Alkaline electrolytic cell hydrogen production system

Abstract

The utility model relates to the technical field of hydrogen production through water electrolysis, and discloses an alkaline electrolytic cell hydrogen production system which comprises an alkaline electrolytic cell, an oxygen separator, an oxygen-water separator, a hydrogen-in-oxygen analyzer and a high-purity oxygen storage tank, a first outlet of the oxygen separator is connected with an inlet of the oxygen-water separator, an oxygen outlet of the oxygen-water separator is connected with the high-purity oxygen storage tank after passing through the hydrogen-in-oxygen tester, a drainage outlet of the oxygen-water separator discharges water, and an outlet of the high-purity oxygen storage tank is connected with a second inlet of the oxygen-water separator. By additionally arranging the high-purity oxygen storage tank, high-purity oxygen flow can be provided under a low load, and the high-purity oxygen storage tank is used for replacing the reduced oxygen yield under the low load and reducing the hydrogen concentration in oxygen in the operation process of the alkaline electrolytic cell under the low load, so that the electrolytic cell obtains a wider power operation range.

Description

Technical Field

[0001] This utility model relates to the field of hydrogen production technology through water electrolysis, and specifically to an alkaline electrolyzer hydrogen production system. Background Technology

[0002] Hydrogen energy, as a sustainable energy carrier, can be converted into various energy sources and is characterized by its cleanliness, efficiency, and lack of pollution. With the increasing installed capacity of renewable energy sources year by year, hydrogen production through water electrolysis has become an important way to absorb renewable energy. To adapt to the unstable nature of renewable energy and meet the needs of green electricity balance and absorption, it is necessary to be able to adjust loads over a wide range. Currently, water electrolysis hydrogen production technologies mainly include alkaline water electrolysis, proton exchange membrane electrolysis, anion exchange membrane electrolysis, and high-temperature solid oxide electrolysis. Alkaline water electrolysis is currently the most cost-effective and scalable renewable energy hydrogen production process and is widely adopted. However, it suffers from an increase in hydrogen concentration in oxygen during low-load operation, which can lead to a series of safety issues. Utility Model Content

[0003] In view of this, the present invention provides an alkaline electrolyzer hydrogen production system to solve the problem of increased hydrogen concentration in oxygen during low-load operation.

[0004] This invention provides an alkaline electrolyzer hydrogen production system, comprising: an alkaline electrolyzer, an oxygen separator, an oxygen-water separator, an oxygen-hydrogen analyzer, and a high-purity oxygen storage tank.

[0005] The oxygen and alkali outlets of the alkaline electrolytic cell are connected to the first inlet of the oxygen separator, the first outlet of the oxygen separator is connected to the inlet of the oxygen-water separator, the oxygen outlet of the oxygen-water separator is connected to the high-purity oxygen storage tank after passing through the oxygen-hydrogen tester, the drain outlet of the oxygen-water separator discharges water, and the outlet of the high-purity oxygen storage tank is connected to the second inlet of the oxygen-water separator.

[0006] This utility model provides an alkaline electrolyzer hydrogen production system that, by adding a high-purity oxygen storage tank, can provide a high-purity oxygen flow rate under low load to replace the reduced oxygen production under low load, thereby reducing the hydrogen concentration in the oxygen during the operation of the alkaline electrolyzer under low load and enabling the electrolyzer to obtain a wider power operating range.

[0007] In one optional embodiment, the system further includes: a hydrogen separator, a hydrogen-water separator, and a second mixing separator, wherein the second mixing separator is equipped with an ultrasonic device.

[0008] The inlet of the hydrogen separator is connected to the hydrogen and alkali outlets of the alkaline electrolyzer. The first outlet of the hydrogen separator is connected to the inlet of the hydrogen-water separator. The hydrogen outlet of the hydrogen-water separator discharges hydrogen, and the drain outlet of the hydrogen-water separator discharges water. The inlet of the second mixing separator is connected to the second outlet of the oxygen separator and the second outlet of the hydrogen separator, respectively. The outlet of the second mixing separator discharges alkali.

