Device and method for removing hydrogen in oxygen of water electrolysis hydrogen production mixed alkali liquor by utilizing flash tank

Abstract

The invention discloses an alkaline electrolysis water hydrogen production system and method capable of deeply reducing the hydrogen content in oxygen in multiple ways, a hydrogen side flash tank is arranged in the alkaline electrolysis water hydrogen production system, and dissolved hydrogen deep removal is carried out on hydrogen side alkali liquor passing through a gas-liquid separator through the hydrogen side flash tank; a mixed alkali liquor flash tank is arranged in an alkaline electrolysis water hydrogen production system, and deep removal of dissolved oxygen and dissolved hydrogen is carried out on mixed alkali liquor through the mixed alkali liquor flash tank; a hydrogen side pressure adjusting part capable of adjusting the pressure of a cathode chamber is arranged in a hydrogen side gas-liquid separator system, and an oxygen side pressure adjusting part capable of adjusting the pressure of an anode chamber is arranged in an oxygen side gas-liquid separation system, so that the pressure of the anode chamber of the alkaline electrolytic cell is higher than that of the cathode chamber, and the amount of hydrogen entering the anode chamber from the cathode chamber through a diaphragm is reduced; the concentration of hydrogen in oxygen in the water electrolysis hydrogen production system is reduced, and the safety of the system is improved.

Description

[0001] This application is a divisional application. The application date of the original application is October 29, 2024. The application number is: CN202411518750.8. The name of the invention is: A system and method for producing hydrogen by alkaline water electrolysis for deeply reducing the hydrogen content in oxygen. Technical Field

[0002] The present invention relates to the technical field of hydrogen production by water electrolysis, and in particular to an alkaline water electrolysis hydrogen production system and method for deeply reducing the hydrogen content in oxygen. Background Art

[0003] As an ideal clean energy, hydrogen has the remarkable characteristics of being pollution-free, renewable, and having a high calorific value, and provides important support for achieving sustainable development. Moreover, hydrogen production through water electrolysis can convert volatile renewable energy sources such as photovoltaics and wind power into green hydrogen energy, providing green raw materials for high-carbon emission industries such as metallurgy and petrochemicals, ensuring large-scale and long-term storage of energy, and is an important guarantee for achieving the national strategic goals of carbon peak and carbon neutrality, and has strategic support for the transformation and development of national energy.

[0004] Among the many hydrogen production technologies, alkaline water electrolysis has attracted much attention due to its relative maturity and sufficient key materials. This technology can not only produce hydrogen on a large scale, but also has the potential to support a hundredfold growth in the market, making it the only hydrogen production technology that can currently meet large-scale market demand. With the continuous advancement of technology and the reduction of costs, alkaline water electrolysis is expected to occupy an important position in the future clean energy market and promote the development of the global energy structure towards a cleaner and more sustainable direction.

[0005] Although hydrogen production by alkaline water electrolysis is currently the most cost-effective and scale-advantaged renewable energy hydrogen production process, the hydrogen content in the by-product oxygen increases as the operating load decreases. Under low load or unstable operating conditions, the hydrogen content in oxygen may approach or reach the explosion limit, posing a safety risk. Refining and chemical companies are particularly strict in controlling the risk of explosion. When carrying out hydrogen production from renewable energy, they need to strictly control the hydrogen in the by-product oxygen to meet safety production requirements.

[0006] Hydrogen is flammable and explosive, and has the material characteristics and safety risks of low ignition energy, large diffusion coefficient, and wide combustion range (4% to 75%). When hydrogen is mixed into the oxygen system, it is easy to form a burning or explosive mixture. Therefore, the hydrogen content in oxygen must be strictly controlled during the operation of the alkaline water electrolysis hydrogen production device, and the safety alarm value of hydrogen in oxygen in the by-product oxygen is set to 1.5%. This indicator is generally used as the upper limit of safety control during the operation of the water electrolysis hydrogen production device.

[0007] The theoretical products of hydrogen production by water electrolysis are pure hydrogen and pure oxygen, but the products of the actual operation of the electrolyzer are often mixed with gases from the opposite electrodes. This phenomenon is called gas cross-permeation. Gas cross-permeation occurs during hydrogen production by alkaline water electrolysis, resulting in the mixing of hydrogen and oxygen and the problem of hydrogen in oxygen. Hydrogen in oxygen mainly comes from three aspects:

[0008] One is the influence of alkali liquid mixing. Water decomposition reaction occurs at the cathode of the electrolytic cell to generate hydrogen and OH-. Driven by the electric field, OH- is transmitted across the diaphragm to the anode, where an oxidation reaction occurs to generate oxygen and water. Hydrogen is dissolved in the cathode alkali liquid, and oxygen is dissolved in the anode alkali liquid. The two alkali liquids are mixed after gas-liquid separation to balance the concentration. The mixing of alkali liquid after the gas-liquid separation tank causes the cross-penetration of hydrogen and oxygen dissolved in the alkali liquid.

[0009] The second is the influence of gas partial pressure difference. The pressure of hydrogen produced by the cathode and oxygen produced by the anode are both the operating pressure of the electrolyzer, but the hydrogen partial pressure on the cathode side and the oxygen partial pressure on the anode side are much higher than the partial pressure of the gas on the opposite side of the diaphragm. There is a partial pressure difference between hydrogen and oxygen gases, which causes hydrogen or oxygen to enter the opposite side space due to the partial pressure difference, resulting in a certain degree of gas cross-permeation.

[0010] The third is the influence of the gas concentration difference in the alkali solution. The alkali solution in the electrolytic chambers on the cathode and anode sides of the electrolytic cell contains the corresponding gases produced by the electrolysis of water on that side, resulting in a concentration difference of hydrogen and oxygen in the alkali solution on both sides of the electrolytic cell diaphragm, that is, gas concentration diffusion occurs through the diaphragm. However, studies have shown that concentration diffusion is a natural convection process, and the proportion of the power transferred and the hydrogen and oxygen intermixing flux caused by the diaphragm is very small, which is not an order of magnitude compared to the influence of alkali solution intermixing and gas partial pressure difference on hydrogen in oxygen.

[0011] Therefore, how to solve the problem of excessive hydrogen content in oxygen caused by alkali solution mixing and gas partial pressure difference when the alkaline electrolyzer is operating under low load or unstable conditions is the key to improving the safety of alkaline water electrolysis hydrogen production system. Summary of the invention

[0012] The object of the present invention is to provide an alkaline water electrolysis hydrogen production system and method for deeply reducing the hydrogen content in oxygen, so as to solve the problem of excessively high hydrogen content in oxygen in the electrolysis hydrogen production system caused by alkali solution mixing and gas partial pressure difference when the alkaline electrolytic cell is under low load or unstable operating conditions.

[0013] To achieve the above object, the present invention adopts the following technical solutions:

[0014] The first aspect of the present invention is to provide an alkaline water electrolysis hydrogen production system for deeply reducing the hydrogen content in oxygen, comprising an alkaline electrolytic cell, a hydrogen-side gas-liquid separator, a hydrogen-side pressure regulator, a first gas processing device, a first alkali liquid circulation pump, an oxygen-side gas-liquid separator, an oxygen-side pressure regulator, a second gas processing device, a second alkali liquid circulation pump, an alkali liquid mixing tank, and a third alkali liquid circulation pump;

[0015] The bottom of the alkaline electrolytic cell is provided with an inlet for mixed alkali solution;

[0016] A first liquid phase outlet is provided at the bottom of the hydrogen side gas-liquid separator, and the first liquid phase outlet is sequentially connected to a first alkali liquid circulation pump, a first pressure reducing valve, a hydrogen side flash tank and an alkali liquid mixing tank through pipelines; the first pressure reducing valve is used to reduce the pressure of the hydrogen side alkali liquid from the first liquid phase outlet so that it enters the hydrogen side flash tank; the hydrogen side flash tank is used to allow the hydrogen side alkali liquid to boil and vaporize rapidly after the pressure is reduced, and to perform gas-liquid separation, thereby deeply removing dissolved hydrogen in the hydrogen side alkali liquid;

[0017] A second liquid phase outlet is provided at the bottom of the oxygen side gas-liquid separator, and the second liquid phase outlet is sequentially connected to a second alkali liquid circulation pump and an alkali liquid mixing tank through a pipeline;

[0018] The alkali solution mixing tank is connected to the third alkali solution circulation pump, the second pressure reducing valve, the mixed alkali solution flash tank, the buffer tank and the mixed alkali solution inlet in sequence through pipelines; the second pressure reducing valve is used to reduce the pressure of the mixed alkali solution from the alkali solution mixing tank so that it enters the mixed alkali solution flash tank; the mixed alkali solution flash tank is used to allow the mixed alkali solution to boil and vaporize rapidly after the pressure is reduced, and to perform gas-liquid separation, so as to deeply remove the dissolved oxygen and dissolved hydrogen in the mixed alkali solution; the buffer tank is used to buffer the pressure fluctuation between the mixed alkali solution flash tank and the alkaline electrolytic cell and adjust the mixed alkali solution after the deep removal of dissolved oxygen and dissolved hydrogen to the working temperature of the alkaline electrolytic cell;

[0019] A first gas phase outlet is provided on the top of the hydrogen side gas-liquid separator, which is connected to the first gas processing device through a ninth pipeline, and the hydrogen side pressure regulating component is arranged on the ninth pipeline; a second gas phase outlet is provided on the top of the oxygen side gas-liquid separator, which is connected to the second gas processing device through a tenth pipeline, and the oxygen side pressure regulating component is arranged on the tenth pipeline; the hydrogen side pressure regulating component and the oxygen side pressure regulating component have different pressure drops at the same fluid flow rate, wherein the pressure drop of the hydrogen side pressure regulating component is greater than the pressure drop of the oxygen side pressure regulating component.

[0020] The present invention deeply removes the dissolved hydrogen in the hydrogen side alkali liquid by cooperating with the first pressure reducing valve and the hydrogen side flash tank, and greatly reduces the solubility of hydrogen in the hydrogen side alkali liquid by utilizing the sudden reduction of the pressure when the hydrogen side alkali liquid enters the hydrogen side flash tank, and rapidly releases it in the form of gas phase, thereby reducing the dissolved hydrogen content in the hydrogen side alkali liquid; deeply removes the dissolved hydrogen and dissolved oxygen in the mixed alkali liquid by cooperating with the second pressure reducing valve and the mixed alkali liquid flash tank, and utilizes the pressure reduction of the mixed alkali liquid entering the mixed alkali liquid flash tank. The sudden decrease in pressure greatly reduces the solubility of oxygen and hydrogen in the mixed alkali solution, and they are quickly released in the form of gas phase, reducing the content of dissolved oxygen and dissolved hydrogen in the mixed alkali solution. By deeply removing the dissolved hydrogen in the alkali solution on the hydrogen side and the dissolved oxygen and dissolved hydrogen in the mixed alkali solution, the concentration of hydrogen in oxygen in the alkaline water electrolysis hydrogen production system can be effectively reduced, thereby reducing the safety hazards of the alkaline water electrolysis hydrogen production system and improving the safety of the system; optimizing the operating efficiency of the entire alkaline water electrolysis hydrogen production system and improving the overall hydrogen production efficiency; by A hydrogen-side pressure regulating member capable of regulating the pressure of the cathode chamber is provided, and an oxygen-side pressure regulating member capable of regulating the pressure of the anode chamber is provided at the second gas phase outlet, and at the same fluid flow rate, the pressure drop of the hydrogen-side pressure regulating member is greater than the pressure drop of the oxygen-side pressure regulating member, that is, the oxygen-side pressure regulating member has a greater resistance to the fluid, so that the pressure generated in the anode chamber is greater, and the pressure of the anode chamber of the alkaline electrolyzer is increased, so that the oxygen-side pressure of the alkaline electrolyzer can be higher than the hydrogen-side pressure, thereby reducing the amount of hydrogen entering the anode chamber from the cathode chamber through the diaphragm, reducing the concentration of hydrogen in oxygen in the alkaline water electrolysis hydrogen production system, avoiding the risk of explosion caused by excessive hydrogen concentration in oxygen, and ensuring the safety of the system; due to the high efficiency of these three devices (hydrogen-side flash tank, mixed alkali liquid flash tank and hydrogen and oxygen pressure regulating members), the efficiency of the separation equipment of the alkaline water electrolysis system is deeply improved, the demand for additional separation equipment and processing steps is reduced, the equipment area of ​​the separation system is reduced, the overall cost of the alkaline electrolyzer is reduced, the stability and reliability of the equipment in long-term operation are ensured, and the maintenance and failure rate are reduced.

[0021] Furthermore, a first gas-liquid mixed phase outlet is provided at the top of the cathode chamber; a second gas-liquid mixed phase outlet is provided at the top of the anode chamber;

[0022] A first gas-liquid mixed phase inlet is provided in the middle of the hydrogen side gas-liquid separator; a second gas-liquid mixed phase inlet is provided in the middle of the oxygen side gas-liquid separator;

[0023] The first gas-liquid mixed phase outlet is connected to the first gas-liquid mixed phase inlet through a first pipeline, and the second gas-liquid mixed phase outlet is connected to the second gas-liquid mixed phase inlet through a third pipeline.

[0024] Furthermore, at the same fluid flow rate, the pressure drop difference between the hydrogen-side pressure regulating component and the oxygen-side pressure regulating component is 1000-2000 Pa.

[0025] Furthermore, the hydrogen side flash tank has a first vertical column cavity, a first tangential inlet is provided in the middle of the first vertical column cavity, a third gas phase outlet is provided at the top, and a third liquid phase outlet is provided at the bottom; the first tangential inlet is connected to the first liquid phase outlet through a fifth pipeline, for receiving the hydrogen side alkali liquid from the first liquid phase outlet, and the first pressure reducing valve is arranged on the fifth pipeline; the third liquid phase outlet is connected to the alkali liquid mixing tank through a sixth pipeline.

[0026] A tangential inlet is used to allow the hydrogen-side alkaline solution to enter the hydrogen-side flash tank tangentially, generating a rotational motion, thereby forming a centrifugal field inside the hydrogen-side flash tank to achieve efficient separation of gas and liquid. The high efficiency of the flash device can reduce the need for additional separation equipment and processing steps in the alkaline water electrolysis hydrogen production system, save energy and resources, and reduce the operating cost of the alkaline water electrolysis hydrogen production system.

[0027] Furthermore, the third gas phase outlet is connected to a third gas processing device through a pipeline, which is used to process the gas removed from the hydrogen side flash tank.

[0028] Furthermore, the third gas phase outlet is provided with a first tapered overflow pipe inside the first vertical column cavity, and the first tapered overflow pipe forms an inverted cone-shaped thick wall around the third gas phase outlet inside the first vertical column cavity, which is used to provide bubble separation force under low pressure loss.

[0029] Furthermore, the mixed alkali liquid flash tank has a second vertical column cavity, a second tangential inlet is provided on the side of the second vertical column cavity, a fourth liquid phase outlet is provided at the bottom, and a fourth gas phase outlet is provided at the top, and the second tangential inlet is connected to the alkali liquid mixing tank through a seventh pipeline for receiving the mixed alkali liquid in the alkali liquid mixing tank; the third alkali liquid circulation pump and the second pressure reducing valve are both arranged on the seventh pipeline; the fourth liquid phase outlet is connected to the buffer tank through an eighth pipeline, and the buffer tank is connected to the mixed alkali liquid inlet through a pipeline.

[0030] A tangential inlet is used to allow the mixed alkali solution to enter the mixed alkali solution flash tank tangentially, generating a rotational motion, thereby forming a centrifugal force field inside the mixed alkali solution flash tank to achieve efficient separation of gas and liquid. The high efficiency of the flash device can reduce the need for additional separation equipment and processing steps in the alkaline water electrolysis hydrogen production system, save energy and resources, and reduce the operating cost of the alkaline water electrolysis hydrogen production system.

