A heat energy recycling system for hydrogen production by electrolysis and a control method thereof

Abstract

The present application proposes a heat energy recycling system for hydrogen production by electrolysis and a control method thereof, comprising a first circulation loop formed by an electrolytic cell, a hydrogen separator and an alkali liquid cooler connected end to end in sequence through pipelines, an oxygen separator, and the oxygen separator is connected end to end with the alkali liquid cooler and the electrolytic cell through pipelines to form a second circulation loop, and a desalted water device is also provided, the desalted water device comprises a raw water tank, a reverse osmosis element and a produced water tank connected in sequence through pipelines, cooling water of a cooling water system is arranged to pass through the alkali liquid cooler and the reverse osmosis element in sequence to exchange heat with the reverse osmosis element, and waste heat from water electrolysis for hydrogen production is used to heat the desalted water device, so that the water temperature of the desalted water device can be maintained at a constant temperature, and the water production of the device does not decrease due to the influence of the water temperature, thereby effectively ensuring that the desalted water device is in an efficient operating state.

Description

Technical Field

[0001] The present application relates to the technical field of hydrogen production by electrolysis, and in particular to a heat energy recycling system for hydrogen production by electrolysis and a control method thereof. Background Art

[0002] The electrolyzer needs to replenish raw water from time to time during operation, and needs to be equipped with a desalted water device to supply raw water to the electrolyzer. The desalted water device adopts a bipolar reverse osmosis process. However, the reverse osmosis membrane element is very sensitive to changes in water temperature. Generally, the equipment manufacturer designs the output at a water temperature of 25°C. Under the same pressure, the water output can increase or decrease by 3-4% for every 1°C increase or decrease in temperature. If the water temperature is low in cold areas, the water output will drop sharply, and the proportion of wastewater will increase, and energy consumption will increase. Traditionally, external steam or electric heat sources are used to heat the pure water process to maintain the operating temperature, which requires additional energy consumption. Summary of the invention

[0003] The present application aims to solve one of the technical problems in the related art at least to some extent.

[0004] To this end, the purpose of the present application is to propose a heat energy recycling system for hydrogen production by electrolysis, by arranging the cooling water of the cooling water system to pass through the alkali liquid cooler and the reverse osmosis element in sequence to exchange heat with the reverse osmosis element, and utilizing the waste heat from water electrolysis for heat exchange with a desalting water device, so that the water temperature of the desalting water device can be maintained at a constant temperature, and the water production of the device will not decrease due to the influence of the water temperature, thereby effectively ensuring that the desalting water device is in an efficient operating state.

[0005] To achieve the above-mentioned purpose, the present application proposes a heat energy recycling system for hydrogen production by electrolysis, comprising a first circulation loop formed by an electrolytic cell, a hydrogen separator and an alkali liquid cooler connected end to end in sequence through pipelines, and also comprising an oxygen separator, wherein the oxygen separator is connected end to end with the alkali liquid cooler and the electrolytic cell through pipelines to form a second circulation loop, and also comprising a desalted water device, wherein the desalted water device comprises a raw water tank, a reverse osmosis element and a produced water tank connected in sequence through pipelines, wherein the raw water tank is used to inject raw water, and also comprising a cooling water system, wherein the cooling water of the cooling water system passes through the alkali liquid cooler and the reverse osmosis element in sequence to exchange heat with the reverse osmosis element.

[0006] Furthermore, the cooling water system includes a circulation pipeline passing through the alkali liquid cooler and the reverse osmosis element, wherein in the direction of the reverse osmosis element flowing to the alkali liquid cooler, a cooling tower and a pneumatic diaphragm regulating valve are sequentially arranged on the circulation pipeline; and in the direction of the alkali liquid cooler flowing to the reverse osmosis element, a regulating valve is arranged on the circulation pipeline.

[0007] Furthermore, it also includes a hydrogen heat exchanger connected to the hydrogen separator through a pipeline and an oxygen heat exchanger connected to the oxygen separator through a pipeline, the cooling water inlets of the hydrogen heat exchanger and the oxygen heat exchanger are connected to the circulation pipeline between the pneumatic diaphragm regulating valve and the alkali liquid cooler through a pipeline, and the cooling water outlets of the hydrogen heat exchanger and the oxygen heat exchanger are connected to the circulation pipeline between the alkali liquid cooler and the regulating valve.

