A hydrogen production drying and regeneration system and its control method

Abstract

This application relates to the field of hydrogen production, and specifically discloses a hydrogen production drying and regeneration system, which includes a water electrolyzer, a gas-water separator, a cooler, a drying tower, a hydrogen storage cylinder, and a fuel cell; during the water electrolysis process, the water electrolyzer electrolyzes water to form hydrogen and outputs a mixture containing hydrogen to the gas-water separator. The gas-water separator separates the gas in the mixture and inputs the separated gas into the cooler. The cooler cools the gas from the steam-water separator and outputs a gas containing water vapor and hydrogen to the drying tower. The drying tower absorbs the water vapor and outputs hydrogen to the hydrogen storage cylinder; during the power generation process, the hydrogen storage cylinder outputs hydrogen to the drying tower. The drying tower releases the water vapor absorbed during the water electrolysis process. The water vapor and hydrogen output by the drying tower are input into the fuel cell through the cooler, and the fuel cell generates electricity using the water vapor and hydrogen. The purpose of this application is to provide a hydrogen production drying system with a cyclic regeneration function.

Description

Technical Field

[0001] This application relates to the technical field of hydrogen production, and in particular to a hydrogen production drying and regeneration system and its control method. Background Art

[0002] The hydrogen produced by electrolyzing water has a high water vapor content. When directly used for high-pressure storage, the condensed water in the product hydrogen will cause corrosion of the gas cylinder and affect the hydrogen storage capacity. Therefore, it is difficult to directly store the hydrogen produced by the electrolyzer without drying treatment.

[0003] The commonly used electrolytic hydrogen production purification and drying technology in industry is a tower structure, such as a single-tower structure. The single-tower structure and control method are simple, but mostly in an intermittent working mode. Specifically, during the electrolysis of water, the drying tower can absorb water from the wet hydrogen; when the drying tower is saturated with water absorption, the hydrogen production drying system stops electrolyzing water and needs to dehydrate and remove water from the drying tower; after the dehydration of the drying tower is completed, the electrolysis process is restarted. Therefore, the working mode of the existing hydrogen production drying system is intermittent, and the existing monomer structure does not have the functions of automatic continuous circulation and regeneration. Summary of the Invention

[0004] This application provides a hydrogen production drying and regeneration system and its control method, aiming to provide a hydrogen production drying system with a circulation and regeneration function.

[0005] In a first aspect, a hydrogen production drying and regeneration system is provided, including an electrolyzer, a gas-water separator, a cooler, a drying tower, a hydrogen storage cylinder, and a fuel cell; the hydrogen production drying and regeneration system is used to perform the electrolysis process and the power generation process; wherein,

[0006] During the electrolysis process, the electrolyzer is used to electrolyze water to form hydrogen and output a mixture containing hydrogen to the gas-water separator. The gas-water separator is used to separate the gas in the mixture and input the separated gas to the cooler. The cooler is used to cool the gas from the gas-water separator and output a gas containing water vapor and hydrogen to the drying tower. The drying tower is used to absorb water vapor and output hydrogen to the hydrogen storage cylinder;

[0007] During the power generation process, the hydrogen storage cylinder is used to output hydrogen to the drying tower. The drying tower is used to release the water vapor absorbed during the electrolysis process. The water vapor and hydrogen output by the drying tower are input to the fuel cell through the cooler. The fuel cell is used to generate electricity using water vapor and hydrogen.

