Device and method for enhancing removal of dissolved hydrogen in hydrogen production by using alkaline electrolyzed water through 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 source, hydrogen boasts significant advantages such as being pollution-free, renewable, and possessing a high calorific value, providing crucial support for sustainable development. Furthermore, hydrogen production through water electrolysis can convert fluctuating renewable energy sources such as photovoltaic and wind power into green hydrogen energy, providing green raw materials for high-carbon emission industries such as metallurgy and petrochemicals. This ensures large-scale, long-term energy storage, providing strategic support for the nation's energy transformation and development.

[0004] Among numerous hydrogen production technologies, alkaline water electrolysis has attracted significant attention due to its relative maturity and abundance of key materials. This technology not only enables large-scale hydrogen production but also has the potential to support a hundredfold market growth, making it the only hydrogen production technology currently capable of meeting large-scale market demand. With continued technological advancements and cost reductions, alkaline water electrolysis is expected to play a significant role in the future clean energy market, driving the global energy mix towards a cleaner and more sustainable direction.

[0005] Although alkaline water electrolysis is currently the most cost-effective and widely used renewable energy hydrogen production process due to its scale advantages, the hydrogen content of the byproduct oxygen increases with decreasing operating load. Under low load or unstable operating conditions, the hydrogen content of oxygen can approach or even reach the explosion limit, posing a safety risk. Refining and chemical companies are particularly strict in controlling explosion risks. When implementing renewable energy hydrogen production, stricter control of hydrogen content in the byproduct oxygen is essential to ensure safe production.

[0006] Hydrogen is flammable and explosive, with low ignition energy, a large diffusion coefficient, and a wide combustion range (4% to 75%), presenting significant safety risks. When hydrogen is mixed with oxygen, it can easily form a combustible or explosive mixture. Therefore, the hydrogen content of oxygen in alkaline water electrolysis hydrogen production systems must be strictly controlled during operation. A safety alarm threshold of 1.5% is set for the hydrogen content of the byproduct oxygen, which is generally used as the upper safety limit for water electrolysis hydrogen production systems.

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

[0008] One is the influence of alkaline solution mixing. A water splitting reaction occurs at the cathode of the electrolyzer, generating hydrogen and OH-. Driven by the electric field, OH- is transported across the diaphragm to the anode, where it undergoes an oxidation reaction to generate oxygen and water. Hydrogen is dissolved in the cathode alkaline solution, and oxygen is dissolved in the anode alkaline solution. After gas-liquid separation, the two alkaline solutions mix to equalize their concentrations. The mixing of the alkaline solutions after the gas-liquid separator tank causes cross-penetration of the hydrogen and oxygen dissolved in the alkaline solutions.

[0009] The second factor is the influence of gas partial pressure differences. The hydrogen produced at the cathode and the oxygen produced at the anode both have the same pressure as the electrolyzer's operating pressure. However, the hydrogen partial pressure on the cathode side and the oxygen partial pressure on the anode side are both much higher than those on the opposite side of the diaphragm. This partial pressure difference between hydrogen and oxygen causes hydrogen or oxygen to enter the opposite side 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 electrolysis chamber 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 transmission power and the hydrogen and oxygen mixing flux caused by the diaphragm is very small. Compared with the influence of alkali solution mixing and gas partial pressure difference on hydrogen in oxygen, it is not on the same order of magnitude.

[0011] Therefore, how to solve the problem of excessive hydrogen content in oxygen caused by alkaline 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 the 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 electrolyzer is operating at low load or unstable conditions.

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

[0014] A 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 from the hydrogen-side alkali liquid;

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

[0018] The alkali solution mixing tank is sequentially connected to a third alkali solution circulation pump, a second pressure reducing valve, a mixed alkali solution flash tank, a buffer tank, and a mixed alkali solution inlet via 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, thereby deeply removing dissolved oxygen and dissolved hydrogen from the mixed alkali solution; the buffer tank is used to buffer pressure fluctuations between the mixed alkali solution flash tank and the alkaline electrolytic cell and to adjust the mixed alkali solution after the deep removal of dissolved oxygen and dissolved hydrogen to the operating temperature of the alkaline electrolytic cell;

