen scrubber separator, diluting the hydrogen concentration in the oxygen inside the separator to cope with wide power fluctuations in the electrolyzer. Finally, controlling the flow rate at the anode and cathode, and thus the pressure difference, reduces the driving force for hydrogen permeation, thereby controlling the purity of the electrolysis-generated gas.

[0003] In current differential pressure PEM hydrogen production equipment, the electrolyte pure water only circulates on the oxygen side of the electrolyzer. To save on raw material pure water, the pure water from the hydrogen separator is added to the oxygen separator. However, the pure water in the hydrogen separator dissolves some hydrogen, which leads to significant fluctuations in the hydrogen purity in the oxygen during the water replenishment process, affecting the normal and stable operation of the system.

[0004] There is an urgent need for an electrolytic water hydrogen production system that can improve the hydrogen purity in oxygen. This would help solve the problem of the lack of an electrolytic water hydrogen production system in the current technology, and the lack of a technical solution to effectively reduce the hydrogen solubility in the pure water supplied from the hydrogen separator to the oxygen separator, thereby improving the hydrogen purity in oxygen and ensuring the normal operation of the system. Utility Model Content:

[0005] In one embodiment, the present invention provides an electrolytic water hydrogen production system for improving the hydrogen purity in oxygen. Water from the hydrogen splitter is supplied to the oxygen separator through a heat exchanger, which helps to solve the technical problem in the prior art of lacking an effective way to reduce the hydrogen solubility in the pure water supplied from the hydrogen separator to the oxygen separator, thereby improving the hydrogen purity in oxygen to ensure the normal operation of the system.

[0006] The water electrolysis hydrogen production system for improving the hydrogen purity in oxygen includes a PEM electrolyzer, an oxygen separator, a hydrogen separator, and a heat exchanger.

[0007] The PEM electrolyzer is used to decompose the connected water source to obtain hydrogen and oxygen.

[0008] The oxygen separator is used to receive the separated oxygen through the first pipeline and then discharge it.

[0009] The hydrogen separator is used to receive the separated hydrogen gas through a second pipeline;

[0010] The heat exchanger is connected in series with the first pipeline, and the water separated from the hydrogen separator exchanges heat with the first pipeline before being added to the oxygen separator.

[0011] In one embodiment, the water electrolysis hydrogen production system for improving the hydrogen purity in oxygen further includes a water tank;

[0012] The water tank is used to hold the water source and replenishes the PEM electrolysis cell through the third pipeline. The water tank is connected to the oxygen separator through the fourth pipeline to achieve water replenishment.

[0013] The water replenishment pump is connected in series on the fourth pipeline.

[0014] In one embodiment, the fourth pipeline connects a circulating pump, a resin tank, and a filter in series from the oxygen separator to the PEM electrolyzer.

[0015] The resin tank has parallel pipelines connected to both ends.

[0016] In one embodiment, the water electrolysis hydrogen production system for improving the hydrogen purity in oxygen further includes a small water separator;

[0017] The water from the small water separator, after being connected to the hydrogen separator via the fifth pipeline, flows into the oxygen separator via the sixth pipeline.

[0018] In one embodiment, the small water separator is further provided with a seventh pipeline, which combines the separated hydrogen with the hydrogen separated by the hydrogen separator and then discharges it.

[0019] In one embodiment, the water electrolysis hydrogen production system for improving the hydrogen purity in oxygen further includes a chiller for cooling the heat exchanger.

[0020] In one embodiment, a cold water on / off solenoid valve is connected in series on the circulation pipe.

[0021] In one embodiment, a water supply on / off solenoid valve is connected in series between the small water separator and the heat exchanger.

[0022] In one embodiment, the PEM electrolyzer is a differential pressure PEM electrolyzer. Attached image description:

[0023] Figure 1 This is a schematic diagram of a water electrolysis hydrogen production system for improving the purity of hydrogen in oxygen, according to an embodiment of the present invention.