[0008] Compared with the prior art, the solution provided by this application has at least the following beneficial technical effects: For a fuel cell - water electrolyzer integrated application system, taking advantage of the fact that the hydrogen required during fuel cell power generation needs to be humidified, the hydrogen for the fuel cell is used to regenerate the drying tower while achieving its own humidification. This process realizes the function of humidifying the anode of the fuel cell while regenerating the drying tower, which is beneficial to improving the power generation performance of the fuel cell. Compared with the traditional tower drying method, this application makes full use of the characteristic that the anode gas of the fuel cell needs to be humidified, and automatically obtains highly humid hydrogen during the regeneration process of the drying tower, eliminating the need to set up a humidifier for the anode hydrogen of the fuel cell. This application uses the hydrogen production by water electrolysis and the application mode of using hydrogen for fuel cell power generation, enabling the automatic regeneration function of the drying tower during the flow of hydrogen, and the entire cyclic regeneration process can achieve lossless consumption of hydrogen, that is, the prepared hydrogen can be reasonably utilized instead of being discharged as waste gas.

[0009] The hydrogen production and drying regeneration system provided by this application can also be particularly applied to a single - tower structure. In the prior art, there is no single - tower structure with cyclic regeneration, and the addition of regeneration devices is complex and the control is cumbersome. This application can achieve the automatic continuous lossless regeneration function of a single drying tower. The execution components of the hydrogen production and drying regeneration system provided by this application are few, the control mode is simple, the operation is stable and reliable, and it uses the existing hydrogen path to achieve regeneration, reducing the addition of redundant complex regeneration devices, and greatly simplifying the system and control method, with high efficiency and strong practicability.

[0010] In combination with the first aspect, in some implementation manners of the first aspect, the hydrogen production and drying regeneration system further includes:

[0011] A back - pressure regulating valve, which is connected to the hydrogen storage device and is used to increase the pressure of the hydrogen output from the drying tower during the water electrolysis process;

[0012] A pressure - reducing valve, which is connected to the hydrogen storage device and is used to reduce the pressure of the hydrogen output from the hydrogen storage bottle during the power generation process.

[0013] By adjusting the hydrogen pressure through the back - pressure regulating valve, the hydrogen pressure stored in the hydrogen storage bottle can meet the hydrogen storage requirements. The low - pressure hydrogen output by the pressure - reducing valve can meet the hydrogen pressure required during the operation of the drying tower and the fuel cell.

[0014] In combination with the first aspect, in some implementation manners of the first aspect, the hydrogen production and drying regeneration system further includes a first three - way valve, the first three - way valve includes a first interface, a second interface and a third interface, the first interface is connected to the drying tower, the second interface is connected to the back - pressure regulating valve, and the third interface is connected to the pressure - reducing valve.

[0015] The first three - way valve can adjust the gas flow distribution on the hydrogen storage bottle side and control the switching between the water electrolysis process and the power generation process.

[0016] In combination with the first aspect, in some implementations of the first aspect, a one-way valve is provided between the hydrogen storage cylinder and the second interface, and the one-way valve is configured to allow hydrogen from the second interface to pass through and block hydrogen from the hydrogen storage cylinder from entering the second interface.

[0017] The one-way valve can restrict the flow direction of hydrogen and reduce the possibility of delivering high-pressure hydrogen to the fuel cell.

[0018] In combination with the first aspect, in some implementations of the first aspect, the hydrogen production drying and regeneration system further includes a second three-way valve, the second three-way valve includes a fourth interface, a fifth interface, and a sixth interface, the fourth interface is connected to the cooler, the fifth interface is connected to the fuel cell, and the sixth interface is connected to the gas-water separator.

[0019] The second three-way valve can adjust the gas flow distribution on the fuel cell side and control the switching between the water electrolysis process and the power generation process.

[0020] In combination with the first aspect, in some implementations of the first aspect, during the water electrolysis process, the cooling temperature of the cooler is a first cooling temperature, and during the power generation process, the cooling temperature of the cooler is a second cooling temperature, where the second cooling temperature is greater than or equal to the first cooling temperature.

[0021] During the water electrolysis process, the cooling temperature of the cooler is relatively low, so that more liquid water can be condensed by the cooler, which is beneficial to reducing the water vapor content output by the cooler to the drying tower and reducing the water absorption amount of the drying tower per unit time, and further beneficial to extending the duration of water electrolysis. During the power generation process, the cooling temperature of the cooler is relatively high, which is beneficial to keeping the power generation efficiency of the fuel cell within an appropriate range and the hydrogen humidity obtained by the fuel cell can be relatively appropriate.

