Low-energy-consumption reverse current suppression method for prolonging service life of alkali liquor electrolytic cell

Abstract

The invention discloses a low-energy-consumption reverse current suppression method for prolonging the service life of an alkali liquor electrolytic bath, which is characterized in that periodic forward current is applied to the alkali liquor electrolytic bath in the shutdown period of the alkali liquor electrolytic bath by an additional power supply device, the reaction process on an electrode is accurately regulated and controlled, metal nickel on a cathode is prevented from being oxidized by the reverse current, and the service life of the alkali liquor electrolytic bath is prolonged. Polar plate reverse current is inhibited, so that electrode corrosion is inhibited, and the service life of the alkali liquor electrolytic bath is prolonged; wherein the forward current flows from the positive electrode of the alkali liquor electrolytic bath to the negative electrode of the alkali liquor electrolytic bath; the amplitude of the forward current is greater than the complete reaction current of the alkali liquor electrolytic cell. According to the method, the service life of the alkali liquor electrolytic cell can be prolonged only through the additional power supply device without improving an electrode material or changing the structure of the alkali liquor electrolytic cell, the energy consumption level is low, and the method has good engineering application value.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy electrolysis hydrogen production in the new energy field, and in particular relates to a low-energy consumption reverse current suppression method for improving the service life of an alkaline solution electrolyzer. Background Art

[0002] As an efficient and low-carbon energy carrier, hydrogen has a wide range of application scenarios in transportation, industry, electricity and other fields, making it the most promising secondary clean energy for sustainable development. Affected by global climate change and environmental issues, the pace of energy conservation, emission reduction and energy cleaning has accelerated, and the potential of hydrogen in energy transformation has once again attracted people's attention. Green hydrogen refers to the production of hydrogen by electrolysis of water using renewable clean energy such as wind or solar energy to generate electricity. Green hydrogen basically does not produce greenhouse gases during the production process, and is the main trend in the development of hydrogen energy. At present, the main technical routes for hydrogen production by electrolysis of renewable energy are alkaline solution electrolysis, proton exchange membrane electrolysis, high-temperature solid oxide electrolysis and anion exchange membrane electrolysis. Compared with the other three technical routes, alkaline solution electrolysis has high maturity, low investment and long service life, and has become the mainstream technical solution for large-scale hydrogen production from renewable energy.

[0003] However, due to the intermittent and volatile characteristics of renewable energy, in the process of renewable energy alkali solution hydrogen production, the alkali solution electrolyzer needs to be frequently started and shut down to cope with the fluctuating renewable energy power. During the shutdown process, a reverse current will be generated inside the electrolyzer, which will corrode the electrolyzer electrodes, seriously shortening the service life of the electrolyzer and increasing the cost of renewable energy hydrogen production. The present invention proposes a low-energy reverse current suppression method for improving the service life of alkali solution electrolyzers. The method relies on an additional power supply device to regulate the electrolyzer current, thereby improving the service life of the electrolyzer, without improving the electrode material or changing the electrolyzer structure, and has a low energy consumption level and good engineering application value. Summary of the invention

[0004] The purpose of the present invention is to provide a low-energy reverse current suppression method for improving the service life of an alkaline liquid electrolyzer in view of the shortcomings of the prior art. The present invention solves the problem of shortened service life caused by frequent start-up and shutdown of the alkaline liquid electrolyzer, so that the alkaline liquid electrolyzer can achieve long-term stable and efficient operation under a wide range of power fluctuation conditions.

[0005] The objective of the present invention is achieved through the following technical solutions: a low-energy consumption reverse current suppression method for improving the service life of an alkaline liquid electrolytic cell, during the shutdown period of the alkaline liquid electrolytic cell, that is, when the alkaline liquid electrolytic cell is in a shutdown state, an additional power supply device is used to apply a periodic forward current to the alkaline liquid electrolytic cell to regulate the reaction process on the electrode and suppress the reverse current of the electrode plate; wherein the flow direction of the forward current is: from the positive electrode of the alkaline liquid electrolytic cell to the negative electrode of the alkaline liquid electrolytic cell; the amplitude of the forward current is greater than the complete reaction current of the alkaline liquid electrolytic cell The duration of the forward current is T, which is used to represent the time interval from the application of the forward current to the removal of the forward current in the alkali solution electrolytic cell. The period of the forward current is , used to indicate the time interval between each application of forward current and the previous removal of forward current; is the duration of the non-corrosive process of the reverse current of the plate, T is 1%-50%.