[0009] The concentration of impurity gases in the circulating alkaline solution is reduced by using an ultrasonic device, which further reduces the hydrogen concentration in the oxygen in the system.

[0010] In one optional embodiment, the system further includes: a first oxygen scrubber, a second oxygen scrubber, an oxygen cooler, and an oxygen drainer, wherein,

[0011] The inlet of the first oxygen scrubber is connected to the first outlet of the oxygen separator, the outlet of the first oxygen scrubber is connected to the inlet of the second oxygen scrubber, the outlet of the second oxygen scrubber is connected to the inlet of the oxygen cooler, the outlet of the oxygen cooler is connected to the inlet of the oxygen-water separator, and the inlet of the oxygen drainer is connected to the drain outlet of the oxygen-water separator.

[0012] In one optional embodiment, the system further includes: a first hydrogen scrubber, a second hydrogen scrubber, a hydrogen cooler, and a hydrogen drainer, wherein,

[0013] The inlet of the first hydrogen scrubber is connected to the first outlet of the hydrogen-water separator, the outlet of the first hydrogen scrubber is connected to the inlet of the second hydrogen scrubber, the outlet of the second hydrogen scrubber is connected to the inlet of the hydrogen cooler, the outlet of the hydrogen cooler is connected to the inlet of the hydrogen-water separator, and the inlet of the hydrogen drainer is connected to the drain outlet of the hydrogen-water separator.

[0014] By setting up two-stage oxygen scrubbers and two-stage hydrogen scrubbers, the alkali in oxygen and hydrogen can be removed more thoroughly, preventing corrosion of the oxygen-hydrogen tester, hydrogen-oxygen tester, and oxygen removal catalyst in subsequent purification devices, thus extending the service life of the equipment.

[0015] In one optional embodiment, the system further includes: an alkali circulation pump set, an alkali cooler, and a filtration device, wherein,

[0016] The inlet of the alkali circulation pump group is connected to the outlet of the second mixing separator, the outlet of the alkali circulation pump group is connected to the inlet of the alkali cooler, the outlet of the alkali cooler is connected to the inlet of the filtration device, and the outlet of the filtration device is connected to the inlet of the alkaline electrolyzer and the alkali replenishment and alkali removal main pipes of the hydrogen production plant, respectively.

[0017] In one optional embodiment, the alkali circulation pump group includes a first alkali circulation pump and a second alkali circulation pump, and the first alkali circulation pump and the second alkali circulation pump are redundantly configured.

[0018] The redundancy settings improve the operational reliability of the alkaline electrolyzer hydrogen production system.

[0019] In one optional embodiment, the system further includes a cooling heat exchange device, which is connected to the alkali cooler, the alkali circulation pump group, the oxygen cooler, and the hydrogen cooler, respectively.

[0020] In one optional embodiment, the system further includes a water supply device, which is connected to the first oxygen scrubber, the second oxygen scrubber, the first hydrogen scrubber, and the second hydrogen scrubber, respectively.

[0021] In one optional embodiment, the system further includes a nitrogen purging device connected to both the hydrogen separator and the oxygen separator.