[0019] A first gas phase outlet is provided at 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 provided on the ninth pipeline; a second gas phase outlet is provided at 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 provided 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 liquor 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 liquor by utilizing the sudden reduction of pressure when the hydrogen side alkali liquor enters the hydrogen side flash tank, and quickly releases it in the form of gas phase, thereby reducing the dissolved hydrogen content in the hydrogen side alkali liquor; deeply removes the dissolved hydrogen and dissolved oxygen in the mixed alkali liquor by cooperating with the second pressure reducing valve and the mixed alkali liquor flash tank, and deeply removes the dissolved hydrogen and dissolved oxygen in the mixed alkali liquor by utilizing the sudden reduction of pressure when the hydrogen side alkali liquor enters the mixed alkali liquor 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 hydrogen-side alkali solution and the dissolved oxygen and dissolved hydrogen in the mixed alkali solution, the concentration of hydrogen in oxygen in the alkaline electrolysis water hydrogen production system can be effectively reduced, thereby reducing the safety hazards of the alkaline electrolysis water hydrogen production system and improving the safety of the system; optimizing the operating efficiency of the entire alkaline electrolysis water hydrogen production system and improving the overall hydrogen production efficiency; by at the first gas phase outlet A hydrogen-side pressure regulator capable of regulating the cathode chamber pressure is provided, and an oxygen-side pressure regulator capable of regulating the anode chamber pressure is provided at the second gas phase outlet. At the same fluid flow rate, the pressure drop of the hydrogen-side pressure regulator is greater than that of the oxygen-side pressure regulator, i.e., the oxygen-side pressure regulator exerts greater resistance to the fluid, resulting in a greater backpressure in the anode chamber and an increase in the pressure in the anode chamber of the alkaline electrolyzer. This allows the oxygen-side pressure of the alkaline electrolyzer to be higher than the hydrogen-side pressure, 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. Due to the high efficiency of these three devices (the hydrogen-side flash tank, the mixed alkali liquor flash tank, and the hydrogen-oxygen pressure regulators), the efficiency of the separation equipment of the alkaline water electrolysis system is greatly improved, the need 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 maintenance and failure rates 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 provided on the fifth pipeline; the third liquid phase outlet is connected to the alkali liquid mixing tank through a sixth pipeline.

[0026] The tangential inlet allows the hydrogen side alkaline solution to enter the hydrogen side flash tank tangentially, generating a rotational motion, thereby forming a centrifugal force field inside the hydrogen side flash tank, achieving efficient separation of gas and liquid. Through the high efficiency of the flash device, the alkaline water electrolysis hydrogen production system can reduce the need for additional separation equipment and processing steps, 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 conical thick wall around the third gas phase outlet inside the first vertical column cavity, which is used to provide bubble separation force with low pressure loss.

[0029] Furthermore, the mixed alkali liquid flash tank has a second vertical column cavity, the side of the second vertical column cavity is provided with a second tangential inlet, the bottom is provided with a fourth liquid phase outlet, and the top is provided with a fourth gas phase outlet. 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, achieving efficient separation of gas and liquid. Through the high efficiency of the flash device, the alkaline water electrolysis hydrogen production system can reduce the need for additional separation equipment and processing steps, 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 conical thick wall around the fourth gas phase outlet inside the second vertical column cavity, which is used to provide bubble separation force with low pressure loss.

[0033] A second aspect of the present invention is to provide a method for producing hydrogen by alkaline water electrolysis that deeply reduces the hydrogen content in oxygen, using the above-mentioned alkaline water electrolysis hydrogen production system that deeply reduces the hydrogen content in oxygen, comprising 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 electrolyzer 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 electrolyzer 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 element to generate a first pressure drop, and then enters the first gas processing device for drying and pressurization before being 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 element to generate a second pressure drop, and then enters the second gas processing device for drying and pressurization before being 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 depressurized by the first pressure reducing valve and then enters the hydrogen-side flash tank for flash evaporation. Due to the sudden drop 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 a 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 liquor and the oxygen-side alkali liquor enter the alkali liquor mixing tank for mixing. Under the action of the third alkali liquor circulation pump, the mixed alkali liquor is decompressed by the second pressure reducing valve and then enters the mixed alkali liquor flash tank. After the decompressed mixed alkali liquor enters the mixed alkali liquor flash tank, due to the sudden drop in pressure, the mixed alkali liquor flashes, which greatly reduces the solubility of hydrogen and oxygen in the mixed alkali liquor. The mixed alkali liquor is rapidly released in the form of gas phase, thereby achieving deep removal of dissolved oxygen and dissolved hydrogen in the mixed alkali liquor. After the deep removal of dissolved oxygen and dissolved hydrogen, the mixed alkali liquor enters the buffer tank. After the mixed alkali liquor in the buffer tank reaches the working temperature of the alkaline electrolyzer, the mixed alkali liquor in the buffer tank is re-pumped into the alkaline electrolyzer for electrolysis through the alkali liquor 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 0.1-0.3 MPa, and the speed is 3 m / s-6 m / s; the mixed alkali liquid pressure at the mixed alkali liquid flash tank inlet is 0.1-0.3 MPa, and the speed is 3 m / s-6 m / s.