[0022] In combination with the first aspect, in some implementations of the first aspect, during the water electrolysis process, the drying temperature of the drying tower is a first drying temperature, and during the power generation process, the drying temperature of the drying tower is a second drying temperature, where the second drying temperature is greater than the first drying temperature.

[0023] The drying temperature of the drying tower can be slightly higher so that the water absorbed by the drying tower during the water electrolysis process can be fully evaporated and discharged.

[0024] In combination with the first aspect, in some implementations of the first aspect, the duration of the power generation process ≤ the rated water absorption amount of the drying tower / the water release amount of the drying tower per unit time.

[0025] By controlling the duration of the power generation process, it can be ensured that the fuel cell can obtain wet hydrogen that meets the requirements and operate normally.

[0026] Combined with the first aspect, in some implementations of the first aspect, the duration of the water electrolysis process ≤ the rated water absorption capacity of the drying tower / the water absorption capacity of the drying tower per unit time.

[0027] By controlling the duration of the water electrolysis process, it is possible to avoid the drying tower outputting hydrogen products that do not meet the requirements.

[0028] Second aspect, a control method for a hydrogen production drying and regeneration system is provided. The control method is applied to the hydrogen production drying and regeneration system described in any one of the implementations in the first aspect above. The control method includes:

[0029] Step 1: Start the water electrolyzer and initialize the timing.

[0030] Step 2: When the timing reaches the first preset time, turn off the water electrolyzer, start the fuel cell, and initialize the timing.

[0031] Step 3: When the timing reaches the second preset time, turn off the fuel cell, and cycle back to Step 1.

[0032] Wherein, the first preset time corresponds to the duration of the water electrolysis process, and the second preset time corresponds to the duration of the power generation process.

[0033] Through the above control method, the two states are automatically switched by the control program after the respective processes are completed. One cycle is completed when each working state works once. The working time of each working state can be determined by parameters such as the specific hydrogen production by water electrolysis and the adsorption capacity of the drying tower. Thus, it can be realized that the hydrogen production drying and regeneration system periodically switches between the water electrolysis process and the power generation process, periodically adjusts the water absorption capacity of the drying tower, and realizes the automatic regeneration function of the drying tower. Description of the Drawings

[0034] Figure 1 It is a schematic structural diagram of a hydrogen production drying and regeneration system provided by an embodiment of the present application;

[0035] Figure 2 It is a schematic flow chart of a control method for a hydrogen production drying and regeneration system provided by an embodiment of the present application.

[0036] Description of the reference numerals: 1. Back pressure regulating valve; 2. Check valve; 3. Pressure reducing valve; 4. First three-way valve; 5. Second three-way valve. Detailed Embodiments

[0037] The present application will be further described in detail below with reference to the drawings and specific embodiments.

[0038] The embodiment of the present application discloses a hydrogen production drying and regeneration system. Referring to Figure 1 , it includes a water electrolyzer, a gas-water separator, a cooler, a drying tower, a hydrogen storage cylinder, and a fuel cell.

[0039] The hydrogen production drying and regeneration system can be used to perform the water electrolysis process. During the water electrolysis process, the water electrolyzer can be started, and water is electrolyzed to form hydrogen, and a mixture containing hydrogen is output to the gas-water separator. The gas-water separator is used to separate the gas in the mixture and input the separated gas into the cooler. The cooler is used to cool the gas from the steam-water separator, so that the water vapor in the gas condenses into liquid water to further reduce the water content in the gas. The cooler can output a gas containing water vapor and hydrogen to the drying tower. The drying tower is used to absorb water vapor and output hydrogen to the hydrogen storage cylinder. In a preferred embodiment, during the water electrolysis process, the fuel cell can be turned off.

