A system for controlling hydrogen in oxygen by separator liquid level in hydrogen production by electrolysis

Abstract

The utility model relates to a system for controlling hydrogen in oxygen by separator liquid level during electrolytic hydrogen production, wherein an oxygen separator is connected to the oxygen side outlet of an electrolyzer, a hydrogen separator is connected to the hydrogen side outlet of the electrolyzer, an oxygen outlet is provided at the bottom of the oxygen separator, and a hydrogen outlet is provided at the bottom of the hydrogen separator; one end of a hydrogen release pipeline is connected to the hydrogen separator, and the other end is connected to the external environment; the infusion end of an alkaline liquid circulation pump is connected to the oxygen outlet and the hydrogen outlet at the same time, and the liquid outlet is connected to the electrolyzer; an oxygen separator liquid level gauge and a hydrogen separator liquid level gauge are respectively provided on the oxygen separator and the hydrogen separator, and a hydrogen pipeline release regulating valve is installed on the hydrogen release pipeline; a PLC control module is electrically connected to the oxygen separator liquid level gauge, the hydrogen separator liquid level gauge, and the hydrogen pipeline release regulating valve at the same time. The utility model realizes the stability of the hydrogen content on the oxygen side of the hydrogen production device during startup and load increase or low-load operation, and ensures the continuous operation of the electrolytic hydrogen production process.

Description

Technical Field

[0001] The utility model relates to a system for controlling hydrogen in oxygen by liquid level of a separator in a process of electrolytic hydrogen production, belonging to the field of new energy technology, and in particular to the field of electrolytic hydrogen production in which the pressure of a gas-liquid separation system is controlled by a liquid level meter and a vent regulating valve through a PLC control module. Background Art

[0002] Hydrogen production by alkaline water electrolysis is a process in which the electrolyte dissolved in water is decomposed into new substances by means of direct current, and the alkali remains in the water. When a certain amount of direct current is passed through, water releases hydrogen at the cathode and oxygen at the anode. The reaction is as follows:

[0003] On the cathode: 2e+2H2O→H2↑+2OH-

[0004] On the anode: 2OH--2e→H2O+1 / 2O2↑

[0005] Overall reaction formula: 2H2O→2H2↑+O2↑

[0006] From the above reaction equation, it can be seen that the molar number of hydrogen produced during the electrolysis of water to produce hydrogen is twice that of oxygen. The pressure rise rate of the system on the cathode hydrogen side of the electrolyzer is faster than that on the anode oxygen side, which makes it easier for hydrogen molecules to diffuse through the membrane to the oxygen side. At the same time, the length of hydrogen molecules is only about 67% of the length of oxygen molecules, which theoretically makes it easier for them to diffuse through the pores of the membrane to the oxygen side. Therefore, it is more likely that the hydrogen content in oxygen will exceed the standard during system startup and load increase or low-load operation.

[0007] Based on this, it is necessary to develop a system that can ensure the stability of the hydrogen content on the oxygen side of the hydrogen production device during startup and load increase or low-load operation, so as to ensure the safe and stable operation of the hydrogen production process by electrolysis. Summary of the invention

[0008] The utility model provides a system for controlling hydrogen in oxygen by liquid level of a separator in a hydrogen production process by electrolysis, which can ensure the stability of hydrogen content on the oxygen side of a hydrogen production device during startup and load increase or low-load operation, thereby ensuring the continuous operation of the hydrogen production process by electrolysis.

[0009] The technical solution adopted by the utility model to solve its technical problems is:

[0010] A system for controlling hydrogen in oxygen by separator liquid level during electrolytic hydrogen production, comprising an electrolyzer, an alkali solution circulation pump, an oxygen separator and a hydrogen separator, wherein the oxygen separator is connected to the oxygen side outlet of the electrolyzer, the hydrogen separator is connected to the hydrogen side outlet of the electrolyzer, an oxygen outlet is provided at the bottom of the oxygen separator, and a hydrogen outlet is provided at the bottom of the hydrogen separator; one end of a hydrogen emission pipeline is connected to the hydrogen separator, and the other end is connected to an external environment; the infusion end of the alkali solution circulation pump is connected to the oxygen outlet and the hydrogen outlet at the same time through a pipeline, and the liquid outlet end of the alkali solution circulation pump is connected to the electrolyzer;

[0011] It also includes an oxygen separator level gauge, a hydrogen separator level gauge, a hydrogen pipeline release regulating valve and a PLC control module. The oxygen separator level gauge is arranged on the oxygen separator tank body, and the hydrogen separator level gauge is arranged on the hydrogen separator tank body;

[0012] Install a hydrogen pipeline release regulating valve on the hydrogen release pipeline;

[0013] The PLC control module is electrically connected to the oxygen separator level gauge, the hydrogen separator level gauge, and the hydrogen pipeline release regulating valve at the same time;

[0014] As a further preferred embodiment of the present invention, the oxygen separator and the hydrogen separator are horizontal separators or vertical separators;

[0015] As a further preferred embodiment of the present invention, the tanks of the oxygen separator and the hydrogen separator have the same size;

[0016] As a further preferred embodiment of the present invention, in the vertical direction to the ground, there is a height difference between the oxygen separator liquid level gauge and the hydrogen separator liquid level gauge;

[0017] As a further preferred embodiment of the present invention, in the direction vertical to the ground, the installation height of the oxygen separator liquid level gauge is lower than the installation height of the hydrogen separator liquid level gauge.