[0041] Controlling the flash pressure of the hydrogen side flash tank and the mixed alkali liquid flash tank to 0.1-0.3 MPa 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] A 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 electrolyzer, 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;

[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 sequentially connected to a first pressure reducing valve and a hydrogen side flash tank 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 from the hydrogen-side alkali liquid through the cooperation of the first pressure reducing valve and the hydrogen-side flash tank. The sudden reduction in pressure when the hydrogen-side alkali liquid enters the hydrogen-side flash tank is utilized to greatly reduce the solubility of hydrogen in the hydrogen-side alkali liquid, and rapidly releases the hydrogen in the form of a 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] Furthermore, the alkaline electrolytic cell has a cathode chamber and an anode chamber;

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

[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 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;

[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 provided on the fifth pipeline; the third liquid phase outlet is connected to the alkali liquid mixing tank through a sixth pipeline.

[0054] The tangential inlet allows the hydrogen side alkaline solution to enter the hydrogen side flash tank tangentially, generating a rotational motion, thereby forming a centrifugal force field inside the hydrogen side flash tank, achieving efficient separation of gas and liquid. Through the high efficiency of the flash device, the alkaline water electrolysis hydrogen production system can reduce the need for additional separation equipment and processing steps, 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 conical thick wall around the third gas phase outlet inside the first vertical column cavity, which is used to provide bubble separation force with 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 alkaline water electrolysis that deeply reduces the hydrogen content in oxygen, using the above-mentioned alkaline water electrolysis hydrogen production system that deeply reduces 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 electrolyzer is pumped into the hydrogen side gas-liquid separator for gas-liquid separation by a first lye circulation pump, and the gas-liquid mixture on the anode side of the alkaline electrolyzer is pumped into the oxygen side gas-liquid separator for gas-liquid separation by a second lye circulation pump;

[0061] S13. The gas separated by the oxygen-side gas-liquid separator enters the second gas treatment unit for drying and pressurization before being collected. The oxygen-side alkali liquor after gas-liquid separation enters the alkali liquor mixing tank. The gas separated by the hydrogen-side gas-liquid separator enters the first gas treatment unit for drying and pressurization before being collected. The hydrogen-side alkali liquor after gas-liquid separation enters the hydrogen-side flash tank after being depressurized 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 be mixed 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 through the alkali liquid circulation pump for electrolysis.

[0063] Furthermore, the volume of the gas-liquid mixture 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 electrolyzer, 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 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 in sequence 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, thereby deeply removing dissolved oxygen and dissolved hydrogen in the mixed alkali liquid; the buffer tank is used to buffer the pressure fluctuations between the mixed alkali liquid flash tank and the alkaline electrolyzer and to adjust the mixed alkali liquid after the dissolved oxygen and dissolved hydrogen are deeply removed to the working temperature of the alkaline electrolyzer.

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

[0071] Furthermore, 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 provided 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. 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, achieving efficient separation of gas and liquid. Through the high efficiency of the flash device, the alkaline water electrolysis hydrogen production system can reduce the need for additional separation equipment and processing steps, 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 conical thick wall around the fourth gas phase outlet inside the second vertical column cavity, which is used to provide bubble separation force with low pressure loss.

[0080] A sixth aspect of the present invention is to provide a method for producing hydrogen by alkaline water electrolysis that deeply reduces the hydrogen content in oxygen, using the above-mentioned alkaline water electrolysis hydrogen production system that deeply reduces 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 electrolyzer is pumped into the hydrogen side gas-liquid separator for gas-liquid separation by a first lye circulation pump, and the gas-liquid mixture on the anode side of the alkaline electrolyzer is pumped into the oxygen side gas-liquid separator for gas-liquid separation by a second lye circulation pump;

[0083] S23. The gas separated by the oxygen-side gas-liquid separator enters the second gas treatment device for drying and pressurization and is then collected. The gas separated by the hydrogen-side gas-liquid separator enters the first gas treatment device for drying and pressurization and is then 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 oxygen and hydrogen 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 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 mixture 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 solution circulation pump, the second alkali solution circulation pump and the third alkali solution circulation pump are all 0.8-1.6 MPa.

[0087] Furthermore, the pressure of the mixed alkali solution 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 0.1-0.3 MPa 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. 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. After the gas-liquid separation, the hydrogen-side alkali liquid returns to the cathode chamber through the hydrogen-side alkali liquid circulation loop for electrolysis again; after the gas-liquid separation, the oxygen-side alkali liquid returns to the anode chamber through the oxygen-side alkali liquid circulation loop for electrolysis again. This 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 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 is 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. The backpressure generated in the anode chamber is greater, and the pressure of the anode chamber of the alkaline electrolyzer is increased, so that the pressure on the oxygen side can be made 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 is provided with a first gas-liquid mixed phase outlet at the top and a first alkali solution inlet at the bottom; the anode chamber is provided with 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 connected to the hydrogen side alkali liquid tank, the first alkali liquid circulation pump and the first alkali liquid inlet in sequence 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 provided 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] An eighth aspect of the present invention is to provide a method for producing hydrogen by alkaline water electrolysis that deeply reduces the hydrogen content in oxygen, using the above-mentioned alkaline water electrolysis hydrogen production system that deeply reduces 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 by a first lye circulation pump for gas-liquid separation, and the gas-liquid mixture in the anode chamber is pumped into the oxygen side gas-liquid separator by a second lye circulation pump for gas-liquid separation;

[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 before collection, 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 before collection;

[0107] S34. After gas-liquid separation, the hydrogen side lye flows back to the hydrogen side lye tank and re-enters the cathode chamber for electrolysis under the action of the first lye circulation pump to form a hydrogen side cycle; after gas-liquid separation, the oxygen side lye flows back to the oxygen side lye tank and re-enters the anode chamber for electrolysis under the action of the second lye 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 This is a partial schematic diagram of the hydrogen side flash tank in Example 1 and Example 4 of the present invention.

