Water electrolysis hydrogen production system and method for reducing hydrogen concentration in oxygen by using superheated water vapor

Abstract

The invention discloses a water electrolysis hydrogen production system and method for reducing the hydrogen concentration in oxygen through superheated water vapor. The water electrolysis hydrogen production system comprises an alkaline electrolytic bath, an anode side gas-liquid separator, an anode side gas treatment device, a cathode side gas-liquid separator, a heat exchanger, a cathode side gas treatment device, a mixed alkali liquor tank and an alkali liquor circulating pump. According to the invention, the overheated water vapor in a bubble form is introduced into the cathode side gas-liquid separator to heat the cathode side circulating alkali liquor in the cathode side gas-liquid separator, deep dehydrogenation is carried out on the cathode side circulating alkali liquor, and the content of dissolved hydrogen in the circulating alkali liquor is reduced, so that the concentration of hydrogen in oxygen in the water electrolysis hydrogen production system is reduced, and the hydrogen production efficiency is improved. And the safety of the system is improved.

Description

Technical Field

[0001] The invention relates to the technical field of water electrolysis hydrogen production, and in particular to a water electrolysis hydrogen production system and method for reducing the concentration of hydrogen in oxygen by using superheated water steam. Background Art

[0002] As the global demand for clean energy continues to grow, hydrogen energy, as a clean and efficient energy carrier, has received widespread attention. The only product of hydrogen combustion is water, which does not pollute the environment. Therefore, it is regarded as an important means to solve energy and environmental problems. Green hydrogen, specifically hydrogen produced by renewable energy such as wind and solar energy, is an important direction for the development of hydrogen energy. Compared with traditional fossil fuel hydrogen production, green hydrogen does not produce greenhouse gases such as carbon dioxide during the production process, and truly achieves zero emissions. This not only helps to achieve large-scale and long-term energy storage, but also has important strategic significance for the transformation of the country's energy structure.

[0003] Among the many hydrogen production technologies, alkaline water electrolysis hydrogen production technology is relatively mature, and the required key materials are sufficient. It is currently the only key hydrogen production technology that can support a hundredfold increase in market size. Compared with proton exchange membrane water electrolysis hydrogen production technology, the manufacturing cost of alkaline electrolyzers is relatively low, the choice of electrode materials and diaphragm materials is more diverse, and the life of alkaline cells is usually longer, and the maintenance and operating costs are relatively low. However, the performance of alkaline water electrolysis hydrogen production systems is limited by the content of hydrogen impurities in oxygen. Hydrogen mixed in oxygen is difficult to separate, and when the electrolyzer is running at low load, the hydrogen content in the oxygen in the system may exceed the safety value of 4% (the industrial standard usually requires less than 2%), and it will explode when encountering sparks or high temperatures, posing a major threat to the safety of hydrogen production equipment and operators.

[0004] In theory, water electrolysis should produce pure hydrogen and pure oxygen, but in actual operation, the electrolyzer product is often mixed with gases from the opposite electrode. In the process of alkaline water electrolysis, this gas cross-permeation phenomenon will cause the mixing of hydrogen and oxygen. The existence of hydrogen in oxygen is the result of the combined action of multiple factors, including alkali solution mixing, changes in gas partial pressure differences, gas concentration differences in alkali solutions, poor equipment sealing, and electrode design defects. Among them, alkali solution mixing is a major reason for the increase in hydrogen concentration in oxygen. At present, mixed alkali solution circulation is widely used in industry due to its simpler system structure and control strategy, which also greatly increases the hydrogen content in oxygen of the electrolysis system. In the electrolyzer, water on the cathode side decomposes to produce hydrogen and hydroxide ions (OH -), these hydroxide ions are driven by the electric field to pass through the diaphragm to the anode, where an oxidation reaction occurs to generate oxygen and water. The alkali liquid in the gas-liquid mixture on the cathode side contains dissolved hydrogen, and the alkali liquid in the gas-liquid mixture on the anode side contains dissolved oxygen and a small amount of dissolved hydrogen. The circulating alkali liquid on the cathode side and the circulating alkali liquid on the anode side are mixed after gas-liquid separation by the gas-liquid separator, and the gas-liquid separator cannot effectively separate the dissolved oxygen and dissolved hydrogen in the circulating alkali liquid. When the electrolyzer is operated at a low load, the dissolved hydrogen content in the alkali liquid will further increase. The circulating alkali liquid containing dissolved hydrogen returns to the alkaline electrolyzer for electrolysis reaction, resulting in an increase in the concentration of hydrogen in oxygen in the alkaline water electrolysis hydrogen production system, which easily causes the hydrogen content in oxygen in the system to exceed the safety value of 4%, and there is an explosion risk. The dissolved hydrogen in the circulating alkali liquid mainly comes from the circulating alkali liquid on the cathode side. Therefore, how to reduce the dissolved hydrogen content in the circulating alkali liquid on the cathode side under low-load operation is the key to reducing the concentration of hydrogen in oxygen in the alkaline water electrolysis hydrogen production system and improving the safety of the system. Summary of the invention