[0022] In one optional embodiment, the system further includes a sewage discharge device, which is connected to the sewage discharge port of the electrolytic cell, the sewage discharge port of the filter device, the sewage discharge port of the hydrogen drainer, and the sewage discharge port of the oxygen drainer, respectively. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of an alkaline electrolyzer hydrogen production system according to an embodiment of the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0026] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0028] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0029] Currently, in water electrolysis hydrogen production systems, the alkaline solution is mixed with the hydrogen (oxygen) separator before entering the circulation pump for further circulation. The main factors affecting the hydrogen content in the oxygen are operating load, alkaline solution mixing, and the partial pressure and concentration differences of the gases across the diaphragm. In particular, the problem of increased hydrogen concentration in the oxygen during alkaline electrolyzer operation under low load can trigger a series of issues. For example, reaching a threshold can cause system shutdown, leading to repeated shutdowns and reduced electrolyzer lifespan. Furthermore, increased hydrogen concentration can pose safety hazards, as there is an explosive limit to the volume fraction of hydrogen in oxygen; it reaches its minimum explosive limit at approximately 4%. Given the numerous uncertainties associated with renewable energy sources like wind and solar power, resulting in significant daily power output fluctuations, the hydrogen production system must have a sufficiently wide power response range to maximize the utilization of wind energy. Therefore, reducing the hydrogen concentration in the oxygen during alkaline electrolyzer operation under low load is extremely important. Therefore, this embodiment provides an alkaline electrolyzer hydrogen production system to reduce the hydrogen concentration in oxygen during the operation of the alkaline electrolyzer under low load.

[0030] like Figure 1As shown, this utility model provides an alkaline electrolyzer hydrogen production system, including: an alkaline electrolyzer, an oxygen separator, an oxygen-water separator, an oxygen-hydrogen analyzer, and a high-purity oxygen storage tank. The oxygen and alkaline solution outlets of the alkaline electrolyzer are connected to the first inlet of the oxygen separator, the first outlet of the oxygen separator is connected to the inlet of the oxygen-water separator, the oxygen outlet of the oxygen-water separator is connected to the high-purity oxygen storage tank after passing through the oxygen-hydrogen analyzer, the drainage outlet of the oxygen-water separator discharges water, and the outlet of the high-purity oxygen storage tank is connected to the second inlet of the oxygen-water separator.

[0031] Specifically, during the operation of the alkaline electrolyzer hydrogen production system, the alkaline solution from the alkaline electrolyzer enters the oxygen separator along with the gas. In the oxygen separator, the oxygen and alkaline solution are initially separated. The oxygen after the initial separation enters the oxygen-water separator for further separation. One of the high-purity oxygens after the second separation is connected to the high-purity oxygen storage tank, and the other is directly discharged into the air. The water in the drain outlet of the oxygen-water separator is directly discharged through the oxygen drainer.

[0032] An oxygen-hydrogen analyzer monitors the oxygen-hydrogen concentration at the oxygen outlet of the oxygen-water separator in real time. The oxygen-hydrogen concentration is used as an indicator to evaluate the safe operation of the water electrolysis hydrogen production system. The sources of oxygen-hydrogen concentration are analyzed, and an oxygen-hydrogen concentration model is established. The main sources of oxygen-hydrogen concentration are concentration gradient diffusion of impurity hydrogen, pressure gradient convection, and dissolution in the electrolyte.

[0033] The hydrogen concentration model in oxygen is established as follows:

[0034]

[0035] In the formula, The flow rate of impurity hydrogen gas. This represents the system's oxygen production.

[0036] According to the mathematical model of oxygen-hydrogen, the main reason for the increase in oxygen-hydrogen concentration is the decrease in oxygen production under low load. Therefore, if the oxygen-hydrogen concentration continues to rise or increases when the load is further reduced, the system will automatically control the supply of oxygen from the high-purity oxygen storage tank to the oxygen separator to compensate for the reduced oxygen production under low load. Furthermore, the system will continuously monitor the changes in oxygen-hydrogen concentration to control the flow rate of oxygen entering the oxygen separator.

[0037] In one alternative implementation, such as Figure 1As shown, the alkaline electrolyzer hydrogen production system also includes: a hydrogen separator, a hydrogen-water separator, and a second mixing separator, wherein the second mixing separator is equipped with an ultrasonic device. The inlet of the hydrogen separator is connected to the hydrogen and alkali outlets of the alkaline electrolyzer; the first outlet of the hydrogen separator is connected to the inlet of the hydrogen-water separator; the hydrogen outlet of the hydrogen-water separator discharges hydrogen; the drain outlet of the hydrogen-water separator discharges water; the inlet of the second mixing separator is connected to the second outlet of the oxygen separator and the second outlet of the hydrogen separator, respectively; and the outlet of the second mixing separator discharges alkali.