[0024] Figure label:

[0025] Water tank 1

[0026] Water pump 2

[0027] Circulating pump 3

[0028] Resin tank 4

[0029] Filter 5

[0030] PEM electrolytic cell 6

[0031] Chiller 7

[0032] Heat exchanger 8

[0033] Small water splitter 9

[0034] Oxygen Separator 10

[0035] Hydrogen Splitter 11

[0036] Water supply on / off solenoid valve 12

[0037] Cold water on / off solenoid valve 13 Detailed implementation method:

[0038] In current differential pressure PEM hydrogen production equipment, the electrolyte pure water only circulates on the oxygen side of the electrolyzer. To save on raw material pure water, the pure water from the hydrogen separator is added to the oxygen separator. However, the pure water in the hydrogen separator dissolves some hydrogen, leading to significant fluctuations in the hydrogen purity in the oxygen during the water replenishment process, affecting the normal and stable operation of the system. This invention provides an electrolytic water hydrogen production system that utilizes waste heat recovery to improve the hydrogen purity in the oxygen, effectively reducing the hydrogen solubility in the pure water added from the hydrogen separator to the oxygen separator, thereby increasing the hydrogen purity in the oxygen and ensuring the normal operation of the system.

[0039] In general, the present invention provides an electrolytic water hydrogen production system that uses waste heat recovery to improve the hydrogen purity in oxygen, characterized in that it includes a hydrogen production unit, a separation unit, a circulation unit, a water replenishment unit, a filtration unit, a cooling unit, and a heating separation unit.

[0040] This invention uses the heat generated by the internal resistance of the pure water electrolyzer to heat the pure water supplied by the hydrogen separator to the oxygen separator, thereby reducing the solubility of hydrogen in the pure water and increasing the purity of hydrogen in the oxygen.

[0041] Figure 1 This is a schematic diagram of a water electrolysis hydrogen production system for improving the hydrogen purity in oxygen according to an embodiment of the present invention, as shown below. Figure 1 As shown,

[0042] In one embodiment, the present invention provides an electrolytic water electrolysis hydrogen production system for improving the hydrogen purity in oxygen, the electrolytic water electrolysis hydrogen production system for improving the hydrogen purity in oxygen includes a PEM electrolyzer 6, an oxygen separator 10, a hydrogen separator 11, and a heat exchanger 8;

[0043] PEM electrolysis cell 6 is used to decompose the connected water source to obtain hydrogen and oxygen;

[0044] Oxygen separator 10, which is used to receive the separated oxygen through a first pipeline and discharge it;

[0045] Hydrogen separator 11 is used to receive the separated hydrogen gas through a second pipeline;

[0046] Heat exchanger 8 is connected in series with the first pipeline and replenishes the oxygen separator 10 with the water separated in the hydrogen separator 11 after exchanging heat with the first pipeline.

[0047] This embodiment provides an electrolytic water hydrogen production system for improving the hydrogen purity in oxygen. This invention uses the heat generated by the internal resistance of the pure water electrolyzer to heat the pure water supplied to the oxygen separator by the hydrogen separator, thereby reducing the solubility of hydrogen in the pure water and improving the hydrogen purity in oxygen. This helps to solve the problem of the lack of an electrolytic water hydrogen production system for improving the hydrogen purity in oxygen in the prior art, and also helps to solve the technical problem of the lack of an effective way to reduce the solubility of hydrogen in the pure water supplied to the oxygen separator by the hydrogen separator and improve the hydrogen purity in oxygen to ensure the normal operation of the system.

[0048] In one embodiment, the water electrolysis hydrogen production system for improving the hydrogen purity in oxygen further includes a water tank 1 and a water replenishment pump 3;

[0049] Water tank 1 is used to hold the water source and replenish water to PEM electrolysis cell 6 through a third pipeline. Water tank 1 is connected to oxygen separator 10 through a fourth pipeline to achieve water replenishment.

[0050] Water pump 3 is connected in series on the fourth pipeline.

[0051] This embodiment provides a specific connection structure between a water tank 1 and a water pump 3, where the water tank 1 is the basic source of water for the system.

[0052] In one embodiment, the fourth pipeline connects the circulation pump 3, resin tank 4, and filter 5 in series from the oxygen separator 10 to the PEM electrolysis cell 6.

[0053] The resin tank 4 has parallel pipelines connected to both ends.

[0054] This embodiment provides a specific implementation method that has functions such as pressurization and filtration between the oxygen separator 10 and the PEM electrolyzer 6.

[0055] In one embodiment, the water electrolysis hydrogen production system for improving the hydrogen purity in oxygen further includes a small water separator 9;

[0056] The water from the small water separator 9, after being connected to the hydrogen separator 11 via the fifth pipeline, flows into the oxygen separator 10 via the sixth pipeline.