[0005] The object of the present invention is to provide a system and method for producing hydrogen by electrolysis of water using superheated water steam to reduce the concentration of hydrogen in oxygen, so as to solve the problem that when the electrolyzer is running at low load, the dissolved hydrogen content in the circulating alkaline solution on the cathode side is too high, resulting in too high concentration of hydrogen in oxygen in the alkaline electrolysis hydrogen production system.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] The first aspect of the present invention is to provide a water electrolysis hydrogen production system that uses superheated water vapor to reduce the concentration of hydrogen in oxygen, comprising an alkaline electrolytic cell, an anode-side gas-liquid separator, an anode-side gas processing device, a cathode-side gas-liquid separator, a cathode-side gas processing device, a mixed alkali liquid tank, and an alkali liquid circulation pump, and also comprising a heat exchanger;

[0008] The heat exchanger is provided with a superheated water steam outlet line, and a first inlet is provided on the side wall of the cathode side gas-liquid separator near the bottom, and the superheated water steam outlet line is connected to the first inlet for passing superheated water steam into the cathode side gas-liquid separator; the heat exchanger is also provided with a heat exchanger control unit for regulating the temperature of the superheated water steam produced by the heat exchanger;

[0009] An aeration device is provided inside the cathode side gas-liquid separator. The aeration device is fixedly arranged at the first inlet and is used to blow superheated water vapor into the cathode side gas-liquid separator in the form of bubbles.

[0010] Furthermore, a pressure-stabilizing valve is provided on the superheated water steam outlet line.

[0011] The use of a pressure-stabilizing valve ensures that the aeration device can obtain a stable pressure supply, allowing the aeration device to operate efficiently, provide uniform bubble distribution, avoid system damage caused by pressure fluctuations, extend the service life of the aeration device, and improve the overall energy efficiency of the system.

[0012] Furthermore, when the diameter of the cathode-side gas-liquid separator is 0.5-1 m and the height is 2-4 m, the length of the heat exchanger is 1.2-1.8 m, the width is 0.5-0.8 m, and the height is 1-1.5 m.

[0013] Preferably, the heat exchanger is a plate heat exchanger with a corrugated structure inside, and the thickness of the corrugated sheets inside is 0.5 to 0.8 mm, and the distance between adjacent corrugated sheets is 2 to 2.5 mm.

[0014] Furthermore, the aeration device is a circular ceramic sintered aeration disk, and the pore size thereof is 20 to 40 um.

[0015] The use of a circular ceramic sintered aeration disk with a pore size of 20 to 40 um can ensure that the superheated water vapor bubble group generated can effectively exchange heat with the gas-liquid mixture in the cathode side gas-liquid separator, maintaining the stability and reliability of the equipment in long-term operation.

[0016] Furthermore, the aeration device has a diameter of 60 to 80 mm and a height of 40 to 50 mm.

[0017] A second aspect of the present invention is to provide a method for producing hydrogen by electrolyzing water using superheated water steam to reduce the concentration of hydrogen in oxygen, and the method comprises the following steps:

[0018] S1. Under the action of direct current, the water in the alkaline electrolytic cell is decomposed into a gas-liquid mixture containing a large number of fine bubbles;

[0019] S2. Pump the gas-liquid mixture on the anode side and the cathode side of the alkaline electrolytic cell into the anode side gas-liquid separator and the cathode side gas-liquid separator respectively through an alkali liquid circulation pump for gas-liquid separation; control the temperature of the produced superheated water steam to be 200-250° C. through a heat exchanger control unit, and pass the superheated water steam through a superheated water steam outlet line and an aeration device in the form of bubbles into the cathode side gas-liquid mixer to transfer heat to the gas-liquid mixture in the cathode side gas-liquid separator, thereby increasing the temperature of the gas-liquid mixture in the cathode side gas-liquid separator, reducing the solubility of hydrogen in the cathode side circulating alkali liquid, achieving deep dehydrogenation of the cathode side circulating alkali liquid, and replenishing water for the circulating alkali liquid;

