Electrolytic hydrogen production system and method adapting to high voltage, low load and frequent start and stop

Abstract

The invention discloses an electrolytic hydrogen production system and method adaptive to high voltage, low load and frequent start and stop. The system comprises an electrolytic bath (1); the oxygen separator (2), the oxygen cooler (4), the oxygen drop catcher (6), the dehydrogenator (8), the oxygen circulating compressor (10) and the oxygen separator (2) are sequentially connected to form circulation; the hydrogen separator (3), the hydrogen cooler (5), the hydrogen drop catcher (7), the deaerator (9), the hydrogen circulating compressor (11) and the hydrogen separator (3) are sequentially connected to form circulation. According to the scheme provided by the invention, the oxygen generated by the electrolytic cell is returned to the oxygen separator after dehydrogenation treatment, and the hydrogen generated by the electrolytic cell is returned to the hydrogen separator after deoxidation treatment, so that the proportion of hydrogen in oxygen to oxygen in hydrogen is reduced, and the situation that the proportion of hydrogen in oxygen or oxygen in hydrogen exceeds the standard when the system operates at high pressure and low load is avoided; therefore, the system is interlocked, stopped and incapable of running.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolytic hydrogen production, and in particular to an electrolytic hydrogen production system and method adaptable to high voltage, low load, and frequent start and stop. Background Art

[0002] Currently, there are many industrial hydrogen production methods, including natural gas steam reforming, methanol reforming, water gas and water electrolysis. The raw water for water electrolysis is inexhaustible and the reaction product after energy use is water. At the same time, the electricity for water electrolysis can utilize environmentally friendly energy such as wind energy, solar energy and nuclear energy. Therefore, water electrolysis has good social and economic benefits.

[0003] As we all know, renewable energy sources such as photovoltaic and wind power generation are characterized by high volatility, wide fluctuation ranges, and frequent starts and stops. Meanwhile, downstream hydrogen-using industries such as chemical synthesis require high hydrogen pressures (>5.5MPa). Alkaline electrolysis hydrogen production systems offer advantages such as low cost and large processing capacity.

[0004] However, the current alkaline electrolysis hydrogen production system has disadvantages such as low operational flexibility, long cold start time, and low operating pressure (≤1.6MPa). The main reason for these shortcomings of alkaline electrolysis hydrogen production is that the diaphragm of the alkaline electrolyzer has poor resistance to hydrogen and oxygen permeation. During the operation and shutdown cycle, a small amount of hydrogen and oxygen will penetrate, causing the system to exceed the oxygen content in hydrogen and hydrogen in oxygen during low load or high pressure operation, resulting in interlocking shutdown. At the same time, the oxygen content in hydrogen and hydrogen in oxygen will also exceed the standard during the shutdown process, and nitrogen replacement has to be used, resulting in a long start-up time and a large amount of hydrogen waste. Therefore, in order to fully adapt to the operating characteristics of renewable energy power generation, it is necessary to optimize the alkaline electrolysis hydrogen production system to meet the system's high pressure, low load and fast start-stop requirements. Summary of the Invention

[0005] The object of the present invention is to provide a system and method for producing hydrogen by electrolysis that is adaptable to high voltage, low load and frequent start and stop conditions, so as to at least partially solve the above-mentioned problems of the prior art.

[0006] To achieve the above objectives, the present invention provides an electrolysis hydrogen production system that is adaptable to high voltage, low load, and frequent start-stop conditions, comprising:

[0007] The electrolyzer 1 is connected to the oxygen separator 2 and the hydrogen separator 3 respectively;

[0008] The oxygen separator 2, oxygen cooler 4, oxygen droplet collector 6, dehydrogenator 8, oxygen circulation compressor 10, and oxygen separator 2 are connected in sequence to form a cycle, wherein the oxygen droplet collector 6 is also connected to the oxygen discharge pipe. The oxygen circulation compressor 10 returns the oxygen treated by the dehydrogenator 8 to the oxygen separator 2 to mix with the oxygen input to the oxygen separator 2 by the electrolyzer 1;

[0009] The hydrogen separator 3, hydrogen cooler 5, hydrogen droplet collector 7, deoxidizer 9, hydrogen circulation compressor 11, and hydrogen separator 3 are connected in sequence to form a cycle, wherein the hydrogen droplet collector 7 is also connected to the hydrogen discharge pipe. The hydrogen circulation compressor 11 returns the hydrogen treated by the deoxidizer 9 to the hydrogen separator 3 and mixes with the hydrogen input to the hydrogen separator 3 from the electrolyzer 1;

[0010] The system further comprises an alkali solution treatment device, which is connected to the oxygen separator 2 and the hydrogen separator 3 respectively, and is used to receive and treat the alkali solution obtained after separation by the oxygen separator 2 and the hydrogen separator 3.

[0011] Preferably, the alkali solution treatment equipment includes an alkali solution circulation pump 13 and an alkali solution cooler 12. The alkali solution circulation pump 13 receives alkali solution separated by the oxygen separator 2 and the hydrogen separator 3 to obtain alkali solution. The alkali solution is cooled by the alkali solution cooler 12 and then returned to the electrolytic cell 1.

[0012] Preferably, the system further comprises a hydrogen content detector for detecting the hydrogen content in the oxygen treated by the oxygen droplet trap 6 , and adjusting the ratio of the oxygen transmitted to the oxygen exhaust pipe and the oxygen transmitted to the dehydrogenator 8 according to the detection result.

[0013] Preferably, the system further includes a circulating oxygen regulating valve V3 provided between the oxygen circulating compressor 10 and the oxygen separator 2, and / or an oxygen outlet regulating valve V1 provided on the oxygen exhaust pipe. The circulating oxygen regulating valve V3 and / or the oxygen outlet regulating valve V1 are used to adjust the ratio of the discharged oxygen and the oxygen returned to the oxygen separator 2.

