Self-protection electrolytic cell in green electricity hydrogen production system

Abstract

The utility model relates to a self-protection electrolytic bath in a green electricity hydrogen production system, a hydrogen output pipeline and an oxygen output pipeline of the electrolytic bath are respectively provided with a check valve, and the check valves only allow gas / liquid from the electrolytic bath to a post-treatment device to flow unidirectionally and do not allow the gas / liquid to flow from the post-treatment device to the electrolytic bath. And mixed liquor of gas, liquid and alkali liquor in the post-treatment device is prevented from flowing backwards into the electrolytic bath, and the safety protection effect on the electrolytic bath is achieved. The check valves on the hydrogen output pipeline and the oxygen output pipeline are respectively provided with a pressure regulating valve, and a pressure transmitter is arranged on the hydrogen output pipeline / oxygen output pipeline between the check valves and the electrolytic cell to regulate the pressure difference between the two sides of the hydrogen and the oxygen, so that the diaphragm is effectively prevented from being broken due to the overlarge pressure difference between the two sides of the diaphragm, and gas and liquid on the two sides of the hydrogen and the oxygen are prevented from channeling; the hydrogen concentration in the oxygen exceeds the standard.

Description

Technical Field

[0001] The utility model relates to a self-protecting electrolyzer in a green electricity hydrogen production system, belonging to the technical field of green electricity hydrogen production. Background Art

[0002] Green electricity hydrogen production system refers to the use of photovoltaic energy or wind energy as the power source for electrolysis of water to produce hydrogen. The green electricity power supply is rectified to power the electrolyzer, and the direct current is used to power the post-processing device, and multiple electrolyzers with independent control and switching are connected in parallel. At present, the mainstream modes of green electricity hydrogen production system are 2 to 1 mode (i.e. 2 electrolyzers correspond to 1 post-processing device); 4 to 1 mode (i.e. 4 electrolyzers correspond to 1 post-processing device); and many to 1 mode (i.e. multiple electrolyzers correspond to 1 post-processing device).

[0003] However, the operating conditions of each electrolyzer in the green electricity hydrogen production system are different, resulting in different gas-liquid pressures entering the separator of the electrolyzer. This results in different outlet resistances for each electrolyzer, leading to an operating defect of pressure imbalance inside the electrolyzer, causing hydrogen and oxygen to pass through the diaphragm and cross-talk. In severe cases, an explosion may occur, affecting the safety of the electrolyzer operation.

[0004] The difference in pressure between each electrolyzer and the separator causes the gas in the separator to flow back into the electrolyzer, causing an imbalance in the pressure between the hydrogen and oxygen sides of the electrolyzer, further increasing the difficulty of controlling the operation of the electrolyzer.

[0005] In summary, the difficulties in controlling the green electricity hydrogen production system lie in: multiple electrolyzers correspond to one post-processing device, the inconsistency of the electrolyzer operating conditions; the imbalance of the gas production and pressure of the electrolyzers; the difference between the pressure in each electrolyzer and the total pressure of the separator, resulting in poor exhaust of the low-pressure electrolyzer and even gas backflow. Summary of the invention

[0006] In order to solve the above problems, the utility model discloses a self-protecting electrolyzer in a green electricity hydrogen production system, and its specific technical solution is as follows:

[0007] A self-protecting electrolyzer in a green electricity hydrogen production system, the green electricity hydrogen production system comprising a plurality of electrolyzers, the electrolyzers being grouped to share a post-processing device, the post-processing device comprising a hydrogen gas-liquid separator and an oxygen liquid separator, the electrolyzer being connected to the hydrogen gas-liquid separator of the post-processing device via a hydrogen output pipeline, the electrolyzer being connected to the oxygen liquid separator of the post-processing device via an oxygen output pipeline, the hydrogen output pipeline and the oxygen output pipeline of the electrolyzer being respectively provided with a check valve, the check valve only allowing a one-way flow of gas / liquid from the electrolyzer to the post-processing device, and not allowing gas / liquid to flow from the post-processing device to the electrolyzer.

[0008] Furthermore, the check valves on the hydrogen output pipeline and the oxygen output pipeline are each provided with a pressure regulating valve, and a pressure transmitter is also provided on the hydrogen output pipeline / oxygen output pipeline between the check valve and the electrolyzer.