[0020] S3. The gas separated by the anode-side gas-liquid separator enters the anode-side gas treatment device for drying and pressurizing treatment and then is collected. The gas separated by the cathode-side gas-liquid separator enters the cathode-side gas treatment device for drying and pressurizing treatment and then is collected. The anode-side circulating alkali liquid and the cathode-side circulating alkali liquid after gas-liquid separation are mixed and then enter the mixed alkali liquid tank. Under the action of the alkali liquid circulation pump, they re-enter the alkaline electrolytic cell for electrolysis.

[0021] Furthermore, the pressure of the pressure stabilizing valve is set to 0.3-0.5 MPa.

[0022] Furthermore, the volume of the gas-liquid mixture in the gas-liquid separators on the cathode side and the anode side is controlled to be 1 / 2 to 3 / 4 of the volume of the gas-liquid separator.

[0023] Furthermore, the outlet pressure of the alkali solution circulation pump is 0.8-1.6 MPa.

[0024] Compared with the prior art, the present invention has at least the following beneficial effects:

[0025] 1. The present invention passes the superheated water vapor generated by the heat exchanger into the cathode side gas-liquid separator, and uses the aeration device to allow the superheated water vapor and the fine bubbles or dissolved hydrogen in the gas-liquid mixed liquid to transfer heat under the turbulence of the flow field, thereby increasing the temperature of the cathode side circulating alkali solution in the cathode side gas-liquid separator, reducing the solubility of hydrogen in the cathode side circulating alkali solution, reducing the dissolved hydrogen content in the cathode side circulating alkali solution, and further reducing the dissolved hydrogen content in the circulating alkali solution, thereby reducing the hydrogen concentration in oxygen in the alkaline water electrolysis hydrogen production system and improving the system safety.

[0026] 2. The present invention heats the cathode side circulating alkali solution in the cathode side gas-liquid separator by introducing superheated water steam in the form of bubbles into the cathode side gas-liquid separator, which can not only reduce the hydrogen concentration in oxygen in the alkaline water electrolysis hydrogen production system, but also replenish the water consumed by the alkaline water electrolysis hydrogen production system during the electrolysis process, thereby avoiding the performance reduction of the alkaline water electrolysis hydrogen production system due to excessively high alkali solution concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the water electrolysis hydrogen production system of the present invention which utilizes superheated water steam to reduce the hydrogen concentration in oxygen.

[0028] Figure 2 This is a partial schematic diagram of the aeration device and heat exchanger.

[0029] In the figure: 10-alkaline electrolytic cell; 11-cathode chamber; 111-first gas-liquid mixed phase outlet; 12-anode chamber; 121-second gas-liquid mixed phase outlet; 13-mixed circulating alkali solution inlet;

[0030] 21-the first alkali solution circulation pump; 22-the second alkali solution circulation pump;

[0031] 30-cathode side gas-liquid separator; 31-first gas-liquid mixed phase inlet; 32-first liquid phase outlet; 33-first gas phase outlet; 34-first inlet; 341-aeration device;

[0032] 40-heat exchanger; 41-superheated steam outlet line; 42-superheated steam inlet line; 43-high-temperature heat source inlet line; 44-high-temperature heat source outlet line;

[0033] 50-pressure stabilizing valve;

[0034] 60- cathode side gas treatment device;

[0035] 70-anode side gas-liquid separator; 71-second gas-liquid mixed phase inlet; 72-second liquid phase outlet; 73-second gas phase outlet;

[0036] 80-Anode side gas treatment device

[0037] 91-first pipeline; 92-second pipeline; 93-third pipeline; 94-fourth pipeline;

[0038] 100-stop valve;

[0039] 110-Mixing lye tank. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below in conjunction with specific implementation methods and examples. It should be understood that the following examples are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-substantial improvements and adjustments made by professionals and technicians in this field based on the content of the present invention still belong to the scope of protection of the present invention.