[0014] Preferably, the input end of the hydrogen content in oxygen detector is connected to the oxygen droplet catcher 6, the first output end of the hydrogen content in oxygen detector is provided with a first valve and connected to the oxygen exhaust pipe, the second output end of the hydrogen content in oxygen detector is provided with a second valve and connected to the dehydrogenator 8, and the hydrogen content in oxygen detector is used to adjust the opening and closing of the first valve and / or the second valve according to the hydrogen content in oxygen detection result.

[0015] Preferably, the system further comprises a hydrogen oxygen content detector for detecting the oxygen content in the hydrogen after treatment by the hydrogen droplet catcher 7 , and adjusting the ratio of the hydrogen transmitted to the hydrogen exhaust pipeline and the hydrogen transmitted to the deoxidizer 9 according to the detection result.

[0016] Preferably, the system further includes a hydrogen outlet regulating valve V2 provided on the hydrogen exhaust pipeline, and / or a circulating hydrogen regulating valve V4 provided between the hydrogen circulation compressor 11 and the hydrogen separator 3, and the hydrogen outlet regulating valve V2 and / or the circulating hydrogen regulating valve V4 are used to adjust the ratio of the discharged hydrogen and the hydrogen returned to the hydrogen separator 3.

[0017] Preferably, the input end of the hydrogen oxygen content detector is connected to the hydrogen droplet catcher 7, the first output end of the hydrogen oxygen content detector is provided with a third valve and connected to the hydrogen exhaust pipe, the second output end of the hydrogen oxygen content detector is provided with a fourth valve and connected to the deoxidizer 9, and the hydrogen oxygen content detector is used to adjust the opening and closing of the third valve and / or the fourth valve according to the detection result of the hydrogen oxygen content.

[0018] Another aspect of the present invention further provides an electrolysis hydrogen production method applied to the above-mentioned electrolysis hydrogen production system, comprising:

[0019] The oxygen separator 2 separates the oxygen received from the electrolytic cell 1, transmits the separated alkali solution to the alkali solution treatment equipment, and transmits the separated oxygen to the oxygen cooler 4;

[0020] At least part of the separated oxygen passes through the oxygen cooler 4, the oxygen droplet collector 6, the dehydrogenator 8, the oxygen circulation compressor 10, and then returns to the oxygen separator 2 to mix with the oxygen input to the oxygen separator 2 from the electrolyzer 1;

[0021] The hydrogen separator 3 separates the hydrogen received from the electrolytic cell 1, transmits the separated alkali solution to the alkali solution treatment equipment, and transmits the separated hydrogen to the hydrogen cooler 5;

[0022] At least part of the separated hydrogen passes through the hydrogen cooler 5, the hydrogen droplet collector 7, the deoxidizer 9, and the hydrogen circulation compressor 11 in sequence and then returns to the hydrogen separator 3 to be mixed with the hydrogen input to the hydrogen separator 3 from the electrolyzer 1.

[0023] Preferably, when the electrolysis hydrogen production system is operated in a high-pressure and low-load operation mode: at least a portion of the separated oxygen passes through the oxygen cooler 4, the oxygen droplet collector 6, the dehydrogenator 8, and the oxygen circulation compressor 10 in sequence and then returns to the oxygen separator 2, and is mixed with the oxygen input to the oxygen separator 2 from the electrolyzer 1; at least a portion of the separated hydrogen passes through the hydrogen cooler 5, the hydrogen droplet collector 7, the deoxygenator 9, and the hydrogen circulation compressor 11 in sequence and then returns to the hydrogen separator 3, and is mixed with the hydrogen input to the hydrogen separator 3 from the electrolyzer 1;

[0024] When the electrolysis hydrogen production system is shut down, the oxygen outlet regulating valve V1 and the hydrogen outlet regulating valve V2 are closed, the oxygen circulation compressor 10 and the hydrogen circulation compressor 11 are opened, and the circulating oxygen regulating valve V3 and the circulating hydrogen regulating valve V4 are opened until the preset conditions are met and then the oxygen circulation compressor 10 and the hydrogen circulation compressor 11 are closed;

[0025] When the electrolytic hydrogen production system is started, the oxygen outlet regulating valve V1 is closed, the oxygen circulation compressor 10 and the hydrogen circulation compressor 11 are opened, the circulating oxygen regulating valve V3 and the circulating hydrogen regulating valve V4 are opened, and the hydrogen outlet regulating valve V2 is set to automatic.

[0026] Preferably, setting the hydrogen outlet regulating valve V2 to automatically include:

[0027] When the electrolytic hydrogen production system is started, the pressure on the oxygen separator 2 side and the pressure on the hydrogen separator 3 side are obtained by a pressure gauge;

[0028] If the pressure on the hydrogen separator 3 side is lower than the pressure on the oxygen separator 2 side and the difference is greater than the pressure difference threshold, then reduce the hydrogen outlet regulating valve V2;

[0029] If the pressure on the hydrogen separator 3 side is higher than the pressure on the oxygen separator 2 side and the difference is greater than the pressure difference threshold, the hydrogen outlet regulating valve V2 is adjusted to a larger value.

[0030] Compared with the prior art, the present invention has at least the following advantages:

[0031] By adopting the solution provided in the embodiment of the present invention, the oxygen generated by the electrolyzer can be returned to the oxygen separator after dehydrogenation treatment, and the hydrogen generated by the electrolyzer can be returned to the hydrogen separator after deoxygenation treatment, thereby reducing the ratio of hydrogen in oxygen in the oxygen output by the oxygen separator and reducing the ratio of oxygen in hydrogen in the hydrogen output by the hydrogen separator. This prevents the system from interlocking and shutting down due to the hydrogen in oxygen or hydrogen in oxygen exceeding the standard when the system is operating at high pressure and low load. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of an example structure of an electrolysis hydrogen production system adapted to high pressure, low load and frequent start and stop, provided in Example 1 of the present invention.

[0033] Figure 2 A schematic flow chart of a method for producing hydrogen by electrolysis according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0035] It should be noted that the terms "first," "second," and the like in the specification and claims of the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate to facilitate understanding of the embodiments of the present invention described herein. In addition, the terms "including," "comprising," and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a product or device comprising a series of elements is not necessarily limited to those elements explicitly listed, but may include other elements not explicitly listed or inherent to the product or device.