[0116] Figure 7 This 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 This is a schematic structural diagram of the hydrogen side flash tank in Example 1 and Example 4 of the present invention.

[0118] Figure 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] Figure 10 This 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] Figure 11 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 alkaline solution inlet; 12-anode chamber; 121-second gas-liquid mixed phase outlet; 122-second alkaline solution inlet; 13-mixed alkaline 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 cavity; 64-first tangential inlet; 65-third liquid phase outlet; 66-third gas phase outlet; 661-first gradually converging 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 tapered 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-first alkali solution circulation pump; 102-second alkali solution circulation pump; 103-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 will be described in further detail below with reference to specific embodiments and examples. It should be understood that the following examples are intended only to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention. Non-substantial improvements and adjustments made by professionals in this field based on the contents of the present invention still fall within 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, which uses 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 treatment device 41, a first alkali solution circulation pump 101, an oxygen-side gas-liquid separator 30, a second gas treatment 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 a first pressure reducing valve 62 and a 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 cooperating with the first pressure reducing valve 62 and the hydrogen-side flash tank 61. The sudden drop in pressure when the hydrogen-side alkali liquid enters the hydrogen-side flash tank 61 is utilized to significantly reduce the solubility of hydrogen in the hydrogen-side alkali liquid, and the hydrogen is rapidly released in the form of a 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, connect the positive electrode of the power supply to the anode of the alkaline electrolytic cell 10, and connect the negative electrode of the power supply 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 alkali 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 alkali 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 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, which greatly reduces the solubility of hydrogen in the hydrogen side alkali liquid and is quickly released 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 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 via a first pipeline 141, and the first alkali liquid circulation pump 101 is provided on the first pipeline 141; the first gas phase outlet 22 is connected to the first gas processing device 41 via a pipeline;

[0147] The second gas-liquid mixed phase outlet 121 is connected to the second gas-liquid mixed phase inlet 21 via a third pipeline 143, and the second alkali solution circulation pump 102 is disposed on the third pipeline 143; the second gas phase outlet 32 ​​is connected to the second gas processing device 42 via a pipeline, and the second liquid phase outlet 33 is connected to the alkali solution mixing tank 53 via a 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 treatment device 43 through a pipeline, for treating 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 force 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 alkaline water electrolysis hydrogen production system can reduce the need for additional separation equipment and processing steps, save energy and resources, and reduce the operating cost of the alkaline water electrolysis hydrogen production system.

[0151] See also Figure 8 、 Figure 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 conical 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.

[0152] 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 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 hydrogen-side and oxygen-side gas-liquid separators 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 dissolved hydrogen content of the alkali solution on the hydrogen side, and the electrolytic hydrogen production system using the flash evaporation device of this embodiment to reduce the dissolved hydrogen content of 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 unit 42 for drying and pressurization before being collected. 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 unit 41 for drying and pressurization before being collected. The hydrogen-side alkali liquid after gas-liquid separation is reduced in pressure by the first pressure reducing valve 62 and enters the hydrogen-side flash tank 61.

[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 mixture 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 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, which uses 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 treatment device 41, a first alkali solution circulation pump 101, an oxygen-side gas-liquid separator 30, a second gas treatment 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 liquid mixing tank 53 through pipelines, and the alkali liquid mixing tank 53 is connected to the third alkali liquid circulation pump 103, the second pressure reducing valve 72, the mixed alkali liquid flash tank 71, the buffer tank 110 and the mixed alkali liquid inlet 13 in sequence through pipelines; the second pressure reducing valve 72 is used to reduce the pressure of the mixed alkali liquid from the alkali liquid mixing tank 53 so that it enters the mixed alkali liquid flash tank 71; the mixed alkali liquid flash tank 71 is used to allow the mixed alkali liquid to boil and vaporize rapidly after the pressure is reduced, and to perform gas-liquid separation, thereby deeply removing dissolved oxygen and dissolved hydrogen in the mixed alkali liquid; the buffer tank 110 is used to buffer the pressure fluctuations between the mixed alkali liquid flash tank 71 and the alkaline electrolyzer 10 and adjust the mixed alkali liquid after the deep removal of dissolved oxygen and dissolved hydrogen to the operating temperature of the alkaline electrolyzer 10 (30-45°C).

