A method and system for controlling hydrogen and oxygen pressure balance

Abstract

The invention discloses a hydrogen-oxygen pressure balance control method and system, and relates to the field of general control systems. The control method comprises the following steps: obtaining an oxygen side pressure and a hydrogen side pressure, and setting a first preset pressure; adjusting the oxygen side pressure so that =, and adjusting the hydrogen side pressure so that = at the same time; when ==, setting a second preset pressure; adjusting the oxygen side pressure so that =, and adjusting the hydrogen side pressure so that = at the same time; when ==, repeating the above steps, sequentially setting a plurality of preset pressures and adjusting the oxygen side pressure and the hydrogen side pressure until == output pressure; the hydrogen-oxygen pressure balance control method provided by the invention adopts a stepwise comparative rising control method for pressure boosting, and the control method can realize equal pressure rising and equal pressure output of the hydrogen and oxygen sides under different production periods.

Description

Technical Field

[0001] The present invention relates to the technical field of control systems, and in particular to a hydrogen-oxygen pressure balance control method and system. Background Art

[0002] In the process of hydrogen production by water electrolysis, when the pressure of the hydrogen and oxygen pipelines at the outlet of the electrolyzer changes, hydrogen and oxygen will permeate each other, which will directly affect the purity of the produced gas. The reduction in purity may lead to poor results or adverse effects in subsequent use; it also threatens the safety of system operation and may cause accidents. Among them, the hydrogen in oxygen exceeds the standard when running at low load, which is a major problem in the operation of equipment for hydrogen production by water electrolysis. When the electrolyzer is running off-grid with wind or solar power generation, the power generation load is very unstable, and the electrolyzer runs below 50% load for a long time. Therefore, the pressure balance on both sides of the oxygen and hydrogen in the alkaline electrolyzer must be dynamically adjusted during the hydrogen production process.

[0003] In the prior art, the electrolyzer pressure control system achieves the pressure balance of the cathode chamber and the anode chamber in the electrolyzer in the electrolyzer system by adjusting the liquid level balance of the hydrogen separator and the oxygen separator in the electrolyzer system, that is, the pressure balance on both sides of hydrogen and oxygen in the electrolyzer is achieved, so that the purity of the oxygen and the purity of the hydrogen obtained by electrolysis are higher. However, the method of controlling the pressure balance on both sides of hydrogen and oxygen in the electrolyzer by controlling the liquid level balance inside the hydrogen separator and the oxygen separator cannot accurately control the pressure on both sides of hydrogen and oxygen in the electrolyzer, so that the pressure difference on both sides of hydrogen and oxygen in the electrolyzer is large, affecting the purity of hydrogen and oxygen obtained by the electrolyzer and the diaphragm life of the electrolyzer. In addition, the prior art also adopts the hydrogen side water tank and the oxygen side water tank connection mode and related control to achieve the pressure balance on the hydrogen and oxygen sides, but this control method has the risk of hydrogen and oxygen mutual channeling. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a hydrogen-oxygen pressure balance control method and system, which can achieve isobaric rise and isobaric output on the hydrogen side and the oxygen side when the hydrogen side and the oxygen side have different production amounts, thereby avoiding mutual crosstalk between hydrogen and oxygen.

[0005] The technical solution of the present invention is as follows:

[0006] In a first aspect of the present invention, a hydrogen-oxygen pressure balance control method is provided, comprising the following steps:

[0007] Get oxygen side pressure and hydrogen side pressure , and set the first preset pressure ;

[0008] Adjust the oxygen side pressure so that = , and adjust the hydrogen side pressure to = ;

[0009] when = = When the second preset pressure is set ;

[0010] Adjust the oxygen side pressure so that = , and adjust the hydrogen side pressure to = ;

[0011] when = = Repeat the above steps to set multiple preset pressures and adjust the oxygen side pressure and hydrogen side pressure , until = = output pressure, wherein multiple preset pressures are set to increase in sequence.

[0012] In some embodiments of the present invention, the first preset pressure Less than the second preset pressure , and the multiple preset pressures increase in equal steps, and the increase value is controlled within 0.1Mpa.

[0013] In some embodiments of the present invention, the first preset pressure The pressure range is 0.1-0.12Mpa, and the second preset pressure The pressure range of the input pressure is 0.2-0.22Mpa, and the pressure range of the output pressure is 2.8-3.2Mpa.

