A reinforced bubble separation device in an alkaline water electrolysis process and a method of use

Abstract

The application relates to the technical field of hydrogen production by alkaline electrolysis of water, and discloses a gas bubble separation device for strengthening an alkaline water electrolysis process and a use method, wherein an electrode structure comprises an electrode base body, a micro-column array and a gradient wetting surface; the gas bubbles generated in the electrode process are affected by the gradient change of the hydrophilicity and hydrophobicity of the electrode surface, the gas bubble contact area and the gas bubble adhesion force are significantly reduced, and effective gas bubble release is realized. A cyclone separator is used for primary separation in a two-stage gas-liquid separator, electrolyte and medium and large bubbles in the electrolyte are preliminarily separated; then a micro-fiber module is used to increase liquid turbulence and the collision probability of the bubbles, to induce micro-bubble coalescence, and to collect the bubbles on the fiber surface, so that secondary separation of the micro-bubbles is realized. The problems of incomplete separation of the traditional gas-liquid separation device are overcome, the gas content rate in the electrolyte is reduced, the efficiency of hydrogen production by alkaline water electrolysis is improved, and the efficient and safe operation of the whole hydrogen production system is ensured.

Description

Technical Field

[0001] This invention relates to the field of alkaline water electrolysis for hydrogen production technology, specifically to a device and method for enhancing bubble separation during alkaline water electrolysis. Background Technology

[0002] Since the beginning of the new century, the consumption of fossil fuels has increased rapidly, and along with the aggravation of environmental pollution, hydrogen energy, with its advantages of being environmentally friendly, carbon-free, flexible, and efficient, has received increasing attention. Currently, alkaline water electrolysis is the most mature method for hydrogen production. Its equipment structure mainly consists of two electrode plates and an asbestos membrane separating the plates. Electrode chambers formed by the electrode plates can be connected in series to increase production capacity. During electrolysis, hydrogen is generated on the cathode surface, and oxygen is generated on the anode surface. Due to the obstruction of the asbestos membrane, the gases generated at the cathode and anode do not mix.

[0003] Efficiently and rapidly separating gas from the electrode surface and electrolyte is one of the key challenges in improving the electrolysis efficiency of electrolysis systems. In traditional electrode structures, hydrogen produced during hydrogen electrolysis adheres to the electrode plates due to the adhesion between the bubbles and the plates. This bubble retention reduces the active area of ​​the electrode, resulting in decreased electrolysis efficiency. Traditional separation equipment using gravity settling is ineffective at separating fine bubbles from the electrolyte, easily leading to gas backmixing. Therefore, developing a method to accelerate bubble growth and separation on the electrodes is of great significance for improving the electrolysis efficiency of alkaline water electrolysis systems.

[0004] The currently published patents CN 116334679 A and CN 116575043 A respectively propose a self-supporting alkaline water electrolysis hydrogen production electrode with a gradient pore structure and a high-stability proton exchange membrane water electrolysis hydrogen production system with anode purging function. However, they have drawbacks such as low utilization rate or complex system equipment structure and incomplete separation of gas and liquid phases.

[0005] Therefore, providing an electrode structure and gas-liquid separation device that is simple in structure and can effectively promote the detachment of bubbles from the electrode surface and the electrolyte during alkaline water electrolysis is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In order to overcome the defects of the existing technology, the purpose of this invention is to provide a bubble separation device and method for enhancing alkaline water electrolysis, so as to solve the technical problems of incomplete separation by traditional gas-liquid separation devices and low efficiency of hydrogen production by alkaline water electrolysis.

[0007] This invention is achieved through the following technical solution:

[0008] A device for enhancing bubble separation during alkaline water electrolysis includes an alkaline electrolytic cell, an anode electrode, a cathode electrode, a two-stage oxygen gas-liquid separator, a two-stage hydrogen gas-liquid separator, a first gas collection device, a second gas collection device, a first filter device, and a second filter device. The alkaline electrolytic cell is filled with electrolyte. The anode and cathode electrodes are located at opposite ends of the cell. The electrolyte output terminal of the anode electrode is connected to the input terminal of the two-stage oxygen gas-liquid separator. The gas phase output terminal of the two-stage oxygen gas-liquid separator is connected to the first gas collection device. The liquid phase output terminal of the two-stage oxygen gas-liquid separator is connected to the electrolyte input terminal of the anode electrode via the first filter device. The electrolyte output terminal of the cathode electrode is connected to the input terminal of the two-stage hydrogen gas-liquid separator. The gas phase output terminal of the two-stage hydrogen gas-liquid separator is connected to the second gas collection device. The liquid phase output terminal of the two-stage hydrogen gas-liquid separator is connected to the electrolyte input terminal of the cathode electrode via the second filter device.