[0009] Furthermore, a diaphragm is provided inside the electrolytic cell, which divides the space above the liquid surface in the electrolytic cell into a hydrogen side and an oxygen side. The hydrogen output pipeline is connected to the hydrogen side of the electrolytic cell, and the oxygen output pipeline is connected to the oxygen side of the electrolytic cell.

[0010] Furthermore, the hydrogen side and oxygen side of the electrolytic cell are respectively provided with pressure sensors and pressure transmitters, and the upstream and downstream sides of the check valve are also provided with pressure sensors and pressure transmitters, and the pressure transmitters on the hydrogen side / oxygen side of the electrolytic cell are interlocked and connected.

[0011] Furthermore, the check valve is an axial flow check valve, a swing check valve or a lift check valve.

[0012] The beneficial effects of the utility model are:

[0013] In the case of fluctuations in renewable energy, the gas production and pressure of each electrolyzer in the green electricity hydrogen production system are different. In order to prevent the gas produced by the electrolyzer with sufficient gas production and high pressure from flowing back to the electrolyzer with small gas production and slightly lower pressure instead of flowing to the hydrogen / oxygen liquid separator, a check valve is installed in the hydrogen output pipeline / oxygen output pipeline of each electrolyzer to prevent the mixture of gas, liquid and alkali solution in the post-processing device from flowing back into the electrolyzer, thereby providing safety protection for the electrolyzer.

[0014] At the same time, inside an electrolyzer, the different pressures on both sides of hydrogen and oxygen may also cause the diaphragm to rupture. In order to ensure that the pressure difference between hydrogen and oxygen is stable at 3kpa (the allowable pressure difference range on both sides of the diaphragm), a pressure regulating valve and a pressure transmitter are installed in the hydrogen output pipeline / oxygen output pipeline between the check valve and the electrolyzer to adjust the pressure difference between hydrogen and oxygen, effectively preventing the diaphragm from rupturing due to excessive pressure difference on both sides of the diaphragm, gas-liquid crosstalk on both sides of hydrogen and oxygen, and excessive hydrogen concentration in oxygen. By installing a pressure regulating valve and a pressure transmitter, the pressure difference on both sides of the diaphragm is ensured to be kept within the allowable range, thereby protecting the diaphragm of the electrolyzer and preventing damage to the electrolyzer caused by diaphragm rupture. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a connection diagram of the utility model.

[0016] List of reference numerals: 1—electrolyzer, 2—hydrogen output pipeline, 3—oxygen output pipeline, 4—check valve, 5—pressure regulating valve, 6—pressure transmitter. DETAILED DESCRIPTION

[0017] The present invention is further described below in conjunction with the accompanying drawings and specific implementations. It should be understood that the following specific implementations are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0018] The green electricity hydrogen production system includes a plurality of electrolyzers 1, and the electrolyzers 1 are grouped to share a post-processing device, and the post-processing device includes a hydrogen gas-liquid separator and an oxygen liquid separator. The electrolyzer 1 is connected to the hydrogen gas-liquid separator of the post-processing device through a hydrogen output pipeline 2, and the electrolyzer 1 is connected to the oxygen liquid separator of the post-processing device through an oxygen output pipeline 3. The downstream of the hydrogen gas-liquid separator and the oxygen liquid separator are also respectively connected to hydrogen / oxygen washing towers and other further gas-liquid separation devices until qualified hydrogen is finally obtained, and the separated alkaline solution is returned to the electrolyzer 1.

[0019] Combined with Figure 1 It can be seen that the hydrogen output pipeline 2 and the oxygen output pipeline 3 of the electrolyzer 1 are respectively provided with a check valve 4. The check valve 4 is a one-way valve that only allows the gas / liquid to flow in one direction from the electrolyzer 1 to the post-processing device, and does not allow the gas / liquid to flow from the post-processing device to the electrolyzer 1, so as to prevent the gas and liquid in the post-processing device from flowing back to the electrolyzer 1 when the pressure in the electrolyzer 1 is lower than the pressure in the hydrogen / oxygen output pipeline or other post-processing devices, so as to cause the gas and liquid flow in the system to be disordered, and damage the low-pressure electrolyzer 1. The reason for the existence of the low-pressure electrolyzer 1 is the instability of green electricity, which will cause some electrolyzers 1 to operate at low load and some electrolyzers 1 to operate at high load, and the pressure in each electrolyzer 1 is not completely consistent. In order to ensure that the gas and liquid after the electrolysis of water to produce hydrogen in the electrolyzer 1 can stably enter the post-processing device, and to protect the electrolyzer 1, the check valve 4 is used to limit the gas and liquid discharge pipeline of the electrolyzer 1 to only go out but not in, so as to prevent backflow.