[0036] In the present invention, terms such as "upper," "lower," "left," "right," "front," "back," "top," "bottom," "inner," "outer," "center," "vertical," "horizontal," "transverse," and "longitudinal" indicate positions or locations based on the positions or locations shown in the accompanying drawings. These terms are primarily intended to better describe the present invention and its embodiments and are not intended to limit the devices, elements, or components indicated to having a specific orientation, or to being constructed or operated in a specific orientation.

[0037] Furthermore, some of the above terms may be used to express other meanings besides indicating a position or location. For example, the term "on" may also be used to indicate a dependency or connection in certain circumstances. Those skilled in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances.

[0038] Furthermore, the terms "installed," "disposed," "provided with," "connected," "connected," and "socketed" should be interpreted broadly. For example, they can refer to fixed connections, removable connections, or integral structures; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; or internal communication between two devices, elements, or components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on specific circumstances.

[0039] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0040] Example 1

[0041] Embodiment 1 of the present invention provides an electrolysis hydrogen production system that is adaptable to high voltage, low load, and frequent start and stop. Figure 1 A schematic diagram showing an example of the system is shown. Figure 1 As shown, the system includes:

[0042] The electrolyzer 1 is connected to the oxygen separator 2 and the hydrogen separator 3 respectively;

[0043] The oxygen separator 2, oxygen cooler 4, oxygen droplet collector 6, dehydrogenator 8, oxygen circulation compressor 10, and oxygen separator 2 are connected in sequence to form a cycle, wherein the oxygen droplet collector 6 is also connected to the oxygen discharge pipe. The oxygen circulation compressor 10 returns the oxygen treated by the dehydrogenator 8 to the oxygen separator 2 to mix with the oxygen input to the oxygen separator 2 by the electrolyzer 1;

[0044] The hydrogen separator 3, hydrogen cooler 5, hydrogen droplet collector 7, deoxidizer 9, hydrogen circulation compressor 11, and hydrogen separator 3 are connected in sequence to form a cycle, wherein the hydrogen droplet collector 7 is also connected to the hydrogen discharge pipe. The hydrogen circulation compressor 11 returns the hydrogen treated by the deoxidizer 9 to the hydrogen separator 3 and mixes with the hydrogen input to the hydrogen separator 3 from the electrolyzer 1;

[0045] The system further comprises an alkali solution treatment device, which is connected to the oxygen separator 2 and the hydrogen separator 3 respectively, and is used to receive and treat the alkali solution obtained after separation by the oxygen separator 2 and the hydrogen separator 3.

[0046] Among them, oxygen separator 2, oxygen cooler 4, oxygen droplet catcher 6, hydrogen separator 3, hydrogen cooler 5, hydrogen droplet catcher 7 are all conventional equipment. Dehydrogenator 8 is a catalytic dehydrogenation device, and its principle is to utilize catalyst to make hydrogen and oxygen react at room temperature to generate water, thereby achieving the purpose of removing hydrogen from the oxygen. Oxygen circulation compressor 10 is a reciprocating or centrifugal compressor, and the main function of this equipment is to supercharge the oxygen circulation, thereby providing the power of the oxygen circulation pipeline. Deoxygenator 9 is a catalytic deoxygenation device, and its principle is similar to that of dehydrogenator, and also utilizes catalyst to make hydrogen and oxygen react at room temperature, thereby achieving the purpose of removing oxygen from the hydrogen. Hydrogen circulation compressor 11 is a reciprocating compressor, and the main function of this equipment is to supercharge the hydrogen circulation, thereby providing the power of the hydrogen circulation pipeline.

[0047] Among them, such as Figure 1 As shown, in a preferred embodiment, the alkali liquid treatment equipment may include an alkali liquid circulation pump 13 and an alkali liquid cooler 12. The alkali liquid circulation pump 13 receives the alkali liquid obtained after separation by the oxygen separator 2 and the hydrogen separator 3, and the alkali liquid is cooled by the alkali liquid cooler 12 and then returned to the electrolytic cell 1. It is easy to understand that other types of alkali liquid treatment equipment may also be used. For example, the alkali liquid may not be recycled, or may be directly returned to the electrolytic cell 1 without cooling, or may be subjected to other treatments before being returned to the electrolytic cell 1.

[0048] In a preferred embodiment, the system further comprises a hydrogen content detector for detecting the hydrogen content in the oxygen treated by the oxygen droplet trap 6 , and adjusting the ratio of the oxygen transmitted to the oxygen exhaust pipe and the oxygen transmitted to the dehydrogenator 8 according to the detection result.

[0049] refer to Figure 1 As shown, the system may further include a circulating oxygen regulating valve V3 provided between the oxygen circulating compressor 10 and the oxygen separator 2, and / or an oxygen outlet regulating valve V1 provided on the oxygen exhaust pipeline. The circulating oxygen regulating valve V3 and / or the oxygen outlet regulating valve V1 are used to adjust the ratio of the discharged oxygen and the oxygen returned to the oxygen separator 2.

[0050] In another embodiment (non Figure 1 As shown), the input end of the hydrogen content in oxygen detector is connected to the oxygen droplet catcher 6, the first output end of the hydrogen content in oxygen detector is provided with a first valve and connected to the oxygen exhaust pipe, the second output end of the hydrogen content in oxygen detector is provided with a second valve and connected to the dehydrogenator 8, and the hydrogen content in oxygen detector is used to adjust the opening and closing of the first valve and / or the second valve according to the detection result of the hydrogen content in oxygen.

[0051] In a preferred embodiment, the system further comprises a hydrogen oxygen content detector for detecting the oxygen content in the hydrogen after treatment by the hydrogen droplet catcher 7 and adjusting the ratio of the hydrogen transmitted to the hydrogen exhaust pipeline and the hydrogen transmitted to the deoxidizer 9 according to the detection result.