[0009] Preferably, a first control valve and a first centrifugal pump are provided between the electrolyte output terminal of the anode electrode in the alkaline electrolytic cell and the input terminal of the oxygen two-stage gas-liquid separator; a second control valve and a second centrifugal pump are provided between the electrolyte output terminal of the cathode electrode in the alkaline electrolytic cell and the input terminal of the hydrogen two-stage gas-liquid separator.

[0010] Preferably, a first gas purification device is provided between the oxygen two-stage gas-liquid separator and the first gas collection device; a second gas purification device is provided between the hydrogen two-stage gas-liquid separator and the second gas collection device.

[0011] Preferably, the anode electrode and the cathode electrode have the same structure, wherein the cathode electrode includes an electrode substrate and a plurality of micropillars arranged in an array on the electrode substrate; the electrode substrate has a trapezoidal structure, wherein one end is the bottom end of the electrode and the other end is the top end of the electrode, and the width of the bottom end of the electrode is smaller than the width of the top end of the electrode; micropillar regions and non-micropillar regions are distributed alternately on the electrode substrate, wherein a plurality of micropillars are arranged in parallel in the micropillar regions, and both the micropillar regions and the non-micropillar regions are gradient wetting surfaces.

[0012] Furthermore, along the direction from the bottom to the top of the electrode on the electrode substrate, the radius of each row of micropillars decreases, while the number of micropillars increases; the center-to-center distance between adjacent micropillars decreases sequentially, and the center-to-center distance between adjacent micropillars in the same row also decreases sequentially.

[0013] Furthermore, the gradient wetting surface of the micropillar region and the non-micropillar region includes several strip-shaped coating areas with a width of 1 mm, wherein the strip-shaped coating areas are coated with wetting surfactants of different mass concentrations; the wetting surfactants are amphiphilic polyurethane solutions.

[0014] Preferably, the oxygen two-stage gas-liquid separator and the hydrogen two-stage gas-liquid separator have the same structure. The hydrogen two-stage gas-liquid separator includes a cyclone separator, a tapered overflow pipe, a wire mesh structure, a flow stabilizer, and a microfiber module. The cyclone separator is located in the middle of the hydrogen two-stage gas-liquid separator. The tapered overflow pipe is located at the gas phase outlet at the top of the cyclone separator, with its central axis offset from the central axis of the hydrogen two-stage gas-liquid separator. The flow stabilizer is located at the bottom of the cyclone separator and is located in the same water column as the liquid phase outlet of the cyclone separator. In the planar aspect, the liquid phase outlet direction is tangential. The wire mesh structure is located in the upper part of the two-stage hydrogen gas-liquid separator and above the gas phase output end of the cyclone separator. The microfiber module is located in the lower part of the two-stage hydrogen gas-liquid separator and below the liquid phase output end of the cyclone separator. The cyclone separator is connected to the electrolyte output end of the cathode electrode in the alkaline electrolyzer through the mixed phase inlet of the cyclone separator and the two-stage hydrogen gas-liquid separator. The mixed phase inlet of the cyclone separator is a downwardly sloping rectangular inlet.

[0015] Furthermore, the microfiber module is made of microfibers woven at a certain angle, with the weaving angle ranging from 0 to 90°. The diameter of the microfibers is 80 to 180 μm, and the porosity is 0.75 to 0.8.

[0016] A method for using a bubble separation device in an enhanced alkaline water electrolysis process, based on the aforementioned bubble separation device in an enhanced alkaline water electrolysis process, includes the following steps:

[0017] The anode and cathode electrodes are placed in an alkaline electrolytic cell. The electrolyte containing a large number of tiny bubbles after electrolysis in the alkaline electrolytic cell is transported to the inlet of the oxygen two-stage gas-liquid separator and the hydrogen two-stage gas-liquid separator, respectively. In the oxygen two-stage gas-liquid separator and the hydrogen two-stage gas-liquid separator, a two-stage separation process is carried out. The gas phase in the oxygen two-stage gas-liquid separator enters the first gas collection device for gas storage. The liquid phase in the oxygen two-stage gas-liquid separator is replenished with pure water through the first filtration device and then re-enters the alkaline electrolytic cell. The gas phase in the hydrogen two-stage gas-liquid separator enters the second gas collection device for gas storage. The liquid phase in the hydrogen two-stage gas-liquid separator is replenished with pure water through the second filtration device and then re-enters the alkaline electrolytic cell.