[0041] In the existing alkaline water electrolysis hydrogen production device and method, only a gas-liquid separator is used to separate the gas-liquid mixture derived from the alkaline electrolyzer, and the dissolved hydrogen and dissolved oxygen in the circulating alkali solution cannot be effectively separated, resulting in an increase in the hydrogen concentration in oxygen in the alkaline water electrolysis hydrogen production system. In particular, when the electrolyzer load drops below a low load, the solubility of hydrogen in the alkali solution is further increased, resulting in a further increase in the dissolved hydrogen content in the circulating alkali solution. The circulating alkali solution returns to the alkaline electrolyzer to participate in the electrolysis reaction, which will further increase the hydrogen content in oxygen in the alkaline water electrolysis system, posing an explosion risk. The dissolved hydrogen in the circulating alkali solution mainly comes from the circulating alkali solution on the cathode side. Therefore, in order to effectively solve the above technical problems, the present invention provides a water electrolysis hydrogen production system and method for reducing the hydrogen concentration in oxygen by using superheated water vapor, wherein superheated water vapor is introduced into the cathode side gas-liquid separator to heat the cathode side circulating alkali solution, thereby reducing the dissolved hydrogen content in the cathode side circulating alkali solution, thereby reducing the hydrogen concentration in oxygen in the alkaline water electrolysis hydrogen production system.

[0042] See also Figure 1-2 The alkaline water electrolysis hydrogen production device of the present invention comprises an alkaline electrolytic cell 10, a cathode side gas-liquid separator 30, a heat exchanger 40, a pressure regulating valve 50, a cathode side gas treatment device 60, an anode side gas-liquid separator 70, an anode side gas treatment device 80 and a mixed alkali liquid tank 110;

[0043] The alkaline electrolytic cell 10 has a cathode chamber 11 and an anode chamber 12;

[0044] The cathode chamber 11 is provided with a first gas-liquid mixed phase outlet 111, and the anode chamber 12 is provided with a second gas-liquid mixed phase outlet 121;

[0045] The cathode side gas-liquid separator 30 is provided with a first gas phase outlet 33 at the top, a first liquid phase outlet 32 ​​at the bottom, a first gas-liquid mixed phase inlet 31 at the middle of the side wall, and a first inlet 34 near the bottom of the side wall. An aeration device 341 is provided inside the cathode side gas-liquid separator 30, and the aeration device 341 is fixedly arranged at the first inlet 34;

[0046] The heat exchanger 40 is provided with a superheated water steam outlet line 41, a superheated water steam inlet line 42, a high temperature heat source inlet line 43 and a high temperature heat source outlet line 44; the superheated water steam outlet line 41 is connected to the first inlet 34, and is used to pass superheated water steam into the cathode side gas-liquid separator 30. Under the action of the aeration device 341, the superheated water steam is blown into the cathode side gas-liquid separator 30 in the form of bubbles;

[0047] The heat exchanger 40 is also equipped with a heat exchanger control unit (not shown in the drawings), which can regulate the output of superheated water steam by changing the temperature, flow rate and pressure of the cold and hot fluids;

[0048] The anode side gas-liquid separator 70 has a second gas phase outlet 73 at the top, a second liquid phase outlet 72 at the bottom, and a second gas-liquid mixed phase inlet 71 at the middle of the side wall;

[0049] The first gas-liquid mixed phase outlet 111 is connected to the first gas-liquid mixed phase inlet 31 through the first pipeline 91, and the first alkali liquid circulation pump 21 is provided on the first pipeline 91; the first liquid phase outlet 32 ​​is connected to the mixed alkali liquid tank 110 through the second pipeline 92, and the first gas phase outlet 33 is connected to the cathode side gas treatment device 60 through a pipeline;

[0050] The second gas-liquid mixed phase outlet 121 is connected to the second gas-liquid mixed phase inlet 71 through the third pipeline 93, and the third pipeline 93 is provided with a second alkali liquid circulation pump 22; the second liquid phase outlet 72 is connected to the mixed alkali liquid tank 110 through the fourth pipeline 94, and the second gas phase outlet 73 is connected to the anode side gas treatment device 80 through a pipeline;

[0051] The mixed alkali solution tank 110 is connected to the bottom of the alkaline electrolytic cell 10 through a pipeline.