[0031] Furthermore, the fourth gas phase outlet is connected to a fourth gas processing device through a pipeline, and the fourth gas processing device is used to process the gas removed from the mixed alkali liquid flash tank.

[0032] Furthermore, the fourth gas phase outlet is provided with a second tapered overflow pipe inside the second vertical column cavity, and the second tapered overflow pipe forms an inverted cone-shaped thick wall around the fourth gas phase outlet inside the second vertical column cavity, which is used to provide bubble separation force under low pressure loss.

[0033] The second aspect of the present invention is to provide a method for producing hydrogen by electrolyzing alkaline water for deeply reducing the hydrogen content in oxygen, and the method comprises the following steps:

[0034] S41. 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;

[0035] S42. The gas-liquid mixture on the cathode side of the alkaline electrolytic cell is pumped into the hydrogen side gas-liquid separator for gas-liquid separation by a first alkali liquid circulation pump, and the gas-liquid mixture on the anode side of the alkaline electrolytic cell is pumped into the oxygen side gas-liquid separator for gas-liquid separation by a second alkali liquid circulation pump;

[0036] S43. The gas separated by the hydrogen-side gas-liquid separator is discharged from the first gas phase outlet, flows through the hydrogen-side pressure regulating component to generate a first pressure drop, enters the first gas processing device for drying and pressurizing treatment, and then is collected; the gas separated by the oxygen-side gas-liquid separator is discharged from the second gas phase outlet, flows through the oxygen-side pressure regulating component to generate a second pressure drop, enters the second gas processing device for drying and pressurizing treatment, and then is collected; wherein the first pressure drop is greater than the second pressure drop;

[0037] S44. After the gas-liquid separation, the hydrogen-side alkali liquid is decompressed by the first pressure reducing valve and then enters the hydrogen-side flash tank for flash evaporation. Due to the sudden decrease in pressure, the hydrogen-side alkali liquid undergoes flash evaporation, which greatly reduces the solubility of hydrogen in the hydrogen-side alkali liquid and rapidly releases it in the form of gas phase, thereby achieving deep removal of dissolved hydrogen in the hydrogen-side alkali liquid. After the deep removal of dissolved hydrogen, the hydrogen-side alkali liquid enters the alkali liquid mixing tank; the oxygen-side alkali liquid after gas-liquid separation enters the alkali liquid mixing tank;

[0038] S45. The hydrogen-side alkali liquid and the oxygen-side alkali liquid enter the alkali liquid mixing tank for mixing. Under the action of the third alkali liquid circulation pump, the mixed alkali liquid is decompressed by the second pressure reducing valve and then enters the mixed alkali liquid flash tank. After the decompressed mixed alkali liquid enters the mixed alkali liquid flash tank, due to the sudden drop in pressure, the mixed alkali liquid flashes, which greatly reduces the solubility of hydrogen and oxygen in the mixed alkali liquid, and is rapidly released in the form of gas phase, thereby achieving deep removal of dissolved oxygen and dissolved hydrogen in the mixed alkali liquid. After the deep removal of dissolved oxygen and dissolved hydrogen, the mixed alkali liquid enters the buffer tank. After the mixed alkali liquid in the buffer tank reaches the working temperature of the alkaline electrolyzer, the mixed alkali liquid in the buffer tank is pumped back into the alkaline electrolyzer for electrolysis through the alkali liquid circulation pump.

[0039] Furthermore, the volume of the gas-liquid mixed liquid in the oxygen-side gas-liquid separator and the hydrogen-side gas-liquid separator is controlled to be 1 / 2 to 3 / 4 of the volume of the gas-liquid separator.

[0040] Furthermore, the hydrogen side alkali liquid pressure at the hydrogen side flash tank inlet is 0.1-0.3Mpa, and the speed is 3m / s-6m / s; the mixed alkali liquid pressure at the mixed alkali liquid flash tank inlet is 0.1-0.3Mpa, and the speed is 3m / s-6m / s.

[0041] Controlling the flash pressure of the hydrogen side flash tank and the mixed alkali liquid flash tank to 0.1-0.3Mpa can ensure the effective operation and safety of the system.

[0042] Furthermore, the outlet pressures of the first alkali solution circulation pump, the second alkali solution circulation pump and the third alkali solution circulation pump are all 0.8-1.6 MPa.

[0043] The third aspect of the present invention is to provide an alkaline water electrolysis hydrogen production system for deeply reducing the hydrogen content in oxygen, comprising an alkaline electrolytic cell, a hydrogen-side gas-liquid separator, a first gas processing device, a first alkali liquid circulation pump, an oxygen-side gas-liquid separator, a second gas processing device, a second alkali liquid circulation pump and an alkali liquid mixing tank;

[0044] A first liquid phase outlet is provided at the bottom of the hydrogen side gas-liquid separator, and the first liquid phase outlet is connected to a first pressure reducing valve and a hydrogen side flash tank in sequence through a pipeline; the first pressure reducing valve is used to reduce the pressure of the hydrogen side alkali liquid from the first liquid phase outlet so that it enters the hydrogen side flash tank; the hydrogen side flash tank is used to allow the hydrogen side alkali liquid to boil and vaporize rapidly after the pressure is reduced, and to perform gas-liquid separation, thereby deeply removing dissolved hydrogen in the hydrogen side alkali liquid.

[0045] The present invention deeply removes dissolved hydrogen in the hydrogen side alkali liquid through the cooperation of the first pressure reducing valve and the hydrogen side flash tank, and utilizes the sudden reduction in pressure when the hydrogen side alkali liquid enters the hydrogen side flash tank to greatly reduce the solubility of hydrogen in the hydrogen side alkali liquid, and quickly releases it in the form of gas phase, thereby reducing the dissolved hydrogen content in the hydrogen side alkali liquid, thereby effectively reducing the hydrogen concentration in oxygen in the alkaline water electrolysis hydrogen production system, thereby reducing the safety hazards of the alkaline water electrolysis hydrogen production system and improving the safety of the system; optimizing the operating efficiency of the entire alkaline water electrolysis hydrogen production system and improving the overall hydrogen production efficiency.

[0046] Further, the alkaline electrolytic cell has a cathode chamber and an anode chamber;

[0047] A first gas-liquid mixed phase outlet is provided at the bottom of the cathode chamber, and a second gas-liquid mixed phase outlet is provided at the bottom of the anode chamber;

[0048] The bottom of the alkaline electrolytic cell is provided with an inlet for mixed alkali solution;

[0049] The hydrogen-side gas-liquid separator is provided with a first gas-liquid mixed phase inlet in the middle, and a first gas phase outlet at the top; the oxygen-side gas-liquid separator is provided with a second gas-liquid mixed phase inlet in the middle, a second gas phase outlet at the top, and a second liquid phase outlet at the bottom;

[0050] The first gas-liquid mixed phase outlet is connected to the first gas-liquid mixed phase inlet through a first pipeline, and the first alkali liquid circulation pump is arranged on the first pipeline; the first gas phase outlet is connected to the first gas processing device through a pipeline;

[0051] The second gas-liquid mixed phase outlet is connected to the second gas-liquid mixed phase inlet through a third pipeline, and the second alkali solution circulation pump is arranged on the third pipeline; the second gas phase outlet is connected to the second gas processing device through a pipeline, and the second liquid phase outlet is connected to the alkali solution mixing tank through a fourth pipeline;

[0052] The alkali solution mixing tank is connected to the mixed alkali solution inlet through a pipeline.

[0053] Furthermore, the hydrogen side flash tank has a first vertical column cavity, a first tangential inlet is provided in the middle of the first vertical column cavity, a third gas phase outlet is provided at the top, and a third liquid phase outlet is provided at the bottom; the first tangential inlet is connected to the first liquid phase outlet through a fifth pipeline, for receiving the hydrogen side alkali liquid from the first liquid phase outlet, and the first pressure reducing valve is arranged on the fifth pipeline; the third liquid phase outlet is connected to the alkali liquid mixing tank through a sixth pipeline.

[0054] A tangential inlet is used to allow the hydrogen-side alkaline solution to enter the hydrogen-side flash tank tangentially, generating a rotational motion, thereby forming a centrifugal field inside the hydrogen-side flash tank to achieve efficient separation of gas and liquid. The high efficiency of the flash device can reduce the need for additional separation equipment and processing steps in the alkaline water electrolysis hydrogen production system, save energy and resources, and reduce the operating cost of the alkaline water electrolysis hydrogen production system.

[0055] Furthermore, the third gas phase outlet is connected to a third gas processing device through a pipeline, which is used to process the gas removed from the hydrogen side flash tank.

[0056] Furthermore, the third gas phase outlet is provided with a first tapered overflow pipe inside the first vertical column cavity, and the first tapered overflow pipe forms an inverted cone-shaped thick wall around the third gas phase outlet inside the first vertical column cavity, which is used to provide bubble separation force under low pressure loss.

[0057] Furthermore, when the diameter of the hydrogen-side gas-liquid separator is 0.5-1 m and the height is 2-4 m, the height of the hydrogen-side flash tank is 1.2-1.8 m and the diameter is 0.7-1.2 m.

[0058] A fourth aspect of the present invention is to provide a method for producing hydrogen by electrolyzing alkaline water for deeply reducing the hydrogen content in oxygen, using the above-mentioned system for producing hydrogen by electrolyzing alkaline water for deeply reducing the hydrogen content in oxygen, comprising the following steps:

[0059] S11. 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;

[0060] S12. The gas-liquid mixture on the cathode side of the alkaline electrolytic cell is pumped into the hydrogen side gas-liquid separator for gas-liquid separation by a first alkali liquid circulation pump, and the gas-liquid mixture on the anode side of the alkaline electrolytic cell is pumped into the oxygen side gas-liquid separator for gas-liquid separation by a second alkali liquid circulation pump;

[0061] S13. The gas separated by the oxygen-side gas-liquid separator enters the second gas treatment device for drying and pressurizing treatment and then is collected, and the oxygen-side alkali liquid after gas-liquid separation enters the alkali liquid mixing tank; the gas separated by the hydrogen-side gas-liquid separator enters the first gas treatment device for drying and pressurizing treatment and then is collected, and the hydrogen-side alkali liquid after gas-liquid separation enters the hydrogen-side flash tank after being reduced in pressure by the first pressure reducing valve;

[0062] S14. After the decompressed hydrogen-side alkali liquid enters the hydrogen-side flash tank, the hydrogen-side alkali liquid flashes due to the sudden drop in pressure, which greatly reduces the solubility of hydrogen in the hydrogen-side alkali liquid and rapidly releases it in the form of gas phase, thereby achieving deep removal of dissolved hydrogen in the hydrogen-side alkali liquid. After the deep removal of dissolved hydrogen, the hydrogen-side alkali liquid enters the alkali liquid mixing tank to mix with the oxygen-side alkali liquid, and the mixed alkali liquid in the alkali liquid mixing tank is pumped back into the alkaline electrolytic cell for electrolysis through the alkali liquid circulation pump.

[0063] Furthermore, the volume of the gas-liquid mixed liquid in the oxygen-side gas-liquid separator and the hydrogen-side gas-liquid separator is controlled to be 1 / 2 to 3 / 4 of the volume of the gas-liquid separator.

[0064] Furthermore, the outlet pressures of the first alkali solution circulation pump and the second alkali solution circulation pump are both 0.8-1.6 MPa.

[0065] Furthermore, the hydrogen-side alkali liquid pressure at the inlet of the hydrogen-side flash tank is 0.1-0.3 MPa, and the speed is 3 m / s-6 m / s.

[0066] Controlling the flash pressure of the hydrogen side flash tank to 0.1-0.3Mpa can ensure the effective operation and safety of the system.

[0067] A fifth aspect of the present invention is to provide an alkaline water electrolysis hydrogen production system for deeply reducing the hydrogen content in oxygen, comprising an alkaline electrolytic cell, a hydrogen-side gas-liquid separator, a first gas treatment device, a first alkali liquid circulation pump, an oxygen-side gas-liquid separator, a second gas treatment device, a second alkali liquid circulation pump and an alkali liquid mixing tank;

[0068] The bottom of the alkaline electrolytic cell is provided with an inlet for mixed alkali solution;

[0069] The hydrogen-side gas-liquid separator and the oxygen-side gas-liquid separator are both connected to the alkali liquid mixing tank through pipelines, and the alkali liquid mixing tank is sequentially connected to the third alkali liquid circulation pump, the second pressure reducing valve, the mixed alkali liquid flash tank, the buffer tank and the mixed alkali liquid inlet through pipelines; the second pressure reducing valve is used to reduce the pressure of the mixed alkali liquid from the alkali liquid mixing tank so that it enters the mixed alkali liquid flash tank; the mixed alkali liquid flash tank is used to allow the mixed alkali liquid to boil and vaporize rapidly after the pressure is reduced, and to perform gas-liquid separation, so as to deeply remove the dissolved oxygen and dissolved hydrogen in the mixed alkali liquid; the buffer tank is used to buffer the pressure fluctuation between the mixed alkali liquid flash tank and the alkaline electrolyzer and to adjust the mixed alkali liquid after the deep removal of dissolved oxygen and dissolved hydrogen to the working temperature of the alkaline electrolyzer.

[0070] The present invention deeply removes dissolved hydrogen and dissolved oxygen in the mixed alkali solution through the cooperation of the second pressure reducing valve and the mixed alkali solution flash tank, and utilizes the sudden reduction in pressure when the mixed alkali solution enters the mixed alkali solution flash tank to greatly reduce the solubility of oxygen and hydrogen in the mixed alkali solution, and quickly releases them in the form of gas phase, which can effectively reduce the concentration of hydrogen in oxygen in the alkaline water electrolysis hydrogen production system, thereby reducing the safety hazards of the alkaline water electrolysis hydrogen production system and improving the safety of the system; optimizes the operating efficiency of the entire alkaline water electrolysis hydrogen production system and improves the overall hydrogen production efficiency.

[0071] Further, the alkaline electrolytic cell has a cathode chamber and an anode chamber;

[0072] The top of the cathode chamber is provided with a first gas-liquid mixed phase outlet, and the top of the anode chamber is provided with a second gas-liquid mixed phase outlet;

[0073] The hydrogen-side gas-liquid separator is provided with a first gas-liquid mixed phase inlet in the middle, a first gas phase outlet at the top, and a first liquid phase outlet at the bottom; the oxygen-side gas-liquid separator is provided with a second gas-liquid mixed phase inlet in the middle, a second gas phase outlet at the top, and a second liquid phase outlet at the bottom;

[0074] The first gas-liquid mixed phase outlet is connected to the first gas-liquid mixed phase inlet through a first pipeline, and the first alkali liquid circulation pump is arranged on the first pipeline; the first gas phase outlet is connected to the first gas processing device through a pipeline, and the first liquid phase outlet is connected to the alkali liquid mixing tank through a second pipeline;

[0075] The second gas-liquid mixed phase outlet is connected to the second gas-liquid mixed phase inlet through a third pipeline, and the second alkali liquid circulation pump is arranged on the third pipeline; the second gas phase outlet is connected to the second gas processing device through a pipeline, and the second liquid phase outlet is connected to the alkali liquid mixing tank through a fourth pipeline.

[0076] Furthermore, the mixed alkali liquid flash tank has a second vertical column cavity, a second tangential inlet is provided in the middle of the second vertical column cavity, a fourth liquid phase outlet is provided at the bottom, and a fourth gas phase outlet is provided at the top, and the second tangential inlet is connected to the alkali liquid mixing tank through a seventh pipeline for receiving the mixed alkali liquid in the alkali liquid mixing tank; the third alkali liquid circulation pump and the second pressure reducing valve are both arranged on the seventh pipeline; the fourth liquid phase outlet is connected to the buffer tank through an eighth pipeline, and the buffer tank is connected to the mixed alkali liquid inlet through a pipeline.