[0018] Preferably, the two-stage separation process is the same in both the oxygen two-stage gas-liquid separator and the hydrogen two-stage gas-liquid separator, wherein the two-stage separation process in the hydrogen two-stage gas-liquid separator is as follows:

[0019] The electrolyte containing numerous tiny bubbles, after electrolysis in the alkaline electrolytic cell, is transported to the inlet of a two-stage hydrogen gas-liquid separator. It flows into the cyclone separator along the mixed phase inlet for primary separation. Due to the centrifugal force of the cyclone, medium and large bubbles in the electrolyte are initially separated. The separated gas phase then exits from the gas phase outlet of the cyclone separator, passing through a wire mesh structure during its ascent to filter out small droplets. The gas phase then flows out along the gas phase outlet of the two-stage hydrogen gas-liquid separator, undergoes a drying process in the second gas purification unit, and finally enters the second gas collection unit for gas storage. The separated liquid phase in the hydrocyclone flows out of the hydrocyclone outlet and into the inner cavity of the two-stage hydrogen gas-liquid separator. During the downward flow, the electrolyte flows through the microfiber module. The microfiber causes the microbubbles in the electrolyte to coalesce and be collected on the fiber surface. This causes the microbubbles to continuously coalesce into larger bubbles. Finally, under the action of buoyancy, the larger bubbles rise and leave the electrolyte, thus realizing the two-stage separation process of microbubbles. The separated electrolyte flows out from the bottom of the two-stage hydrogen gas-liquid separator, passes through the second filtration device for filtration, and then is replenished with an appropriate amount of pure water before being recycled back into the alkaline electrolytic cell.

[0020] Compared with the prior art, the present invention has the following beneficial technical effects:

[0021] This invention provides a device for enhancing bubble separation during alkaline water electrolysis. The device comprises placing the anode and cathode electrodes at opposite ends of an alkaline electrolytic cell. The electrolyte output of the anode electrode in the alkaline electrolytic cell is connected to the input of a two-stage oxygen gas-liquid separator. The gas phase output of the two-stage oxygen gas-liquid separator is connected to a first gas collection device. The liquid phase output of the two-stage oxygen gas-liquid separator is connected to the electrolyte input of the anode electrode in the alkaline electrolytic cell via a first filtration device. The electrolyte output of the cathode electrode in the alkaline electrolytic cell is connected to the input of a two-stage hydrogen gas-liquid separator. The gas phase output of the separator is connected to the second gas collection device, and the liquid phase output of the two-stage hydrogen gas-liquid separator is connected to the electrolyte input of the cathode electrode in the alkaline electrolyzer via the second filter device. The two-stage separation using the two-stage gas-liquid separator effectively promotes the detachment of bubbles from the electrolyte. This not only solves the problem of bubbles being difficult to detach from the electrode surface during electrolysis, but also effectively promotes the detachment of bubbles from the electrolyte. This overcomes the problem of incomplete separation in traditional gas-liquid separation devices, reduces the gas content in the electrolyte, improves the efficiency of alkaline water electrolysis for hydrogen production, and ensures the efficient and safe operation of the entire hydrogen production system.

[0022] Furthermore, the anode electrode and the cathode electrode have the same structure, wherein the cathode electrode includes an electrode substrate and several micropillars arranged in an array on the electrode substrate; the electrode substrate has a trapezoidal structure, and by utilizing the gradient electrode structure, the bubbles generated during alkaline water electrolysis are affected by the change in the hydrophilicity-hydrophobicity gradient of the electrode surface, and the bubble contact area and bubble adhesion are significantly reduced, thereby enabling the bubbles to detach quickly from the electrode surface.

[0023] Furthermore, the hydrogen two-stage gas-liquid separator has the same structure as the standard two-stage gas-liquid separator. The standard two-stage gas-liquid separator includes a cyclone separator, a converging overflow pipe, a wire mesh structure, a flow stabilizer, and a microfiber module. The cyclone separator, wire mesh structure, and microfiber module in the two-stage gas-liquid separator effectively promote the detachment of bubbles from the electrolyte. The electrolyte first enters the cyclone separator to achieve initial separation of medium and large bubbles; secondly, as the gas phase flows upwards, it passes through the wire mesh structure, thus filtering out small droplets; finally, when the electrolyte flows through the microfiber module, the microfibers cause the microbubbles in the electrolyte to coalesce, ultimately leading to the coalescence of microbubbles into large bubbles. Under the action of buoyancy, these large bubbles detach from the electrolyte, achieving a secondary separation process of microbubbles and increasing the electrolysis efficiency of the alkaline electrolyzer.

[0024] This invention also provides a method for using a bubble separation device to enhance alkaline water electrolysis. The electrode structure includes an electrode substrate, a micropillar array, and a gradient wetting surface. During the electrode process, the bubbles generated are significantly reduced in contact area and adhesion due to the change in the hydrophilicity / hydrophobicity gradient of the electrode surface, thus achieving effective bubble release. Specifically, a cyclone separator is used within a two-stage gas-liquid separator for primary separation, initially separating the electrolyte from medium and large bubbles. Then, a microfiber module is used to increase liquid turbulence, increasing the probability of bubble collisions, inducing microbubble aggregation, and collecting the bubbles on the fiber surface, thereby achieving secondary separation of microbubbles. The gradient electrode structure and gas-liquid separation device of this invention not only effectively reduce the time required for bubbles to detach from the electrode surface but also promote bubble detachment from the electrolyte, thereby reducing the gas content in the electrolyte and ultimately improving the efficiency of hydrogen production through alkaline water electrolysis. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the bubble separation device used in the enhanced alkaline water electrolysis process of the present invention.