[0038] Specifically, during the operation of the alkaline electrolyzer hydrogen production system, the alkaline solution from the alkaline electrolyzer enters the hydrogen separator along with the gas. In the hydrogen separator, hydrogen and alkaline solution undergo preliminary separation. The hydrogen after preliminary separation enters the hydrogen-water separator for further separation. The hydrogen after further separation is then sent to the purification system, and the separated water is discharged. The alkaline solution separated from the oxygen separator and hydrogen separator is mixed and enters the second mixing separator. The alkaline solution discharged from the second mixing separator is then recycled back to the alkaline electrolyzer.

[0039] Furthermore, after monitoring that the hydrogen concentration in oxygen continues to rise or rises when the load is further reduced, while controlling the replenishment of oxygen from the high-purity oxygen storage tank to the oxygen separator, the ultrasonic device is turned on to reduce the solubility of the gas in the solution, reduce the content of gaseous impurities in the alkaline solution of the second mixing separator, and vent the generated gas. In this way, by reducing the concentration of impurity gas in the circulating alkaline solution, the hydrogen concentration in oxygen in the system is further reduced.

[0040] In one alternative implementation, such as Figure 1 As shown, the alkaline electrolyzer hydrogen production system also includes: a first oxygen scrubber, a second oxygen scrubber, an oxygen cooler, and an oxygen drainer. The inlet of the first oxygen scrubber is connected to the first outlet of the oxygen separator; the outlet of the first oxygen scrubber is connected to the inlet of the second oxygen scrubber; the outlet of the second oxygen scrubber is connected to the inlet of the oxygen cooler; the outlet of the oxygen cooler is connected to the inlet of the oxygen-water separator; and the inlet of the oxygen drainer is connected to the outlet of the oxygen-water separator. The alkaline electrolyzer hydrogen production system also includes: a first hydrogen scrubber, a second hydrogen scrubber, a hydrogen cooler, and a hydrogen drainer. The inlet of the first hydrogen scrubber is connected to the first outlet of the hydrogen-water separator; the outlet of the first hydrogen scrubber is connected to the inlet of the second hydrogen scrubber; the outlet of the second hydrogen scrubber is connected to the inlet of the hydrogen cooler; the outlet of the hydrogen cooler is connected to the inlet of the hydrogen-water separator; and the inlet of the hydrogen drainer is connected to the outlet of the hydrogen-water separator.

[0041] Specifically, the alkaline electrolyzer hydrogen production system also includes a hydrogen-oxygen analyzer. One path of the hydrogen from the hydrogen-water separator outlet, after passing through the hydrogen-oxygen analyzer, enters the purification equipment, while the other path is directly discharged. Water from the hydrogen-water separator outlet passes through a hydrogen drainer and then enters the drainage water seal. This embodiment, by setting up two-stage oxygen scrubbers and two-stage hydrogen scrubbers, can more thoroughly remove alkali from oxygen and hydrogen, preventing corrosion of the oxygen-hydrogen analyzer, hydrogen-oxygen analyzer, and the oxygen removal catalyst in the subsequent purification unit, thus extending the equipment's service life.

[0042] In one alternative implementation, such as Figure 1 As shown, the alkaline electrolyzer hydrogen production system also includes: an alkaline solution circulation pump set, an alkaline cooler, and a filter device. The inlet of the alkaline solution circulation pump set is connected to the outlet of the second mixing separator; the outlet of the alkaline solution circulation pump set is connected to the inlet of the alkaline cooler; the outlet of the alkaline cooler is connected to the inlet of the filter device; and the outlet of the filter device is connected to the inlet of the alkaline electrolyzer and the alkali replenishment and removal headers of the hydrogen production plant.