[0077] A tangential inlet is used to allow the mixed alkali solution to enter the mixed alkali solution flash tank tangentially, generating a rotational motion, thereby forming a centrifugal force field inside the mixed alkali solution flash tank to achieve efficient separation of gas and liquid. The high efficiency of the flash device can reduce the need for additional separation equipment and processing steps in the alkaline water electrolysis hydrogen production system, save energy and resources, and reduce the operating cost of the alkaline water electrolysis hydrogen production system.

[0078] Furthermore, the fourth gas phase outlet is connected to a fourth gas processing device through a pipeline, and the fourth gas processing device is used to process the gas removed from the mixed alkali liquid flash tank.

[0079] Furthermore, the fourth gas phase outlet is provided with a second tapered overflow pipe inside the second vertical column cavity, and the second tapered overflow pipe forms an inverted cone-shaped thick wall around the fourth gas phase outlet inside the second vertical column cavity, which is used to provide bubble separation force under low pressure loss.

[0080] A sixth aspect of the present invention is to provide a method for producing hydrogen by electrolyzing alkaline water for deeply reducing the hydrogen content in oxygen, using the above-mentioned system for producing hydrogen by electrolyzing alkaline water for deeply reducing the hydrogen content in oxygen, comprising the following steps:

[0081] S21. 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;

[0082] S22. The gas-liquid mixture on the cathode side of the alkaline electrolytic cell is pumped into the hydrogen side gas-liquid separator for gas-liquid separation by a first alkali liquid circulation pump, and the gas-liquid mixture on the anode side of the alkaline electrolytic cell is pumped into the oxygen side gas-liquid separator for gas-liquid separation by a second alkali liquid circulation pump;

[0083] S23. The gas separated by the oxygen-side gas-liquid separator enters the second gas treatment device for drying and pressurizing treatment and then is collected, and the gas separated by the hydrogen-side gas-liquid separator enters the first gas treatment device for drying and pressurizing treatment and then is collected; the oxygen-side alkali liquid and the hydrogen-side alkali liquid after gas-liquid separation enter the alkali liquid mixing tank for mixing;

[0084] S24. Under the action of the third alkali solution circulation pump, the mixed alkali solution enters the mixed alkali solution flash tank after passing through the second pressure reducing valve. Due to the sudden drop in pressure, the mixed alkali solution flashes, which greatly reduces the solubility of oxygen and hydrogen in the mixed alkali solution. The mixed alkali solution is rapidly released in the form of gas phase, thereby achieving deep removal of dissolved oxygen and dissolved hydrogen in the mixed alkali solution. After the deep removal of dissolved oxygen and dissolved hydrogen, the mixed alkali solution enters the buffer tank. After the mixed alkali solution in the buffer tank reaches the working temperature of the alkaline electrolytic cell, the mixed alkali solution in the buffer tank is re-pumped into the alkaline electrolytic cell for electrolysis through the first alkali solution circulation pump and the second alkali solution circulation pump.

[0085] Furthermore, the volume of the gas-liquid mixed liquid in the oxygen-side gas-liquid separator and the hydrogen-side gas-liquid separator is controlled to be 1 / 2 to 3 / 4 of the volume of the gas-liquid separator.

[0086] Furthermore, the outlet pressures of the first alkali liquid circulation pump, the second alkali liquid circulation pump and the third alkali liquid circulation pump are all 0.8-1.6 MPa.

[0087] Furthermore, the mixed alkali solution pressure at the inlet of the mixed alkali solution flash tank is 0.1-0.3 MPa, and the speed is 3 m / s-6 m / s.

[0088] Controlling the flash pressure of the mixed alkali solution flash tank to 0.1-0.3Mpa can ensure the effective operation and safety of the system.

[0089] A seventh aspect of the present invention is to provide an alkaline water electrolysis hydrogen production system for deeply reducing the hydrogen content in oxygen, comprising an alkaline electrolytic cell, a hydrogen-side gas-liquid separator, a hydrogen-side alkali liquid tank, a first alkali liquid circulation pump, a first gas treatment device, an oxygen-side gas-liquid separator, an oxygen-side alkali liquid tank, a second alkali liquid circulation pump and a second gas treatment device;

[0090] The alkaline electrolytic cell has a cathode chamber and an anode chamber;

[0091] The cathode chamber, the hydrogen side gas-liquid separator, the hydrogen side alkali liquid tank, the first alkali liquid circulation pump and the first gas processing device are connected by pipelines to form a hydrogen side gas-liquid separation system; the anode chamber, the oxygen side gas-liquid separator, the oxygen side alkali liquid tank, the second alkali liquid circulation pump and the second gas processing device are connected by pipelines to form an oxygen side gas-liquid separation system;

[0092] The hydrogen side gas-liquid separation system also includes a hydrogen side pressure regulating component for regulating the cathode chamber pressure, and the oxygen side gas-liquid separation system also includes an oxygen side pressure regulating component for regulating the anode chamber pressure, and the hydrogen side pressure regulating component and the oxygen side pressure regulating component have different pressure drops at the same fluid flow rate, wherein the pressure drop of the hydrogen side pressure regulating component is greater than the pressure drop of the oxygen side pressure regulating component.

[0093] The present invention sets two independent alkali liquid circulation loops, and the hydrogen-side alkali liquid after gas-liquid separation returns to the cathode chamber through the hydrogen-side alkali liquid circulation loop for electrolysis again; the oxygen-side alkali liquid after gas-liquid separation returns to the anode chamber through the oxygen-side alkali liquid circulation loop for electrolysis again, which can reduce the increase of hydrogen content in oxygen caused by alkali liquid mixing, reduce the hydrogen concentration in oxygen in the alkaline water electrolysis hydrogen production system, and improve the safety of the alkaline water electrolysis hydrogen production system; by providing a hydrogen-side pressure regulating component for regulating the cathode chamber pressure in the hydrogen-side gas-liquid separation system of the alkaline water electrolysis hydrogen production device, and providing an oxygen-side pressure regulating component for regulating the anode chamber pressure in the oxygen-side gas-liquid separation system, and under the same fluid flow rate, the hydrogen-side pressure regulating component The pressure drop of the node is greater than the pressure drop of the oxygen-side pressure regulating element, that is, the oxygen-side pressure regulating element has a greater resistance to the fluid, so that the resistance of the gas-liquid mixture or gas (mixed with some liquid) in the oxygen-side gas-liquid separation system when flowing through the oxygen-side pressure regulating element is greater than the resistance of the gas-liquid mixture or gas (mixed with some liquid) in the hydrogen-side gas-liquid separation system when flowing through the hydrogen-side pressure regulating element, and the pressure in the anode chamber is greater, which increases the pressure in the anode chamber of the alkaline electrolyzer, so that the pressure on the oxygen side can be higher than the pressure on the hydrogen side, thereby reducing the amount of hydrogen that enters the anode chamber from the cathode chamber through the diaphragm, reducing the concentration of hydrogen in oxygen in the alkaline water electrolysis hydrogen production system, avoiding the risk of explosion caused by excessive hydrogen concentration in oxygen, and ensuring the safety of the system.

[0094] Furthermore, at the same fluid flow rate, the pressure drop difference between the hydrogen-side pressure regulating component and the oxygen-side pressure regulating component is 1000-2000 Pa.

[0095] Furthermore, the cathode chamber has a first gas-liquid mixed phase outlet at the top and a first alkali solution inlet at the bottom; the anode chamber has a second gas-liquid mixed phase outlet at the top and a second alkali solution inlet at the bottom;

[0096] The hydrogen-side gas-liquid separator is provided with a first gas phase outlet at the top, a first liquid phase outlet at the bottom, and a first gas-liquid mixed phase inlet in the middle; the oxygen-side gas-liquid separator is provided with a second gas phase outlet at the top, a second liquid phase outlet at the bottom, and a second gas-liquid mixed phase inlet in the middle;

[0097] The first gas-liquid mixed phase outlet is connected to the first gas-liquid mixed phase inlet through a first pipeline, the first gas phase outlet is connected to the first gas processing device through a ninth pipeline, and the first liquid phase outlet is sequentially connected to the hydrogen side alkali liquid tank, the first alkali liquid circulation pump and the first alkali liquid inlet through pipelines;

[0098] The second gas-liquid mixed phase outlet is connected to the second gas-liquid mixed phase inlet through the third pipeline, the second gas phase outlet is connected to the second gas processing device through the tenth pipeline, and the second liquid phase outlet is connected to the oxygen side alkali liquid tank, the second alkali liquid circulation pump and the second alkali liquid inlet in sequence through pipelines.

[0099] Furthermore, the hydrogen side pressure regulating component is arranged on the first pipeline or the ninth pipeline.

[0100] Furthermore, the hydrogen side pressure regulating component is arranged inside the hydrogen side gas-liquid separator, and is fixedly arranged at the first gas-liquid mixed phase inlet or the first gas phase outlet.

[0101] Furthermore, the oxygen-side pressure regulating component is arranged on the third pipeline or the tenth pipeline.

[0102] Furthermore, the oxygen-side pressure regulating component is arranged inside the oxygen-side gas-liquid separator, and is fixedly arranged at the second gas-liquid mixed phase inlet or the second gas phase outlet.

[0103] The eighth aspect of the present invention is to provide a method for producing hydrogen by electrolyzing alkaline water for deeply reducing the hydrogen content in oxygen, using the above-mentioned system for producing hydrogen by electrolyzing alkaline water for deeply reducing the hydrogen content in oxygen, comprising the following steps:

[0104] S31. 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;

[0105] S32. The gas-liquid mixture in the cathode chamber is pumped into the hydrogen side gas-liquid separator for gas-liquid separation by the first alkali liquid circulation pump, and the gas-liquid mixture in the anode chamber is pumped into the oxygen side gas-liquid separator for gas-liquid separation by the second alkali liquid circulation pump;

[0106] S33. After gravity settling, the gas mixed with some liquid separated by the hydrogen side gas-liquid separator enters the first gas treatment device for drying and pressurizing treatment and then collected, and the gas mixed with some liquid separated by the oxygen side gas-liquid separator enters the second gas treatment device for drying and pressurizing treatment and then collected;

[0107] S34. After the gas-liquid separation, the hydrogen-side alkali liquid flows back to the hydrogen-side alkali liquid tank, and re-enters the cathode chamber for electrolysis under the action of the first alkali liquid circulation pump to form a hydrogen-side cycle; after the gas-liquid separation, the oxygen-side alkali liquid flows back to the oxygen-side alkali liquid tank, and re-enters the anode chamber for electrolysis under the action of the second alkali liquid circulation pump to form an oxygen-side cycle;

[0108] Among them, the gas-liquid mixture or gas mixed with some liquid in the hydrogen side gas-liquid separation system flows through the hydrogen side pressure regulating component, and the gas-liquid mixture or gas mixed with some liquid in the oxygen side gas-liquid separation system flows through the oxygen side pressure regulating component, so that the pressure in the anode chamber is higher than the pressure in the cathode chamber.

[0109] Furthermore, the volume of the electrolyte in the hydrogen-side gas-liquid separator and the oxygen-side gas-liquid separator is controlled to be 1 / 2 to 3 / 4 of the volume of the gas-liquid separator. BRIEF DESCRIPTION OF THE DRAWINGS

[0110] Figure 1 This is a schematic diagram of an alkaline water electrolysis hydrogen production system for deeply reducing the hydrogen content in oxygen according to Example 1 of the present invention.

[0111] Figure 2 This is a schematic diagram of an alkaline water electrolysis hydrogen production system for deeply reducing the hydrogen content in oxygen according to Example 2 of the present invention.

[0112] Figure 3 This is a schematic diagram of an alkaline water electrolysis hydrogen production system for deeply reducing the hydrogen content in oxygen according to Example 3 of the present invention.

[0113] Figure 4 This is a schematic diagram of an alkaline water electrolysis hydrogen production system for deeply reducing the hydrogen content in oxygen by using a cyclone separator and an axial flow separator as pressure regulating components according to Example 3 of the present invention.

[0114] Figure 5 This is a schematic diagram of an alkaline water electrolysis hydrogen production system for deeply reducing the hydrogen content in oxygen according to Example 4 of the present invention.

[0115] Figure 6 It is a partial schematic diagram of the hydrogen side flash tank in Example 1 and Example 4 of the present invention.

[0116] Figure 7 It is a partial schematic diagram of the mixed alkali solution flash tank in Example 2 and Example 4 of the present invention.

[0117] Figure 8 It is a schematic diagram of the structure of the hydrogen side flash tank in Example 1 and Example 4 of the present invention.

[0118] Fig. 9 It is a schematic cross-sectional view of the hydrogen side flash tank in Example 1 and Example 4 of the present invention.

[0119] Fig.10 It is a schematic diagram of the structure of the mixed alkali solution flash tank in Example 2 and Example 4 of the present invention.

[0120] Fig.11 It is a schematic cross-sectional view of the mixed alkali solution flash tank in Example 2 and Example 4 of the present invention.

[0121] In the figure: 10-alkaline electrolytic cell; 11-cathode chamber; 111-first gas-liquid mixed phase outlet; 112-first alkali solution inlet; 12-anode chamber; 121-second gas-liquid mixed phase outlet; 122-second alkali solution inlet; 13-mixed alkali solution inlet;

[0122] 20-hydrogen side gas-liquid separator; 21-first gas-liquid mixed phase inlet; 22-first gas phase outlet; 23-first liquid phase outlet; 24-first reflux port;

[0123] 30- oxygen side gas-liquid separator; 31- second gas-liquid mixed phase inlet; 32- second gas phase outlet; 33- second liquid phase outlet; 34- second reflux port;

[0124] 41-first gas processing device; 42-second gas processing device; 43-third gas processing device; 44-fourth gas processing device;

[0125] 51-hydrogen side alkali liquid tank; 52-oxygen side alkali liquid tank; 53-alkali liquid mixing tank;

[0126] 61-hydrogen side flash tank; 62-first pressure reducing valve; 63-first vertical column chamber; 64-first tangential inlet; 65-third liquid phase outlet; 66-third gas phase outlet; 661-first gradually contracting overflow pipe;

[0127] 71-mixed alkali liquid flash tank; 72-second pressure reducing valve; 73-second vertical column chamber; 74-second tangential inlet; 75-fourth liquid phase outlet; 76-fourth gas phase outlet; 761-second gradually contracting overflow pipe;

[0128] 80-hydrogen side pressure regulating member; 81-cyclone separator; 82-first air inlet; 83-first air outlet; 84-first discharge port;

[0129] 90 - oxygen side pressure regulating member; 91 - axial flow separator; 92 - second air inlet; 93 - second air outlet; 94 - second discharge port;

[0130] 101-a first alkali solution circulation pump; 102-a second alkali solution circulation pump; 103-a third alkali solution circulation pump;

[0131] 110-buffer tank;

[0132] 120-stop valve;

[0133] 130-Hydrogen sensor / pressure sensor

[0134] 141 - first pipeline; 142 - second pipeline; 143 - third pipeline; 144 - fourth pipeline; 145 - fifth pipeline; 146 - sixth pipeline; 147 - seventh pipeline; 148 - eighth pipeline; 149 - ninth pipeline; 1410 - tenth pipeline. DETAILED DESCRIPTION

[0135] 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.

[0136] It should be noted that the low-load operation in the present invention refers to an operating condition where the operating load of the alkaline electrolytic cell is less than 50%.

[0137] Example 1

[0138] join Figure 1 , Figure 6 The electrolytic hydrogen production system of this embodiment using a flash evaporation device to reduce the dissolved hydrogen content of the hydrogen-side alkali solution includes an alkaline electrolytic cell 10, a hydrogen-side gas-liquid separator 20, a first gas processing device 41, a first alkali solution circulation pump 101, an oxygen-side gas-liquid separator 30, a second gas processing device 42, a second alkali solution circulation pump 102 and an alkali solution mixing tank 53;

[0139] A first liquid phase outlet 23 is provided at the bottom of the hydrogen side gas-liquid separator 20, and the first liquid phase outlet 23 is connected to the first pressure reducing valve 62 and the hydrogen side flash tank 61 in sequence through a pipeline; the first pressure reducing valve 62 is used to reduce the pressure of the hydrogen side alkali liquid from the first liquid phase outlet 23 so that it enters the hydrogen side flash tank 61; the hydrogen side flash tank 61 is used to allow the hydrogen side alkali liquid to boil and vaporize rapidly after the pressure is reduced, and to perform gas-liquid separation, thereby deeply removing the dissolved hydrogen in the hydrogen side alkali liquid.