[0006] Furthermore, the shutdown state of the alkali liquid electrolytic cell is specifically: the current applied to the alkali liquid electrolytic cell by the main power supply device is 0, but the alkali liquid electrolytic cell is in a hot standby state.

[0007] Furthermore, the types of the additional power supply device include a battery energy storage device and a supercapacitor energy storage device.

[0008] Furthermore, the alkali solution electrolytic cell completely reacts with the current It is determined by the alkali solution channel leakage current effect and the plate current bunching effect under low current conditions. The calculation formula is: ; in, is the alkali channel leakage current, is the plate current, and its calculation formulas are: ; ; Where N is the number of electrolytic chambers connected in series, is the reversible voltage, is the alkali solution channel resistance, is the resistivity of alkali solution, is the cross-sectional area of ​​the alkali solution channel, is the length of the alkali solution channel, is the bunching effect coefficient, Rated current of alkali solution electrolyzer.

[0009] Furthermore, the duration of the non-corrosive process of the reverse current of the plate is equal to the time from the moment when the forward current on the alkaline solution electrolytic cell is removed to the moment when the reverse current of the plate begins to corrode the nickel electrode. Assuming that the moment when the forward current on the alkaline solution electrolytic cell is removed is time 0, the duration of the non-corrosive process of the reverse current of the plate is expressed as: ; in, is the duration of the non-corrosive process of the reverse current of the plate, This is the moment when the reverse current of the plate begins to corrode the nickel electrode.

[0010] Furthermore, the moment when the reverse current of the plate begins to corrode the nickel electrode is defined as: the moment when the metal nickel of the nickel electrode begins to be oxidized into nickel hydroxide during the continuous process of the reverse current of the plate, that is, the moment when the following reaction begins to occur: ; in, For metallic nickel, is the hydroxide ion, is nickel hydroxide, For electronics.

[0011] The beneficial effect of the present invention is that the present invention proposes a low-energy reverse current suppression method for improving the service life of an alkaline solution electrolytic cell. By relying on an additional power supply device, a periodic forward current is applied to the electrolytic cell during the shutdown phase of the electrolytic cell, the reaction process on the electrode is regulated, and the nickel on the cathode is prevented from being oxidized into nickel hydroxide by the reverse current, thereby inhibiting electrode corrosion, improving the service life of the alkaline solution electrolytic cell, and realizing long-term stable and efficient operation of the alkaline solution electrolytic cell. The present invention does not require improvement of the electrode material or change of the electrolytic cell structure, and the service life of the alkaline solution electrolytic cell can be improved only by an additional power supply device, and the energy consumption level is low, which has good engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the current waveform applied to the alkali solution electrolytic cell by the additional power supply device of the present invention; Figure 2 It is a schematic diagram of the change process of the reverse current of the plate in the natural state when the alkaline solution electrolytic cell of the present invention is shut down; Figure 3 : is the electrode potential-pH diagram of the nickel electrode of the present invention. DETAILED DESCRIPTION

[0013] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of devices and methods consistent with some aspects of the present invention as detailed in the appended claims.

[0014] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The singular forms "a", "the" and "the" used in the present invention and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0015] It should be understood that although the terms first, second, third, etc. may be used in the present invention to describe various information, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present invention, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0016] The present invention is described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the features of the following embodiments and implementations can be combined with each other.