[0052] When in use, the alkaline electrolytic cell 10 is first connected to a DC power supply, the positive electrode of the power supply is connected to the anode chamber 12 of the alkaline electrolytic cell 10, and the negative electrode of the power supply is connected to the cathode chamber 11 of the alkaline electrolytic cell 10; under the action of the DC power, the water in the alkaline electrolytic cell 10 is decomposed into a gas-liquid mixed liquid containing a large number of fine bubbles; the gas-liquid mixed liquid in the cathode chamber 11 is pumped into the cathode side gas-liquid separator 30 through the first pipeline 91 by the first alkali liquid circulation pump 21 for gas-liquid separation, and the gas-liquid mixed liquid in the anode chamber 12 is pumped into the anode side gas-liquid separator 70 through the third pipeline 93 by the second alkali liquid circulation pump 22 for gas-liquid separation, and the temperature of the superheated water steam produced by the heat exchanger is controlled to be 200-250° C. by the heat exchanger control unit, and the superheated water steam is passed into the cathode side gas-liquid mixer 30 in the form of bubbles after passing through the superheated water steam outlet line 41 and the aeration device 341 to transfer heat to the gas-liquid mixed liquid in the cathode side gas-liquid separator 30, thereby improving the gas-liquid separation on the cathode side. The temperature of the gas-liquid mixed liquid in the separator 30 is increased, the solubility of hydrogen in the cathode side circulating alkali liquid is reduced, the deep dehydrogenation of the cathode side circulating alkali liquid is achieved, and the circulating alkali liquid is supplemented with water at the same time; the gas separated from the cathode side gas-liquid separator 30 is discharged from the first gas phase outlet 33, enters the cathode side gas treatment device 60 for drying and pressurization treatment and then collected, and the cathode side circulating alkali liquid after deep dehydrogenation is discharged from the first liquid phase outlet 32, and enters the mixed alkali liquid tank 110 through the second pipeline 92; the gas separated from the anode side gas-liquid separator 70 is discharged from the second gas phase outlet 73, enters the anode side gas treatment device 80 for drying and pressurization treatment and then collected, and the anode side circulating alkali liquid after gas-liquid separation is discharged from the second liquid phase outlet 72, enters the mixed alkali liquid tank 110 through the fourth pipeline 94, and the cathode side and anode side circulating alkali liquids are mixed in the mixed alkali liquid tank 110, and under the action of the first and second alkali liquid circulation pumps, re-enters the alkaline electrolytic cell for electrolysis.

[0053] In a preferred embodiment of the present invention, the alkali solution circulation pump is a centrifugal pump.

[0054] Continue to see Figure 2 Preferably, a pressure-stabilizing valve 50 is provided on the superheated steam outlet line 41 .

[0055] The pressure regulating valve 50 is used to ensure that the aeration device 341 can obtain a stable pressure supply, so that the aeration device 341 can operate efficiently, provide uniform bubble distribution, avoid system damage caused by pressure fluctuations, extend the service life of the aeration device 341, and improve the overall energy efficiency of the system.

[0056] Continue to see Figure 1In a preferred embodiment of the present invention, a stop valve 100 is provided before and after the first alkali solution circulation pump 21 and the second alkali solution circulation pump 22 (the front and back in the present invention refers to the front and back along the fluid flow direction of the present invention).

[0057] Continue to participate Figure 1 , Figure 2 In a preferred embodiment of the present invention, a stop valve 100 is provided on the second pipeline 92 , the fourth pipeline 94 , the superheated water steam outlet line 40 , the high-temperature heat source inlet line 43 and the high-temperature heat source outlet line 44 .

[0058] In a preferred embodiment of the present invention, when the diameter of the cathode side gas-liquid separator 30 is 0.5-1m and the height is 2-4m, the length of the heat exchanger 40 is 1.2-1.8m, the width is 0.5-0.8m, and the height is 1-1.5m.

[0059] In a preferred embodiment of the present invention, the heat exchanger 40 is a plate heat exchanger with a corrugated structure inside. The thickness of the corrugated sheets inside the plate is 0.5 to 0.8 mm, and the distance between adjacent corrugated sheets is 2 to 2.5 mm.

[0060] In a preferred embodiment of the present invention, the aeration device 341 is a circular ceramic sintered aeration disk, and the pore size thereof is 20-40 um.

[0061] The use of a circular ceramic sintered aeration disk with a pore size of 20 to 40 um can ensure that the generated superheated steam bubble group can effectively exchange heat with the gas-liquid mixture in the cathode side gas-liquid separator 30, maintaining the stability and reliability of the equipment in long-term operation.

[0062] In a preferred embodiment of the present invention, the diameter of the aeration device 341 is 60-80 mm and the height is 40-50 mm.