[0040] In some embodiments, the drying tower contains an internal desiccant and a heating device, which are used to dry the wet hydrogen produced by water electrolysis to obtain qualified dry hydrogen. The desiccant can have a water absorption function. Before the end of the water electrolysis process, the absorption amount of the desiccant can reach saturation or tend to saturation. The hydrogen storage device is used to store the dry hydrogen produced and stored for it when the water electrolysis for hydrogen production is started.

[0041] The hydrogen production drying and regeneration system can also be used to perform the power generation process. During the water electrolysis process, the fuel cell can be started. The hydrogen storage cylinder is used to supply hydrogen to the fuel cell when the fuel cell is started. The hydrogen storage cylinder can output hydrogen to the drying tower. The drying tower is used to release the water vapor absorbed during the water electrolysis process. The water vapor and hydrogen output by the drying tower are input into the fuel cell through the cooler. The cooler can cool the high-temperature gas output by the drying tower so that the wet hydrogen entering the fuel cell has a suitable temperature. The fuel cell is used to generate electricity using water vapor and hydrogen. In a preferred embodiment, during the power generation process, the water electrolyzer can be turned off.

[0042] According to the foregoing, during the power generation process, the desiccant is at a relatively high drying temperature, and the desiccant can release water vapor to realize dehydration of the drying tower. The water vapor can be discharged following the hydrogen, so that the water absorption amount of the desiccant can gradually decrease during the power generation process, which is beneficial to the subsequent absorption of moisture in the wet hydrogen by the drying tower during the water electrolysis process.

[0043] In some embodiments, the hydrogen production drying and regeneration system further includes: a back pressure regulating valve 1, which is connected to the hydrogen storage device and is used to increase the pressure of the hydrogen output by the drying tower during the water electrolysis process. The pressure of the dry hydrogen output by the drying tower is relatively small, while the pressure of the hydrogen stored in the hydrogen storage cylinder is relatively large. By adjusting the hydrogen pressure through the back pressure regulating valve 1, the pressure of the hydrogen stored in the hydrogen storage cylinder can meet the hydrogen storage requirements.

[0044] In some embodiments, the hydrogen production drying and regeneration system further includes a pressure reducing valve 3. The pressure reducing valve 3 is connected to the hydrogen storage device and is used to reduce the pressure of the hydrogen output from the hydrogen storage cylinder during the power generation process. The low-pressure hydrogen output by the pressure reducing valve 3 can meet the hydrogen pressure required for the operation of the drying tower and the fuel cell.

[0045] In some embodiments, the hydrogen production drying and regeneration system further includes a first three-way valve 4. The first three-way valve 4 includes a first interface, a second interface, and a third interface. The first interface is connected to the drying tower, the second interface is connected to the back pressure regulating valve 1, and the third interface is connected to the pressure reducing valve 3. The first three-way valve 4 can be used to adjust the gas flow distribution and control the switching between the water electrolysis process and the power generation process. In a possible scenario, during the water electrolysis process, the first interface and the second interface can be opened, and the third interface can be closed; during the power generation process, the first interface and the third interface can be opened, and the second interface can be closed.

[0046] In some embodiments, a check valve 2 is provided between the hydrogen storage cylinder and the second interface. The check valve 2 is used to allow the hydrogen from the second interface to pass through and block the hydrogen from the hydrogen storage cylinder from entering the second interface. Combined Figure 1 , the check valve 2 can be located between the second interface and the back pressure regulating valve 1, or between the back pressure regulating valve 1 and the hydrogen storage cylinder.

[0047] In some embodiments, the hydrogen production drying and regeneration system further includes a second three-way valve 5. The second three-way valve 5 includes a fourth interface, a fifth interface, and a sixth interface. The fourth interface is connected to the cooler, the fifth interface is connected to the fuel cell, and the sixth interface is connected to the gas-water separator. The second three-way valve 5 can be used to adjust the gas flow distribution and control the switching between the water electrolysis process and the power generation process. In a possible scenario, during the water electrolysis process, the fourth interface and the sixth interface can be opened, and the fifth interface can be closed; during the power generation process, the fourth interface and the fifth interface can be opened, and the sixth interface can be closed.