[0017] The low-energy consumption reverse current suppression method for improving the service life of the alkali liquid electrolytic cell of the present invention specifically comprises: during the shutdown period of the alkali liquid electrolytic cell, that is, when the alkali liquid electrolytic cell is in a shutdown state, using an additional power supply device to apply the following Figure 1 The periodic forward current shown in the figure regulates the reaction process on the electrode and suppresses the reverse current of the electrode plate. The flow direction of the forward current is: from the positive electrode of the alkali solution electrolytic cell to the negative electrode of the alkali solution electrolytic cell; the amplitude of the forward current is greater than the complete reaction current of the alkali solution electrolytic cell. The duration of the forward current is T, which is used to represent the time interval from the application of the forward current to the removal of the forward current in the alkali solution electrolytic cell. The period of the forward current is , used to indicate the time interval between each application of forward current and the previous removal of forward current; is the duration of the non-corrosive process of the reverse current of the plate, T is 1%-50%, and its specific value can be determined according to the structural size and electrical parameters of the alkali solution electrolytic cell.

[0018] It should be understood that the present invention relies on an additional power supply device to apply a periodic forward current to the alkaline solution electrolytic cell during the electrolytic cell shutdown period, accurately regulate the reaction process on the electrode, prevent the metal nickel on the cathode from being oxidized by the reverse current, inhibit the reverse current of the plate, thereby inhibiting electrode corrosion and improving the service life of the alkaline solution electrolytic cell. The present invention does not require improving the electrode material or changing the electrolytic cell structure, and can achieve the improvement of the service life of the alkaline solution electrolytic cell only by an additional power supply device, and has a low energy consumption level and good engineering application value.

[0019] Furthermore, the shutdown state of the alkali liquid electrolytic cell is specifically: the current applied to the alkali liquid electrolytic cell by the main power supply device is 0, but the alkali liquid electrolytic cell is in a hot standby state.

[0020] Furthermore, the types of additional power supply devices include but are not limited to battery energy storage devices, supercapacitor energy storage devices, etc.

[0021] Furthermore, the alkali solution electrolyzer complete reaction current It is determined by fully considering the leakage current effect of the alkali solution channel and the current bunching effect of the plate under low current conditions. The calculation formula is:

[0022] in, is the alkali channel leakage current, is the plate current, and its calculation formulas are:

[0023]

[0024] Where N is the number of electrolytic chambers connected in series, is the reversible voltage, is the alkali solution channel resistance, is the resistivity of alkali solution, is the cross-sectional area of ​​the alkali solution channel, is the length of the alkali solution channel, is the bunching effect coefficient, is the rated current of the alkali solution electrolytic cell. N, , , All of these can be obtained by measuring and calculating the structural dimensions of the alkali solution electrolytic cell and the alkali solution concentration; the bunching effect coefficient It is usually taken as 0.2-0.4, and the specific value can be determined according to the structural dimensions and electrical parameters of the alkali solution electrolytic cell.

[0025] Furthermore, the duration of the non-corrosive process of the plate reverse current is equal to the time from the moment when the forward current on the alkaline solution electrolytic cell is removed to the moment when the plate reverse current begins to corrode the nickel electrode. Assuming that the moment when the forward current on the alkaline solution electrolytic cell is removed is time 0, Figure 2 As shown, the duration of the non-corrosive process of the reverse current of the plate is expressed as:

[0026] in, is the duration of the non-corrosive process of the reverse current of the plate, It is the moment when the reverse current of the plate begins to corrode the nickel electrode. The forward current on the alkali electrolytic cell refers to the forward current applied to the alkali electrolytic cell by the additional power supply device.

[0027] Furthermore, the moment when the reverse current of the plate begins to corrode the nickel electrode is defined as the moment when the metal nickel of the nickel electrode begins to be oxidized into nickel hydroxide during the continuous reverse current of the plate, that is, the moment when the following reaction begins to occur:

[0028] in, For metallic nickel, is the hydroxide ion, is nickel hydroxide, For electronics.

[0029] Furthermore, the moment when the reverse current of the plate begins to corrode the nickel electrode The specific determination method is: if the pH value of the electrolyte in the alkaline solution electrolytic cell is equal to c, according to the potential-pH diagram of the nickel electrode, that is, according to Figure 3 The electrode potential-pH diagram shown above can be used to obtain the corresponding electrode potential when the above-mentioned metal nickel is oxidized to nickel hydroxide. ; By measuring the plate potential-time curve after the forward current on the alkali solution electrolyzer is removed, it is determined that the plate potential is equal to The moment when the reverse current of the plate begins to corrode the nickel electrode .