[0140] In this embodiment, the dissolved hydrogen in the hydrogen side alkali liquid is deeply removed by the cooperation of the first pressure reducing valve 62 and the hydrogen side flash tank 61. The solubility of hydrogen in the hydrogen side alkali liquid is greatly reduced by utilizing the sudden reduction in pressure when the hydrogen side alkali liquid enters the hydrogen side flash tank 61, and the hydrogen is rapidly released in the form of gas phase, thereby reducing the dissolved hydrogen content in the hydrogen side alkali liquid, thereby effectively reducing the hydrogen concentration in oxygen in the alkaline water electrolysis hydrogen production system, thereby reducing the safety hazards of the alkaline water electrolysis hydrogen production system and improving the safety of the system; optimizing the operating efficiency of the entire alkaline water electrolysis hydrogen production system and improving the overall hydrogen production efficiency.

[0141] Continue to participate Figure 1 , Figure 6When in use, first connect the alkaline electrolytic cell 10 to a DC power supply, the positive electrode of the power supply is connected to the anode of the alkaline electrolytic cell 10, and the negative electrode of the power supply is connected to the cathode of the alkaline electrolytic cell 10; under the action of the DC power, the alkaline electrolyte in the alkaline electrolytic cell 10 becomes a gas-liquid mixture containing a large number of fine bubbles; the gas-liquid mixture on the anode side of the alkaline electrolytic cell 10 is pumped into the oxygen side gas-liquid separator 30 for gas-liquid separation through the second alkaline liquid circulation pump 102, and the gas-liquid mixture on the cathode side of the alkaline electrolytic cell 10 is pumped into the hydrogen side gas-liquid separator 20 for gas-liquid separation through the first alkaline liquid circulation pump 101; the gas separated by the oxygen side gas-liquid separator 30 enters the second gas processing device 42 for drying and pressurization treatment and then collected, and the gas separated by the hydrogen side gas-liquid separator 20 enters the first The gas treatment device 41 is dried and pressurized and then collected; the oxygen side alkali liquid after gas-liquid separation enters the alkali liquid mixing tank 53; the hydrogen side alkali liquid after gas-liquid separation is decompressed by the first pressure reducing valve 62 and enters the hydrogen side flash tank 61; after the decompressed hydrogen side alkali liquid enters the hydrogen side flash tank 61, due to the sudden drop in pressure, the hydrogen side alkali liquid flashes, so that the solubility of hydrogen in the hydrogen side alkali liquid is greatly reduced, and it is quickly released in the form of gas phase, so as to achieve deep removal of dissolved hydrogen in the hydrogen side alkali liquid; after the deep removal of dissolved hydrogen is completed, the hydrogen side alkali liquid enters the alkali liquid mixing tank 53 to mix with the oxygen side alkali liquid, and the mixed alkali liquid in the alkali liquid mixing tank 53 is pumped back into the alkaline electrolytic cell 10 for electrolysis through the first alkali liquid circulation pump 101 and the second alkali liquid circulation pump 102.

[0142] Continue to see Figure 1 , further, the alkaline electrolytic cell 10 has a cathode chamber 11 and an anode chamber 12;

[0143] A first gas-liquid mixed phase outlet 111 is provided at the top of the cathode chamber 11, and a second gas-liquid mixed phase outlet 121 is provided at the top of the anode chamber 12;

[0144] A mixed alkali solution inlet 13 is provided at the bottom of the alkaline electrolytic cell 11;

[0145] The hydrogen side gas-liquid separator 20 has a first gas-liquid mixed phase inlet 21 in the middle and a first gas phase outlet 22 at the top; the oxygen side gas-liquid separator 30 has a second gas-liquid mixed phase inlet 31 in the middle, a second gas phase outlet 32 ​​at the top and a second liquid phase outlet 33 at the bottom;

[0146] The first gas-liquid mixed phase outlet 111 is connected to the first gas-liquid mixed phase inlet 21 through the first pipeline 141, and the first alkali liquid circulation pump 101 is arranged on the first pipeline 141; the first gas phase outlet 22 is connected to the first gas processing device 41 through a pipeline;

[0147] The second gas-liquid mixed phase outlet 121 is connected to the second gas-liquid mixed phase inlet 21 through the third pipeline 143, and the second alkali liquid circulation pump 102 is arranged on the third pipeline 143; the second gas phase outlet 32 ​​is connected to the second gas processing device 42 through a pipeline, and the second liquid phase outlet 33 is connected to the alkali liquid mixing tank 53 through the fourth pipeline 144;

[0148] The alkali solution mixing tank 53 is connected to the mixed alkali solution inlet 13 through a pipeline.

[0149] Continue to see Figure 1 , Figure 6 Furthermore, the hydrogen side flash tank 61 has a first vertical column cavity 63, a first tangential inlet 64 is provided in the middle of the first vertical column cavity 63, a third gas phase outlet 66 is provided at the top, and a third liquid phase outlet 65 is provided at the bottom; the first tangential inlet 64 is connected to the first liquid phase outlet 23 through a fifth pipeline 145, for receiving the hydrogen side alkali liquid from the first liquid phase outlet 23, and the first pressure reducing valve 62 is arranged on the fifth pipeline 145; the third liquid phase outlet 65 is connected to the alkali liquid mixing tank 53 through a sixth pipeline 146; the third gas phase outlet 66 is connected to the third gas processing device 43 through a pipeline, for processing the gas removed from the hydrogen side flash tank 61.

[0150] A tangential inlet is used to allow the hydrogen-side alkaline solution to enter the hydrogen-side flash tank 61 tangentially, generating a rotational motion, thereby forming a centrifugal field inside the hydrogen-side flash tank 61 to achieve efficient separation of gas and liquid. Through the high efficiency of the flash device, the need for additional separation equipment and processing steps in the alkaline water electrolysis hydrogen production system can be reduced, energy and resources can be saved, and the operating cost of the alkaline water electrolysis hydrogen production system can be reduced.

[0151] See also Figure 8 , Fig. 9 Furthermore, the third gas phase outlet 66 is provided with a first tapered overflow pipe 661 inside the first vertical column cavity 63. The first tapered overflow pipe 661 forms an inverted cone-shaped thick wall on the peripheral wall of the third gas phase outlet 66 inside the first vertical column cavity 63, which is used to provide bubble separation force under low pressure loss.

[0152] Further, when the diameter of the hydrogen-side gas-liquid separator 20 is 0.5-1 m and the height is 2-4 m, the height of the hydrogen-side flash tank 61 is 1.2-1.8 m and the diameter is 0.7-1.2 m.

[0153] Furthermore, the inner diameter of the first tangential inlet 64 of the hydrogen-side flash tank 61 is 15 mm, the inner diameter of the top end of the first tapered overflow pipe 661 is 10 mm, and the inner diameter of the bottom end is 15 mm.

[0154] Furthermore, the gas-liquid separators on the hydrogen side and the oxygen side in the present invention are both vertical tanks.

[0155] refer to Figure 1 , Figure 6 The electrolytic hydrogen production method of this embodiment using a flash evaporation device to reduce the content of dissolved hydrogen in the alkali solution on the hydrogen side, and the electrolytic hydrogen production system using the flash evaporation device of this embodiment to reduce the content of dissolved hydrogen in the alkali solution on the hydrogen side include the following steps:

[0156] S11. Under the action of direct current, the alkaline electrolyte in the alkaline electrolytic cell 10 becomes a gas-liquid mixture containing a large number of fine bubbles;

[0157] S12. The gas-liquid mixture on the cathode side of the alkaline electrolytic cell 10 is pumped into the hydrogen side gas-liquid separator 20 for gas-liquid separation by the first alkali liquid circulation pump 101, and the gas-liquid mixture on the anode side of the alkaline electrolytic cell 10 is pumped into the oxygen side gas-liquid separator 30 for gas-liquid separation by the second alkali liquid circulation pump 102;

[0158] S13. The gas separated by the oxygen-side gas-liquid separator 30 enters the second gas processing device 42 for drying and pressurizing treatment and then is collected, and the oxygen-side alkali liquid after gas-liquid separation enters the alkali liquid mixing tank 53; the gas separated by the hydrogen-side gas-liquid separator 20 enters the first gas processing device 41 for drying and pressurizing treatment and then is collected, and the hydrogen-side alkali liquid after gas-liquid separation enters the hydrogen-side flash tank 61 after being reduced in pressure by the first pressure reducing valve 62;

[0159] S14. After the decompressed hydrogen-side alkali liquid enters the hydrogen-side flash tank 61, the hydrogen-side alkali liquid flashes due to the sudden drop in pressure, which greatly reduces the solubility of hydrogen in the hydrogen-side alkali liquid and rapidly releases it in the form of gas phase, thereby achieving deep removal of dissolved hydrogen in the hydrogen-side alkali liquid; after the deep removal of dissolved hydrogen, the hydrogen-side alkali liquid enters the alkali liquid mixing tank 53 to mix with the oxygen-side alkali liquid, and the mixed alkali liquid in the alkali liquid mixing tank 53 is pumped back into the alkaline electrolytic cell 10 for electrolysis through the first alkali liquid circulation pump 101 and the second alkali liquid circulation pump 102.

[0160] Furthermore, the volume of the gas-liquid mixed liquid in the oxygen-side gas-liquid separator 30 and the hydrogen-side gas-liquid separator 20 is controlled to be 1 / 2 to 3 / 4 of the volume of the gas-liquid separator.

[0161] Furthermore, the outlet pressures of the first alkali solution circulation pump 101 and the second alkali solution circulation pump 102 are both 0.8-1.6 MPa.

[0162] Furthermore, the hydrogen-side alkali liquid pressure at the inlet of the hydrogen-side flash tank 61 is 0.1-0.3 MPa, and the speed is 3 m / s-6 m / s.

[0163] Controlling the flash pressure of the hydrogen-side flash tank 61 to be 0.1-0.3 MPa can ensure the effective operation and safety of the system.

[0164] Example 2

[0165] join Figure 2 , Figure 7 The electrolytic hydrogen production system of this embodiment using a flash evaporation device to reduce the dissolved hydrogen content of a mixed alkali solution includes an alkaline electrolytic cell 10, a hydrogen-side gas-liquid separator 20, a first gas processing device 41, a first alkali solution circulation pump 101, an oxygen-side gas-liquid separator 30, a second gas processing device 42, a second alkali solution circulation pump 102, and an alkali solution mixing tank 53;

[0166] A mixed alkali solution inlet 13 is provided at the bottom of the alkaline electrolytic cell 10;

[0167] The hydrogen-side gas-liquid separator 20 and the oxygen-side gas-liquid separator 30 are both connected to the alkali solution mixing tank 53 through pipelines, and the alkali solution mixing tank 53 is connected to the third alkali solution circulation pump 103, the second pressure reducing valve 72, the mixed alkali solution flash tank 71, the buffer tank 110 and the mixed alkali solution inlet 13 in sequence through pipelines; the second pressure reducing valve 72 is used to reduce the pressure of the mixed alkali solution from the alkali solution mixing tank 53 so that it enters the mixed alkali solution flash tank 71; the mixed alkali solution flash tank 71 is used to allow the mixed alkali solution to boil and vaporize rapidly after the pressure is reduced, and to perform gas-liquid separation, so as to deeply remove the dissolved oxygen and dissolved hydrogen in the mixed alkali solution; the buffer tank 110 is used to buffer the pressure fluctuation between the mixed alkali solution flash tank 71 and the alkaline electrolyzer 10 and adjust the mixed alkali solution after the deep removal of dissolved oxygen and dissolved hydrogen to the working temperature (30-45°C) of the alkaline electrolyzer 10.

[0168] In this embodiment, the dissolved hydrogen and dissolved oxygen in the mixed alkali solution are deeply removed by the cooperation of the second pressure reducing valve 72 and the mixed alkali solution flash tank 71. The solubility of oxygen and hydrogen in the mixed alkali solution is greatly reduced by utilizing the sudden reduction in pressure when the mixed alkali solution enters the mixed alkali solution flash tank 71, and the oxygen and hydrogen are quickly released in the form of gas phase, which can effectively reduce the concentration of hydrogen in oxygen in the alkaline water electrolysis hydrogen production system, thereby reducing the safety hazards of the alkaline water electrolysis hydrogen production system and improving the safety of the system; optimizing the operating efficiency of the entire alkaline water electrolysis hydrogen production system and improving the overall hydrogen production efficiency.

[0169] Continue to participate Figure 2 , Figure 7When in use, first connect the alkaline electrolytic cell 10 to a DC power supply, the positive electrode of the power supply is connected to the anode chamber of the alkaline electrolytic cell 10, and the negative electrode of the power supply is connected to the cathode 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 mixture containing a large number of fine bubbles; the gas-liquid mixture on the anode side of the alkaline electrolytic cell 10 is pumped into the oxygen side gas-liquid separator 30 for gas-liquid separation through the second alkaline liquid circulation pump 102, and the gas-liquid mixture on the cathode side of the alkaline electrolytic cell 10 is pumped into the hydrogen side gas-liquid separator 20 for gas-liquid separation through the first alkaline liquid circulation pump 101; the gas separated by the oxygen side gas-liquid separator 30 enters the second gas treatment device 42 for drying and pressurization treatment and then is collected, and the gas separated by the hydrogen side gas-liquid separator 20 enters the first gas treatment device 41 for drying and pressurization The alkali liquid on the hydrogen side and the alkali liquid on the oxygen side after gas-liquid separation enter the alkali liquid mixing tank 53 for mixing; the mixed alkali liquid enters the mixed alkali liquid flash tank 71 through the second pressure reducing valve 72 under the action of the third alkali liquid circulation pump 103. Due to the sudden drop in pressure, the mixed alkali liquid flashes, which greatly reduces the solubility of oxygen and hydrogen in the mixed alkali liquid, and is quickly released in the form of gas phase, thereby achieving deep removal of dissolved oxygen and dissolved hydrogen in the mixed alkali liquid; after the mixed alkali liquid has completed the deep removal of dissolved oxygen and dissolved hydrogen, it enters the buffer tank 110. After the mixed alkali liquid in the buffer tank 110 reaches the working temperature of the alkaline electrolytic cell 10, the mixed alkali liquid in the buffer tank 110 is pumped back into the alkaline electrolytic cell 10 for electrolysis by the first alkali liquid circulation pump 101 and the second alkali liquid circulation pump 102.

[0170] Continue to see Figure 2 , Figure 7 , further, the alkaline electrolytic cell 10 has a cathode chamber 11 and an anode chamber 12;

[0171] A first gas-liquid mixed phase outlet 111 is provided at the top of the cathode chamber 11, and a second gas-liquid mixed phase outlet 121 is provided at the top of the anode chamber 12;

[0172] The hydrogen side gas-liquid separator 20 has a first gas-liquid mixed phase inlet 21 in the middle, a first gas phase outlet 22 at the top, and a first liquid phase outlet 23 at the bottom; the oxygen side gas-liquid separator 30 has a second gas-liquid mixed phase inlet 31 in the middle, a second gas phase outlet 32 ​​at the top, and a second liquid phase outlet 33 at the bottom;

[0173] The first gas-liquid mixed phase outlet 111 is connected to the first gas-liquid mixed phase inlet 21 through the first pipeline 141, and the first alkali liquid circulation pump 101 is arranged on the first pipeline 141; the first gas phase outlet 22 is connected to the first gas processing device 41 through a pipeline, and the first liquid phase outlet 23 is connected to the alkali liquid mixing tank 53 through the second pipeline 142;

[0174] The second gas-liquid mixed phase outlet 121 is connected to the second gas-liquid mixed phase inlet 31 through the third pipeline 143, and the second alkali liquid circulation pump 102 is arranged on the third pipeline 143; the second gas phase outlet 32 ​​is connected to the second gas processing device 42 through a pipeline, and the second liquid phase outlet 33 is connected to the alkali liquid mixing tank 53 through the fourth pipeline 144.