[0057] This embodiment provides a specific device, namely a small water separator 9, that allows water from the hydrogen separator 11 to flow into the oxygen separator 10 through the sixth pipe after passing through the fifth pipe.

[0058] In one embodiment, the small water separator 9 is also provided with a seventh pipeline, which merges the separated hydrogen with the hydrogen separated by the hydrogen separator 11 and then discharges it.

[0059] This embodiment provides a specific implementation method for the specific path of hydrogen gas after separation by a small water separator 9.

[0060] In one embodiment, the water electrolysis hydrogen production system for improving the hydrogen purity in oxygen further includes a chiller 7, which is used for cooling heat exchange of the heat exchanger 8.

[0061] This embodiment provides a specific implementation method for cooling heat exchanger 8 by chiller 7.

[0062] In one embodiment, the chiller 7 is connected to the heat exchanger 8 via a circulation pipe.

[0063] This embodiment provides a specific implementation method for connecting the chiller 7 and the heat exchanger 8 through the circulation pipe.

[0064] In one embodiment, a cold water on / off solenoid valve 13 is connected in series on the circulation pipe.

[0065] This embodiment provides a specific implementation of a cold water on / off solenoid valve 13 installed on the circulation pipe.

[0066] In one embodiment, a water supply on / off solenoid valve 12 is connected in series between the small water separator 9 and the heat exchanger 8.

[0067] In this embodiment, a specific implementation method is provided for setting a solenoid valve between a small water separator 9 and a heat exchanger 8.

[0068] In one embodiment, the PEM electrolyzer 6 is a differential pressure PEM electrolyzer.

[0069] This embodiment provides a specific implementation method for a specific type of PEM electrolytic cell 6.

[0070] The basic principle of the system above is as follows:

[0071] When the liquid level in oxygen separator 10 is too low, water pump 2 replenishes the pure water in water tank 1. Circulation pump 3 pumps the pure water from the oxygen separator through ion exchange resin 4 and conductivity meter 5 into pure water electrolysis cell 6, then from the oxygen side outlet of the cell through plate heat exchanger 8 back into the oxygen separator, completing the circulation process. This replenishes the pure water consumed in water electrolysis and removes heat generated by the cell. Chiller 7 is connected to plate heat exchanger 8, and the cooling water is controlled by solenoid valve 13. When the cooling water flows through the heat exchanger, it exchanges heat with the mixture of oxygen and pure water, thereby regulating the circulating water temperature. When the balance valve 12 in the middle of the hydrogen-oxygen separator is opened, the water discharged from hydrogen separator 11 to the oxygen separator is first preheated by the plate heat exchanger, reducing the solubility of hydrogen in pure water and causing hydrogen to precipitate. It then passes through a small separation tank 9 to separate the precipitated hydrogen from the pure water. The reduced hydrogen content in the water replenishing the oxygen separator lowers the hydrogen content in the oxygen.

[0072] Hydrogen ions pass through the proton exchange membrane as hydrated hydrogen ions, resulting in the formation of liquid water on the hydrogen side. Water is only added to the oxygen separator when the hydrogen separator level is too high. At this point, hydrogen dissolved in the water directly enters the oxygen separator, causing drastic fluctuations in hydrogen purity and affecting equipment safety. The heating separation unit of this invention preheats the water added from the hydrogen separator to the oxygen separator via a plate heat exchanger, reducing the solubility of hydrogen in pure water. The gas-water mixture is then separated by gravity in a small separation tank, and the released hydrogen is discharged through a vent, thus ensuring system stability.