[0026] Figure 2 This is a schematic diagram of the cathode electrode structure in this invention;

[0027] Figure 3 This is a front view of the cathode electrode structure in this invention;

[0028] Figure 4This is a schematic diagram of the surfactant coating area on the cathode electrode in this invention;

[0029] Figure 5 This is a schematic diagram of the internal structure of the cathode two-stage gas-liquid separator in this invention;

[0030] In the diagram: 1-Alkaline electrolytic cell; 2-Anode electrode; 3-Cathode electrode; 4-First control valve; 5-Second control valve; 6-First centrifugal pump; 7-Second centrifugal pump; 8-Two-stage oxygen gas-liquid separator; 9-Two-stage hydrogen gas-liquid separator; 10-First gas purification device; 11-Second gas purification device; 12-First gas collection device; 13-Second gas collection device; 14-First filtration device; 15-Second filtration device; 31-Electrode substrate; 32-Bottom of electrode; 33-Top of electrode; 34-Microcolumn; 35-Gradient wetted surface; 91-Mixed phase inlet of cyclone separator; 92-Cyclone separator; 93-Gradually narrowing overflow pipe; 94-Wire mesh structure; 95-Flow stabilizer; 96-Microfiber module. Detailed Implementation

[0031] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0032] The present invention will now be described in further detail with reference to the accompanying drawings:

[0033] The purpose of this invention is to provide an enhanced bubble separation device and method for use in alkaline water electrolysis, so as to solve the technical problems of incomplete separation by traditional gas-liquid separation devices and low efficiency of hydrogen production by alkaline water electrolysis.

[0034] See Figure 1In one embodiment of the present invention, a device for enhancing bubble separation during alkaline water electrolysis is provided, comprising an alkaline electrolytic cell 1, an anode electrode 2, a cathode electrode 3, a two-stage oxygen gas-liquid separator 8, a two-stage hydrogen gas-liquid separator 9, a first gas collection device 12, a second gas collection device 13, a first filtration device 14, and a second filtration device 15; the alkaline electrolytic cell 1 is filled with electrolyte, the anode electrode 2 and the cathode electrode 3 are respectively located at opposite ends of the alkaline electrolytic cell 1, and the electrolyte output terminal of the anode electrode 2 in the alkaline electrolytic cell 1 is connected to the input terminal of the two-stage oxygen gas-liquid separator 8. The gas phase output of the oxygen two-stage gas-liquid separator 8 is connected to the first gas collection device 12, and the liquid phase output of the oxygen two-stage gas-liquid separator 8 is connected to the electrolyte input of the anode electrode 2 in the alkaline electrolytic cell 1 via the first filter device 14; the electrolyte output of the cathode electrode 3 in the alkaline electrolytic cell 1 is connected to the input of the hydrogen two-stage gas-liquid separator 9, the gas phase output of the hydrogen two-stage gas-liquid separator 9 is connected to the second gas collection device 13, and the liquid phase output of the hydrogen two-stage gas-liquid separator 9 is connected to the electrolyte input of the cathode electrode 3 in the alkaline electrolytic cell 1 via the second filter device 15.

[0035] The first filter device 14 and the second filter device 15 are connected to the inlet of the alkaline electrolytic cell 1 to receive the electrolyte from the liquid phase outlet of the hydrogen two-stage gas-liquid separator 9 of the oxygen two-stage gas-liquid separator 8, filter the obtained electrolyte, and then transport it to the alkaline electrolytic cell 1 for recycling.

[0036] Specifically, a first control valve 4 and a first centrifugal pump 6 are provided between the electrolyte output end of the anode electrode 2 in the alkaline electrolytic cell 1 and the input end of the oxygen two-stage gas-liquid separator 8; a second control valve 5 and a second centrifugal pump 7 are provided between the electrolyte output end of the cathode electrode 3 in the alkaline electrolytic cell 1 and the input end of the hydrogen two-stage gas-liquid separator 9.

[0037] The first centrifugal pump 6 and the second centrifugal pump 7 are used to transport the electrolyte after electrolysis in the alkaline electrolysis cell 1 to the oxygen two-stage gas-liquid separator 8 and the hydrogen two-stage gas-liquid separator 9 respectively for gas-liquid separation.

[0038] Specifically, a first gas purification device 10 is provided between the oxygen two-stage gas-liquid separator 8 and the first gas collection device 12; a second gas purification device 11 is provided between the hydrogen two-stage gas-liquid separator 9 and the second gas collection device 13; wherein, the first gas purification device 10 and the second gas collection device 13 are respectively used to receive the gas from the oxygen two-stage gas-liquid separator 8 and the hydrogen two-stage gas-liquid separator 9, and dry and purify the obtained gas, and then transport it to the first gas collection device 12 and the second gas collection device 13 for collection.