[0175] See also Figure 7 Furthermore, the mixed alkali liquid flash tank 71 has a second vertical column cavity 73, a second tangential inlet 74 is provided in the middle of the second vertical column cavity 73, a fourth liquid phase outlet 75 is provided at the bottom, and a fourth gas phase outlet 76 is provided at the top. The second tangential inlet 74 is connected to the alkali liquid mixing tank 53 through the seventh pipeline 147, and is used to receive the mixed alkali liquid in the alkali liquid mixing tank 53; the third alkali liquid circulation pump 103 and the second pressure reducing valve 72 are both arranged on the seventh pipeline 147; the fourth liquid phase outlet 75 is connected to the buffer tank 110 through the eighth pipeline 148, and the buffer tank 110 is connected to the mixed alkali liquid inlet 13 through a pipeline.

[0176] A tangential inlet is used to allow the mixed alkali solution to enter the mixed alkali solution flash tank 71 tangentially, generating a rotational motion, thereby forming a centrifugal force field inside the mixed alkali solution flash tank 71 to achieve efficient separation of gas and liquid. The high efficiency of the flash device can reduce the need for additional separation equipment and processing steps in the alkaline water electrolysis hydrogen production system, save energy and resources, and reduce the operating cost of the alkaline water electrolysis hydrogen production system.

[0177] Furthermore, the fourth gas phase outlet 76 is connected to a fourth gas processing device 44 via a pipeline, and the fourth gas processing device 44 is used to process the gas removed from the mixed alkali liquid flash tank 71 .

[0178] See also Fig.10 , Fig.11 Furthermore, the fourth gas phase outlet 76 is provided with a second tapered overflow pipe 761 inside the second vertical column cavity 73, and the second tapered overflow pipe 761 forms an inverted cone-shaped thick wall on the peripheral wall of the fourth gas phase outlet 76 inside the second vertical column cavity 73, which is used to provide bubble separation force under low pressure loss.

[0179] Further, when the diameter of the gas-liquid separator 20 is 0.5-1 m and the height is 2-4 m, the height of the mixed alkali liquid flash tank 71 is 1.2-1.8 m and the diameter is 0.6-0.9 m.

[0180] Furthermore, the inner diameter of the second tangential inlet 74 of the mixed alkali solution flash tank 71 is 15 mm, the inner diameter of the top end of the second tapered overflow pipe 761 is 10 mm, and the inner diameter of the bottom end is 15 mm.

[0181] Furthermore, the gas-liquid separators on the hydrogen side and the oxygen side in the present invention are both vertical tanks.

[0182] Continue to see Figure 2 , Figure 7 The electrolytic hydrogen production method of this embodiment using a flash evaporation device to reduce the content of dissolved hydrogen in a mixed alkali solution, and the electrolytic hydrogen production system using a flash evaporation device to reduce the content of dissolved hydrogen in a mixed alkali solution of this embodiment, include the following steps:

[0183] S21. 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;

[0184] S22. The gas-liquid mixture on the cathode side of the alkaline electrolytic cell 10 is pumped into the hydrogen side gas-liquid separator 20 for gas-liquid separation by the first alkali liquid circulation pump 101, and the gas-liquid mixture on the anode side of the alkaline electrolytic cell 10 is pumped into the oxygen side gas-liquid separator 30 for gas-liquid separation by the second alkali liquid circulation pump 102;

[0185] S23. The gas separated by the oxygen-side gas-liquid separator 30 enters the second gas processing device 42 for drying and pressurizing treatment and then collected, and the gas separated by the hydrogen-side gas-liquid separator 20 enters the first gas processing device 41 for drying and pressurizing treatment and then collected; the oxygen-side alkali liquid and the hydrogen-side alkali liquid after gas-liquid separation enter the alkali liquid mixing tank 53 for mixing;

[0186] S24. Under the action of the third alkali solution circulation pump 103, the mixed alkali solution enters the mixed alkali solution flash tank 71 after passing through the second pressure reducing valve 72. Due to the sudden drop in pressure, the mixed alkali solution flashes, which greatly reduces the solubility of oxygen and hydrogen in the mixed alkali solution, and is rapidly released in the form of gas phase, thereby achieving deep removal of dissolved oxygen and dissolved hydrogen in the mixed alkali solution; after the mixed alkali solution completes the deep removal of dissolved oxygen and dissolved hydrogen, it enters the buffer tank 110. After the mixed alkali solution in the buffer tank 110 reaches the operating temperature (30-45°C) of the alkaline electrolytic cell 10, the mixed alkali solution in the buffer tank 110 is pumped back into the alkaline electrolytic cell 10 for electrolysis through the first alkali solution circulation pump 101 and the second alkali solution circulation pump 102.

[0187] Furthermore, the volume of the gas-liquid mixed liquid in the oxygen-side gas-liquid separator 30 and the hydrogen-side gas-liquid separator 20 is controlled to be 1 / 2 to 3 / 4 of the volume of the gas-liquid separator.

[0188] Furthermore, the outlet pressures of the first alkali solution circulation pump 101 , the second alkali solution circulation pump 102 and the third alkali solution circulation pump 103 are all 0.8-1.6 MPa.

[0189] Furthermore, the pressure of the mixed alkali solution at the inlet of the mixed alkali solution flash tank 71 is 0.1-0.3 MPa, and the speed is 3 m / s-6 m / s.

[0190] Controlling the flash pressure of the mixed alkali solution flash tank 71 to be 0.1-0.3 MPa can ensure the effective operation and safety of the system.

[0191] Example 3

[0192] join Figure 3 , Figure 4 The electrolytic hydrogen production system of this embodiment for adjusting the pressure difference in the electrolytic cell to reduce the concentration of hydrogen in oxygen includes an alkaline electrolytic cell 10, a hydrogen-side gas-liquid separator 20, a hydrogen-side alkali liquid tank 51, a first alkali liquid circulation pump 101, a first gas processing device 41, an oxygen-side gas-liquid separator 30, an oxygen-side alkali liquid tank 52, a second alkali liquid circulation pump 102, and a second gas processing device 42;

[0193] The alkaline electrolytic cell 10 has a cathode chamber 11 and an anode chamber 12;

[0194] The cathode chamber 11, the hydrogen side gas-liquid separator 20, the hydrogen side alkali liquid tank 51, the first alkali liquid circulation pump 101 and the first gas processing device 41 are connected by pipelines to form a hydrogen side gas-liquid separation system; the anode chamber 12, the oxygen side gas-liquid separator 30, the oxygen side alkali liquid tank 52, the second alkali liquid circulation pump 102 and the second gas processing device 42 are connected by pipelines to form an oxygen side gas-liquid separation system;

[0195] The hydrogen side gas-liquid separation system also includes a hydrogen side pressure regulating component 80 for regulating the pressure of the cathode chamber 11, and the oxygen side gas-liquid separation system also includes an oxygen side pressure regulating component 90 for regulating the pressure of the anode chamber 12. The hydrogen side pressure regulating component 80 and the oxygen side pressure regulating component 90 have different pressure drops at the same fluid flow rate, wherein the pressure drop of the hydrogen side pressure regulating component 80 is greater than the pressure drop of the oxygen side pressure regulating component 90.

[0196] In this embodiment, two independent alkali liquid circulation loops are set up, and the hydrogen-side alkali liquid after gas-liquid separation returns to the cathode chamber 11 through the hydrogen-side alkali liquid circulation loop for electrolysis again; the oxygen-side alkali liquid after gas-liquid separation returns to the anode chamber 12 through the oxygen-side alkali liquid circulation loop for electrolysis again, which can reduce the increase in the content of hydrogen in oxygen caused by the mixing of alkali liquids, reduce the concentration of hydrogen in oxygen in the alkaline water electrolysis hydrogen production system, and improve the safety of the alkaline water electrolysis hydrogen production system; by providing a hydrogen-side pressure regulating member 80 for regulating the cathode chamber pressure in the hydrogen-side gas-liquid separation system of the alkaline water electrolysis hydrogen production system, and providing an oxygen-side pressure regulating member 90 for regulating the anode chamber pressure in the oxygen-side gas-liquid separation system, and at the same fluid flow rate, the hydrogen-side pressure regulating member 80 The pressure drop is greater than the pressure drop of the oxygen side pressure regulating member 90, that is, the oxygen side pressure regulating member 90 has a greater resistance to the fluid, so that the resistance of the gas-liquid mixture or gas (mixed with some liquid) in the oxygen side gas-liquid separation system when flowing through the oxygen side pressure regulating member 90 is greater than the resistance of the gas-liquid mixture or gas (mixed with some liquid) in the hydrogen side gas-liquid separation system when flowing through the hydrogen side pressure regulating member 80, and the back pressure generated in the anode chamber 12 is greater, thereby increasing the pressure of the anode chamber 12 of the alkaline electrolyzer, so that the oxygen side pressure can be higher than the hydrogen side pressure, thereby reducing the amount of hydrogen that passes through the diaphragm from the cathode chamber 11 into the anode chamber 12, reducing the concentration of hydrogen in oxygen in the alkaline water electrolysis hydrogen production system, avoiding the risk of explosion caused by excessive hydrogen concentration in oxygen, and ensuring the safety of the system.

[0197] Continue to see Figure 3 , Figure 4When in use, first connect the alkaline electrolytic cell 10 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 hydrogen side gas-liquid separator 20 through the first alkali liquid circulation pump 101 for gas-liquid separation, and the hydrogen side circulating alkali liquid after gas-liquid separation flows back to the hydrogen side alkali liquid tank 51, and is recirculated under the action of the first alkali liquid circulation pump 101. Enter the cathode chamber 11 for electrolysis, forming a hydrogen side circulation; the gas-liquid mixture in the anode chamber 12 is pumped into the oxygen side gas-liquid separator 30 through the second alkali liquid circulation pump 102 for gas-liquid separation, and the oxygen side circulating alkali liquid after gas-liquid separation flows back to the oxygen side alkali liquid tank 52, and re-enters the anode chamber 12 for electrolysis under the action of the second alkali liquid circulation pump 102, forming an oxygen side circulation; the gas separated by the hydrogen side gas-liquid separator 20 (mixed with some liquid) is discharged through the first gas phase outlet 22, and enters the first gas processing device 41 through the hydrogen side pressure regulating member 80 for drying The gas (mixed with some liquid) separated by the oxygen-side gas-liquid separator 30 is discharged through the second gas phase outlet 32, passes through the oxygen-side pressure regulating member 90 and enters the second gas processing device 42 for drying and pressurization treatment, and then is collected; because at the same fluid flow rate, the pressure drop of the hydrogen-side pressure regulating member 80 is greater than the pressure drop of the oxygen-side pressure regulating member 90, that is, the oxygen-side pressure regulating member 90 has a greater resistance to the fluid, so that the gas-liquid mixture or gas (mixed with some liquid) in the oxygen-side gas-liquid separation system has a greater resistance when flowing through the oxygen-side pressure regulating member 90 than the hydrogen-side gas-liquid separator. The gas-liquid mixture or gas (mixed with some liquid) in the separation system has a large resistance when flowing through the hydrogen side pressure regulating member 80, and the generated pressure is greater, thereby increasing the pressure of the anode chamber 12 of the alkaline electrolyzer, so that the pressure on the oxygen side (anode chamber 12) of the alkaline electrolyzer 10 can be higher than the pressure on the hydrogen side (cathode chamber 11) of the alkaline electrolyzer 10, reducing the amount of hydrogen that passes through the diaphragm from the cathode chamber 11 into the anode chamber 12, avoiding the explosion hazard caused by the mutual crosstalk between hydrogen and oxygen, further reducing the concentration of hydrogen in oxygen in the alkaline water electrolysis hydrogen production system, and ensuring the safety of the system.

[0198] Furthermore, for current density of 10 to 100 A / m 3 The alkaline electrolytic cell 10 has a gas-liquid separator with a diameter of 0.4 to 0.6 m and a height of 1 to 4 m. The pressure drop difference between the hydrogen-side pressure regulating component 20 and the oxygen-side pressure regulating component 90 is 1000 to 2000 Pa (at the same fluid flow rate).

[0199] Furthermore, the volume of the electrolyte in the hydrogen-side gas-liquid separator 20 and the oxygen-side gas-liquid separator 30 is controlled to be 1 / 2 to 3 / 4 of the volume of the gas-liquid separator.

[0200] Furthermore, the hydrogen side pressure regulating component 80 and the oxygen side pressure regulating component 90 include but are not limited to cyclone separators and axial flow separators, and may also be internal components such as filter membranes, filter screens, and valves. The present invention can control the pressure difference between the hydrogen and oxygen sides of the alkaline electrolyzer by replacing the pressure regulating components on both sides of the hydrogen and oxygen, so that the pressure on the oxygen side is higher than the pressure on the hydrogen side.

[0201] Furthermore, the cathode chamber 11 has a first gas-liquid mixed phase outlet 111 at the top and a first alkali solution inlet 112 at the bottom; the anode chamber 12 has a second gas-liquid mixed phase outlet 121 at the top and a second alkali solution inlet 122 at the bottom;

[0202] The hydrogen side gas-liquid separator 20 is provided with a first gas phase outlet 22 at the top, a first liquid phase outlet 23 at the bottom, and a first gas-liquid mixed phase inlet 21 at the middle; the oxygen side gas-liquid separator 30 is provided with a second gas phase outlet 32 ​​at the top, a second liquid phase outlet 33 at the bottom, and a second gas-liquid mixed phase inlet 31 at the middle;

[0203] The first gas-liquid mixed phase outlet 111 is connected to the first gas-liquid mixed phase inlet 21 through the first pipeline 141, the first gas phase outlet 22 is connected to the first gas processing device 41 through the ninth pipeline 149, and the first liquid phase outlet 23 is connected to the hydrogen side alkali liquid tank 51, the first alkali liquid circulation pump 101 and the first alkali liquid inlet 112 in sequence through pipelines;

[0204] The second gas-liquid mixed phase outlet 121 is connected to the second gas-liquid mixed phase inlet 31 through the third pipeline 143, the second gas phase outlet 32 ​​is connected to the second gas processing device 42 through the tenth pipeline 1410, and the second liquid phase outlet 33 is connected to the oxygen side alkali liquid tank 52, the second alkali liquid circulation pump 102 and the second alkali liquid inlet 122 in sequence through pipelines.

[0205] Furthermore, the hydrogen-side pressure regulating component 80 is disposed on the first pipeline 141 or the ninth pipeline 149 .

[0206] Furthermore, the hydrogen side pressure regulating component 80 is disposed inside the hydrogen side gas-liquid separator 20 , and is fixedly disposed at the first gas-liquid mixed phase inlet 21 or the first gas phase outlet 22 .

[0207] Further, the oxygen-side pressure regulating component 90 is disposed on the third pipeline 143 or the tenth pipeline 1410 .

[0208] Furthermore, the oxygen-side pressure regulating member 90 is disposed inside the oxygen-side gas-liquid separator 30 , and is fixedly disposed at the second gas-liquid mixed phase inlet 31 or the second gas phase outlet 32 ​​.

[0209] Furthermore, the hydrogen side pressure regulating component 80 and the oxygen side pressure regulating component 90 include but are not limited to cyclone separators and axial flow separators, and may also be internal components such as filter membranes, filter screens, and valves. The present invention can control the pressure difference between the hydrogen and oxygen sides of the alkaline electrolyzer by replacing the pressure regulating components on both sides of the hydrogen and oxygen, so that the pressure on the oxygen side is higher than the pressure on the hydrogen side.