[0168] In this embodiment, the dissolved hydrogen and dissolved oxygen in the mixed alkali solution are deeply removed by cooperating with the second pressure reducing valve 72 and the mixed alkali solution flash tank 71. The sudden drop in pressure when the mixed alkali solution enters the mixed alkali solution flash tank 71 is utilized to greatly reduce the solubility of oxygen and hydrogen in the mixed alkali solution, 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, with the positive electrode of the power supply connected to the anode chamber of the alkaline electrolytic cell 10, and the negative electrode of the power supply 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 alkali 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 alkali 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 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 liquor on the hydrogen side and the alkali liquor on the oxygen side after gas-liquid separation enter the alkali liquor mixing tank 53 for mixing; the mixed alkali liquor enters the mixed alkali liquor flash tank 71 after passing through the second pressure reducing valve 72 under the action of the third alkali liquor circulation pump 103. Due to the sudden drop in pressure, the mixed alkali liquor flashes, which greatly reduces the solubility of oxygen and hydrogen in the mixed alkali liquor and rapidly releases them in the form of gas phase, thereby achieving deep removal of dissolved oxygen and dissolved hydrogen in the mixed alkali liquor; after the mixed alkali liquor completes the deep removal of dissolved oxygen and dissolved hydrogen, it enters the buffer tank 110. After the mixed alkali liquor in the buffer tank 110 reaches the operating temperature of the alkaline electrolytic cell 10, the mixed alkali liquor in the buffer tank 110 is pumped back into the alkaline electrolytic cell 10 for electrolysis through the first alkali liquor circulation pump 101 and the second alkali liquor 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 is provided with 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 is provided with 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 via a first pipeline 141, and the first alkali liquid circulation pump 101 is disposed on the first pipeline 141; the first gas phase outlet 22 is connected to the first gas processing device 41 via a pipeline, and the first liquid phase outlet 23 is connected to the alkali liquid mixing tank 53 via a 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 treatment 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, achieving efficient separation of gas and liquid. Through the high efficiency of the flash device, the alkaline water electrolysis hydrogen production system can reduce the need for additional separation equipment and processing steps, 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. The fourth gas processing device 44 is used to process the gas removed from the mixed alkali liquid flash tank 71 .

[0178] See also Figure 10 、 Figure 11 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, which is used to provide bubble separation force under low pressure loss.

[0179] Furthermore, 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 solution 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 hydrogen-side and oxygen-side gas-liquid separators 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 dissolved hydrogen content of the mixed alkali solution, and the electrolytic hydrogen production system using the flash evaporation device of this embodiment to reduce the dissolved hydrogen content of the mixed alkali solution, 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 treatment device 42 for drying and pressurization and then is collected. The gas separated by the hydrogen-side gas-liquid separator 20 enters the first gas treatment device 41 for drying and pressurization and then is collected. After gas-liquid separation, the oxygen-side alkali liquid and the hydrogen-side alkali liquid 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. The oxygen and hydrogen 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 deep removal of dissolved oxygen and dissolved hydrogen, the mixed alkali solution 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 mixture 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 treatment 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 treatment 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. After the gas-liquid separation, the hydrogen-side alkali liquid returns to the cathode chamber 11 through the hydrogen-side alkali liquid circulation loop for electrolysis again; after the gas-liquid separation, the oxygen-side alkali liquid returns to the anode chamber 12 through the oxygen-side alkali liquid circulation loop for electrolysis again, which can reduce the increase in the hydrogen content in the oxygen caused by the mixing of the alkali liquids, reduce the hydrogen concentration in the 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 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 component 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 component 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. The backpressure generated in the anode chamber 12 is greater, and the pressure of the anode chamber 12 of the alkaline electrolyzer is increased, so that the oxygen side pressure can be made 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, connect the positive electrode of the power supply to the anode chamber 12 of the alkaline electrolytic cell 10, and connect the negative electrode of the power supply 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 mixture containing a large number of fine bubbles; the gas-liquid mixture 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 re-circulated 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, passes through the hydrogen side pressure regulating member 80 and enters the first gas treatment device 41 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 treatment device 42 for drying and pressurization treatment before being collected; since 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 at the same fluid flow rate, that is, the resistance of the oxygen-side pressure regulating member 90 to the fluid is greater, 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 experiences great resistance when flowing through the hydrogen-side pressure regulating member 80, resulting in greater backpressure, thereby increasing the pressure in the anode chamber 12 of the alkaline electrolyzer. This allows the pressure on the oxygen side (anode chamber 12) of the alkaline electrolyzer 10 to be higher than the pressure on the hydrogen side (cathode chamber 11) of the alkaline electrolyzer 10, thereby reducing the amount of hydrogen that passes through the diaphragm from the cathode chamber 11 into the anode chamber 12, avoiding the risk of explosion caused by 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 10-100 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 20 and the oxygen-side pressure regulating member 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 can also be internal components such as filter membranes, filter screens, and valves. The present invention can regulate 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 via the first pipeline 141, the first gas phase outlet 22 is connected to the first gas processing device 41 via 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 via 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 treatment 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 through pipelines in sequence.