[0048] In some embodiments, during the water electrolysis process, the cooling temperature of the cooler is a first cooling temperature, and during the power generation process, the cooling temperature of the cooler is a second cooling temperature, where the second cooling temperature is greater than or equal to the first cooling temperature.

[0049] During the water electrolysis process, the lower the cooling temperature of the cooler, the more liquid water can be condensed by the cooler, which is beneficial to reducing the water vapor content output by the cooler to the drying tower and reducing the water absorption amount of the drying tower per unit time, and further beneficial to extending the duration of the water electrolysis. Therefore, the cooling temperature of the cooler can be relatively low during the water electrolysis process.

[0050] During the power generation process, the cooling temperature of the cooler is relatively high. The amount of liquid water condensed by the cooler can be relatively small, so the water content output by the cooler is relatively high, making it easier for the humidity of hydrogen to meet the working requirements of the fuel cell. The temperature of the wet hydrogen required by the fuel cell can be normal temperature or slightly higher than normal temperature. If the temperature provided to the fuel cell is too low, the power generation efficiency of the fuel cell may be reduced. Therefore, during the power generation process, the cooling temperature of the cooler can be relatively high.

[0051] In some embodiments, during the water electrolysis process, the drying temperature of the drying tower is the first drying temperature, and during the power generation process, the drying temperature of the drying tower is the second drying temperature, where the second drying temperature can be greater than the first drying temperature. That is to say, during the power generation process, the drying temperature of the drying tower can be slightly higher so that the moisture absorbed by the drying tower during the water electrolysis process can be fully evaporated and discharged.

[0052] In some embodiments, the duration of the water electrolysis process ≤ the rated water absorption of the drying tower / the water absorption of the drying tower per unit time. After the water absorption of the drying tower reaches saturation, the drying tower cannot further absorb water vapor, resulting in the drying tower being unable to output hydrogen products that meet the requirements. Therefore, by controlling the duration of the water electrolysis process, it is possible to prevent the drying tower from outputting hydrogen products that do not meet the requirements.

[0053] In some embodiments, the duration of the power generation process ≤ the rated water absorption of the drying tower / the water release of the drying tower per unit time. After the water absorption of the drying tower is completely released, the drying tower cannot further release water vapor, resulting in the drying tower being unable to output wet hydrogen and affecting the normal operation of the fuel cell. Therefore, by controlling the duration of the power generation process, it is possible to ensure that the fuel cell can obtain wet hydrogen that meets the requirements and operate normally.

[0054] The embodiments of the present application disclose a control method for a hydrogen production drying and regeneration system, referring to Figure 2 . The control method can be applied to a hydrogen production drying and regeneration system as shown in Figure 1 . The control method may include:

[0055] Step 1: Start the water electrolyzer and initialize the timing.

[0056] Step 2: When the timing reaches the first preset time, turn off the water electrolyzer, start the fuel cell, and initialize the timing.

[0057] Step 3: When the timing reaches the second preset time, turn off the fuel cell and loop back to Step 1.

[0058] Among them, the first preset time corresponds to the duration of the water electrolysis process, and the second preset time corresponds to the duration of the power generation process.

[0059] Through the above control method, after the respective processes of the two states are completed, they are automatically switched by the control program. One cycle is completed when each of the two states works once. The working time of each working state can be determined by parameters such as the specific hydrogen production by water electrolysis and the adsorption capacity of the drying tower. Thus, it is possible to achieve the periodic switching of the hydrogen production drying and regeneration system between the water electrolysis process and the power generation process, periodically adjust the water absorption capacity of the drying tower, and realize the automatic regeneration function of the drying tower.

[0060] Although the present invention is disclosed above in preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be determined by the scope defined by the claims of the present invention.