[0014] In some embodiments of the present invention, the oxygen side pressure The pressure on the hydrogen side is obtained through the differential pressure transmitter on the oxygen output pipe. Obtained through the differential pressure transmitter on the hydrogen output pipe.

[0015] In some embodiments of the present invention, when the oxygen side pressure is adjusted by adjusting the opening of the pneumatic diaphragm regulating valve on the oxygen pipe, the hydrogen side pressure is adjusted by adjusting the opening of the pneumatic diaphragm regulating valve on the hydrogen pipe.

[0016] In a second aspect of the present invention, a hydrogen-oxygen pressure balance control system is provided, comprising: an electrolyzer, a hydrogen-water separator, an oxygen-water separator and a controller; the hydrogen outlet of the electrolyzer is connected to the hydrogen-water separator via a hydrogen delivery pipe, and the oxygen outlet of the electrolyzer is connected to the oxygen-water separator via an oxygen delivery pipe;

[0017] The oxygen-water separator is connected to an oxygen output pipe and an oxygen vent pipe, the oxygen output pipe and the oxygen vent pipe are connected through an oxygen connecting pipe, and a first pneumatic diaphragm regulating valve is arranged on the oxygen connecting pipe;

[0018] The hydrogen-water separator is connected to a hydrogen output pipe and a hydrogen vent pipe, the hydrogen output pipe and the hydrogen vent pipe are connected through a hydrogen connecting pipe, and a second pneumatic diaphragm regulating valve is arranged on the hydrogen connecting pipe;

[0019] The controller controls the opening degree of the first pneumatic diaphragm regulating valve and the second pneumatic diaphragm regulating valve to control the hydrogen and oxygen pressure balance.

[0020] In some embodiments of the present invention, a first pressure transmitter, a first back pressure valve and a first check valve are sequentially disposed at the oxygen outlet of the oxygen output pipe.

[0021] In some embodiments of the present invention, a second pressure transmitter, a second back pressure valve and a second check valve are sequentially arranged at the hydrogen outlet of the hydrogen output pipe.

[0022] In some embodiments of the present invention, a water tank is further included, wherein the water tank is connected to the oxygen-water separator through a pipeline, and the discharge port of the oxygen-water separator is connected to the electrolytic cell through a water supply pipe.

[0023] In some embodiments of the present invention, a water replenishment pump is provided on the water replenishment pipe, and a Y-type filter is provided at the water replenishment port of the electrolytic cell.

[0024] One or more technical solutions of the present invention have the following beneficial effects:

[0025] (1) Compared with the prior art, the hydrogen-oxygen pressure balance control method provided by the present invention adopts a method of disconnecting the hydrogen side and the oxygen side, which can fundamentally solve the risk of hydrogen-oxygen mixing. By adopting a step-by-step comparative increase control method for pressure increase, the pressure difference on the hydrogen and oxygen sides can be controlled to be less than 0.1 MPa, and the maximum pressure difference is relatively low. This control method can achieve equal pressure increase and equal pressure output on the hydrogen and oxygen sides under different production periods.

[0026] (2) The hydrogen-oxygen pressure balance control method provided by the present invention can accurately control the pressures on both sides of the hydrogen and oxygen inside the electrolyzer, thereby reducing the large pressure difference between the hydrogen and oxygen inside the electrolyzer, improving the purity of the hydrogen and oxygen produced by the electrolyzer, and improving the life of the diaphragm of the electrolyzer.

[0027] (3) The hydrogen-oxygen pressure balance control system provided by the present invention connects the oxygen output pipe and the oxygen vent pipe through the oxygen connecting pipe, and a first pneumatic diaphragm regulating valve is arranged on the oxygen connecting pipe. The hydrogen output pipe and the hydrogen vent pipe are connected through the hydrogen connecting pipe, and a second pneumatic diaphragm regulating valve is arranged on the hydrogen connecting pipe. The controller can effectively realize pressure regulation on the oxygen side and the hydrogen side by controlling the opening degree of the first pneumatic diaphragm regulating valve and the second pneumatic diaphragm regulating valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of a hydrogen and oxygen pressure balance control system according to Example 2 of the present invention.