[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] Furthermore, 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 component 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 can also be internal components such as filter membranes, filter screens, and valves. The present invention can regulate 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 reducing the concentration of hydrogen in oxygen by adjusting the pressure difference in the electrolytic cell is provided. The electrolytic hydrogen production system of this embodiment for reducing the concentration of hydrogen in oxygen by adjusting the pressure difference in the electrolytic cell is provided, including 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 lye 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 lye 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 treatment device 41 for drying and pressurization before collection. The gas mixed with some liquid separated by the oxygen-side gas-liquid separator 30 enters the second gas treatment device 42 for drying and pressurization before collection.

[0214] S34. After 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 cycle; after 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 cycle;

[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 element 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 element 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. 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 via 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, thereby deeply removing dissolved hydrogen from 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 pipelines;

[0222] The alkali solution mixing tank 53 is sequentially 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 via 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, allowing it to enter 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, thereby deeply removing dissolved oxygen and dissolved hydrogen from the mixed alkali solution. The buffer tank 110 is used to buffer pressure fluctuations between the mixed alkali solution flash tank 71 and the alkaline electrolytic cell 10 and to adjust the mixed alkali solution after the deep removal of dissolved oxygen and dissolved hydrogen to the operating 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 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.

[0224] In this embodiment, the dissolved hydrogen in the hydrogen side alkali liquid is deeply removed by cooperating with 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 decrease in pressure when the hydrogen side alkali liquid enters the hydrogen side flash tank 61, and the hydrogen is quickly 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 cooperating with 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 decrease 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 hydrogen side alkali solution 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. 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 generated in the anode chamber 12 is greater, thereby increasing the pressure of the anode chamber 12 of the alkaline electrolytic cell, 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 gas from the cathode chamber 11 through the diaphragm into the anode chamber 12. The amount of hydrogen is increased, the concentration of hydrogen in oxygen in the alkaline water electrolysis hydrogen production system is reduced, the explosion hazard caused by excessive hydrogen concentration in oxygen is avoided, and the safety of the system is ensured; 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 greatly 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 via a first pipeline 141 , and the second gas-liquid mixed phase outlet 121 is connected to the second gas-liquid mixed phase inlet 31 via a third pipeline 143 .

[0228] Furthermore, the setting position of the hydrogen side pressure regulating component 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 component 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 component 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 component 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 10-100 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 height of the hydrogen-side flash tank 61 and the mixed alkali liquid flash tank 71 are both 1.2-1.8 m and the diameter is 0.6-1.2 m.

[0231] Furthermore, the hydrogen-side and oxygen-side gas-liquid separators 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 can also be internal components such as filter membranes, filter screens, and valves. The present invention can regulate 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 a fifth pipeline 145, for receiving the hydrogen side alkali solution from the first liquid phase outlet 13, the first alkali solution 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 solution mixing tank through a 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 force 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 alkaline water electrolysis hydrogen production system can reduce the need for additional separation equipment and processing steps, save energy and resources, and reduce the operating cost of the alkaline water electrolysis hydrogen production system.

[0235] Furthermore, the third gas phase outlet 66 is connected to the third gas processing device 43 via a pipeline, which 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 conical thick wall around the third gas phase outlet 66 inside the first vertical column cavity 63, which is used to provide bubble separation force with 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, achieving efficient separation of gas and liquid. Through the high efficiency of the flash device, the alkaline water electrolysis hydrogen production system can reduce the need for additional separation equipment and processing steps, 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 the fourth gas processing device 44 via a pipeline. 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 conical thick wall around the fourth gas phase outlet 76 inside the second vertical column cavity 73, which is used 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 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.

[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 element 80 to generate a first pressure drop, and then enters the first gas processing device 41 for drying and pressurization before being 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 element 90 to generate a second pressure drop, and then enters the second gas processing device 42 for drying and pressurization before being collected; wherein the first pressure drop is greater than the second pressure drop.