[0063] The present invention also provides a method for producing hydrogen by electrolyzing water using superheated water steam to reduce the concentration of hydrogen in oxygen. The method adopts the above-mentioned device for producing hydrogen by electrolyzing water using superheated water steam to reduce the concentration of hydrogen in oxygen, comprising the following steps:

[0064] S1. Under the action of direct current, the water in the alkaline electrolytic cell 10 is decomposed into a gas-liquid mixture containing a large number of fine bubbles;

[0065] S2. The gas-liquid mixture on the anode side and the cathode side of the alkaline electrolytic cell is pumped into the anode side gas-liquid separator 70 and the cathode side gas-liquid separator 30 respectively through the alkali liquid circulation pump for gas-liquid separation; (at this time, the content of dissolved hydrogen in the cathode side circulating alkali liquid separated by the cathode side gas-liquid separator 30 before the superheated water steam is introduced is 2-4%); the temperature of the produced superheated water steam is regulated to be 200-250° C. by the heat exchanger control unit, and the superheated water steam is introduced into the cathode side gas-liquid mixer 30 in the form of bubbles after passing through the superheated water steam outlet line 41 and the aeration device 341 to transfer heat to the gas-liquid mixture in the cathode side gas-liquid separator 30, thereby increasing the temperature of the gas-liquid mixture in the cathode side gas-liquid separator 30 and reducing the solubility of hydrogen in the cathode side circulating alkali liquid 30 (the temperature of the cathode side circulating alkali liquid after heat exchange is 80-100° C., which can effectively reduce the content of dissolved hydrogen in the cathode side circulating alkali liquid), thereby achieving deep dehydrogenation of the cathode side circulating alkali liquid and replenishing water for the circulating alkali liquid;

[0066] S3. The gas separated by the anode side gas-liquid separator 70 enters the anode side gas treatment device 80 for drying and pressurizing treatment and then is collected, and the gas separated by the cathode side gas-liquid separator 30 enters the cathode side gas treatment device 60 for drying and pressurizing treatment and then is collected; the anode side circulating alkali liquid and the cathode side circulating alkali liquid after gas-liquid separation are mixed and enter the mixed alkali liquid tank 110, and under the action of the alkali liquid circulation pump, re-enter the alkaline electrolytic cell 10 for electrolysis.

[0067] In a preferred embodiment of the present invention, the pressure of the pressure-stabilizing valve 50 is set to 0.3-0.5 MPa.

[0068] In a preferred embodiment of the present invention, the volume of the gas-liquid mixture in the cathode-side gas-liquid separator 30 and the anode-side gas-liquid separator 70 is controlled to be 1 / 2 to 3 / 4 of the volume of the gas-liquid separator.

[0069] In a preferred embodiment of the present invention, the outlet pressures of the first and second alkali solution circulation pumps are both 0.8-1.6 MPa.

[0070] Example 1

[0071] The system and method for producing hydrogen by electrolyzing water using superheated water vapor to reduce the concentration of hydrogen in oxygen are used to prepare hydrogen.

[0072] Among them, the cathode side gas-liquid separator 30 and the anode side gas-liquid separator 70 are vertical tanks with a diameter of 1m and a height of 3m; the heat exchanger 40 is 1.5m long, 0.6m wide and 1.2m high; the corrugated sheet is 0.5mm thick and the plate spacing is 2.5mm; the aeration device 341 is a circular ceramic sintered aeration disk with a diameter of 70mm, a height of 45mm and a pore size of 25um; the volume of the gas-liquid mixed liquid in the cathode side gas-liquid separator 30 and the anode side gas-liquid separator 70 is controlled to be 3 / 4 of the volume of the gas-liquid separator; the steps are as follows:

[0073] S1. Under the action of direct current, the water in the alkaline electrolytic cell 10 is decomposed into a gas-liquid mixture containing a large number of fine bubbles;