[0029] In the figure: 1, electrolyzer; 2, oxygen-water separator; 3, hydrogen-water separator; 4, water tank; 5, oxygen vent pipe; 6, oxygen output pipe; 7, oxygen connecting pipe; 8, oxygen delivery pipe; 9, hydrogen delivery pipe; 10, hydrogen output pipe; 11, hydrogen vent pipe; 12, hydrogen connecting pipe; 13, first pneumatic diaphragm regulating valve; 14, first pressure transmitter; 15, first back pressure valve; 16, first non-return valve; 17, second pneumatic diaphragm regulating valve; 18, second pressure transmitter; 19, second back pressure valve; 20, second non-return valve; 21, first liquid outlet pipe; 22, second liquid outlet pipe; 23, water supply pipe; 24, Y-type filter; 25, first water supply pump; 26, second water supply pump; 27, first solenoid valve; 28, first safety valve; 29, second solenoid valve; 30, second safety valve; 31, differential pressure transmitter. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0031] Example 1

[0032] Water electrolysis produces hydrogen and oxygen. Since the production amounts of hydrogen and oxygen are different, the pressures on the hydrogen side and the oxygen side in the same device are also different. In order to reduce the pressure difference inside the electrolytic cell, in a typical embodiment of the present invention, a hydrogen-oxygen pressure balance control method is proposed, comprising the following steps:

[0033] Get oxygen side pressure and hydrogen side pressure , and set the first preset pressure ;

[0034] Adjust the oxygen side pressure so that = , and adjust the hydrogen side pressure to = ;

[0035] when = = When the second preset pressure is set ;

[0036] Adjust the oxygen side pressure so that = , and adjust the hydrogen side pressure to = ;

[0037] when = = Repeat the above steps to set multiple preset pressures and adjust the oxygen side pressure and hydrogen side pressure , until = = output pressure, wherein multiple preset pressures are set to increase in sequence.

[0038] In this embodiment, the first preset pressure Less than the second preset pressure , and the plurality of preset pressures are increased in sequence and are increased isobarically to achieve the purpose of reducing the oxygen side pressure and hydrogen side pressure The isobaric rise is achieved and the isobaric output is finally realized, thereby reducing the pressure difference inside the electrolyzer, improving the purity of the hydrogen and oxygen produced by the electrolyzer, and increasing the life of the diaphragm of the electrolyzer.

[0039] Furthermore, the first preset pressure The pressure range is 0.1-0.12Mpa. Preferably, the first preset pressure =0.1Mpa, the second preset pressure The pressure range is 0.2-0.22Mpa. Preferably, the second preset pressure =0.2 Mpa, the pressure range of the output pressure is 2.8-3.2 Mpa, preferably, the output pressure is 3.0 Mpa. The increase value of the multiple preset pressures is controlled within 0.1 Mpa, and the pressure difference on the hydrogen and oxygen sides can be controlled to be always less than 0.1 MPa, so that the maximum pressure difference in the electrolyzer is low, avoiding the cross-talk between hydrogen and oxygen.

[0040] In this embodiment, the oxygen side pressure The pressure on the hydrogen side is obtained through the differential pressure transmitter on the oxygen output pipe. Obtained through the differential pressure transmitter on the hydrogen output pipe.

[0041] In this embodiment, when the oxygen side pressure is adjusted by adjusting the opening of the pneumatic diaphragm regulating valve on the oxygen pipe, the hydrogen side pressure is adjusted by adjusting the opening of the pneumatic diaphragm regulating valve on the hydrogen pipe.

[0042] Since the amount of oxygen and hydrogen produced by the electrolyzer at the same time is inconsistent, and there is some water circulating in the oxygen-water separator in addition to oxygen, a step-by-step comparative increase control method is used to increase the pressure during electrolysis. This control method can achieve equal pressure increase and equal pressure output on the hydrogen and oxygen sides under different production periods.

[0043] Example 2

[0044] In a typical implementation of this embodiment, a hydrogen-oxygen pressure balance control system is provided to implement the hydrogen-oxygen pressure balance control method described in Example 1, such as Figure 1 As shown, it includes: an electrolyzer 1, a hydrogen-water separator 3, an oxygen-water separator 2 and a controller; the hydrogen outlet of the electrolyzer 1 is connected to the hydrogen-water separator 3 through a hydrogen delivery pipe 9, and the oxygen outlet of the electrolyzer 1 is connected to the oxygen-water separator 2 through an oxygen delivery pipe 8;

[0045] The top of the oxygen-water separator 2 is connected to an oxygen output pipe 6 and an oxygen vent pipe 5, and the bottom is connected to a first liquid outlet pipe 21. The oxygen output pipe 6 and the oxygen vent pipe 5 are connected through an oxygen connecting pipe 7, and a first pneumatic film regulating valve 13 is provided on the oxygen connecting pipe 7.