[0210] Continue to see Figure 3 , Figure 4 The electrolytic hydrogen production method of this embodiment for adjusting the pressure difference in the electrolytic cell to reduce the concentration of hydrogen in oxygen, and the electrolytic hydrogen production system of this embodiment for adjusting the pressure difference in the electrolytic cell to reduce the concentration of hydrogen in oxygen include the following steps:

[0211] S31. 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;

[0212] S32. The gas-liquid mixture in the cathode chamber 11 is pumped into the hydrogen side gas-liquid separator 20 for gas-liquid separation by the first alkali liquid circulation pump 101, and the gas-liquid mixture in the anode chamber 12 is pumped into the oxygen side gas-liquid separator 30 for gas-liquid separation by the second alkali liquid circulation pump 102;

[0213] S33. After gravity settling, the gas mixed with some liquid separated by the hydrogen-side gas-liquid separator 20 enters the first gas processing device 41 for drying and pressurizing treatment and then collected, and the gas mixed with some liquid separated by the oxygen-side gas-liquid separator 30 enters the second gas processing device 42 for drying and pressurizing treatment and then collected;

[0214] S34. After the gas-liquid separation, the hydrogen-side alkali liquid flows back to the hydrogen-side alkali liquid tank 51, and re-enters the cathode chamber 11 for electrolysis under the action of the first alkali liquid circulation pump 101, constituting a hydrogen-side circulation; after the gas-liquid separation, the oxygen-side alkali liquid flows back to the oxygen-side alkali liquid tank 52, and re-enters the anode chamber 12 for electrolysis under the action of the second alkali liquid circulation pump 102, constituting an oxygen-side circulation;

[0215] Among them, the gas-liquid mixture or gas mixed with some liquid in the hydrogen side gas-liquid separation system flows through the hydrogen side pressure regulating component 80, and the gas-liquid mixture or gas mixed with some liquid in the oxygen side gas-liquid separation system flows through the oxygen side pressure regulating component 90, so that the pressure of the anode chamber 12 is higher than the pressure of the cathode chamber 11.

[0216] Furthermore, the volume of the electrolyte in the hydrogen-side gas-liquid separator 20 and the oxygen-side gas-liquid separator 30 is controlled to be 1 / 2 to 3 / 4 of the volume of the gas-liquid separator.

[0217] Example 4

[0218] See also Figures 5 to 11The alkaline water electrolysis hydrogen production system for deeply reducing the hydrogen content in oxygen of this embodiment includes an alkaline electrolytic cell 10, a hydrogen-side gas-liquid separator 20, a hydrogen-side pressure regulating member 80, a first gas processing device 41, a first alkali liquid circulation pump 101, an oxygen-side gas-liquid separator 30, an oxygen-side pressure regulating member 90, a second gas processing device 42, a second alkali liquid circulation pump 102, an alkali liquid mixing tank 53, and a third alkali liquid circulation pump 103;

[0219] A mixed alkali solution inlet 13 is provided at the bottom of the alkaline electrolytic cell 10;

[0220] A first liquid phase outlet 23 is provided at the bottom of the hydrogen side gas-liquid separator 20, and the first liquid phase outlet 23 is sequentially connected to the first alkali liquid circulation pump 102, the first pressure reducing valve 62, the hydrogen side flash tank 61 and the alkali liquid mixing tank 53 through pipelines; the first pressure reducing valve 62 is used to reduce the pressure of the hydrogen side alkali liquid from the first liquid phase outlet 23 so that it enters the hydrogen side flash tank 61; the hydrogen side flash tank 61 is used to allow the hydrogen side alkali liquid to boil and vaporize rapidly after the pressure is reduced, and to perform gas-liquid separation, so as to deeply remove the dissolved hydrogen in the hydrogen side alkali liquid;

[0221] A second liquid phase outlet 33 is provided at the bottom of the oxygen side gas-liquid separator 30, and the second liquid phase outlet 33 is sequentially connected to the second alkali liquid circulation pump 102 and the alkali liquid mixing tank 53 through a pipeline;

[0222] The alkali solution mixing tank 53 is connected to the third alkali solution circulation pump 103, the second pressure reducing valve 72, the mixed alkali solution flash tank 71, the buffer tank 110 and the mixed alkali solution inlet 13 in sequence through pipelines; the second pressure reducing valve 72 is used to reduce the pressure of the mixed alkali solution from the alkali solution mixing tank 53 so that it enters the mixed alkali solution flash tank 71; the mixed alkali solution flash tank 71 is used to allow the mixed alkali solution to boil and vaporize rapidly after the pressure is reduced, and to perform gas-liquid separation, so as to deeply remove the dissolved oxygen and dissolved hydrogen in the mixed alkali solution; the buffer tank 110 is used to buffer the pressure fluctuation between the mixed alkali solution flash tank 71 and the alkaline electrolytic cell 10 and adjust the mixed alkali solution after the deep removal of dissolved oxygen and dissolved hydrogen to the working temperature of the alkaline electrolytic cell 10;

[0223] A first gas phase outlet 22 is provided at the top of the hydrogen side gas-liquid separator 20, and the first gas phase outlet 22 is connected to the first gas processing device 41 through a ninth pipeline 149, and the hydrogen side pressure regulating component 80 is arranged on the ninth pipeline 149; a second gas phase outlet 32 ​​is provided at the top of the oxygen side gas-liquid separator 30, and the second gas phase outlet 32 ​​is connected to the second gas processing device 42 through a tenth pipeline 1410, and the oxygen side pressure regulating component 90 is arranged on the tenth pipeline 1410; the pressure drops of the hydrogen side pressure regulating component 80 and the oxygen side pressure regulating component 90 at the same fluid flow rate are different, wherein the pressure drop of the hydrogen side pressure regulating component 80 is greater than the pressure drop of the oxygen side pressure regulating component 90.

[0224] In this embodiment, the dissolved hydrogen in the hydrogen side alkali liquid is deeply removed by the cooperation of the first pressure reducing valve 62 and the hydrogen side flash tank 51. The solubility of hydrogen in the hydrogen side alkali liquid is greatly reduced by utilizing the sudden reduction in pressure when the hydrogen side alkali liquid enters the hydrogen side flash tank 61, and the hydrogen is rapidly released in the form of gas phase, thereby reducing the dissolved hydrogen content in the hydrogen side alkali liquid. The dissolved hydrogen and dissolved oxygen in the mixed alkali liquid are deeply removed by the cooperation of the second pressure reducing valve 72 and the mixed alkali liquid flash tank 71. The oxygen and hydrogen in the mixed alkali liquid are released by utilizing the sudden reduction in pressure when the mixed alkali liquid enters the mixed alkali liquid flash tank 71. The solubility of the gas is greatly reduced, and it is quickly released in the form of gas phase, reducing the content of dissolved oxygen and dissolved hydrogen in the mixed alkali solution. By deeply removing the dissolved hydrogen in the alkali solution on the hydrogen side and the dissolved oxygen and dissolved hydrogen in the mixed alkali solution, the concentration of hydrogen in oxygen in the alkaline water electrolysis hydrogen production system can be effectively reduced, thereby reducing the safety hazards of the alkaline water electrolysis hydrogen production system and improving the safety of the system; optimizing the operating efficiency of the entire alkaline water electrolysis hydrogen production system and improving the overall hydrogen production efficiency; by arranging a hydrogen pressure regulating device capable of adjusting the pressure of the cathode chamber 11 on the ninth pipeline 149 at the first gas phase outlet 22 The oxygen side pressure regulating member 80 is provided on the tenth pipeline 1410 at the second gas phase outlet, and the oxygen side pressure regulating member 90 capable of regulating the pressure of the anode chamber 12 is provided, and at the same fluid flow rate, the pressure drop of the hydrogen side pressure regulating member 80 is greater than the pressure drop of the oxygen side pressure regulating member 90, that is, the oxygen side pressure regulating member 90 has a greater resistance to the fluid, so that the pressure of the anode chamber 12 is greater, and the pressure of the anode chamber 12 of the alkaline electrolytic cell is increased, so that the oxygen side pressure of the alkaline electrolytic cell 10 can be higher than the hydrogen side pressure, thereby reducing the flow of oxygen from the cathode chamber 11 through the diaphragm into the anode chamber 12. The amount of hydrogen reduces the concentration of hydrogen in oxygen in the alkaline water electrolysis hydrogen production system, avoids the risk of explosion caused by excessive hydrogen concentration in oxygen, and ensures the safety of the system; due to the high efficiency of these three devices (hydrogen side flash tank 61, mixed alkali liquid flash tank 71 and hydrogen and oxygen side pressure regulating parts), the efficiency of the separation equipment of the alkaline water electrolysis system is deeply improved, the demand for additional separation equipment and processing steps is reduced, the equipment area of ​​the separation system is reduced, the overall cost of the alkaline electrolyzer is reduced, the stability and reliability of the equipment in long-term operation are ensured, and the maintenance and failure rate are reduced.

[0225] Furthermore, a first gas-liquid mixed phase outlet 111 is provided at the top of the cathode chamber 11; a second gas-liquid mixed phase outlet 121 is provided at the top of the anode chamber 12;

[0226] A first gas-liquid mixed phase inlet 21 is provided in the middle of the hydrogen-side gas-liquid separator 20; a second gas-liquid mixed phase inlet 31 is provided in the middle of the oxygen-side gas-liquid separator 30;

[0227] The first gas-liquid mixed phase outlet 111 is connected to the first gas-liquid mixed phase inlet 21 through a first pipeline 141 , and the second gas-liquid mixed phase outlet 121 is connected to the second gas-liquid mixed phase inlet 31 through a third pipeline 143 .

[0228] Furthermore, the setting position of the hydrogen side pressure regulating device 80 includes but is not limited to the ninth pipeline 149, and can also be set on the first pipeline 141 and in the hydrogen side gas-liquid separator 20. When the hydrogen side pressure regulating device 80 is set in the hydrogen side gas-liquid separator 20, it is fixedly set at the first gas-liquid mixed phase inlet 21 or the first gas phase outlet 22; the setting position of the oxygen side pressure regulating device 90 includes but is not limited to the tenth pipeline 1410, and can also be set on the third pipeline 143 and in the oxygen side gas-liquid separator 30. When the oxygen side pressure regulating device 90 is set in the oxygen side gas-liquid separator 30, it is fixedly set at the second gas-liquid mixed phase inlet 31 or the second gas phase outlet 32.

[0229] Furthermore, for current density of 10 to 100 A / m 3 The alkaline electrolytic cell 10 has a gas-liquid separator with a diameter of 0.4 to 0.6 m and a height of 1 to 4 m. The pressure drop difference between the hydrogen-side pressure regulating member 30 and the oxygen-side pressure regulating member 80 is 1000 to 2000 Pa (at the same fluid flow rate).

[0230] Furthermore, when the diameter of the hydrogen-side gas-liquid separator 20 is 0.5-1 m and the height is 2-4 m, the heights of the hydrogen-side flash tank 61 and the mixed alkali liquid flash tank 71 are both 1.2-1.8 m and the diameters are both 0.6-1.2 m.

[0231] Furthermore, the gas-liquid separators on the hydrogen side and the oxygen side in the present invention are both vertical tanks.

[0232] Furthermore, the hydrogen side pressure regulating component 80 and the oxygen side pressure regulating component 90 include but are not limited to cyclone separators and axial flow separators, and may also be internal components such as filter membranes, filter screens, and valves. The present invention can control the pressure difference between the hydrogen and oxygen sides of the alkaline electrolyzer by replacing the pressure regulating components on both sides of the hydrogen and oxygen, so that the pressure on the oxygen side is higher than the pressure on the hydrogen side.

[0233] Furthermore, the hydrogen side flash tank 61 has a first vertical column cavity 63, a first tangential inlet 64 is provided in the middle of the first vertical column cavity 63, a third gas phase outlet 66 is provided at the top, and a third liquid phase outlet 65 is provided at the bottom; the first tangential inlet 64 is connected to the first liquid phase outlet 23 through the fifth pipeline 145, and is used to receive the hydrogen side alkali liquid from the first liquid phase outlet 13, and the first alkali liquid circulation pump 101 and the first pressure reducing valve 62 are both arranged on the fifth pipeline 145; the third liquid phase outlet 65 is connected to the alkali liquid mixing tank through the sixth pipeline 146.

[0234] A tangential inlet is used to allow the hydrogen-side alkaline solution to enter the hydrogen-side flash tank 61 tangentially, generating a rotational motion, thereby forming a centrifugal field inside the hydrogen-side flash tank 61 to achieve efficient separation of gas and liquid. Through the high efficiency of the flash device, the need for additional separation equipment and processing steps in the alkaline water electrolysis hydrogen production system can be reduced, energy and resources can be saved, and the operating cost of the alkaline water electrolysis hydrogen production system can be reduced.

[0235] Furthermore, the third gas phase outlet 66 is connected to a third gas processing device 43 via a pipeline, and is used to process the gas removed from the hydrogen-side flash tank 61 .

[0236] Furthermore, the third gas phase outlet 66 is provided with a first tapered overflow pipe 661 inside the first vertical column cavity 63. The first tapered overflow pipe 661 forms an inverted cone-shaped thick wall around the third gas phase outlet 66 inside the first vertical column cavity 63, which is used to provide bubble separation force under low pressure loss.

[0237] Furthermore, the mixed alkali liquid flash tank 71 has a second vertical column cavity 73, a second tangential inlet 74 is provided on the side of the second vertical column cavity 73, a fourth liquid phase outlet 75 is provided at the bottom, and a fourth gas phase outlet 76 is provided at the top, the second tangential inlet 74 is connected to the alkali liquid mixing tank 53 through the seventh pipeline 147, and is used to receive the mixed alkali liquid in the alkali liquid mixing tank 53; the third alkali liquid circulation pump 103 and the second pressure reducing valve 72 are both arranged on the seventh pipeline 147; the fourth liquid phase outlet 75 is connected to the buffer tank 110 through the eighth pipeline 148, and the buffer tank 110 is connected to the mixed alkali liquid inlet 13 through a pipeline.

[0238] A tangential inlet is used to allow the mixed alkali solution to enter the mixed alkali solution flash tank 71 tangentially, generating a rotational motion, thereby forming a centrifugal force field inside the mixed alkali solution flash tank 71 to achieve efficient separation of gas and liquid. The high efficiency of the flash device can reduce the need for additional separation equipment and processing steps in the alkaline water electrolysis hydrogen production system, save energy and resources, and reduce the operating cost of the alkaline water electrolysis hydrogen production system.

[0239] Furthermore, the fourth gas phase outlet 76 is connected to a fourth gas processing device 44 via a pipeline, and the fourth gas processing device 44 is used to process the gas removed from the mixed alkali liquid flash tank 71 .

[0240] Furthermore, the fourth gas phase outlet 76 is provided with a second tapered overflow pipe 761 inside the second vertical column cavity 73. The second tapered overflow pipe 761 forms an inverted cone-shaped thick wall around the fourth gas phase outlet 76 inside the second vertical column cavity 73 to provide bubble separation force with low pressure loss.

[0241] Furthermore, the inner diameter of the first tangential inlet 64 of the hydrogen side flash tank 61 is 15 mm, the inner diameter of the top end of the first tapered overflow pipe 661 is 10 mm, and the inner diameter of the bottom end is 15 mm; the inner diameter of the second tangential inlet 74 of the mixed alkali liquid flash tank 71 is 15 mm, the inner diameter of the top end of the second tapered overflow pipe 761 is 10 mm, and the inner diameter of the bottom end is 15 mm.