[0074] S2. The gas-liquid mixture in the cathode chamber 11 is pumped into the cathode side gas-liquid separator 30 through the first pipeline 91 by the first alkali liquid circulation pump 21 for gas-liquid separation; the gas-liquid mixture in the anode chamber 12 is pumped into the anode side gas-liquid separator 70 through the third pipeline 93 by the second alkali liquid circulation pump 22 for gas-liquid separation; a pressure regulating valve 50 is provided on the superheated water steam outlet line 41, and the set pressure is 0.4Mpa; the temperature of the superheated water steam produced is regulated to 200-250℃ by the heat exchanger control unit, and the superheated water steam is After passing through the superheated water steam outlet line 41 and the aeration device 341, the superheated water steam is introduced into the cathode side gas-liquid mixer 30 in the form of bubbles to transfer heat to the gas-liquid mixed liquid in the cathode side gas-liquid separator 30, thereby increasing the temperature of the gas-liquid mixed liquid in the cathode side gas-liquid separator 30 and reducing the solubility of hydrogen in the cathode side circulating alkali solution 30 (the temperature of the cathode side circulating alkali solution after heat exchange is 80-100° C., which can effectively reduce the content of dissolved hydrogen in the cathode side circulating alkali solution), thereby achieving deep dehydrogenation of the cathode side circulating alkali solution and replenishing water for the circulating alkali solution;

[0075] S3. The gas separated by the anode side gas-liquid separator 70 enters the anode side gas treatment device 80 for drying and pressurizing treatment and then is collected, and the gas separated by the cathode side gas-liquid separator 30 enters the cathode side gas treatment device 60 for drying and pressurizing treatment and then is collected; the anode side circulating alkali liquid and the cathode side circulating alkali liquid after gas-liquid separation are mixed and enter the mixed alkali liquid tank 110, and under the action of the alkali liquid circulation pump, re-enter the alkaline electrolytic cell 10 for electrolysis.

[0076] The operating load parameter of the alkaline electrolytic cell is set to 50%, so that the alkaline electrolytic cell enters a low-load operating state; it is measured that before the superheated water vapor is introduced into the cathode side gas-liquid separator 30, the Reynolds number of the circulating alkali solution on the cathode side is 1500-3500, and the rising speed of the fine bubbles is 0.005 m / s; after the superheated water vapor is introduced through the aeration device, the viscosity of the circulating alkali solution on the cathode side decreases due to the temperature change, and the Reynolds number of the flowing electrolyte increases to 2000-4200, and at the same time, the fine bubbles are disturbed by the water vapor, and their rising speed increases to 0.006-0.007 m / s; finally, the content of dissolved hydrogen in the circulating alkali solution on the cathode side discharged from the hydrogen side gas-liquid separator is 0.85%.

[0077] Comparative Example 1

[0078] The difference between this comparative example and Example 1 is that the alkaline water electrolysis hydrogen production device does not use the heat exchanger 40 and the aeration device 341, but only uses the traditional cathode side and anode side gas-liquid separators. The circulating alkali liquid directly enters the mixed alkali liquid tank 110, and the volume of the gas-liquid mixed liquid in the cathode side gas-liquid separator 30 and the anode side gas-liquid separator 70 is controlled to be 3 / 4 of the volume of the gas-liquid separator; the Reynolds number of the circulating alkali liquid on the cathode side is 1500-3500, and the rising speed of the fine bubbles is 0.005m / s.

[0079] According to the detection, the dissolved hydrogen content of the cathode side circulating alkaline solution discharged from the cathode side gas-liquid separator 30 is 2.1%.

[0080] From the comparison results, it can be seen that the alkaline water electrolysis hydrogen production system of the present invention introduces superheated water steam in the form of bubbles into the cathode side gas-liquid separator 30 through the heat exchanger 40 and the aeration device 341 to deeply dehydrogenate the cathode side circulating alkali solution, and the dissolved hydrogen content in the cathode side circulating alkali solution is reduced from 2.1% to 0.85%, which can effectively reduce the dissolved hydrogen content in the mixed circulating alkali solution, thereby reducing the hydrogen content in the oxygen of the water electrolysis hydrogen production system and improving the safety of alkaline water electrolysis hydrogen production.

[0081] It should be noted that the above-described embodiments should be understood as illustrative rather than limiting the scope of protection of the present invention. For those skilled in the art, non-essential improvements and adjustments made to the present invention without departing from the essence and scope of the present invention still fall within the scope of protection of the present invention.

Claims

1. A water electrolysis hydrogen production system using superheated water steam to reduce the concentration of hydrogen in oxygen, comprising: An alkaline electrolytic cell, an anode-side gas-liquid separator, an anode-side gas processing device, a cathode-side gas-liquid separator, a cathode-side gas processing device, a mixed alkali liquid tank and an alkali liquid circulation pump, characterized in that: Also included is a heat exchanger; The heat exchanger is provided with a superheated water steam outlet line, and a first inlet is provided on the side wall of the cathode side gas-liquid separator near the bottom, and the superheated water steam outlet line is connected to the first inlet for passing superheated water steam into the cathode side gas-liquid separator; the heat exchanger is also provided with a heat exchanger control unit for regulating the temperature of the superheated water steam produced by the heat exchanger; An aeration device is provided inside the cathode side gas-liquid separator. The aeration device is fixedly arranged at the first inlet and is used to blow superheated water vapor into the cathode side gas-liquid separator in the form of bubbles.