[0052] refer to Figure 1 As shown, the system may further include a hydrogen outlet regulating valve V2 provided on the hydrogen exhaust pipeline, and / or a circulating hydrogen regulating valve V4 provided between the hydrogen circulation compressor 11 and the hydrogen separator 3. The hydrogen outlet regulating valve V2 and / or the circulating hydrogen regulating valve V4 are used to adjust the ratio of the discharged hydrogen and the hydrogen returned to the hydrogen separator 3.

[0053] In another embodiment (non Figure 1 As shown), the input end of the hydrogen oxygen content detector is connected to the hydrogen droplet catcher 7, the first output end of the hydrogen oxygen content detector is provided with a third valve and connected to the hydrogen exhaust pipe, the second output end of the hydrogen oxygen content detector is provided with a fourth valve and connected to the deoxidizer 9, and the hydrogen oxygen content detector is used to adjust the opening and closing of the third valve and / or the fourth valve according to the detection result of the oxygen content in hydrogen.

[0054] refer to Figure 1 As shown, an example of the operation process of the system provided by the embodiment of the present invention is as follows:

[0055] When operating in high-pressure and low-load mode, the electrolyzer 1 generates oxygen, which is separated from the alkali solution by the oxygen separator 2. The oxygen is then cooled by the oxygen cooler 4 and then passes through the oxygen droplet trap 6. A portion of the gas is then discharged or vented through the regulating valve V1, while the remaining portion of the gas is catalytically dehydrogenated by the dehydrogenator 8. The hydrogen in the oxygen is then removed through the oxygen compressor 10 and the circulating oxygen regulating valve V3 before being returned to the oxygen separator. This reduces the amount of hydrogen in the oxygen and prevents system interlock shutdowns. Similar to the oxygen cycle, the hydrogen generated by the electrolyzer passes through the hydrogen separator 3 to separate the alkali solution from the hydrogen. The hydrogen is then cooled by the hydrogen cooler 5 and then passes through the hydrogen droplet trap 7. A portion of the gas is then discharged through the regulating valve V2, while the remaining portion of the gas is catalytically deoxygenated by the deoxygenator 9. The oxygen in the hydrogen is then removed through the hydrogen circulating compressor 11 before returning to the oxygen separator. This reduces the amount of hydrogen in the hydrogen and prevents hydrogen venting and system interlock shutdowns.

[0056] When the system is running at high load or low pressure and the hydrogen in oxygen and oxygen in hydrogen in the system do not exceed the standard, the circulating compressor and circulating gas regulating valve can be closed, and all gases can be vented or enter the downstream unit, thereby reducing energy consumption and extending the life of the compressor and catalyst.

[0057] When the system is shut down, the gas pressure can be reduced to a safe pressure (for example, 0.5 MPa) through the oxygen and hydrogen outlet regulating valves V1 and V2, and then the electrolyzer is gradually closed, and the oxygen and hydrogen outlet regulating valves V1 and V2 are completely closed. At the same time, the hydrogen and oxygen circulation compressors 10 and 11 are opened, and the circulating gas regulating valves V3 and V4 are opened to eliminate the infiltrated hydrogen and oxygen generated during the shutdown process, ensuring that the oxygen in hydrogen and hydrogen in oxygen in the system meet the standards during the shutdown process, until the alkali solution circulation pump circulates for the preset time and / or the alkali solution temperature is lower than the threshold, the circulating compressor and the circulating gas regulating valve are closed to maintain the pressure, thereby ensuring that the system hydrogen and oxygen meet the safety requirements and achieve the purpose of rapid startup.

[0058] When the system is started, the oxygen side regulating valve V1 can be closed, and the oxygen side circulating compressor and the oxygen side circulating gas regulating valve can be opened at the same time to quickly increase the pressure. The hydrogen side regulating valve V2 can be adjusted to automatic to ensure the system liquid level balance. At the same time, the hydrogen side circulating compressor and the hydrogen side circulating gas regulating valve can be opened to ensure that the oxygen in the hydrogen is quickly qualified and enters the downstream process.

[0059] Among them, pressure gauges can be respectively provided on the oxygen separator 2 side and the hydrogen separator 3 side, and the pressure gauges can be flexibly provided in the circulation system on the oxygen separator 2 side and the circulation system on the hydrogen separator 3 side.

[0060] When the electrolytic hydrogen production system is started, the air pressure on the oxygen separator 2 side and the air pressure on the hydrogen separator 3 side are obtained through the pressure gauge; if the air pressure on the hydrogen separator 3 side is lower than the air pressure on the oxygen separator 2 side and the difference is greater than the pressure difference threshold, the hydrogen outlet regulating valve V2 is adjusted down; if the air pressure on the hydrogen separator 3 side is higher than the air pressure on the oxygen separator 2 side and the difference is greater than the pressure difference threshold, the hydrogen outlet regulating valve V2 is adjusted up.

[0061] By adopting the solution provided in the embodiment of the present invention, the oxygen generated by the electrolyzer can be returned to the oxygen separator after dehydrogenation treatment, and the hydrogen generated by the electrolyzer can be returned to the hydrogen separator after deoxygenation treatment, thereby reducing the ratio of hydrogen in oxygen in the oxygen output by the oxygen separator and reducing the ratio of oxygen in hydrogen in the hydrogen output by the hydrogen separator. This prevents the system from interlocking and shutting down due to the hydrogen in oxygen or hydrogen in oxygen exceeding the standard when the system is operating at high pressure and low load.

[0062] By setting regulating valves, the circulation volume of hydrogen and oxygen in the system can be flexibly controlled and adjusted, and the circulation volume can be intelligently controlled according to different loads. Under the premise of ensuring that the concentration does not exceed the standard, energy consumption and catalyst consumption can be reduced.

[0063] During the system shutdown and startup process, hydrogen and oxygen are circulated through the hydrogen and oxygen loops to eliminate the hydrogen and oxygen that penetrate during the shutdown process, avoiding excessive levels of oxygen in hydrogen and hydrogen in oxygen. This eliminates the need for the traditional nitrogen purge and replacement process, enabling rapid system startup and shutdown and rapid achievement of oxygen in hydrogen standards, meeting the needs of wind power and photovoltaic hydrogen production.