[0242] Continue to see Figures 5 to 11 The alkaline water electrolysis hydrogen production method for deeply reducing the hydrogen content in oxygen of this embodiment adopts the alkaline water electrolysis hydrogen production system for deeply reducing the hydrogen content in oxygen of this embodiment, comprising the following steps:

[0243] S41. 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;

[0244] S42. The gas-liquid mixture on the cathode side of the alkaline electrolytic cell 10 is pumped into the hydrogen side gas-liquid separator 20 for gas-liquid separation by the first alkali liquid circulation pump 101, and the gas-liquid mixture on the anode side of the alkaline electrolytic cell 10 is pumped into the oxygen side gas-liquid separator 30 for gas-liquid separation by the second alkali liquid circulation pump 102;

[0245] S43. The gas separated by the hydrogen-side gas-liquid separator 20 is discharged from the first gas phase outlet 22, flows through the hydrogen-side pressure regulating component 80 to generate a first pressure drop, enters the first gas processing device 41 for drying and pressurizing treatment, and then is collected; the gas separated by the oxygen-side gas-liquid separator 30 is discharged from the second gas phase outlet 32, flows through the oxygen-side pressure regulating component 90 to generate a second pressure drop, enters the second gas processing device 42 for drying and pressurizing treatment, and then is collected; wherein the first pressure drop is greater than the second pressure drop;

[0246] S44. After the gas-liquid separation, the hydrogen-side alkali liquid is decompressed by the first pressure reducing valve 62 and then enters the hydrogen-side flash tank 61 for flash evaporation. Due to the sudden decrease in pressure, the hydrogen-side alkali liquid flashes, which greatly reduces the solubility of hydrogen in the hydrogen-side alkali liquid and rapidly releases it in the form of gas phase, thereby achieving deep removal of dissolved hydrogen in the hydrogen-side alkali liquid. After the deep removal of dissolved hydrogen, the hydrogen-side alkali liquid enters the alkali liquid mixing tank 53; the oxygen-side alkali liquid after gas-liquid separation enters the alkali liquid mixing tank 53;

[0247] S45. The hydrogen-side alkali liquid and the oxygen-side alkali liquid enter the alkali liquid mixing tank 53 for mixing. Under the action of the third alkali liquid circulation pump 103, the mixed alkali liquid is decompressed by the second pressure reducing valve 72 and then enters the mixed alkali liquid flash tank 71. After the decompressed mixed alkali liquid enters the mixed alkali liquid flash tank 71, due to the sudden drop in pressure, the mixed alkali liquid flashes, so that the solubility of hydrogen and oxygen in the mixed alkali liquid is greatly reduced, and they are quickly released in the form of gas phase, thereby achieving deep removal of dissolved oxygen and dissolved hydrogen in the mixed alkali liquid; after the mixed alkali liquid completes the deep removal of dissolved oxygen and dissolved hydrogen, it enters the buffer tank 110. After the mixed alkali liquid in the buffer tank 110 reaches the working temperature (30-45°C) of the alkaline electrolytic cell 10, the mixed alkali liquid in the buffer tank 110 is pumped back into the alkaline electrolytic cell 10 for electrolysis by the first alkali liquid circulation pump 101 and the second alkali liquid circulation pump 102.

[0248] Furthermore, the volume of the gas-liquid mixed liquid in the oxygen-side gas-liquid separator 30 and the hydrogen-side gas-liquid separator 20 is controlled to be 1 / 2 to 3 / 4 of the volume of the gas-liquid separator.

[0249] Furthermore, the hydrogen side alkali liquid pressure at the inlet of the hydrogen side flash tank 61 is 0.1-0.3 MPa, and the speed is 3 m / s-6 m / s; the mixed alkali liquid pressure at the inlet of the mixed alkali liquid flash tank 71 is 0.1-0.3 MPa, and the speed is 3 m / s-6 m / s.

[0250] Controlling the flash pressure of the hydrogen-side flash tank 61 and the mixed alkali liquid flash tank 71 to be 0.1-0.3 MPa can ensure the effective operation and safety of the system.

[0251] Furthermore, the outlet pressures of the first alkali solution circulation pump 101 , the second alkali solution circulation pump 102 and the third alkali solution circulation pump 103 are all 0.8-1.6 MPa.

[0252] It should be noted that the first pipeline 141, the second pipeline 142, the third pipeline 143, the fourth pipeline 143, the fifth pipeline 145, the sixth pipeline 146, the seventh pipeline 147, the eighth pipeline 148, the ninth pipeline 149, and the tenth pipeline 1410 of the alkaline water electrolysis hydrogen production system for deeply reducing the hydrogen content in oxygen of the present invention are all provided with stop valves 120.

[0253] Application Example 1

[0254] The hydrogen is prepared by using the electrolytic hydrogen production system and method for reducing the dissolved hydrogen content of the alkali solution on the hydrogen side by using a flash evaporation device in Example 1;

[0255] Among them, the hydrogen side gas-liquid separator 20 and the oxygen side gas-liquid separator 30 are vertical tanks with a diameter of 0.8m and a height of 3m; the hydrogen side flash tank 61 has a diameter of 0.7m and a height of 1.2m; the inner diameter of the first tangential inlet is 15mm, the inner diameter of the top of the first tapered overflow pipe 661 is 10mm, and the inner diameter of the bottom is 15mm; the steps are as follows:

[0256] S11. 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;

[0257] S12. The gas-liquid mixture on the cathode side of the alkaline electrolytic cell 10 is pumped into the hydrogen side gas-liquid separator 20 for gas-liquid separation by the first alkali liquid circulation pump 101, and the gas-liquid mixture on the anode side of the alkaline electrolytic cell 10 is pumped into the oxygen side gas-liquid separator 30 for gas-liquid separation by the second alkali liquid circulation pump 102, wherein the volume of the gas-liquid mixture in the oxygen side gas-liquid separator 30 and the hydrogen side gas-liquid separator 20 is controlled to be 3 / 4 of the volume of the gas-liquid separator, and the outlet pressure of the first alkali liquid circulation pump 101 and the second alkali liquid circulation pump 102 are both 0.8Mpa;

[0258] S13. The gas separated by the oxygen-side gas-liquid separator 30 enters the second gas processing device 42 for drying and pressurizing treatment and then is collected, and the oxygen-side alkali liquid after gas-liquid separation enters the alkali liquid mixing tank 53; the gas separated by the hydrogen-side gas-liquid separator 20 enters the first gas processing device 41 for drying and pressurizing treatment and then is collected, and the hydrogen-side alkali liquid after gas-liquid separation enters the hydrogen-side flash tank 61 after being decompressed by the first pressure reducing valve 62, and the pressure of the hydrogen-side alkali liquid at the inlet of the hydrogen-side flash tank 61 is controlled to be 0.1Mpa, and the speed is 3m / s;

[0259] S14. After the decompressed hydrogen-side alkali liquid enters the hydrogen-side flash tank 61, the hydrogen-side alkali liquid flashes due to the sudden drop in pressure, which greatly reduces the solubility of hydrogen in the hydrogen-side alkali liquid and rapidly releases it in the form of gas phase, thereby achieving deep removal of dissolved hydrogen in the hydrogen-side alkali liquid; after the deep removal of dissolved hydrogen, the hydrogen-side alkali liquid enters the alkali liquid mixing tank 53 to mix with the oxygen-side alkali liquid, and the mixed alkali liquid in the alkali liquid mixing tank 53 is pumped back into the alkaline electrolytic cell 10 for electrolysis through the first alkali liquid circulation pump 101 and the second alkali liquid circulation pump 102.

[0260] The operating load parameter of the alkaline electrolytic cell was set to 30%, so that the alkaline electrolytic cell entered a low-load operating state; the hydrogen content in the oxygen of the gas collected at the gas phase outlet of the oxygen-side gas-liquid separator 30 was measured to be 0.95%.

[0261] Application Example 2

[0262] The hydrogen is prepared by using the electrolytic hydrogen production system and method for reducing the dissolved hydrogen content of the mixed alkali solution by using a flash evaporation device in Example 2;

[0263] Among them, the hydrogen side gas-liquid separator 20 and the oxygen side gas-liquid separator 30 are vertical tanks with a diameter of 0.5m and a height of 2m; the diameter of the mixed alkali liquid flash tank 71 is 0.7m and the height is 1.2m; the inner diameter of the second tangential inlet is 15mm, the inner diameter of the top of the second tapered overflow pipe 761 is 10mm, and the inner diameter of the bottom is 15mm; the steps are as follows:

[0264] S21. 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;

[0265] S22. The gas-liquid mixture on the cathode side of the alkaline electrolytic cell 10 is pumped into the hydrogen side gas-liquid separator 20 for gas-liquid separation by the first alkali liquid circulation pump 101, and the gas-liquid mixture on the anode side of the alkaline electrolytic cell 10 is pumped into the oxygen side gas-liquid separator 30 for gas-liquid separation by the second alkali liquid circulation pump 102, wherein the volume of the gas-liquid mixture in the oxygen side gas-liquid separator 30 and the hydrogen side gas-liquid separator 20 is controlled to be 3 / 4 of the volume of the gas-liquid separator, and the outlet pressure of the first alkali liquid circulation pump 101 and the second alkali liquid circulation pump 102 are both 0.8Mpa;

[0266] S23. The gas separated by the oxygen-side gas-liquid separator 30 enters the second gas processing device 42 for drying and pressurizing treatment and then collected, and the gas separated by the hydrogen-side gas-liquid separator 20 enters the first gas processing device 41 for drying and pressurizing treatment and then collected; the oxygen-side alkali liquid and the hydrogen-side alkali liquid after gas-liquid separation enter the alkali liquid mixing tank 53 for mixing;

[0267] S24. Under the action of the third alkali solution circulation pump 103, the mixed alkali solution enters the mixed alkali solution flash tank 71 after passing through the second pressure reducing valve 72, and the outlet pressure of the third alkali solution circulation pump 103 is controlled to be 0.8Mpa, and the pressure of the mixed alkali solution at the inlet of the mixed alkali solution flash tank 71 is 0.1Mpa, and the speed is 3m / s; due to the sudden drop in pressure, the mixed alkali solution flashes, so that the solubility of oxygen and hydrogen in the mixed alkali solution is greatly reduced, and it is quickly released in the form of gas phase, so as to achieve deep removal of dissolved oxygen and dissolved hydrogen in the mixed alkali solution; after the mixed alkali solution completes the deep removal of dissolved oxygen and dissolved hydrogen, it enters the buffer tank 110, and after the mixed alkali solution in the buffer tank 110 reaches the working temperature (30-45°C) of the alkaline electrolytic cell 10, the mixed alkali solution in the buffer tank 110 is pumped back into the alkaline electrolytic cell 10 for electrolysis by the first alkali solution circulation pump 101 and the second alkali solution circulation pump 102.

[0268] The operating load parameter of the alkaline electrolytic cell was set to 30%, so that the alkaline electrolytic cell entered a low-load operating state; the hydrogen content in the oxygen of the gas collected at the gas phase outlet of the oxygen-side gas-liquid separator 30 was measured to be 0.96%.

[0269] Application Example 3

[0270] See also Figure 4 , the electrolytic hydrogen production system and method for adjusting the pressure difference in the electrolytic cell to reduce the hydrogen concentration in oxygen in Example 3 are used to prepare hydrogen, wherein the hydrogen-side gas-liquid separator 20 and the oxygen-side gas-liquid separator 30 are both vertical tanks with a diameter of 0.8m and a height of 3m, and the volume of the electrolyte in the hydrogen-side gas-liquid separator 20 and the oxygen-side gas-liquid separator 30 is controlled to be 3 / 4 of the volume of the gas-liquid separator, and the hydrogen-side pressure regulating member 80 adopts a cyclone separator 81, and the cyclone separator 81 is provided with a first air inlet 82 on the side, a first air outlet 83 on the top, and a first discharge port 84 on the bottom, and the side of the hydrogen-side gas-liquid separator 20 is provided with a first reflux port 24 near the bottom; the gas phase outlet of the hydrogen-side gas-liquid separator 20 is connected to the first air inlet 82, the first discharge port 84 is connected to the first reflux port 24, and the first air outlet 83 is connected to the first gas processing device 41 is connected; the oxygen side pressure regulating member 90 adopts an axial flow separator 91, a second air inlet 92 is provided at the bottom of the axial flow separator 91, a second air outlet 93 is provided at the top, a second discharge port 94 is provided at the side, and a second reflux port 34 is provided at the side of the oxygen side gas-liquid separator 30 near the bottom; the gas phase outlet of the oxygen side gas-liquid separator 30 is connected to the second air inlet 92, the second discharge port 94 is connected to the second reflux port 34, and the second air outlet 93 is connected to the second gas treatment device 42; the inner diameter of the cylinder of the cyclone separator 81 is 100mm, the inner diameters of the first air inlet 82, the first air outlet 83, and the first discharge port 84 are all 20mm, the inner diameter of the cylinder of the axial flow separator 91 is 100mm, the inner diameters of the second air inlet 92, the second air outlet 93, and the second discharge port 94 are all 20mm, and the inner diameters of other pipelines are all 16mm.

[0271] S31. 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;

[0272] S32. The gas-liquid mixture in the cathode chamber 11 is pumped into the hydrogen side gas-liquid separator 20 for gas-liquid separation by the first alkali liquid circulation pump 101, and the gas-liquid mixture in the anode chamber 12 is pumped into the oxygen side gas-liquid separator 30 for gas-liquid separation by the second alkali liquid circulation pump 102; the volume of the gas-liquid mixture in the oxygen side gas-liquid separator 30 and the hydrogen side gas-liquid separator 20 is controlled to be 3 / 4 of the volume of the gas-liquid separator, and the outlet pressures of the first alkali liquid circulation pump 101 and the second alkali liquid circulation pump 102 are both 0.8Mpa;

[0273] S33. After gravity sedimentation, the gas mixed with some liquid separated by the hydrogen side gas-liquid separator 20 enters the cyclone separator 81 through the first air inlet 82, and undergoes cyclone separation in the cyclone separator 81. The gas is discharged from the first air outlet 83, enters the first gas treatment device 41 for drying and pressurization treatment and then collected, and the liquid is discharged from the first discharge port 84 and flows into the hydrogen side gas-liquid separator 20 through the first reflux port 24; the gas mixed with some liquid separated by the oxygen side gas-liquid separator 30 enters the axial flow separator 91 through the second air inlet 92, and undergoes cyclone separation in the axial flow separator 91. The gas is discharged from the second air outlet 93, enters the second gas treatment device 42 for drying and pressurization treatment and then collected, and the liquid is discharged from the second discharge port 94 and flows into the oxygen side gas-liquid separator 30 through the second reflux port 34;

[0274] S34. The hydrogen-side circulating alkali liquid after gas-liquid separation flows back to the hydrogen-side alkali liquid tank 51, and re-enters the cathode chamber 11 for electrolysis under the action of the first alkali liquid circulation pump 101, constituting a hydrogen-side circulation; the oxygen-side circulating alkali liquid after gas-liquid separation flows back to the oxygen-side alkali liquid tank 52, and re-enters the anode chamber 12 for electrolysis under the action of the second alkali liquid circulation pump 102, constituting an oxygen-side circulation;

[0275] At the same fluid flow rate, the pressure drop of the cyclone separator 81 is greater than the pressure drop of the axial flow separator 91, and the pressure drop difference between the two is 2000 Pa.

[0276] The operating load parameter of the alkaline electrolyzer is set to 30%, so that the alkaline electrolyzer enters a low-load operating state; after testing, the hydrogen content in the oxygen of the gas collected from the gas phase outlet of the oxygen-side gas-liquid separator 30 is 1%, and the liquid content is 0.34%, and the liquid content of the gas phase product collected from the gas phase outlet of the hydrogen-side gas-liquid separator 20 is 0.47%.