[0039] Specifically, the anode electrode 2 and the cathode electrode 3 have the same structure, according to Figure 2 and Figure 3 As shown, the cathode electrode 3 includes an electrode substrate 31 and a plurality of micropillars 34 arranged in an array on the electrode substrate 31; the electrode substrate 31 has a trapezoidal structure, with one end being the bottom end 32 of the electrode and the other end being the top end 33 of the electrode, the width of the bottom end 32 being smaller than the width of the top end 33 of the electrode; micropillar regions and non-micropillar regions are distributed alternately on the electrode substrate 31, wherein a plurality of micropillars 34 are arranged in parallel in the micropillar regions, and both the micropillar regions and non-micropillar regions are gradient wetting surfaces 35, wherein the gradient wetting surfaces 35 are obtained by a chemical treatment method.

[0040] Among them, according to Figure 2 and Figure 3 As shown, along the direction from the bottom end 32 to the top end 33 of the electrode on the electrode substrate 31, the radius of each row of micropillars 34 decreases, and the number of micropillars 34 increases; the center-to-center distance between adjacent micropillars 34 decreases sequentially, and the center-to-center distance between adjacent micropillars 34 in the same row also decreases sequentially.

[0041] Among them, according to Figure 2 and Figure 3 As shown, along the direction from the bottom end 32 to the top end 33 of the electrode on the electrode substrate 31, the number of micropillars contained in each micropillar 34 increases in a gradient, gradually becoming denser; the radius of the micropillars contained in each micropillar 34 decreases uniformly from 100 μm to 25 μm; the center-to-center distance between several micropillars 34 on the surface of the electrode substrate 31 decreases uniformly from 160 μm to 90 μm; the center-to-center distance between adjacent micropillar structures contained in each micropillar 34 decreases uniformly from 160 μm to 90 μm; the height of the micropillars in the gradient micropillars 34 remains constant at 30 μm; therefore, the micropillars 34 have a gradient distribution.

[0042] Among them, according to Figure 2 and Figure 3 The gradient wetting surface 35 of the micropillar region and the non-micropillar region shown includes several strip-shaped coating areas with a width of 1 mm. The strip-shaped coating areas are coated with wetting surfactants of different mass concentrations. The wetting surfactants are amphiphilic polyurethane solutions.

[0043] Among them, according to Figure 4 As shown, the mass concentration of the wetting surfactant coated on the electrode substrate 31 along the direction from the bottom end 32 to the top end 33 of the electrode gradually increases from 0%; for every 1 mm strip coating area, the mass concentration of the wetting surfactant increases by 0.025%.

[0044] Specifically, according to Figure 5As shown, the oxygen two-stage gas-liquid separator 8 and the hydrogen two-stage gas-liquid separator 9 have the same structure. The hydrogen two-stage gas-liquid separator 9 includes a cyclone separator 92, a tapered overflow pipe 93, a wire mesh structure 94, a flow stabilizer 95, and a microfiber module 96. The cyclone separator 92 is located in the middle of the hydrogen two-stage gas-liquid separator 9. The tapered overflow pipe 93 is located at the gas phase outlet at the top of the cyclone separator 92, with its central axis offset from the central axis of the hydrogen two-stage gas-liquid separator 9. The flow stabilizer 95 is located at the bottom of the cyclone separator 92 and is positioned near the liquid phase outlet of the cyclone separator 92. On the same horizontal plane, with the liquid phase outlet direction being tangential, the wire mesh structure 94 is located in the upper part of the two-stage hydrogen gas-liquid separator 9 and above the gas phase output end of the cyclone separator 92. The microfiber module 96 is located in the lower part of the two-stage hydrogen gas-liquid separator 9 and below the liquid phase output end of the cyclone separator 92. The cyclone separator 92 is connected to the electrolyte output end of the cathode electrode 3 in the alkaline electrolytic cell 1 via the mixed phase inlet 91 of the cyclone separator and the two-stage hydrogen gas-liquid separator 9. The mixed phase inlet 91 of the cyclone separator is a downwardly sloping rectangular inlet.

[0045] The hydrocyclone separator 92 has a mixed-phase inlet in its middle section to receive the electrolyte transported by the second centrifugal pump 7. The hydrocyclone separator 92 is a vertical cylindrical cavity structure with a gas phase outlet, a mixed-phase inlet, and a liquid phase outlet at its top, middle, and bottom, respectively. The mixed-phase inlet is a downward-sloping rectangular inlet with an inlet angle of 27° to further optimize gas-liquid separation performance. The liquid phase outlets are tangentially oriented, with two outlets arranged horizontally and symmetrically, and their bottom surfaces are on the same horizontal plane as the bottom surface of the hydrocyclone separator 92, which helps to further improve the liquid phase transport efficiency.