[0046] The top of the hydrogen-water separator 3 is connected to a hydrogen output pipe 10 and a hydrogen vent pipe 11, and the bottom is connected to a second liquid outlet pipe 22. The hydrogen output pipe 10 and the hydrogen vent pipe 11 are connected through a hydrogen connecting pipe 12, and a second pneumatic diaphragm regulating valve 17 is provided on the hydrogen connecting pipe 12;

[0047] The controller controls the opening degree of the first pneumatic diaphragm regulating valve 13 and the second pneumatic diaphragm regulating valve 17 to control the hydrogen and oxygen pressure balance.

[0048] Furthermore, a first pressure transmitter 14 , a first back pressure valve 15 and a first check valve 16 are sequentially arranged at the oxygen outlet of the oxygen output pipe 6 .

[0049] Furthermore, a second pressure transmitter 18 , a second back pressure valve 19 and a second check valve 20 are sequentially disposed at the hydrogen outlet of the hydrogen output pipe 10 .

[0050] A differential pressure transmitter 31 is added between the hydrogen side and the oxygen side to protect the system, and an alarm is triggered when the differential pressure is ≥ 0.15 MPa.

[0051] In this embodiment, a first solenoid valve 27 and a first safety valve 28 are provided on the oxygen venting pipe 5 , and a second solenoid valve 29 and a second safety valve 30 are provided on the hydrogen venting pipe 11 .

[0052] Furthermore, it also includes a water tank 4, which is connected to the oxygen-water separator 2 through a pipeline, and the discharge port of the oxygen-water separator 2 is connected to the electrolytic cell 1 through a water replenishment pipe 23, and a first water replenishment pump 25 is provided on the water replenishment pipe 23, and a Y-type filter 24 is provided at the water replenishment port of the electrolytic cell 1. A second water replenishment pump 26 is provided on the pipeline connecting the water tank 4 and the oxygen-water separator 2.

[0053] The control principle of the hydrogen and oxygen pressure balance control system provided in this embodiment is:

[0054] The second water replenishment pump 26 replenishes the water in the water tank 4 into the oxygen-water separator 2, and the water separated by the oxygen-water separator 2 is pumped into the electrolyzer 1 through the first water replenishment pump 25. The electrolyzer 1 electrolyzes the water into hydrogen and oxygen under the action of electricity, wherein the hydrogen enters the hydrogen-water separator 3, and the remaining water and oxygen enter the oxygen-water separator 2. In order to ensure the pressure balance of hydrogen and oxygen inside the electrolyzer, the controller uses the control method in Example 1 to adjust the hydrogen side pressure and the oxygen side pressure to ensure that the pressures of the hydrogen-water separator 3 and the oxygen-water separator 2 are basically the same, thereby reducing the pressure difference between the hydrogen side and the oxygen side in the electrolyzer. In this case, hydrogen and oxygen are output for use.

[0055] The specific control process of the controller is as follows:

[0056] In the initial state, the first pressure transmitter 14 on the oxygen output pipe 6 collects the oxygen side pressure of the oxygen output pipe 6. The second pressure transmitter 18 on the hydrogen output pipe 10 collects the pressure on the hydrogen side of the hydrogen output pipe 10. , the controller sets the first preset pressure , adjust the opening degree of the first pneumatic diaphragm regulating valve 13 on the oxygen connecting pipe 7, so that = At the same time, adjust the opening degree of the second pneumatic diaphragm regulating valve 17 on the hydrogen connecting pipe 12 so that = ,when = = When the controller adjusts the pressure in sequence according to the preset pressures, and When the output pressure is met, the first back pressure valve 15 and the first check valve 16 are opened to output oxygen, and the second back pressure valve 19 and the second check valve 20 are opened to output hydrogen, so that the hydrogen and oxygen sides can achieve isobaric rise and isobaric output under different production periods.