[0073] The pure water electrolyzer itself has internal resistance, which converts some electrical energy into internal energy. The perfluorosulfonic acid proton exchange membrane has a glass transition temperature; excessively high temperatures lead to loss of mechanical properties and irreversible dehydration. Therefore, the pure water electrolyzer must have circulating water to remove the heat generated by the internal resistance during operation. The circulation unit uses a circulating pump to pump pure water from the oxygen separator, through ion exchange resin and a conductivity meter, into the pure water electrolyzer. From the oxygen side outlet of the tank, it passes through a plate heat exchanger and then re-enters the oxygen separator, completing the circulation of the electrolyte pure water. This replenishes the pure water consumed in the electrolysis and removes the heat generated in the tank. The hydrogen production unit is a pure water electrolyzer device, consisting of multiple electrolysis chambers connected in series and secured together with bolts. In each chamber, water molecules decompose, generating hydrogen and oxygen on both sides of a metal bipolar plate, ultimately converging at the hydrogen and oxygen outlet. Perfluorosulfonic acid proton exchange membranes coated with hydrogen and oxygen evolution catalysts are used as membrane electrodes; the small electrode spacing allows operation at high current densities. The electrolytic water hydrogen production system of this invention is a differential pressure system, with the hydrogen side pressurized and the oxygen side at atmospheric pressure. Therefore, the heat exchanger used in this invention is a plate heat exchanger with relatively weak pressure resistance but small size. Hydrogen ions pass through the proton exchange membrane in the form of hydrated hydrogen ions, resulting in the generation of liquid water on the hydrogen side. Water is only added to the oxygen separator when the liquid level in the hydrogen separator is too high. At this time, the hydrogen dissolved in the water directly enters the oxygen separator, causing drastic fluctuations in the hydrogen purity in the oxygen, affecting the safe operation of the equipment. The heating separation unit of this invention preheats the water added to the oxygen separator by passing it through a plate heat exchanger, reducing the solubility of hydrogen in pure water. Then, the gas-water mixture is separated by gravity in a small separation tank, and the released hydrogen is discharged through the vent, thereby ensuring the stability of the system operation.

[0074] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A water electrolysis hydrogen production system for improving the hydrogen purity in oxygen, characterized in that, The water electrolysis hydrogen production system for improving the hydrogen purity in oxygen includes: A PEM electrolyzer (6) is used to decompose the connected water source to obtain hydrogen and oxygen; An oxygen separator (10) is used to receive the separated oxygen through a first pipeline and discharge it. A hydrogen separator (11) is used to receive the separated hydrogen gas through a second pipeline; A heat exchanger (8) is connected in series with the first pipeline and replenishes the oxygen separator (10) with the water separated in the hydrogen separator (11) after exchanging heat with the first pipeline.

2. The water electrolysis hydrogen production system for improving the hydrogen purity in oxygen according to claim 1, characterized in that, The water electrolysis hydrogen production system that improves the hydrogen purity in oxygen also includes: A water tank (1) is used to hold the water source and to replenish the PEM electrolysis cell (6) through a third pipeline. The water tank (1) is connected to the oxygen separator (10) through a fourth pipeline to achieve water replenishment. A water replenishment pump (2) is connected in series on the fourth pipeline.

3. The water electrolysis hydrogen production system for improving the hydrogen purity in oxygen according to claim 2, characterized in that, The fourth pipeline connects the oxygen separator (10) to the PEM electrolysis cell (6) in series with the circulation pump (3), resin tank (4), and filter (5); The resin tank (4) has parallel pipelines connected to both ends.

4. The water electrolysis hydrogen production system for improving the hydrogen purity in oxygen according to claim 3, characterized in that, The water electrolysis hydrogen production system for improving the purity of hydrogen in oxygen also includes a small water separator (9); The small water separator (9) is connected to the hydrogen separator (11). After the water passes through the fifth pipeline, it flows into the oxygen separator (10) through the sixth pipeline.

5. The water electrolysis hydrogen production system for improving the hydrogen purity in oxygen according to claim 4, characterized in that, The small water separator (9) is also equipped with a seventh pipeline, which merges the separated hydrogen with the hydrogen separated by the hydrogen separator (11) and then discharges it.

6. The water electrolysis hydrogen production system for improving the hydrogen purity in oxygen according to claim 5, characterized in that, The water electrolysis hydrogen production system for improving the purity of hydrogen in oxygen also includes a chiller (7), which is used for cooling heat exchange of the heat exchanger (8).

7. The water electrolysis hydrogen production system for improving the hydrogen purity in oxygen according to claim 6, characterized in that, The chiller (7) is connected to the heat exchanger (8) via a circulation pipe.

8. The water electrolysis hydrogen production system for improving the hydrogen purity in oxygen according to claim 7, characterized in that, A cold water on / off solenoid valve (13) is connected in series on the circulation pipe.

9. The water electrolysis hydrogen production system for improving the hydrogen purity in oxygen according to claim 8, characterized in that, A water supply on / off solenoid valve (12) is connected in series between the small water separator (9) and the heat exchanger (8).

10. The water electrolysis hydrogen production system for improving the hydrogen purity in oxygen according to claim 9, characterized in that, The PEM electrolytic cell (6) is a differential pressure PEM electrolytic cell.

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