2. The system for producing hydrogen by electrolysis of water using superheated water steam to reduce the concentration of hydrogen in oxygen according to claim 1, characterized in that: A pressure stabilizing valve is arranged on the superheated water steam outlet line.

3. The water electrolysis hydrogen production system using superheated water steam to reduce the concentration of hydrogen in oxygen according to claim 1, characterized in that: When the diameter of the cathode side gas-liquid separator is 0.5-1 m and the height is 2-4 m, the length of the heat exchanger is 1.2-1.8 m, the width is 0.5-0.8 m, and the height is 1-1.5 m.

4. The system for producing hydrogen by electrolysis of water using superheated water steam to reduce the concentration of hydrogen in oxygen according to claim 1, characterized in that: The heat exchanger is a plate heat exchanger with a corrugated structure inside. The thickness of the corrugated sheets inside the heat exchanger is 0.5-0.8 mm, and the distance between adjacent corrugated sheets is 2-2.5 mm.

5. The system for producing hydrogen by electrolysis of water using superheated water steam to reduce the concentration of hydrogen in oxygen according to claim 1, characterized in that: The aeration device is a circular ceramic sintered aeration disk, and the aperture size thereof is 20-40 um.

6. The system for producing hydrogen by electrolysis of water using superheated water steam to reduce the concentration of hydrogen in oxygen according to claim 5, characterized in that: The aeration device has a diameter of 60 to 80 mm and a height of 40 to 50 mm.

7. A method for producing hydrogen by electrolyzing water using superheated water steam to reduce the concentration of hydrogen in oxygen, characterized in that: The water electrolysis hydrogen production system using superheated water steam to reduce the concentration of hydrogen in oxygen as described in any one of claims 1 to 6 comprises the following steps: S1. Under the action of direct current, the water in the alkaline electrolytic cell is decomposed into a gas-liquid mixture containing a large number of fine bubbles; S2. Pump the gas-liquid mixture on the anode side and the cathode side of the alkaline electrolytic cell into the anode side gas-liquid separator and the cathode side gas-liquid separator respectively through an alkali liquid circulation pump for gas-liquid separation; control the temperature of the produced superheated water steam to be 200-250° C. through a heat exchanger control unit, and pass the superheated water steam through a superheated water steam outlet line and an aeration device in the form of bubbles into the cathode side gas-liquid mixer to transfer heat to the gas-liquid mixture in the cathode side gas-liquid separator, thereby increasing the temperature of the gas-liquid mixture in the cathode side gas-liquid separator, reducing the solubility of hydrogen in the cathode side circulating alkali liquid, achieving deep dehydrogenation of the cathode side circulating alkali liquid, and replenishing water for the circulating alkali liquid; S3. The gas separated by the anode-side gas-liquid separator enters the anode-side gas treatment device for drying and pressurizing treatment and then is collected. The gas separated by the cathode-side gas-liquid separator enters the cathode-side gas treatment device for drying and pressurizing treatment and then is collected. The anode-side circulating alkali liquid and the cathode-side circulating alkali liquid after gas-liquid separation are mixed and then enter the mixed alkali liquid tank. Under the action of the alkali liquid circulation pump, they re-enter the alkaline electrolytic cell for electrolysis.

8. The method for producing hydrogen by electrolyzing water using superheated water steam to reduce the concentration of hydrogen in oxygen according to claim 7, characterized in that: The pressure of the pressure stabilizing valve is set to 0.3-0.5 MPa.

9. The method for producing hydrogen by electrolyzing water using superheated water steam to reduce the concentration of hydrogen in oxygen according to claim 7, characterized in that: The volume of the gas-liquid mixed liquid in the gas-liquid separators on the cathode side and the anode side is controlled to be 1 / 2 to 3 / 4 of the volume of the gas-liquid separator.

10. The method for producing hydrogen by electrolyzing water using superheated water steam to reduce the concentration of hydrogen in oxygen according to claim 7, characterized in that: The outlet pressure of the alkali solution circulation pump is 0.8-1.6Mpa.

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