[0030] In summary, the present invention relies on an additional power supply device to apply a periodic forward current to the electrolytic cell during the shutdown phase of the electrolytic cell, thereby regulating the reaction process on the electrode, preventing the nickel on the cathode from being oxidized into nickel hydroxide by the reverse current, thereby inhibiting electrode corrosion, improving the service life of the alkaline solution electrolytic cell, and achieving long-term stable and efficient operation of the alkaline solution electrolytic cell; the present invention does not need to improve the electrode material or change the electrolytic cell structure, and the service life of the alkaline solution electrolytic cell can be improved only by an additional power supply device, and the energy consumption level is low, which has good engineering application value.

[0031] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low-energy reverse current suppression method for improving the service life of an alkaline solution electrolytic cell, characterized in that: During the shutdown period of the alkali liquid electrolytic cell, that is, when the alkali liquid electrolytic cell is in a shutdown state, an additional power supply device is used to apply a periodic forward current to the alkali liquid electrolytic cell to regulate the reaction process on the electrode and suppress the reverse current of the electrode plate; wherein the flow direction of the forward current is: from the positive electrode of the alkali liquid electrolytic cell to the negative electrode of the alkali liquid electrolytic cell; the amplitude of the forward current is greater than the complete reaction current of the alkali liquid electrolytic cell The duration of the forward current is T, which is used to represent the time interval from the application of the forward current to the removal of the forward current in the alkali solution electrolytic cell. The period of the forward current is , used to indicate the time interval between each application of forward current and the previous removal of forward current; is the duration of the non-corrosive process of the reverse current of the plate, T is 1%-50%.

2. The low-energy consumption reverse current suppression method for improving the service life of an alkaline solution electrolytic cell according to claim 1, characterized in that: The shutdown state of the alkali liquid electrolytic cell is specifically: the current applied to the alkali liquid electrolytic cell by the main power supply device is 0, but the alkali liquid electrolytic cell is in a hot standby state.

3. The low-energy consumption reverse current suppression method for improving the service life of an alkaline solution electrolytic cell according to claim 1, characterized in that: The types of the additional power supply device include battery energy storage device and supercapacitor energy storage device.

4. The low-energy consumption reverse current suppression method for improving the service life of an alkaline solution electrolytic cell according to claim 1, characterized in that: The complete reaction current of the alkaline solution electrolytic cell It is determined by the alkali solution channel leakage current effect and the plate current bunching effect under low current conditions. The calculation formula is: ； in, is the alkali channel leakage current, is the plate current, and its calculation formulas are: ； ； Where N is the number of electrolytic chambers connected in series, is the reversible voltage, is the alkali solution channel resistance, is the resistivity of alkali solution, is the cross-sectional area of ​​the alkali solution channel, is the length of the alkali solution channel, is the bunching effect coefficient, Rated current of alkali solution electrolyzer.

5. The low-energy consumption reverse current suppression method for improving the service life of an alkaline solution electrolytic cell according to claim 1, characterized in that: The duration of the non-corrosive process of the reverse current of the plate is equal to the time from the moment when the forward current on the alkaline solution electrolytic cell is removed to the moment when the reverse current of the plate begins to corrode the nickel electrode. Assuming that the moment when the forward current on the alkaline solution electrolytic cell is removed is time 0, the duration of the non-corrosive process of the reverse current of the plate is expressed as: ； in, is the duration of the non-corrosive process of the reverse current of the plate, This is the moment when the reverse current of the plate begins to corrode the nickel electrode.

6. The low-energy consumption reverse current suppression method for improving the service life of an alkaline solution electrolytic cell according to claim 5, characterized in that: The moment when the reverse current of the plate begins to corrode the nickel electrode is defined as the moment when the metal nickel of the nickel electrode begins to be oxidized into nickel hydroxide during the continuous process of the reverse current of the plate, that is, the moment when the following reaction begins to occur: ； in, For metallic nickel, is the hydroxide ion, is nickel hydroxide, For electronics.

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