[0018] Through the above technical solution, compared with the prior art, the utility model has the following beneficial effects:

[0019] The utility model provides a system for controlling hydrogen in oxygen by using separator liquid level in the process of electrolytic hydrogen production. An oxygen separator liquid level gauge is arranged on the oxygen separator tank body, and a hydrogen separator liquid level gauge is arranged on the hydrogen separator tank body. A PLC control module controls automatic adjustment of a hydrogen pipeline venting regulating valve through real-time liquid level information of the oxygen separator liquid level gauge and the hydrogen separator liquid level gauge, thereby ensuring the stability of hydrogen content on the oxygen side of the hydrogen production device during startup and load increase or low-load operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0021] Figure 1 It is a schematic diagram of the connection state of the utility model.

[0022] In the figure: 1-oxygen separator level gauge, 2-hydrogen separator level gauge, 3-hydrogen pipeline release regulating valve, 4-oxygen separator, 5-hydrogen separator, 6-alkali solution circulation pump, 7-electrolyzer. DETAILED DESCRIPTION

[0023] The utility model is now further described in detail in conjunction with the accompanying drawings. In the description of this application, it should be understood that the terms "left side", "right side", "upper part", "lower part" and the like indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the utility model. The specific dimensions used in this embodiment are only for illustrating the technical solution by example, and do not limit the scope of protection of the utility model.

[0024] As described in the background technology, the number of moles of hydrogen produced during the alkaline water electrolysis hydrogen production process is much greater than that of oxygen, which results in a faster pressure rise on the hydrogen side when the hydrogen production system is started up or running at low load, and the pressure difference makes it easier for hydrogen to diffuse to the oxygen side. At the same time, in these more special operating stages, the stability of the hydrogen production system is relatively poor, and dynamic processes such as pressure balance and material exchange on both sides of the membrane are more prone to fluctuations and abnormalities. Combined with the fact that the length of hydrogen molecules is only about 67% of the length of oxygen molecules, the probability and degree of hydrogen diffusion through the membrane to the oxygen side are greatly increased, which makes it easier for the problem of excessive hydrogen in oxygen to occur.

[0025] In order to solve the above problems, the utility model provides a system for controlling the hydrogen in oxygen by the liquid level of the separator in the process of electrolytic hydrogen production, such as Figure 1 As shown, it includes an electrolytic cell 7, an alkali liquid circulation pump 6, an oxygen separator 4 and a hydrogen separator 5, wherein the oxygen separator 4 is connected to the oxygen side outlet of the electrolytic cell 7, the hydrogen separator 5 is connected to the hydrogen side outlet of the electrolytic cell 7, an oxygen outlet is provided at the bottom of the oxygen separator 4, and a hydrogen outlet is provided at the bottom of the hydrogen separator 5; one end of the hydrogen emission pipeline is connected to the hydrogen separator 5, and the other end is connected to the external environment; the infusion end of the alkali liquid circulation pump 6 is connected to the oxygen outlet and the hydrogen outlet at the same time through a pipeline, and the liquid outlet end of the alkali liquid circulation pump 6 is connected to the electrolytic cell 7.

[0026] As the innovation of this application, Figure 1The system shown also includes an oxygen separator level gauge 1, a hydrogen separator level gauge 2, a hydrogen pipeline release regulating valve 3 and a PLC control module. The oxygen separator level gauge 1 is arranged on the tank body of the oxygen separator 4, and the hydrogen separator level gauge 2 is arranged on the tank body of the hydrogen separator 5; the hydrogen pipeline release regulating valve 3 is installed on the hydrogen release pipeline; the PLC control module is electrically connected to the oxygen separator level gauge 1, the hydrogen separator level gauge 2, and the hydrogen pipeline release regulating valve 3 at the same time.

[0027] The principle is that an oxygen separator level gauge 1 and a hydrogen separator level gauge 2 are installed on the tank body of the oxygen separator 4 and the tank body of the hydrogen separator 5 respectively. Both of these level gauges have a remote transmission function and can realize automatic adjustment of the hydrogen pipeline release regulating valve 3 through the PLC control module to ensure that the possibility of hydrogen cross-talk to the oxygen side is reduced during the startup and load increase process of the electrolyzer 7 or the low-load operation process, so that the hydrogen in the oxygen is always at a low level.

[0028] If the above system is to achieve the optimal effect of controlling hydrogen in oxygen, the oxygen separator 4 and the hydrogen separator 5 are horizontal separators or vertical separators, and the tanks of the oxygen separator 4 and the hydrogen separator 5 are of the same size.