[0246] S44. After gas-liquid separation, the hydrogen-side alkali liquid is depressurized by the first pressure reducing valve 62 and then enters the hydrogen-side flash tank 61 for flash evaporation. Due to the sudden pressure drop, the hydrogen-side alkali liquid flashes, significantly reducing the solubility of hydrogen in the hydrogen-side alkali liquid, and rapidly releasing it in the gas phase, thereby achieving deep removal of dissolved hydrogen from 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 liquor and the oxygen-side alkali liquor enter the alkali liquor mixing tank 53 for mixing. Under the action of the third alkali liquor circulation pump 103, the mixed alkali liquor is decompressed by the second pressure reducing valve 72 and then enters the mixed alkali liquor flash tank 71. After the decompressed mixed alkali liquor enters the mixed alkali liquor flash tank 71, due to the sudden drop in pressure, the mixed alkali liquor undergoes flash evaporation, which greatly reduces the solubility of hydrogen and oxygen in the mixed alkali liquor and rapidly releases them in the form of gas phase, thereby achieving deep removal of dissolved oxygen and dissolved hydrogen in the mixed alkali liquor. After the deep removal of dissolved oxygen and dissolved hydrogen, the mixed alkali liquor enters the buffer tank 110. After the mixed alkali liquor in the buffer tank 110 reaches the operating temperature (30-45°C) of the alkaline electrolytic cell 10, the mixed alkali liquor in the buffer tank 110 is pumped back into the alkaline electrolytic cell 10 for electrolysis by the first alkali liquor circulation pump 101 and the second alkali liquor circulation pump 102.

[0248] Furthermore, 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 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 solution 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 a stop valve 120.

[0253] Application Example 1

[0254] The electrolytic hydrogen production system and method using a flash evaporation device to reduce the dissolved hydrogen content of the alkali solution on the hydrogen side in Example 1 are used to produce hydrogen;

[0255] The hydrogen-side gas-liquid separator 20 and the oxygen-side gas-liquid separator 30 are vertical tanks with a diameter of 0.8 m and a height of 3 m. The hydrogen-side flash tank 61 has a diameter of 0.7 m and a height of 1.2 m. The inner diameter of the first tangential inlet is 15 mm, and 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 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. 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. The outlet pressure of the first alkali liquid circulation pump 101 and the second alkali liquid circulation pump 102 are both 0.8 MPa.

[0258] S13. The gas separated by the oxygen-side gas-liquid separator 30 enters the second gas treatment unit 42 for drying and pressurization before being collected. 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 treatment unit 41 for drying and pressurization before being collected. The hydrogen-side alkali liquid after gas-liquid separation is depressurized by the first pressure reducing valve 62 and enters the hydrogen-side flash tank 61. The pressure of the hydrogen-side alkali liquid at the inlet of the hydrogen-side flash tank 61 is controlled to be 0.1 MPa and the speed is 3 m / 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 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 are used to produce hydrogen;

[0263] The hydrogen-side gas-liquid separator 20 and the oxygen-side gas-liquid separator 30 are vertical tanks with a diameter of 0.5 m and a height of 2 m. The mixed alkali liquid flash tank 71 has a diameter of 0.7 m and a height of 1.2 m. The inner diameter of the second tangential inlet is 15 mm, and 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. 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. 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. 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. The outlet pressure of the first alkali liquid circulation pump 101 and the second alkali liquid circulation pump 102 is 0.8 MPa.

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

[0267] S24. Under the action of the third alkali liquor circulation pump 103, the mixed alkali liquor enters the mixed alkali liquor flash tank 71 after passing through the second pressure reducing valve 72, and the outlet pressure of the third alkali liquor circulation pump 103 is controlled to be 0.8 MPa, the pressure of the mixed alkali liquor at the inlet of the mixed alkali liquor flash tank 71 is 0.1 MPa, and the speed is 3 m / s; due to the sudden drop in pressure, the mixed alkali liquor flashes, so that the solubility of oxygen and hydrogen in the mixed alkali liquor is greatly reduced, and is rapidly released in the form of gas phase, thereby achieving deep removal of dissolved oxygen and dissolved hydrogen in the mixed alkali liquor; after the mixed alkali liquor completes the deep removal of dissolved oxygen and dissolved hydrogen, it enters the buffer tank 110, and after the mixed alkali liquor in the buffer tank 110 reaches the operating temperature (30-45°C) of the alkaline electrolytic cell 10, the mixed alkali liquor in the buffer tank 110 is re-pumped into the alkaline electrolytic cell 10 for electrolysis through the first alkali liquor circulation pump 101 and the second alkali liquor 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 is 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. 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. 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. 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, the bottom of the axial flow separator 91 is provided with a second air inlet 92, the top is provided with a second air outlet 93, the side is provided with a second discharge port 94, and 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 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 100 mm, 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, 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 pipes are all 16 mm.