[0046] The top of the cyclone separator 92 is provided with a gas phase outlet. The gas phase outlet is provided with a gradually narrowing overflow pipe 93 arranged in an offset manner in the vertical column cavity. Its central axis is offset from the central axis of the hydrogen two-stage gas-liquid separator 9 to increase the force of bubble separation.

[0047] The bottom of the cyclone separator 92 is provided with a flow stabilizer 95. The flow stabilizer 95 has a diameter of 18 mm and a height of 80 mm, and its bottom surface is on the same horizontal plane as the bottom surface of the liquid phase outlet of the cyclone separator 92.

[0048] The cyclone separator 92 has an inner diameter of 20 mm for both the mixed phase inlet and the liquid phase outlet. The top inner diameter of the tapered overflow pipe 93 is 15 mm, and the bottom inner diameter is 20 mm. The column cavity diameter of the cyclone separator 92 is 80 mm, the column cavity height is 640 mm, and the length-to-diameter ratio of the column cavity is approximately 8.

[0049] Among them, the microfiber module 96 is woven from microfibers at a certain angle, with the weaving angle ranging from 0 to 90°. The diameter of the microfibers is 80 to 180 μm, and the porosity is 0.75 to 0.8. This is used to provide a large throughput while increasing the probability of bubble collision. The surface of the microfiber module 96 is treated to increase the roughness, making it easier for the fiber surface to capture bubbles.

[0050] Among them, the separation wire mesh structure 94 is selected as a wire mesh demister with a mesh layer thickness of 150mm, a wire mesh type of SP, and an upper-mounted type.

[0051] The present invention also provides a method for using a bubble separation device in an enhanced alkaline water electrolysis process, which, based on the above-described bubble separation device in an enhanced alkaline water electrolysis process, includes the following steps:

[0052] Anode electrode 2 and cathode electrode 3 are placed in alkaline electrolytic cell 1. The electrolyte containing a large number of tiny bubbles after electrolysis in alkaline electrolytic cell 1 is transported to the inlet of oxygen two-stage gas-liquid separator 8 and hydrogen two-stage gas-liquid separator 9, respectively. Two-stage separation processes are carried out in oxygen two-stage gas-liquid separator 8 and hydrogen two-stage gas-liquid separator 9, respectively. The gas phase in oxygen two-stage gas-liquid separator 8 enters the first gas collection device 12 for gas storage. The liquid phase in oxygen two-stage gas-liquid separator 8 is replenished with pure water through the first filter device 14 and then re-enters the alkaline electrolytic cell. The gas phase in hydrogen two-stage gas-liquid separator 9 enters the second gas collection device 13 for gas storage. The liquid phase in hydrogen two-stage gas-liquid separator 9 is replenished with pure water through the second filter device 15 and then re-enters the alkaline electrolytic cell.

[0053] Specifically, the two-stage separation process is the same in both the oxygen two-stage gas-liquid separator 8 and the hydrogen two-stage gas-liquid separator 9. The two-stage separation process in the hydrogen two-stage gas-liquid separator 9 is as follows:

[0054] The electrolyte containing a large number of tiny bubbles after electrolysis in the alkaline electrolytic cell 1 is transported to the inlet of the hydrogen two-stage gas-liquid separator 9 and flows into the cyclone separator 92 along the mixed phase inlet 91 for the first-stage separation process. Due to the centrifugal force field of the cyclone, the medium and large bubbles in the electrolyte are initially separated. The separated gas phase is then discharged from the gas phase outlet of the cyclone separator. During the ascent, it passes through the wire mesh structure 94 to filter out the small droplets. Then the gas phase flows out along the gas phase outlet of the hydrogen two-stage gas-liquid separator 9, passes through the second gas purification device 11 for drying, and finally enters the second gas collection device 13 for gas storage. The liquid phase separated in the hydrocyclone separator 92 flows out along the liquid phase outlet of the hydrocyclone separator 92 and enters the inner cavity of the hydrogen two-stage gas-liquid separator 9. During the downward flow, the electrolyte flows through the microfiber module 96. The microfiber causes the microbubbles in the electrolyte to coalesce and collect on the fiber surface. This causes the microbubbles to continuously coalesce into large bubbles. Finally, under the action of buoyancy, the large bubbles rise and leave the electrolyte, thus realizing the two-stage separation process of microbubbles. The separated electrolyte flows out from the bottom of the hydrogen two-stage gas-liquid separator 9, passes through the second filter device 15 for filtration, and then is replenished with an appropriate amount of pure water before being recycled back into the alkaline electrolytic cell.