[0064] Example 2

[0065] Example 2 of the present invention provides an electrolytic hydrogen production method applied to the electrolytic hydrogen production system provided in Example 1, such as Figure 2 As shown, the method includes:

[0066] In step 201 , the oxygen separator 2 separates the oxygen received from the electrolytic cell 1 , transmits the separated alkali solution to the alkali solution treatment equipment, and transmits the separated oxygen to the oxygen cooler 4 .

[0067] In step 202 , at least part of the separated oxygen passes through the oxygen cooler 4 , the oxygen droplet collector 6 , the dehydrogenator 8 , and the oxygen circulation compressor 10 in sequence and then returns to the oxygen separator 2 to be mixed with the oxygen input to the oxygen separator 2 from the electrolyzer 1 .

[0068] In step 203 , the hydrogen separator 3 separates the hydrogen received from the electrolytic cell 1 , transmits the separated alkali solution to the alkali solution treatment equipment, and transmits the separated hydrogen to the hydrogen cooler 5 .

[0069] In step 204 , at least part of the separated hydrogen passes through the hydrogen cooler 5 , the hydrogen droplet collector 7 , the deoxidizer 9 , and the hydrogen circulation compressor 11 in sequence and then returns to the hydrogen separator 3 to be mixed with the hydrogen input from the electrolyzer 1 to the hydrogen separator 3 .

[0070] There is no necessary order between steps 201 and 203, and they can be performed simultaneously or independently.

[0071] The method may include: referring to Figure 1 As shown, the ratio of discharged oxygen to oxygen returned to the oxygen separator 2 can be adjusted by the circulating oxygen regulating valve V3 provided between the oxygen circulating compressor 10 and the oxygen separator 2, and / or the oxygen outlet regulating valve V1 provided on the oxygen discharge pipeline. The oxygen outlet regulating valve V1 and the circulating oxygen regulating valve V3 can be provided simultaneously, or only one can be provided. The ratio of oxygen transmitted to the oxygen discharge pipeline to oxygen transmitted to the dehydrogenator 8 can be varied by adjusting the valve opening. Similarly, the ratio of discharged hydrogen to hydrogen returned to the hydrogen separator 3 can be adjusted by the circulating hydrogen regulating valve V4 provided between the hydrogen circulating compressor 11 and the hydrogen separator 3, and / or the hydrogen outlet regulating valve V2 provided on the hydrogen discharge pipeline. The hydrogen outlet regulating valve V2 and the circulating hydrogen regulating valve V4 can be provided simultaneously, or only one can be provided. The ratio of hydrogen transmitted to the hydrogen discharge pipeline to hydrogen transmitted to the dehydrogenator 9 can be varied by adjusting the valve opening.

[0072] The method may further include: detecting the hydrogen content in the oxygen after treatment by the oxygen droplet catcher 6 by means of a hydrogen-in-oxygen content detector, and adjusting the ratio of the oxygen transmitted to the oxygen exhaust pipeline to the oxygen transmitted to the dehydrogenator 8 according to the detection result. For example, the input end of the hydrogen-in-oxygen content detector is connected to the oxygen droplet catcher 6, the first output end of the hydrogen-in-oxygen content detector is provided with a first valve and connected to the oxygen exhaust pipeline, the second output end of the hydrogen-in-oxygen content detector is provided with a second valve and connected to the dehydrogenator 8, and the hydrogen-in-oxygen content detector is used to adjust the opening and closing of the first valve and / or the second valve according to the detection result of the hydrogen-in-oxygen content. Similarly, the method may further include: detecting the oxygen content in the hydrogen after treatment by the hydrogen droplet catcher 7 by means of an oxygen-in-hydrogen content detector, and adjusting the ratio of the hydrogen transmitted to the hydrogen exhaust pipeline to the hydrogen transmitted to the dehydrogenator 9 according to the detection result. For example, the input end of the oxygen content in hydrogen detector is connected to the hydrogen droplet catcher 7, the first output end of the oxygen content in hydrogen detector is provided with a third valve and connected to the hydrogen exhaust pipe, the second output end of the oxygen content in hydrogen detector is provided with a fourth valve and connected to the deoxidizer 9, and the oxygen content in hydrogen detector is used to adjust the opening and closing of the third valve and / or the fourth valve according to the detection result of the oxygen content in hydrogen.

[0073] When the electrolytic hydrogen production system operates in a high-pressure and low-load mode, at least a portion of the separated oxygen passes through an oxygen cooler 4, an oxygen droplet trap 6, a dehydrogenator 8, and an oxygen circulation compressor 10, and then returns to the oxygen separator 2, where it is mixed with the oxygen input to the oxygen separator 2 from the electrolyzer 1. At least a portion of the separated hydrogen passes through a hydrogen cooler 5, a hydrogen droplet trap 7, a deoxidizer 9, and a hydrogen circulation compressor 11, and then returns to the hydrogen separator 3, where it is mixed with the hydrogen input to the hydrogen separator 3 from the electrolyzer 1. For example, when the electrolyzer 1 is operating, oxygen generated by the oxygen separator 2 separates the alkali liquid from the oxygen. The oxygen is then cooled by the oxygen cooler 4 and then passes through the oxygen droplet trap 6. A portion of the gas is then discharged or vented through a regulating valve V1, while the remaining portion of the gas passes through the dehydrogenator 8 for catalytic dehydrogenation, removing the hydrogen from the oxygen. The gas then passes through the oxygen compressor 10 and the circulating oxygen regulating valve V3, and then returns to the oxygen separator, thereby reducing the hydrogen content in the oxygen and preventing the system from interlocking and shutting down. Similar to the oxygen cycle, the hydrogen generated by the electrolyzer passes through the hydrogen separator 3 to separate the alkali liquid from the hydrogen, and then the hydrogen is cooled by the hydrogen cooler 5 and passes through the hydrogen droplet collector 7. Part of the gas is sent out through the regulating valve V2, and the other part of the gas is catalytically deoxidized by the deoxidizer 9. After the oxygen in the hydrogen is removed, it returns to the oxygen separator after passing through the hydrogen circulation compressor 11, thereby reducing the oxygen in the hydrogen, preventing hydrogen from being vented and the system from being interlocked and shut down.