[0008] Furthermore, it also includes a hydrogen scrubber connected to the hydrogen heat exchanger through a pipeline and an oxygen scrubber connected to the oxygen heat exchanger through a pipeline, the hydrogen scrubber is connected to a hydrogen exhaust pipe, and the oxygen scrubber is connected to an oxygen exhaust pipe.

[0009] Furthermore, the desalted water device also includes a water pump and a filtering device arranged on the pipeline between the raw water tank and the reverse osmosis element.

[0010] Furthermore, a control cabinet is also included, and the regulating valve is electrically connected to the control cabinet.

[0011] Furthermore, a first flow meter is provided at the water outlet of the reverse osmosis element, and a second flow meter is provided at the waste water outlet of the reverse osmosis element. The first flow meter and the second flow meter are electrically connected to the control cabinet respectively.

[0012] Furthermore, a temperature sensor is provided at the water outlet of the reverse osmosis element, and the temperature sensor is electrically connected to the control cabinet.

[0013] A control method for a heat recycling system for producing hydrogen by electrolysis is applied to the above-mentioned heat recycling system for producing hydrogen by electrolysis, and comprises the following steps: obtaining the amount of produced water of a reverse osmosis element by a first flowmeter arranged at a water production port of the reverse osmosis element; obtaining the amount of wastewater of the reverse osmosis element by a second flowmeter arranged at a wastewater port of the reverse osmosis element; comparing the ratio of the produced water amount to the wastewater amount with a preset value; and controlling a regulating valve according to the comparison result.

[0014] Furthermore, controlling the regulating valve according to the comparison result specifically includes: when the ratio is smaller than a preset value, increasing the opening of the regulating valve; when the ratio is larger than the preset value, decreasing the opening of the regulating valve.

[0015] Furthermore, it also includes obtaining the water production temperature of the reverse osmosis element by means of a temperature sensor disposed at the water production port of the reverse osmosis element; comparing the water production temperature with a preset temperature, and when the water production temperature is lower than the preset temperature, increasing the opening of the regulating valve; when the water production temperature is lower than the preset temperature, reducing the opening of the regulating valve.

[0016] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0018] Figure 1 This is a partial structural diagram of a heat energy recycling system for electrolysis hydrogen production proposed in one embodiment of the present application. Figure 1 ;

[0019] Figure 2 This is a partial structural diagram of a heat energy recycling system for electrolysis hydrogen production proposed in another embodiment of the present application. Figure 2 . DETAILED DESCRIPTION

[0020] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be construed as limiting the present application. On the contrary, the embodiments of the present application include all changes, modifications and equivalents that fall within the spirit and connotation of the appended claims.

[0021] Figure 1 and Figure 2 It is a structural schematic diagram of a heat energy recycling system for producing hydrogen through electrolysis proposed in one embodiment of the present application.

[0022] See also Figure 1 and Figure 2 A heat energy recycling system for producing hydrogen by electrolysis, comprising an electrolyzer 1, a hydrogen separator 2 and an alkaline liquid cooler 3 connected end to end in sequence through pipelines to form a first circulation loop, an oxygen separator 4, the oxygen separator 4 being connected end to end with the alkaline liquid cooler 3 and the electrolyzer 1 through pipelines to form a second circulation loop, a desalted water device, the desalted water device comprising a raw water tank 5, a reverse osmosis element 6 and a produced water tank 7 connected in sequence through pipelines, the raw water tank 5 being used to inject raw water, and a cooling water system, the cooling water of the cooling water system passing through the alkaline liquid cooler 3 and the reverse osmosis element 6 in sequence to exchange heat with the reverse osmosis element 6.