[0020] At the same time, in order to ensure that the pressure difference on both sides of the diaphragm inside the electrolyzer 1 is kept within a safe range to avoid damage to the diaphragm, the check valves 4 on the hydrogen output pipeline 2 and the oxygen output pipeline 3 are each provided with a pressure regulating valve 5, and a pressure transmitter 6 is also provided on the hydrogen output pipeline 2 / oxygen output pipeline 3 between the check valve 4 and the electrolyzer 1. A diaphragm is provided inside the electrolyzer 1, and the diaphragm divides the space above the liquid surface in the electrolyzer 1 into a hydrogen side and an oxygen side. The hydrogen output pipeline 2 is connected to the hydrogen side of the electrolyzer 1, and the oxygen output pipeline 3 is connected to the oxygen side of the electrolyzer 1. Pressure sensors and pressure transmitters 6 are respectively provided on the hydrogen side and the oxygen side of the electrolytic cell 1, and pressure sensors and pressure transmitters 6 are provided on the upstream and downstream sides of the check valve 4. The pressure transmitters 6 on both sides of hydrogen / oxygen are interlocked and associated to ensure that the pressure difference between the two pressure transmitters 6 does not exceed 3Kpa, so as to adjust the opening of the pressure transmitters 6 on both sides of hydrogen / oxygen, protect the diaphragm of the electrolytic cell 1, prevent the diaphragm from rupture and hydrogen and oxygen from cross-talk, and ensure the safety of the electrolytic cell 1. When the pressure difference on both sides of the diaphragm in the electrolytic cell 1 exceeds the allowable pressure difference of the diaphragm, the pressure transmitter 6 is controlled to adjust the pressure.

[0021] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0022] The term “connection” as used in this application may mean a direct connection between components or an indirect connection between components via other components.

[0023] Based on the above ideal embodiments of the utility model, the relevant staff can make various changes and modifications without departing from the technical concept of the utility model through the above description. The technical scope of the utility model is not limited to the content of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A self-protected electrolyzer in a green electricity hydrogen production system, the green electricity hydrogen production system comprising a plurality of electrolyzers, the electrolyzers are grouped to share a post-processing device, the post-processing device comprises a hydrogen gas-liquid separator and an oxygen liquid separator, the electrolyzer is connected to the hydrogen gas-liquid separator of the post-processing device through a hydrogen output pipeline, and the electrolyzer is connected to the oxygen liquid separator of the post-processing device through an oxygen output pipeline, characterized in that: The hydrogen output pipeline and the oxygen output pipeline of the electrolyzer are respectively provided with a check valve, which only allows gas / liquid to flow in one direction from the electrolyzer to the post-processing device, and does not allow gas / liquid to flow back from the post-processing device to the electrolyzer.

2. The self-protected electrolyzer in the green electricity hydrogen production system according to claim 1 is characterized in that: The check valves on the hydrogen output pipeline and the oxygen output pipeline are each provided with a pressure regulating valve, and a pressure transmitter is also provided on the hydrogen output pipeline / oxygen output pipeline between the check valve and the electrolyzer.

3. The self-protected electrolyzer in the green electricity hydrogen production system according to claim 1 is characterized in that: A diaphragm is arranged inside the electrolytic cell, which divides the space above the liquid surface in the electrolytic cell into a hydrogen side and an oxygen side. The hydrogen output pipeline is connected to the hydrogen side of the electrolytic cell, and the oxygen output pipeline is connected to the oxygen side of the electrolytic cell.

4. The self-protected electrolyzer in the green electricity hydrogen production system according to claim 3 is characterized in that: The hydrogen side and oxygen side of the electrolytic cell are respectively provided with a pressure sensor and a pressure transmitter, and the upstream and downstream sides of the check valve are also provided with a pressure sensor and a pressure transmitter. The pressure transmitters on the hydrogen side / oxygen side of the electrolytic cell are interlocked and associated.

5. The self-protected electrolyzer in the green electricity hydrogen production system according to claim 1 is characterized in that: The check valve is selected from an axial flow check valve, a swing check valve or a lift check valve.

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