[0074] When the electrolytic hydrogen production system is shut down, the oxygen outlet regulating valve V1 and hydrogen outlet regulating valve V2 are closed, the oxygen circulation compressor 10 and hydrogen circulation compressor 11 are opened, and the circulating oxygen regulating valve V3 and circulating hydrogen regulating valve V4 are opened until preset conditions are met, at which point the oxygen circulation compressor 10 and hydrogen circulation compressor 11 are closed. For example, when the electrolyzer 1 is in operation, oxygen is generated. After oxygen separator 2 separates the alkali liquid and oxygen, the oxygen is cooled by oxygen cooler 4 and then passes through oxygen droplet collector 6. A portion of the gas is then discharged or vented through regulating valve V1, while the remaining portion of the gas is catalytically dehydrogenated by dehydrogenator 8. The hydrogen in the oxygen is then removed and then returned to the oxygen separator through oxygen compressor 10 and circulating oxygen regulating valve V3, thereby reducing the hydrogen in the oxygen and preventing the system from interlocking and shutting down. Similar to the oxygen cycle, the hydrogen generated by the electrolyzer passes through the hydrogen separator 3 to separate the alkali liquid from the hydrogen, and then the hydrogen is cooled by the hydrogen cooler 5 and passes through the hydrogen droplet collector 7. Part of the gas is sent out through the regulating valve V2, and the other part of the gas is catalytically deoxidized by the deoxidizer 9. After the oxygen in the hydrogen is removed, it returns to the oxygen separator after passing through the hydrogen circulation compressor 11, thereby reducing the oxygen in the hydrogen, preventing hydrogen from being vented and the system from being interlocked and shut down.

[0075] When the electrolytic hydrogen production system is started, the oxygen outlet regulating valve V1 is closed, the oxygen circulation compressor 10 and the hydrogen circulation compressor 11 are started, and the circulating oxygen regulating valve V3 and the circulating hydrogen regulating valve V4 are opened. The hydrogen outlet regulating valve V2 is set to automatic. For example, the pressure on the oxygen separator 2 side and the pressure on the hydrogen separator 3 side are measured using a pressure gauge. If the pressure on the hydrogen separator 3 side is lower than the pressure on the oxygen separator 2 side and the difference is greater than the pressure differential threshold, the hydrogen outlet regulating valve V2 is adjusted downward. If the pressure on the hydrogen separator 3 side is higher than the pressure on the oxygen separator 2 side and the difference is greater than the pressure differential threshold, the hydrogen outlet regulating valve V2 is adjusted upward.

[0076] By adopting the solution provided in the embodiment of the present invention, the oxygen generated by the electrolyzer can be returned to the oxygen separator after dehydrogenation treatment, and the hydrogen generated by the electrolyzer can be returned to the hydrogen separator after deoxygenation treatment, thereby reducing the ratio of hydrogen in oxygen in the oxygen output by the oxygen separator and reducing the ratio of oxygen in hydrogen in the hydrogen output by the hydrogen separator. This prevents the system from interlocking and shutting down due to the hydrogen in oxygen or hydrogen in oxygen exceeding the standard when the system is operating at high pressure and low load.

[0077] By setting regulating valves, the amount of hydrogen and oxygen circulating in the system can be flexibly controlled and adjusted. The circulation volume can be intelligently controlled according to different loads, reducing energy consumption and catalyst consumption while ensuring that the concentration does not exceed the standard. During system shutdown and startup, the hydrogen and oxygen loops circulate to eliminate hydrogen and oxygen that have penetrated during the shutdown process, preventing excessive levels of oxygen in hydrogen and hydrogen in oxygen. This eliminates the need for the traditional nitrogen purge and replacement process, enabling rapid system startup and shutdown, and quickly meeting the oxygen content in hydrogen standards, meeting the needs of wind power and photovoltaic hydrogen production.

[0078] Example 3

[0079] Example 3 of the present invention provides an application example of the electrolysis hydrogen production system provided in Example 1. Figure 1 The system shown in the figure adds oxygen dehydrogenation and hydrogen deoxygenation cycles to the alkaline electrolysis hydrogen production system, and carries out targeted removal of hydrogen and oxygen that penetrate into the system under high pressure and low load and during system start-up and shutdown, thereby achieving stable operation of the entire system under high pressure and low load, and realizing rapid start-up and shutdown of the alkaline system, and quickly achieving the purpose of hydrogen reaching the standard and being transferred to downstream purification.

[0080] Taking a 2000 cubic meter alkaline hydrogen production system as an example, the process is as follows:

[0081] When the system is started, close the oxygen side regulating valve V1, open the oxygen side circulating compressor 10 and the oxygen side circulating gas regulating valve V3 at the same time, and quickly increase the load (for example, the load is required to be greater than 800Nm 3 / hH2), and the hydrogen side regulating valve V2 is adjusted to automatic to ensure the balance of the alkali liquid level. At the same time, the hydrogen side circulating compressor 11 and the hydrogen side circulating gas regulating valve V4 are opened to ensure that the oxygen in the hydrogen is quickly qualified (for example, <0.5%) and enters the downstream process.

[0082] When operating in 5.5MPa high pressure and low load mode below 30%, open V1 and V2, two 1000 cubic electrolyzers or one 2000 cubic electrolyzer 1 will generate less than 300Nm 3 / h oxygen with a hydrogen content of 3%.

[0083] The oxygen separator 2 receives less than 300Nm generated by the electrolyzer 1 3 / h oxygen with a hydrogen content of 3%, and 1200Nm 3 / h oxygen with 0% hydrogen content is combined, and after the alkali solution and oxygen are separated, 1500Nm 3 / h oxygen with a hydrogen content of 0.6% is cooled by the oxygen cooler 4 and then passes through the oxygen droplet collector 6, 300Nm 3 / h Oxygen with a hydrogen content of 0.6% is sent out or vented through the regulating valve V1, 1200Nm 3 / h oxygen with a hydrogen content of 0.6% is catalytically dehydrogenated by the dehydrogenator 8, 200Nm 3 / h oxygen with a hydrogen content of 0% is introduced into the oxygen separator 2 after passing through the oxygen compressor 10 and the circulating oxygen regulating valve V3.