[0055] In summary, this invention provides a device and method for enhancing bubble separation during alkaline water electrolysis. The anode and cathode electrodes are located at opposite ends of an alkaline electrolytic cell. The electrolyte output of the anode electrode in the alkaline electrolytic cell is connected to the input of a two-stage oxygen gas-liquid separator. The gas phase output of the two-stage oxygen gas-liquid separator is connected to a first gas collection device. The liquid phase output of the two-stage oxygen gas-liquid separator is connected to the electrolyte input of the anode electrode in the alkaline electrolytic cell via a first filter device. The electrolyte output of the cathode electrode in the alkaline electrolytic cell is connected to the input of a two-stage hydrogen gas-liquid separator. The gas phase output of the two-stage gas-liquid separator is connected to the second gas collection device, and the liquid phase output of the two-stage hydrogen gas-liquid separator is connected to the electrolyte input of the cathode electrode in the alkaline electrolyzer via the second filter device. The two-stage separation using the two-stage gas-liquid separator effectively promotes the detachment of bubbles from the electrolyte. This not only solves the problem of bubbles being difficult to detach from the electrode surface during electrolysis, but also effectively promotes the detachment of bubbles from the electrolyte. This overcomes the problem of incomplete separation in traditional gas-liquid separation devices, reduces the gas content in the electrolyte, improves the efficiency of alkaline water electrolysis for hydrogen production, and ensures the efficient and safe operation of the entire hydrogen production system.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A bubble separation device for enhancing alkaline water electrolysis, characterized in that, The system includes an alkaline electrolytic cell (1), an anode electrode (2), a cathode electrode (3), an oxygen two-stage gas-liquid separator (8), a hydrogen two-stage gas-liquid separator (9), a first gas collection device (12), a second gas collection device (13), a first filter device (14), and a second filter device (15). The alkaline electrolytic cell (1) is filled with electrolyte. The anode electrode (2) and the cathode electrode (3) are located at opposite ends of the alkaline electrolytic cell (1). The electrolyte output end of the anode electrode (2) in the alkaline electrolytic cell (1) is connected to the input end of the oxygen two-stage gas-liquid separator (8). The gas phase of the oxygen two-stage gas-liquid separator (8) is... The output end is connected to the first gas collection device (12), and the liquid phase output end of the oxygen two-stage gas-liquid separator (8) is connected to the electrolyte input end of the anode electrode (2) in the alkaline electrolytic cell (1) via the first filter device (14); the electrolyte output end of the cathode electrode (3) in the alkaline electrolytic cell (1) is connected to the input end of the hydrogen two-stage gas-liquid separator (9), the gas phase output end of the hydrogen two-stage gas-liquid separator (9) is connected to the second gas collection device (13), and the liquid phase output end of the hydrogen two-stage gas-liquid separator (9) is connected to the electrolyte input end of the cathode electrode (3) in the alkaline electrolytic cell (1) via the second filter device (15); The anode electrode (2) and the cathode electrode (3) have the same structure. The cathode electrode (3) includes an electrode substrate (31) and a plurality of micropillars (34) arranged in an array on the electrode substrate (31). The electrode substrate (31) has a trapezoidal structure, with one end being the bottom end (32) of the electrode and the other end being the top end (33) of the electrode. The width of the bottom end (32) of the electrode is smaller than the width of the top end (33) of the electrode. Micropillar regions and non-micropillar regions are distributed alternately on the electrode substrate (31). A plurality of micropillars (34) are arranged in parallel in the micropillar regions. Both the micropillar regions and the non-micropillar regions are gradient wetted surfaces (35). Along the direction from the bottom end (32) to the top end (33) of the electrode on the electrode substrate (31), the radius of each row of micropillars (34) decreases, and the number of micropillars (34) increases; the center-to-center distance between adjacent micropillars (34) decreases sequentially, and the center-to-center distance between adjacent micropillars (34) in the same row decreases sequentially. The gradient wetting surface (35) of the micropillar region and the non-micropillar region includes several strip-shaped coating areas with a width of 1 mm, and the strip-shaped coating areas are coated with wetting surfactants of different mass concentrations; the wetting surfactant is an amphiphilic polyurethane solution. The oxygen two-stage gas-liquid separator (8) and the hydrogen two-stage gas-liquid separator (9) have the same structure. The hydrogen two-stage gas-liquid separator (9) includes a cyclone separator (92), a tapered overflow pipe (93), a wire mesh structure (94), a flow stabilizer (95), and a microfiber module (96). The cyclone separator (92) is located in the middle of the hydrogen two-stage gas-liquid separator (9). The tapered overflow pipe (93) is located at the gas phase outlet at the top of the cyclone separator (92), and its central axis is offset from the central axis of the hydrogen two-stage gas-liquid separator (9). The flow stabilizer (95) is located at the bottom of the cyclone separator (92) and is located at the liquid phase of the cyclone separator (92). The outlets are located on the same horizontal plane, with the liquid phase outlet direction being tangential. The wire mesh structure (94) is located in the upper part of the hydrogen two-stage gas-liquid separator (9) and above the gas phase output end of the cyclone separator (92). The microfiber module (96) is located in the lower part of the hydrogen two-stage gas-liquid separator (9) and below the liquid phase output end of the cyclone separator (92). The cyclone separator (92) is connected to the electrolyte output end of the cathode electrode (3) in the alkaline electrolytic cell (1) via the cyclone separator mixed phase inlet (91) through the hydrogen two-stage gas-liquid separator (9). The component type of the cyclone separator mixed phase inlet (91) is a downwardly inclined rectangular inlet.