[0029] Since the density of oxygen and hydrogen is different, and the density of hydrogen is much smaller than that of oxygen, then under the same pressure conditions, hydrogen usually gathers in the upper space of the system, while oxygen is relatively located at the lower position. Therefore, in order to more accurately measure the liquid level condition on the oxygen side, Figure 1 The oxygen separator level gauge 1 is installed relatively low in the perspective, while the hydrogen separator level gauge 2 is installed relatively high, in order to better correspond to the area where hydrogen gathers, so as to achieve accurate monitoring and control of the respective gas-liquid separation conditions. That is, in the system of separator level control of hydrogen in oxygen during electrolytic hydrogen production provided in the present application, in the vertical direction of the ground, there is a height difference between the oxygen separator level gauge 1 and the hydrogen separator level gauge 2; specifically, the installation height of the oxygen separator level gauge 1 is lower than the installation height of the hydrogen separator level gauge 2.

[0030] In actual working conditions, the height difference between the oxygen separator level gauge 1 and the hydrogen separator level gauge 2 needs to be reasonably set according to the characteristics of oxygen and hydrogen, as well as the system operation requirements.

[0031] Finally, the present application also provides an implementation example of the use state of the above system, which specifically includes the following steps:

[0032] Step S1: When the hydrogen production system is started normally, the system pressure continues to rise;

[0033] Step S2: The hydrogen production system starts to produce hydrogen, and the PLC control module monitors the hydrogen separator level gauge 2 and the oxygen separator level gauge 1 to find that the liquid level in the hydrogen separator tank is slowly decreasing, and the liquid level in the oxygen separator tank is slowly increasing;

[0034] Step S3: The hydrogen production system continues to produce hydrogen, and the PLC control module sends a start-stop command to the hydrogen pipeline release regulating valve 3, so that the hydrogen pipeline release regulating valve 3 is intermittently vented to maintain the oxygen side pressure slightly higher than the hydrogen side pressure, thereby reducing the frequency of hydrogen entering the oxygen side.

[0035] In summary, the system for controlling hydrogen in oxygen by separator liquid level during hydrogen production by electrolysis provided in the present application can ensure stable hydrogen content in oxygen during startup and load increase or low-load operation of the hydrogen production system, thereby ensuring safe operation of the hydrogen production system.

[0036] 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.

[0037] The meaning of "and / or" described in this application means that the situations where each exists alone or both exist at the same time are included.

[0038] The term “connection” as used in this application may mean a direct connection between components or an indirect connection between components via other components.

[0039] Based on the above ideal embodiments of the utility model, the relevant staff can make various changes and modifications without deviating 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 system for controlling hydrogen in oxygen by separator liquid level during hydrogen production by electrolysis, comprising an electrolyzer, an alkali solution circulation pump, an oxygen separator and a hydrogen separator, wherein the oxygen separator is connected to the oxygen side outlet of the electrolyzer, the hydrogen separator is connected to the hydrogen side outlet of the electrolyzer, an oxygen outlet is provided at the bottom of the oxygen separator, and a hydrogen outlet is provided at the bottom of the hydrogen separator; one end of a hydrogen emission pipeline is connected to the hydrogen separator, and the other end is connected to an external environment; the infusion end of the alkali solution circulation pump is connected to the oxygen outlet and the hydrogen outlet at the same time through a pipeline, and the liquid outlet end of the alkali solution circulation pump is connected to the electrolyzer; characterized in that: It also includes an oxygen separator level gauge, a hydrogen separator level gauge, a hydrogen pipeline release regulating valve and a PLC control module. The oxygen separator level gauge is arranged on the oxygen separator tank body, and the hydrogen separator level gauge is arranged on the hydrogen separator tank body; Install a hydrogen pipeline release regulating valve on the hydrogen release pipeline; The PLC control module is electrically connected to the oxygen separator level gauge, the hydrogen separator level gauge, and the hydrogen pipeline release regulating valve at the same time.

2. The system for controlling hydrogen in oxygen by separator liquid level in the process of electrolytic hydrogen production according to claim 1, characterized in that: The oxygen separator and the hydrogen separator are horizontal separators or vertical separators.

3. The system for controlling hydrogen in oxygen by separator liquid level in the process of electrolytic hydrogen production according to claim 1, characterized in that: The tanks of the oxygen separator and the hydrogen separator have the same size.

4. The system for controlling hydrogen in oxygen by separator liquid level in the process of electrolytic hydrogen production according to claim 1, characterized in that: In the vertical direction above the ground, there is a height difference between the oxygen separator level gauge and the hydrogen separator level gauge.

5. The system for controlling hydrogen in oxygen by separator liquid level in the process of electrolytic hydrogen production according to claim 1, characterized in that: In the vertical direction above the ground, there is a height difference between the oxygen separator level gauge and the hydrogen separator level gauge.

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