[0084] Similar to the oxygen cycle, the electrolyzer produces 600Nm 3 / h Hydrogen with an oxygen content of 1.2% and 1200Nm 3 / h Hydrogen with 0% oxygen content is combined and then passes through hydrogen separator 3 to separate the alkali solution from the hydrogen. 1800Nm 3 / h The oxygen content of hydrogen is 0.4% and the hydrogen is cooled by hydrogen cooler 5 and then passes through hydrogen droplet collector 7, 600Nm 3 / h Hydrogen with an oxygen content of 0.4% is sent out through the regulating valve V2, 1200Nm 3 / h Hydrogen with an oxygen content of 0.4% is catalytically deoxidized by the deoxidizer 9, 1200Nm 3 / h Hydrogen with an oxygen content of 0% returns to the oxygen separator after passing through the hydrogen circulation compressor 11, thereby reducing the oxygen in the hydrogen and preventing the system from being interlocked and shut down and then venting the hydrogen.

[0085] When the system pressure is lower than 1.6MPa or the operating load is greater than 800Nm 3 / h, when the hydrogen content in the system is less than 1.5% and the oxygen content in the hydrogen is less than 0.5%, the circulating compressor and the circulating gas regulating valve can be closed, and all the gas can be vented or enter the downstream unit, thereby reducing energy consumption and extending the life of the compressor and catalyst.

[0086] When the system is shut down, the gas pressure can be reduced to a safe pressure (e.g. 0.5 MPa), and then the electrolyzer is gradually closed, and the hydrogen and oxygen outlet regulating valves V1 and V2 are completely closed. At the same time, the hydrogen and oxygen circulation compressors 10 and 11 are opened, and the circulating gas regulating valves V3 and V4 are opened. The oxygen circulating gas volume is greater than 400 Nm 3 / h, the hydrogen circulation volume is about 800Nm 3 / h, used to eliminate the infiltrated hydrogen and oxygen generated during the shutdown process, to ensure that the oxygen in hydrogen and hydrogen in oxygen in the system meet the standards during the shutdown process, until the alkali solution circulation pump circulates for more than half an hour and the alkali solution temperature is lower than 50℃, then the circulation compressor and the circulation gas price regulating valve are closed to maintain pressure, thereby ensuring that the system hydrogen and oxygen meet safety requirements and achieve the purpose of rapid startup.

[0087] When the system is started, the oxygen side regulating valve V1 can be closed, and the oxygen side circulating compressor and the oxygen side circulating gas regulating valve can be opened at the same time to quickly increase the load (for example, more than 800Nm 3 / hH2), and the hydrogen side regulating valve V2 is adjusted to automatic to ensure the system liquid level balance. At the same time, the hydrogen side circulating compressor and the hydrogen side circulating gas regulating valve are opened to ensure that the oxygen in the hydrogen quickly meets the requirements (<0.5%) and enters the downstream process.

[0088] It is easy to understand that the parameters of the system implementation provided in Example 3 of the present invention are examples and are not intended to limit the application scenarios of the system and method provided by the present invention. Without violating the technical concept and principles of the present invention, there can be electrolysis hydrogen production systems with various parameters.

[0089] Finally, it should be noted that the above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit them. Those skilled in the art will appreciate that the technical solutions described in the aforementioned embodiments may be modified, or some of the technical features thereof may be replaced with equivalents; such modifications or replacements do not deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An electrolysis hydrogen production system adapted to high pressure, low load and frequent start and stop, characterized by: include: The electrolyzer (1) is connected to an oxygen separator (2) and a hydrogen separator (3); The oxygen separator (2), the oxygen cooler (4), the oxygen droplet collector (6), the dehydrogenator (8), the oxygen circulation compressor (10), and the oxygen separator (2) are sequentially connected to form a cycle, wherein the oxygen droplet collector (6) is also connected to an oxygen discharge pipe, and the oxygen circulation compressor (10) returns the oxygen processed by the dehydrogenator (8) to the oxygen separator (2) to be mixed with the oxygen input to the oxygen separator (2) from the electrolyzer (1); A hydrogen separator (3), a hydrogen cooler (5), a hydrogen droplet catcher (7), a deoxidizer (9), a hydrogen circulation compressor (11), and a hydrogen separator (3) are sequentially connected to form a cycle, wherein the hydrogen droplet catcher (7) is also connected to a hydrogen discharge pipe, and the hydrogen circulation compressor (11) returns the hydrogen processed by the deoxidizer (9) to the hydrogen separator (3) to be mixed with the hydrogen input to the hydrogen separator (3) from the electrolyzer (1); The system further comprises an alkali solution treatment device, which is respectively connected to the oxygen separator (2) and the hydrogen separator (3) and is used for receiving and treating the alkali solution obtained after separation by the oxygen separator (2) and the hydrogen separator (3).

2. The electrolysis hydrogen production system adapted to high pressure, low load and frequent start and stop according to claim 1 is characterized in that: The alkali solution treatment equipment comprises an alkali solution circulation pump (13) and an alkali solution cooler (12). The alkali solution circulation pump (13) receives alkali solution separated by an oxygen separator (2) and a hydrogen separator (3) to obtain alkali solution. The alkali solution is cooled by the alkali solution cooler (12) and then returned to the electrolytic cell (1).

3. The electrolysis hydrogen production system adapted to high pressure, low load and frequent start and stop according to claim 1 is characterized in that: It also includes a hydrogen content detector for detecting the hydrogen content in the oxygen treated by the oxygen droplet trap (6), and adjusting the ratio of the oxygen transmitted to the oxygen exhaust pipeline and the oxygen transmitted to the dehydrogenator (8) according to the detection result.