2. The bubble separation device for enhanced alkaline water electrolysis according to claim 1, characterized in that, A first control valve (4) and a first centrifugal pump (6) are provided between the electrolyte output end of the anode electrode (2) in the alkaline electrolytic cell (1) and the input end of the oxygen two-stage gas-liquid separator (8); a second control valve (5) and a second centrifugal pump (7) are provided between the electrolyte output end of the cathode electrode (3) in the alkaline electrolytic cell (1) and the input end of the hydrogen two-stage gas-liquid separator (9).

3. The bubble separation device for enhanced alkaline water electrolysis according to claim 1, characterized in that, A first gas purification device (10) is provided between the oxygen two-stage gas-liquid separator (8) and the first gas collection device (12); a second gas purification device (11) is provided between the hydrogen two-stage gas-liquid separator (9) and the second gas collection device (13).

4. The bubble separation device for enhanced alkaline water electrolysis according to claim 1, characterized in that, The microfiber module (96) is woven from microfibers at a certain angle, with the weaving angle ranging from 0 to 90°. The diameter of the microfibers is 80 to 180 μm, and the porosity is 0.75 to 0.

8.

5. A method of using a bubble separation device in an enhanced alkaline water electrolysis process, based on the bubble separation device in an enhanced alkaline water electrolysis process according to any one of claims 1-4, characterized in that, Includes the following steps: The anode electrode (2) and cathode electrode (3) are placed in the alkaline electrolytic cell (1). The electrolyte containing a large number of tiny bubbles after electrolysis in the alkaline electrolytic cell (1) is transported to the inlet of the oxygen two-stage gas-liquid separator (8) and the hydrogen two-stage gas-liquid separator (9), respectively. The two-stage separation process is carried out in the oxygen two-stage gas-liquid separator (8) and the hydrogen two-stage gas-liquid separator (9). The gas phase in the oxygen two-stage gas-liquid separator (8) enters the first gas collection device (12) for gas storage. The liquid phase in the oxygen two-stage gas-liquid separator (8) is replenished with pure water through the first filter device (14) and then re-enters the alkaline electrolytic cell. The gas phase in the hydrogen two-stage gas-liquid separator (9) enters the second gas collection device (13) for gas storage. The liquid phase in the hydrogen two-stage gas-liquid separator (9) is replenished with pure water through the second filter device (15) and then re-enters the alkaline electrolytic cell.

6. The method of using the bubble separation device in the enhanced alkaline water electrolysis process according to claim 5, characterized in that, The two-stage separation process is the same in both the oxygen two-stage gas-liquid separator (8) and the hydrogen two-stage gas-liquid separator (9). The two-stage separation process in the hydrogen two-stage gas-liquid separator (9) is as follows: The electrolyte containing a large number of tiny bubbles after electrolysis in the alkaline electrolytic cell (1) is transported to the inlet of the hydrogen two-stage gas-liquid separator (9) and flows into the cyclone separator (92) through the mixed phase inlet (91) for primary separation. Due to the centrifugal force field of the cyclone, medium and large bubbles in the electrolyte are initially separated. The separated gas phase is then discharged from the gas phase outlet of the cyclone separator. During its ascent, it passes through the wire mesh structure (94) to filter out small droplets. Then, the gas phase flows out through the gas phase outlet of the hydrogen two-stage gas-liquid separator (9), undergoes a drying process in the second gas purification device (11), and finally enters the second gas collection device (13) for gas storage. The liquid phase separated in the hydrocyclone separator (92) flows out along the liquid phase outlet of the hydrocyclone separator (92) and enters the inner cavity of the hydrogen two-stage gas-liquid separator (9). During the downward flow, the electrolyte flows through the microfiber module (96). The microfiber will cause the microbubbles in the electrolyte to coalesce and collect them on the fiber surface. This will cause the microbubbles to continuously coalesce into large bubbles. Finally, under the action of buoyancy, the large bubbles rise and leave the electrolyte, thus realizing the two-stage separation process of microbubbles. The separated electrolyte flows out from the bottom of the hydrogen two-stage gas-liquid separator (9), passes through the second filter device (15) for filtration, and then adds an appropriate amount of pure water to re-enter the alkaline electrolytic cell for recycling.

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