Claims

1. A hydrogen production drying and regeneration system, characterized in that, It includes a water electrolyzer, a gas-water separator, a cooler, a drying tower, a hydrogen storage cylinder and a fuel cell; the hydrogen production drying and regeneration system is used to perform the water electrolysis process and the power generation process; wherein, In the water electrolysis process, the water electrolyzer is used to electrolyze water to form hydrogen and output a mixture containing hydrogen to the gas-water separator. The gas-water separator is used to separate the gas in the mixture and input the separated gas to the cooler. The cooler is used to cool the gas from the gas-water separator and output a gas containing water vapor and hydrogen to the drying tower. The drying tower is used to absorb water vapor and output hydrogen to the hydrogen storage cylinder; In the power generation process, the hydrogen storage cylinder is used to output hydrogen to the drying tower. The drying tower is used to release the water vapor absorbed in the water electrolysis process. The water vapor and hydrogen output by the drying tower are input to the fuel cell through the cooler. The fuel cell is used to generate electricity using water vapor and hydrogen.

2. The hydrogen production drying and regeneration system according to claim 1, wherein The hydrogen production drying and regeneration system further includes: A back pressure regulating valve, which is connected to the hydrogen storage cylinder and is used to boost the pressure of the hydrogen output by the drying tower during the water electrolysis process; A pressure reducing valve, which is connected to the hydrogen storage cylinder and is used to reduce the pressure of the hydrogen output by the hydrogen storage cylinder during the power generation process.

3. The hydrogen production drying and regeneration system according to claim 2, wherein The hydrogen production drying and regeneration system further includes a first three-way valve, which includes a first interface, a second interface and a third interface. The first interface is connected to the drying tower, the second interface is connected to the back pressure regulating valve, and the third interface is connected to the pressure reducing valve.

4. The hydrogen production drying and regeneration system according to claim 3, wherein A check valve is provided between the hydrogen storage cylinder and the second interface. The check valve is used to pass the hydrogen from the second interface and block the hydrogen from the hydrogen storage cylinder from entering the second interface.

5. The hydrogen production drying and regeneration system according to any one of claims 1 to 4, characterized in that, The hydrogen production drying and regeneration system further includes a second three-way valve, which includes a fourth interface, a fifth interface and a sixth interface. The fourth interface is connected to the cooler, the fifth interface is connected to the fuel cell, and the sixth interface is connected to the gas-water separator.

6. The hydrogen production drying and regeneration system according to any one of claims 1 to 4, characterized in that In the water electrolysis process, the cooling temperature of the cooler is the first cooling temperature. In the power generation process, the cooling temperature of the cooler is the second cooling temperature, wherein the second cooling temperature is greater than or equal to the first cooling temperature.

7. The hydrogen production drying and regeneration system according to any one of claims 1 to 4, characterized in that In the water electrolysis process, the drying temperature of the drying tower is the first drying temperature. In the power generation process, the drying temperature of the drying tower is the second drying temperature, wherein the second drying temperature is greater than the first drying temperature.

8. The hydrogen production drying and regeneration system according to any one of claims 1 to 4, characterized in that, The duration of the power generation process ≤ the rated water absorption capacity of the drying tower / the water release amount per unit time of the drying tower.

9. The hydrogen production drying and regeneration system according to any one of claims 1 to 4, characterized in that, The duration of the water electrolysis process ≤ the rated water absorption capacity of the drying tower / the water absorption amount per unit time of the drying tower.

10. A control method for a hydrogen production drying and regeneration system, characterized in that, The control method is applied to the hydrogen production drying and regeneration system according to any one of claims 1 to 9. The control method includes: Step 1: Start the water electrolyzer and initialize the timing; Step 2: When the timing reaches the first preset time, turn off the water electrolyzer, start the fuel cell, and initialize the timing; Step 3: When the timing reaches the second preset time, turn off the fuel cell and loop back to Step 1; Wherein, the first preset time corresponds to the duration of the water electrolysis process, and the second preset time corresponds to the duration of the power generation process.

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