[0043] Specifically, the alkali circulation pump set includes a first alkali circulation pump and a second alkali circulation pump, which are redundantly configured. One of the first and second alkali circulation pumps is in operation while the other is on standby. This redundancy improves the operational reliability of the alkaline electrolyzer hydrogen production system.

[0044] In one optional embodiment, the alkaline electrolyzer hydrogen production system further includes a cooling heat exchange device, which is connected to an alkali cooler, an alkali circulation pump group, an oxygen cooler, and a hydrogen cooler, respectively.

[0045] Specifically, the cooling heat exchange device includes a circulating cooling water pump, a circulating cooling water inlet pipe for the plant, and circulating cooling water pipes. The circulating cooling water pump... Figure 1 (Not shown in the diagram). Under the action of the circulating cooling water pump, the circulating cooling water inlet pipe of the hydrogen production plant is connected to the alkali cooler, the first alkali circulating pump, the second alkali circulating pump, the oxygen cooler, and the hydrogen cooler via the circulating cooling water pipe, finally returning to the circulating cooling water return pipe of the hydrogen production plant to provide cooling and heat exchange for the water electrolysis hydrogen production system. The path of the cooling circulating water is shown in [reference needed]. Figure 1 .

[0046] In one optional embodiment, the alkaline electrolyzer hydrogen production system further includes a water supply device, which is connected to the first oxygen scrubber, the second oxygen scrubber, the first hydrogen scrubber, and the second hydrogen scrubber, respectively.

[0047] Specifically, the water supply system includes a water supply pump, a demineralized water makeup head pipe, and a makeup water pipe, wherein the water supply pump is... Figure 1(Not shown in the diagram). Under the action of the feedwater pump, the demineralized water makeup water header of the hydrogen production plant connects to the first oxygen scrubber, the second oxygen scrubber, the first hydrogen scrubber, and the second hydrogen scrubber via makeup water pipes, providing makeup water for the water electrolysis hydrogen production system. The flow path of the demineralized water is shown in [reference needed]. Figure 1 .

[0048] In one optional embodiment, the alkaline electrolyzer hydrogen production system further includes a nitrogen purging device. The nitrogen purging device is connected to both the hydrogen separator and the oxygen separator.

[0049] Specifically, the nitrogen replacement device is a nitrogen manifold, wherein the nitrogen manifold is in Figure 1 Not shown in the diagram. See [link to diagram]. For the nitrogen replacement pathway, see [link to diagram]. Figure 1 .

[0050] In one optional embodiment, the alkaline electrolyzer hydrogen production system further includes a drain device. The drain device is connected to the drain outlet of the electrolyzer, the drain outlet of the filter, the drain outlet of the hydrogen drainer, and the drain outlet of the oxygen drainer, respectively.

[0051] Specifically, the drain outlets for the electrolytic cell are located at the bottom of the left and right sides. The drain outlet for the filter unit is located at the bottom of the filter unit. The drain outlet for the hydrogen drainer is located at the bottom of the hydrogen drainer, discharging liquid entrained with hydrogen. The drain outlet for the oxygen drainer is located at the bottom of the oxygen drainer, discharging liquid entrained with oxygen. See the drain path for details. Figure 1 .

[0052] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. An alkaline electrolyzer hydrogen production system, characterized in that, The system includes: an alkaline electrolyzer, an oxygen separator, an oxygen-water separator, an oxygen-hydrogen analyzer, and a high-purity oxygen storage tank. The oxygen and alkali outlets of the alkaline electrolytic cell are connected to the first inlet of the oxygen separator, the first outlet of the oxygen separator is connected to the inlet of the oxygen-water separator, the oxygen outlet of the oxygen-water separator is connected to the high-purity oxygen storage tank after passing through the oxygen-hydrogen tester, the drain outlet of the oxygen-water separator discharges water, and the outlet of the high-purity oxygen storage tank is connected to the second inlet of the oxygen-water separator.