[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 at 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 0.8 MPa;

[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, undergoes cyclone separation in the cyclone separator 81, and is discharged from the first air outlet 83 and enters the first gas treatment device 41 for drying and pressurization treatment and then collection. 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, undergoes cyclone separation in the axial flow separator 91, and is discharged from the second air outlet 93 and enters the second gas treatment device 42 for drying and pressurization treatment and then collection. 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. After the gas-liquid separation, the hydrogen side circulating 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 circulating 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;

[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 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 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%. 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] Hydrogen is prepared by using the alkaline water electrolysis hydrogen production system and method for deeply reducing the hydrogen content in oxygen in Example 4. 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 diameter of the hydrogen side flash tank 61 is 0.7m and the height is 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 of the hydrogen side gas-liquid separator 20 is provided at the bottom of the cyclone separator 81; The first outlet 84 is connected to the first reflux port 24, and the first 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 air inlet 92 at the bottom, a second air 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 air inlet The first air inlet 82, the first air outlet 83 and the first discharge port 84 are 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 pipes 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 is 0.8 MPa;

[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 element 80 to generate a first pressure drop, and then enters the first gas treatment device 41 for drying and pressurization before being 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 element 90 to generate a second pressure drop, and then enters the second gas treatment device 42 for drying and pressurization before being collected. The first pressure drop is greater than the second pressure drop, and the difference between the first and second pressure drops is 2000 Pa.

[0282] S44. After gas-liquid separation, the hydrogen-side alkali liquid is depressurized 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 0.1 MPa and the speed is 3 m / s. Due to the sudden drop 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 gas phase, 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.

[0283] S45. The hydrogen side alkali liquor and the oxygen side alkali liquor enter the alkali liquor mixing tank 53 for mixing. Under the action of the third alkali liquor circulation pump 103, the mixed alkali liquor is decompressed by the second pressure reducing valve 72 and enters the mixed alkali liquor flash tank 71. The outlet pressure of the third alkali liquor circulation pump 103 is controlled to be 0.8 MPa, the pressure of the hydrogen side alkali liquor at the inlet of the mixed alkali liquor flash tank 71 is 0.1 MPa, and the speed is 3 m / s. After the decompressed mixed alkali liquor enters the mixed alkali liquor flash tank 71, the mixed alkali liquor flashes due to the sudden drop in pressure. The solubility of hydrogen and oxygen in the mixed alkali solution 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 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.

[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 of the gaseous 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. After gas-liquid separation, the hydrogen-side alkali liquid and the oxygen-side alkali liquid enter the alkali liquid mixing tank 53 for mixing and are 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 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 in the oxygen 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%. 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 member (cyclone separator 81) and the oxygen side pressure regulating member (axial flow separator 91) used in Example 3 can effectively reduce the liquid content of hydrogen and oxygen, facilitating 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 operate better, an 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 hydrogen and oxygen side pressure regulating parts in the present invention; a hydrogen sensor / pressure sensor 130 can also be set at each device and pipeline of the alkaline water electrolysis hydrogen production system of the present invention to monitor the operating status of the system; and the various technical solutions in the present invention can be arbitrarily combined to perform deep dehydrogenation on the alkaline water electrolysis hydrogen production system, as long as the structure and function of each device in the individual technical solutions do not cause significant negative interference.

[0290] It should be noted that the above-described embodiments are to 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 to the present invention, without departing from the spirit and scope of the present invention, still fall within the scope of protection of the present invention.

Claims

1. A device for removing dissolved hydrogen by strengthening alkaline water electrolysis hydrogen production using a flash tank, characterized in that: It includes an alkaline electrolyzer, 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; 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.

2. The device for removing dissolved hydrogen by strengthening alkaline water electrolysis 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; 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; The bottom of the alkaline electrolytic cell is provided with an inlet for mixed alkali solution; 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; 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; 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; The alkali solution mixing tank is connected to the mixed alkali solution inlet through a pipeline.

3. The device for removing dissolved hydrogen by strengthening alkaline water electrolysis hydrogen production using a flash tank according to claim 2, characterized in that: 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, and is used to receive 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.

4. The device for removing dissolved hydrogen by strengthening alkaline water electrolysis hydrogen production using a flash tank according to claim 3, characterized in that: 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.

5. The device for removing dissolved hydrogen by strengthening alkaline water electrolysis hydrogen production using a flash tank according to claim 4, characterized in that: The third gas phase outlet is provided with a first tapered overflow pipe inside the first vertical column cavity. 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.

6. The device for removing dissolved hydrogen by strengthening alkaline water electrolysis hydrogen production using a flash tank according to claim 1, characterized in that: 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.

7. A method for enhancing the removal of dissolved hydrogen by alkaline water electrolysis hydrogen production using a flash tank, using the device for enhancing the removal of dissolved hydrogen by alkaline water electrolysis hydrogen production using a flash tank according to any one of claims 1 to 6, comprising the following steps: 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; 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; 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; 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.

8. The method for removing dissolved hydrogen by strengthening alkaline water electrolysis hydrogen production using a flash tank according to claim 7, 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.

9. The method for removing dissolved hydrogen by strengthening alkaline water electrolysis hydrogen production using a flash tank according to claim 8, characterized in that: The outlet pressures of the first alkali solution circulation pump and the second alkali solution circulation pump are both 0.8-1.6Mpa.

10. The method for removing dissolved hydrogen by strengthening alkaline water electrolysis hydrogen production using a flash tank according to claim 7, characterized in that: 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.

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