4. The electrolysis hydrogen production system adapted to high pressure, low load and frequent start and stop according to claim 1 or 3, characterized in that: The invention also includes a circulating oxygen regulating valve (V3) provided between the oxygen circulating compressor (10) and the oxygen separator (2), and / or an oxygen outlet regulating valve (V1) provided on the oxygen discharge pipeline. The circulating oxygen regulating valve (V3) and / or the oxygen outlet regulating valve (V1) are used to adjust the ratio of discharged oxygen and oxygen returned to the oxygen separator (2).

5. The electrolysis hydrogen production system adapted to high pressure, low load and frequent start and stop according to claim 3 is characterized in that: The input end of the hydrogen content in oxygen detector is connected to the oxygen droplet trap (6); the first output end of the hydrogen content in oxygen detector is provided with a first valve and connected to the oxygen exhaust pipe; the second output end of the hydrogen content in oxygen detector is provided with a second valve and connected to the dehydrogenator (8); the hydrogen content in oxygen detector is used to adjust the opening and closing of the first valve and / or the second valve according to the hydrogen content detection result.

6. The electrolysis hydrogen production system adapted to high pressure, low load and frequent start and stop according to claim 1 is characterized in that: It also includes an oxygen content detector for detecting the oxygen content in the hydrogen after being treated by the hydrogen droplet catcher (7), and adjusting the ratio of the hydrogen transmitted to the hydrogen exhaust pipeline and the hydrogen transmitted to the deoxidizer (9) according to the detection result.

7. The electrolysis hydrogen production system adapted to high pressure, low load and frequent start and stop according to claim 1 or 6, characterized in that: The invention also includes a hydrogen outlet regulating valve (V2) provided on the hydrogen discharge pipeline, and / or a circulating hydrogen regulating valve (V4) provided between the hydrogen circulation compressor (11) and the hydrogen separator (3). The hydrogen outlet regulating valve (V2) and / or the circulating hydrogen regulating valve (V4) are used to adjust the ratio of the discharged hydrogen and the hydrogen returned to the hydrogen separator (3).

8. The electrolysis hydrogen production system adapted to high pressure, low load and frequent start and stop according to claim 6 is characterized in that: The input end of the hydrogen oxygen content detector is connected to the hydrogen droplet catcher (7), the first output end of the hydrogen oxygen content detector is provided with a third valve and connected to the hydrogen exhaust pipe, the second output end of the hydrogen oxygen content detector is provided with a fourth valve and connected to the deoxidizer (9), and the hydrogen oxygen content detector is used to adjust the opening and closing of the third valve and / or the fourth valve according to the detection result of the hydrogen oxygen content.

9. A method for producing hydrogen by electrolysis applied to the electrolysis hydrogen production system according to any one of claims 1 to 8, characterized in that: include: The oxygen separator (2) separates the oxygen received from the electrolytic cell (1), transmits the separated alkali solution to the alkali solution treatment equipment, and transmits the separated oxygen to the oxygen cooler (4); At least part of the separated oxygen passes through an oxygen cooler (4), an oxygen droplet trap (6), a dehydrogenator (8), and an oxygen circulation compressor (10) in sequence and then returns to the oxygen separator (2) to be mixed with the oxygen input to the oxygen separator (2) from the electrolyzer (1); The hydrogen separator (3) separates the hydrogen received from the electrolytic cell (1), transmits the separated alkali solution to the alkali solution treatment equipment, and transmits the separated hydrogen to the hydrogen cooler (5); At least part of the separated hydrogen passes through a hydrogen cooler (5), a hydrogen droplet collector (7), a deoxidizer (9), and a hydrogen circulation compressor (11) in sequence and then returns to the hydrogen separator (3) to be mixed with the hydrogen input to the hydrogen separator (3) from the electrolyzer (1).

10. The method according to claim 9, characterized in that When the electrolytic hydrogen production system operates in a high-pressure and low-load operation mode: at least a portion of the separated oxygen passes through an oxygen cooler (4), an oxygen droplet collector (6), a dehydrogenator (8), and an oxygen circulation compressor (10) in sequence, and then returns to the oxygen separator (2), and is mixed with the oxygen input to the oxygen separator (2) from the electrolyzer (1); at least a portion of the separated hydrogen passes through a hydrogen cooler (5), a hydrogen droplet collector (7), a deoxidizer (9), and a hydrogen circulation compressor (11) in sequence, and then returns to the hydrogen separator (3), and is mixed with the hydrogen input to the hydrogen separator (3) from the electrolyzer (1); When the electrolytic hydrogen production system is shut down, the oxygen outlet regulating valve (V1) and the hydrogen outlet regulating valve (V2) are closed, the oxygen circulation compressor (10) and the hydrogen circulation compressor (11) are opened, and the circulating oxygen regulating valve (V3) and the circulating hydrogen regulating valve (V4) are opened until preset conditions are met, and then the oxygen circulation compressor (10) and the hydrogen circulation compressor (11) are closed; When the electrolytic hydrogen production system is started, the oxygen outlet regulating valve (V1) is closed, the oxygen circulation compressor (10) and the hydrogen circulation compressor (11) are started, and the circulating oxygen regulating valve (V3) and the circulating hydrogen regulating valve (V4) are opened, and the hydrogen outlet regulating valve (V2) is set to automatic.

11. The method according to claim 10, characterized in that Setting the hydrogen outlet regulating valve (V2) to automatic includes: When the electrolytic hydrogen production system is started, the gas pressure on the oxygen separator (2) side and the gas pressure on the hydrogen separator (3) side are obtained by a pressure gauge; If the pressure on the hydrogen separator (3) side is lower than the pressure on the oxygen separator (2) side and the difference is greater than the pressure difference threshold, the hydrogen outlet regulating valve (V2) is adjusted downward; If the air pressure on the hydrogen separator (3) side is higher than the air pressure on the oxygen separator (2) side and the difference is greater than the pressure difference threshold, the hydrogen outlet regulating valve (V2) is adjusted to a larger value.

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