2. The alkaline electrolyzer hydrogen production system according to claim 1, characterized in that, The system further includes: a hydrogen separator, a hydrogen-water separator, and a second mixing separator, wherein the second mixing separator is equipped with an ultrasonic device. The inlet of the hydrogen separator is connected to the hydrogen and alkali outlets of the alkaline electrolyzer. The first outlet of the hydrogen separator is connected to the inlet of the hydrogen-water separator. The hydrogen outlet of the hydrogen-water separator discharges hydrogen, and the drain outlet of the hydrogen-water separator discharges water. The inlet of the second mixing separator is connected to the second outlet of the oxygen separator and the second outlet of the hydrogen separator, respectively. The outlet of the second mixing separator discharges alkali.

3. The alkaline electrolyzer hydrogen production system according to claim 2, characterized in that, The system further includes: a first oxygen scrubber, a second oxygen scrubber, an oxygen cooler, and an oxygen drainer, wherein, The inlet of the first oxygen scrubber is connected to the first outlet of the oxygen separator, the outlet of the first oxygen scrubber is connected to the inlet of the second oxygen scrubber, the outlet of the second oxygen scrubber is connected to the inlet of the oxygen cooler, the outlet of the oxygen cooler is connected to the inlet of the oxygen-water separator, and the inlet of the oxygen drainer is connected to the drain outlet of the oxygen-water separator.

4. The alkaline electrolyzer hydrogen production system according to claim 3, characterized in that, The system further includes: a first hydrogen scrubber, a second hydrogen scrubber, a hydrogen cooler, and a hydrogen drainer, wherein, The inlet of the first hydrogen scrubber is connected to the first outlet of the hydrogen-water separator, the outlet of the first hydrogen scrubber is connected to the inlet of the second hydrogen scrubber, the outlet of the second hydrogen scrubber is connected to the inlet of the hydrogen cooler, the outlet of the hydrogen cooler is connected to the inlet of the hydrogen-water separator, and the inlet of the hydrogen drainer is connected to the drain outlet of the hydrogen-water separator.

5. The alkaline electrolyzer hydrogen production system according to claim 4, characterized in that, The system also includes: an alkali circulation pump set, an alkali cooler, and a filtration device, wherein... The inlet of the alkali circulation pump group is connected to the outlet of the second mixing separator, the outlet of the alkali circulation pump group is connected to the inlet of the alkali cooler, the outlet of the alkali cooler is connected to the inlet of the filtration device, and the outlet of the filtration device is connected to the inlet of the alkaline electrolyzer and the alkali replenishment and alkali removal main pipes of the hydrogen production plant, respectively.

6. The alkaline electrolyzer hydrogen production system according to claim 5, characterized in that, The alkali circulation pump group includes a first alkali circulation pump and a second alkali circulation pump, and the first alkali circulation pump and the second alkali circulation pump are redundantly configured.

7. The alkaline electrolyzer hydrogen production system according to claim 5, characterized in that, The system further includes a cooling heat exchange device, which is connected to the alkali cooler, the alkali circulation pump group, the oxygen cooler and the hydrogen cooler respectively.

8. The alkaline electrolyzer hydrogen production system according to claim 4, characterized in that, The system further includes a water supply device, which is connected to the first oxygen scrubber, the second oxygen scrubber, the first hydrogen scrubber, and the second hydrogen scrubber.

9. The alkaline electrolyzer hydrogen production system according to claim 2, characterized in that, The system further includes a nitrogen purging device, which is connected to the hydrogen separator and the oxygen separator respectively.

10. The alkaline electrolyzer hydrogen production system according to claim 5, characterized in that, The system further includes a sewage discharge device, which is connected to the sewage discharge port of the electrolytic cell, the sewage discharge port of the filter device, the sewage discharge port of the hydrogen drainer, and the sewage discharge port of the oxygen drainer, respectively.

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