[0277] Application Example 4

[0278] The alkaline water electrolysis hydrogen production system and method for deeply reducing the hydrogen content in oxygen in Example 4 are used to prepare hydrogen. The hydrogen-side gas-liquid separator 20 and the oxygen-side gas-liquid separator 30 are vertical tanks with a diameter of 0.8m and a height of 3m; the hydrogen-side flash tank 61 has a diameter of 0.7m and a height of 1.2m; the inner diameter of the first tangential inlet is 15mm, the inner diameter of the top of the first tapered overflow pipe 661 is 10mm, and the inner diameter of the bottom is 15mm; the diameter of the mixed alkali solution flash tank 71 is 0 .7m, height 1.2m; the inner diameter of the second tangential inlet is 15mm, the inner diameter of the top of the second tapered overflow pipe 761 is 10mm, and the inner diameter of the bottom is 15mm; the hydrogen side pressure regulating member 80 adopts a cyclone separator 81, the cyclone separator 81 is provided with a first air inlet 82 on the side, a first air outlet 83 on the top, and a first discharge port 84 on the bottom, and the side of the hydrogen side gas-liquid separator 20 is provided with a first reflux port 24 near the bottom; the gas phase outlet 82 of the hydrogen side gas-liquid separator 20 is provided at the bottom of the first discharge port 84; the gas phase outlet 83 of the hydrogen side gas-liquid separator 20 is provided at the bottom of the first discharge port 84; the gas phase outlet 82 ... The first discharge port 84 is connected to the first reflux port 24, and the first gas outlet 83 is connected to the first gas processing device 41; the oxygen side pressure regulating member 90 adopts an axial flow separator 91, and the axial flow separator 91 is provided with a second gas inlet 92 at the bottom, a second gas outlet 93 at the top, and a second discharge port 94 at the side; the side of the oxygen side gas-liquid separator 30 is provided with a second reflux port 34 near the bottom; the gas phase outlet of the oxygen side gas-liquid separator 30 is connected to the second gas inlet The first air inlet 82, the first air outlet 83 and the first discharge port 84 are all connected to each other, the second discharge port 94 is connected to the second reflux port 34, and the second air outlet 93 is connected to the second gas treatment device 42; the inner diameter of the cylinder of the cyclone separator 81 is 100 mm, and the inner diameters of the first air inlet 82, the first air outlet 83 and the first discharge port 84 are all 20 mm; the inner diameter of the cylinder of the axial flow separator 91 is 100 mm, and the inner diameters of the second air inlet 92, the second air outlet 93 and the second discharge port 94 are all 20 mm, and the inner diameters of other pipelines are all 16 mm.

[0279] S41. 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;

[0280] S42. The gas-liquid mixture on the cathode side of the alkaline electrolytic cell 10 is pumped into the hydrogen side gas-liquid separator 20 for gas-liquid separation by the first alkali liquid circulation pump 101, and the gas-liquid mixture on the anode side of the alkaline electrolytic cell 10 is pumped into the oxygen side gas-liquid separator 30 for gas-liquid separation by the second alkali liquid circulation pump 102; wherein the volume of the gas-liquid mixture in the oxygen side gas-liquid separator 30 and the hydrogen side gas-liquid separator 20 is controlled to be 3 / 4 of the volume of the gas-liquid separator, and the outlet pressure of the first alkali liquid circulation pump 101 and the second alkali liquid circulation pump 102 are both 0.8Mpa;

[0281] S43. The gas separated by the hydrogen-side gas-liquid separator 20 is discharged from the first gas phase outlet 22, flows through the hydrogen-side pressure regulating component 80 to generate a first pressure drop, enters the first gas processing device 41 for drying and pressurizing treatment, and then is collected; the gas separated by the oxygen-side gas-liquid separator 30 is discharged from the second gas phase outlet 32, flows through the oxygen-side pressure regulating component 90 to generate a second pressure drop, enters the second gas processing device 42 for drying and pressurizing treatment, and then is collected; wherein, the first pressure drop is greater than the second pressure drop and the difference between the first pressure drop and the second pressure drop is 2000pa;

[0282] S44. After the gas-liquid separation, the hydrogen-side alkali liquid is decompressed by the first pressure reducing valve 62 and then enters the hydrogen-side flash tank 61 for flash evaporation. The pressure of the hydrogen-side alkali liquid at the inlet of the hydrogen-side flash tank 61 is controlled to be 0.1Mpa and the speed is 3m / s. Due to the sudden decrease in pressure, the hydrogen-side alkali liquid flashes, so that the solubility of hydrogen in the hydrogen-side alkali liquid is greatly reduced, and it is quickly released in the form of gas phase, so as to achieve deep removal of dissolved hydrogen in the hydrogen-side alkali liquid. After the deep removal of dissolved hydrogen, the hydrogen-side alkali liquid enters the alkali liquid mixing tank 53; the oxygen-side alkali liquid after gas-liquid separation enters the alkali liquid mixing tank 53;

[0283] S45. The hydrogen side alkali liquid and the oxygen side alkali liquid enter the alkali liquid mixing tank 53 for mixing. Under the action of the third alkali liquid circulation pump 103, the mixed alkali liquid is decompressed by the second pressure reducing valve 72 and enters the mixed alkali liquid flash tank 71. The outlet pressure of the third alkali liquid circulation pump 103 is controlled to be 0.8Mpa, the pressure of the hydrogen side alkali liquid at the inlet of the mixed alkali liquid flash tank 71 is 0.1Mpa, and the speed is 3m / s. After the decompressed mixed alkali liquid enters the mixed alkali liquid flash tank 71, the mixed alkali liquid flashes due to the sudden drop in pressure, so that The solubility of hydrogen and oxygen in the mixed alkali solution is greatly reduced, and they are rapidly released in the form of gas phase, thereby achieving deep removal of dissolved oxygen and dissolved hydrogen in the mixed alkali solution; after the mixed alkali solution completes the deep removal of dissolved oxygen and dissolved hydrogen, it enters the buffer tank 110, and after the mixed alkali solution in the buffer tank 110 reaches the working temperature (30-45°C) of the alkaline electrolytic cell 10, the mixed alkali solution in the buffer tank 110 is pumped back into the alkaline electrolytic cell 10 for electrolysis through the first alkali solution circulation pump 101 and the second alkali solution circulation pump 102.

[0284] The operating load parameter of the alkaline electrolytic cell is set to 30%, so that the alkaline electrolytic cell enters a low-load operating state; after testing, the hydrogen content in the gas phase product oxygen collected from the gas phase outlet of the oxygen-side gas-liquid separator 30 is 0.60%.

[0285] Comparative Example 1

[0286] Compared with application examples 1 to 4, this comparative example only uses the traditional hydrogen-side gas-liquid separator 20 and the oxygen-side gas-liquid separator 30. The hydrogen-side alkali liquid and the oxygen-side alkali liquid after gas-liquid separation enter the alkali liquid mixing tank 53 and are mixed and then directly pumped into the alkaline electrolytic cell 10 to participate in electrolysis again. The volume of the gas-liquid mixed liquid in the hydrogen-side gas-liquid separator 20 and the oxygen-side gas-liquid separator 30 is controlled to be 3 / 4 of the volume of the gas-liquid separator; the outlet pressure of the alkali liquid circulation pump is 0.8 MPa;

[0287] The operating load parameter of the alkaline electrolytic cell is set to 30%, so that the alkaline electrolytic cell enters a low-load operating state; after testing, the hydrogen content of the gas collected from the gas phase outlet of the oxygen-side gas-liquid separator 30 is 2.5%, and the liquid content is 0.67%, and the liquid content of the gas collected from the gas phase outlet of the hydrogen-side gas-liquid separator 20 is 0.66%.

[0288] By comparing the results of Examples 1 to 4 and the comparative example, it can be seen that the alkaline water electrolysis hydrogen production system and method for deeply reducing the hydrogen content in oxygen of the present invention can significantly reduce the hydrogen content in oxygen in the system, and reduce the hydrogen content in oxygen in the alkaline water electrolysis hydrogen production system from 2.5% to below 1%, thereby improving the safety of the alkaline water electrolysis hydrogen production system. In addition, the hydrogen side pressure regulating component (cyclone separator 81) and the oxygen side pressure regulating component (axial flow separator 91) used in Example 3 can effectively reduce the liquid content of hydrogen and oxygen, which is convenient for subsequent gas processing and collection.

[0289] It should be noted that the alkali liquid circulation pump in the present invention is set as needed. In order to make the system run better, the alkali liquid circulation pump can be set on other pipelines in the alkaline water electrolysis hydrogen production system, as long as it does not affect the effects of the hydrogen side flash tank, the mixed alkali liquid flash tank and the pressure regulating parts on both sides of hydrogen and oxygen in the present invention; hydrogen sensors / pressure sensors 130 can also be set at the various devices and pipelines of the alkaline water electrolysis hydrogen production system of the present invention to monitor the operating status of the system; and the various technical schemes in the present invention can be arbitrarily combined to perform deep dehydrogenation on the alkaline water electrolysis hydrogen production system, as long as the structures and functions of the various devices in the individual technical schemes do not cause major negative interference.

[0290] 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 device for removing hydrogen from mixed alkali liquid oxygen by electrolyzing water to produce hydrogen using a flash tank, characterized in that: It includes an alkaline electrolyzer, a hydrogen-side gas-liquid separator, a first gas processing device, a first alkali liquid circulation pump, an oxygen-side gas-liquid separator, a second gas processing device, a second alkali liquid circulation pump and an alkali liquid mixing tank; The bottom of the alkaline electrolytic cell is provided with an inlet for mixed alkali solution; The hydrogen-side gas-liquid separator and the oxygen-side gas-liquid separator are both connected to the alkali liquid mixing tank through pipelines, and the alkali liquid mixing tank is sequentially connected to the third alkali liquid circulation pump, the second pressure reducing valve, the mixed alkali liquid flash tank, the buffer tank and the mixed alkali liquid inlet through pipelines; the second pressure reducing valve is used to reduce the pressure of the mixed alkali liquid from the alkali liquid mixing tank so that it enters the mixed alkali liquid flash tank; the mixed alkali liquid flash tank is used to allow the mixed alkali liquid to boil and vaporize rapidly after the pressure is reduced, and to perform gas-liquid separation, so as to deeply remove dissolved oxygen and dissolved hydrogen in the mixed alkali liquid; The buffer tank is used to buffer the pressure fluctuation between the mixed alkali solution flash tank and the alkaline electrolytic cell and to adjust the mixed alkali solution after deep removal of dissolved oxygen and dissolved hydrogen to the working temperature of the alkaline electrolytic cell.

2. The device for removing hydrogen from mixed alkali liquid oxygen by electrolysis of water for hydrogen production using a flash tank according to claim 1, characterized in that: The alkaline electrolytic cell has a cathode chamber and an anode chamber; The top of the cathode chamber is provided with a first gas-liquid mixed phase outlet, and the top of the anode chamber is provided with a second gas-liquid mixed phase outlet; The hydrogen-side gas-liquid separator is provided with a first gas-liquid mixed phase inlet in the middle, a first gas phase outlet at the top, and a first liquid phase outlet at the bottom; the oxygen-side gas-liquid separator is provided with a second gas-liquid mixed phase inlet in the middle, a second gas phase outlet at the top, and a second liquid phase outlet at the bottom; The first gas-liquid mixed phase outlet is connected to the first gas-liquid mixed phase inlet through a first pipeline, and the first alkali liquid circulation pump is arranged on the first pipeline; the first gas phase outlet is connected to the first gas processing device through a pipeline, and the first liquid phase outlet is connected to the alkali liquid mixing tank through a second pipeline; The second gas-liquid mixed phase outlet is connected to the second gas-liquid mixed phase inlet through a third pipeline, and the second alkali liquid circulation pump is arranged on the third pipeline; the second gas phase outlet is connected to the second gas processing device through a pipeline, and the second liquid phase outlet is connected to the alkali liquid mixing tank through a fourth pipeline.

3. The device for removing hydrogen from mixed alkali liquid oxygen by electrolyzing water to produce hydrogen using a flash tank according to claim 2, characterized in that: The mixed alkali liquid flash tank has a second vertical column cavity, a second tangential inlet is provided in the middle of the second vertical column cavity, a fourth liquid phase outlet is provided at the bottom, and a fourth gas phase outlet is provided at the top. The second tangential inlet is connected to the alkali liquid mixing tank through a seventh pipeline for receiving the mixed alkali liquid in the alkali liquid mixing tank; the third alkali liquid circulation pump and the second pressure reducing valve are both arranged on the seventh pipeline; the fourth liquid phase outlet is connected to the buffer tank through an eighth pipeline, and the buffer tank is connected to the mixed alkali liquid inlet through a pipeline.

4. The device for removing hydrogen from mixed alkali liquid oxygen by electrolysis of water for hydrogen production using a flash tank according to claim 3, characterized in that: The fourth gas phase outlet is connected to a fourth gas processing device through a pipeline, and the fourth gas processing device is used to process the gas removed from the mixed alkali liquid flash tank.

5. The device for removing hydrogen from mixed alkali liquid oxygen by electrolyzing water to produce hydrogen using a flash tank according to claim 4, characterized in that: The fourth gas phase outlet is provided with a second tapered overflow pipe inside the second vertical column cavity. The second tapered overflow pipe forms an inverted cone-shaped thick wall around the fourth gas phase outlet inside the second vertical column cavity, which is used to provide bubble separation force under low pressure loss.

6. A method for removing hydrogen from mixed alkali liquid oxygen in water electrolysis hydrogen production using a flash tank, characterized in that: The device for removing hydrogen from mixed alkali liquid oxygen by electrolyzing water to produce hydrogen using a flash tank as described in any one of claims 1 to 5 comprises the following steps: S21. 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; S22. The gas-liquid mixture on the cathode side of the alkaline electrolytic cell is pumped into the hydrogen side gas-liquid separator for gas-liquid separation by a first alkali liquid circulation pump, and the gas-liquid mixture on the anode side of the alkaline electrolytic cell is pumped into the oxygen side gas-liquid separator for gas-liquid separation by a second alkali liquid circulation pump; S23. The gas separated by the oxygen-side gas-liquid separator enters the second gas treatment device for drying and pressurizing treatment and then is collected, and the gas separated by the hydrogen-side gas-liquid separator enters the first gas treatment device for drying and pressurizing treatment and then is collected; the oxygen-side alkali liquid and the hydrogen-side alkali liquid after gas-liquid separation enter the alkali liquid mixing tank for mixing; S24. Under the action of the third alkali solution circulation pump, the mixed alkali solution enters the mixed alkali solution flash tank after passing through the second pressure reducing valve. Due to the sudden drop in pressure, the mixed alkali solution flashes, which greatly reduces the solubility of oxygen and hydrogen in the mixed alkali solution. The mixed alkali solution is rapidly released in the form of gas phase, thereby achieving deep removal of dissolved oxygen and dissolved hydrogen in the mixed alkali solution. After the deep removal of dissolved oxygen and dissolved hydrogen, the mixed alkali solution enters the buffer tank. After the mixed alkali solution in the buffer tank reaches the working temperature of the alkaline electrolytic cell, the mixed alkali solution in the buffer tank is re-pumped into the alkaline electrolytic cell for electrolysis through the first alkali solution circulation pump and the second alkali solution circulation pump.

7. The method for removing hydrogen from mixed alkali liquid oxygen by electrolyzing water to produce hydrogen using a flash tank according to claim 6, characterized in that: The volume of the gas-liquid mixed liquid in the oxygen-side gas-liquid separator and the hydrogen-side gas-liquid separator is controlled to be 1 / 2 to 3 / 4 of the volume of the gas-liquid separator.

8. The method for removing hydrogen from mixed alkali liquid oxygen by electrolyzing water to produce hydrogen using a flash tank according to claim 6, characterized in that: The outlet pressures of the first alkali solution circulation pump, the second alkali solution circulation pump and the third alkali solution circulation pump are all 0.8-1.6Mpa.

9. The method for removing hydrogen from mixed alkali liquid oxygen by electrolyzing water to produce hydrogen using a flash tank according to claim 7, characterized in that: The mixed alkali solution pressure at the inlet of the mixed alkali solution flash tank is 0.1-0.3Mpa, and the speed is 3m / s-6m / s.

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