[0057] The hydrogen-oxygen pressure balance control system provided in the present embodiment connects the oxygen output pipe 6 and the oxygen vent pipe 5 through the oxygen connecting pipe 7, and a first pneumatic diaphragm regulating valve 13 is provided on the oxygen connecting pipe 7, which can effectively realize the regulation of the oxygen output pressure on the oxygen output pipe 6, and connects the hydrogen output pipe 10 and the hydrogen vent pipe 11 through the hydrogen connecting pipe 12, and a second pneumatic diaphragm regulating valve 17 is provided on the hydrogen connecting pipe 12, which can effectively realize the regulation of the hydrogen output pressure on the hydrogen output pipe 10.

[0058] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A hydrogen and oxygen pressure balance control method, characterized in that: The hydrogen-oxygen pressure balance control system comprises an electrolyzer, a hydrogen-water separator, an oxygen-water separator and a controller; the hydrogen outlet of the electrolyzer is connected to the hydrogen-water separator through a hydrogen delivery pipe, and the oxygen outlet of the electrolyzer is connected to the oxygen-water separator through an oxygen delivery pipe; The oxygen-water separator is connected to an oxygen output pipe and an oxygen vent pipe, the oxygen output pipe and the oxygen vent pipe are connected through an oxygen connecting pipe, and a first pneumatic diaphragm regulating valve is arranged on the oxygen connecting pipe; The hydrogen-water separator is connected to a hydrogen output pipe and a hydrogen vent pipe, the hydrogen output pipe and the hydrogen vent pipe are connected through a hydrogen connecting pipe, and a second pneumatic diaphragm regulating valve is arranged on the hydrogen connecting pipe; The controller controls the opening degree of the first pneumatic diaphragm regulating valve and the second pneumatic diaphragm regulating valve to control the hydrogen and oxygen pressure balance; The hydrogen-oxygen pressure balance control method comprises the following steps: Get oxygen side pressure and hydrogen side pressure , and set the first preset pressure ; Adjust the oxygen side pressure so that = , and adjust the hydrogen side pressure to = ; when = = When the second preset pressure is set ; Adjust the oxygen side pressure so that = , and adjust the hydrogen side pressure to = ; when = = Repeat the above steps to set multiple preset pressures and adjust the oxygen side pressure and hydrogen side pressure , until = = output pressure, wherein the multiple preset pressures are set to increase in sequence; The first preset pressure Less than the second preset pressure , and the multiple preset pressures increase in equal steps, and the increase value is controlled within 0.1Mpa.

2. The hydrogen and oxygen pressure balance control method according to claim 1, characterized in that: The first preset pressure The pressure range is 0.1-0.12Mpa, and the second preset pressure The pressure range of the input pressure is 0.2-0.22Mpa, and the pressure range of the output pressure is 2.8-3.2Mpa.

3. The hydrogen-oxygen pressure balance control method according to claim 1, characterized in that: The oxygen side pressure The pressure on the hydrogen side is obtained through the differential pressure transmitter on the oxygen output pipe. Obtained through the differential pressure transmitter on the hydrogen output pipe.

4. The hydrogen and oxygen pressure balance control method according to claim 1, characterized in that: When the pressure on the oxygen side is adjusted by adjusting the opening of the pneumatic diaphragm regulating valve on the oxygen pipe, the pressure on the hydrogen side is adjusted by adjusting the opening of the pneumatic diaphragm regulating valve on the hydrogen pipe.

5. A hydrogen-oxygen pressure balance control system, used to implement the hydrogen-oxygen pressure balance control method according to claim 1, characterized in that: The oxygen outlet of the oxygen output pipe is also provided with a first pressure transmitter, a first back pressure valve and a first check valve in sequence.

6. The hydrogen and oxygen pressure balance control system according to claim 5, characterized in that: A second pressure transmitter, a second back pressure valve and a second one-way valve are also arranged in sequence at the hydrogen outlet of the hydrogen output pipe.

7. The hydrogen and oxygen pressure balance control system according to claim 5, characterized in that: It also includes a water tank, which is connected to the oxygen-water separator through a pipeline, and the discharge port of the oxygen-water separator is connected to the electrolytic cell through a water supply pipe.

8. The hydrogen and oxygen pressure balance control system according to claim 7, characterized in that: A water supply pump is arranged on the water supply pipe, and a Y-type filter is arranged at the water supply port of the electrolytic cell.

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