[0023] In this embodiment, the first circulation loop and the second circulation loop constitute the electrolytic hydrogen production system 100. The desalted water device is used to replenish water for the electrolytic hydrogen production system 100 after desalting and filtering the raw water. Specifically, the water produced by the desalted water device enters the hydrogen and oxygen scrubbers respectively through the replenishment pump, and then enters the hydrogen and oxygen separators through the scrubber overflow pipe, merges with the alkali solution, and then enters the electrolyzer through the alkali solution circulation pump to be consumed by electrolysis. In other embodiments, the water produced by the desalted water device can also be directly replenished in the electrolyzer 1. The cooling water system is used to cool the alkali solution cooler 3 of the electrolytic hydrogen production system so that the temperature of the alkali solution refluxed to the electrolyzer 1 meets the requirements. In this application, the cooling water system is improved and designed so that it bypasses the alkali solution cooler and the reverse osmosis element of the desalted water device, and the waste heat of the electrolytic hydrogen production system is utilized to maintain the reverse osmosis element at a constant temperature and ensure the water production efficiency of the desalted water device.

[0024] The cooling water system includes a circulation pipeline 8 passing through the alkali liquid cooler 3 and the reverse osmosis element 6, wherein in the direction of the reverse osmosis element 6 flowing toward the alkali liquid cooler 3, a cooling tower 9 and a pneumatic membrane regulating valve 10 are sequentially arranged on the circulation pipeline 8; and in the direction of the alkali liquid cooler 3 flowing toward the reverse osmosis element 6, a regulating valve 13 is arranged on the circulation pipeline 8.

[0025] In the present embodiment, in the direction of the reverse osmosis element 6 flowing to the alkali liquid cooler 3, that is, the cooling water and the reverse osmosis element 6 are refluxed after the heat exchange is completed, and the cooling water has a lower temperature after circulation, and a pneumatic film regulating valve 10 is set on the circulation pipeline 8, and the cooling water enters the alkali liquid cooler through the pneumatic film regulating valve 10. The cooling water volume is automatically controlled according to the high and low temperature of the circulating alkali liquid, thereby achieving the purpose of controlling the temperature of the electrolyzer. The cooling tower 9 is used to further cool the cooling water that flows back to the alkali liquid cooler 3 or the heat exchanger to ensure that it has a good cooling effect. In other embodiments, the cooling water system can also be replenished by the cooling tower 9, which is convenient for immediate replenishment. In order to improve the circulation efficiency of the cooling water in the cooling water system, a cooling circulation water pump can also be set between the cooling tower 9 and the pneumatic film regulating valve 10 to improve the cooling effect of the cooling water system on the electrolytic hydrogen production system. In the direction of the alkali liquid cooler 3 flowing toward the reverse osmosis element 6, a regulating valve 13 is arranged on the circulation pipeline 8. By adjusting the opening of the regulating valve 13, the amount of cooling water flowing through the reverse osmosis element is controlled, thereby controlling the heat exchange temperature of the reverse osmosis element to achieve a higher water production efficiency.

[0026] The cooling circulating water after heat exchange from the water electrolysis hydrogen production device first passes through the regulating valve 13 to adjust the flow rate and then enters the reverse osmosis element of the desalted water device for heat exchange, and then enters the cooling tower 9 after heat exchange.

[0027] A heat energy recycling system for hydrogen production by electrolysis also includes a hydrogen heat exchanger 11 connected to the hydrogen separator 2 through a pipeline and an oxygen heat exchanger 12 connected to the oxygen separator 4 through a pipeline, the cooling water inlets of the hydrogen heat exchanger 11 and the oxygen heat exchanger 12 are connected to the circulation pipeline 8 between the pneumatic diaphragm regulating valve 10 and the alkali liquid cooler 3 through a pipeline, and the cooling water outlets of the hydrogen heat exchanger 11 and the oxygen heat exchanger 12 are connected to the circulation pipeline between the alkali liquid cooler 3 and the regulating valve 13.

[0028] In this embodiment, by connecting the hydrogen heat exchanger 11 and the oxygen heat exchanger 12 to the cooling water system for heat exchange circulation, the cooling water system further improves the utilization of waste heat from the hydrogen production electrolysis system. The temperature of the cooling water after heat exchange between the cooling water system and the hydrogen production electrolysis system is higher, which is beneficial to maintaining the temperature of the reverse osmosis element.

[0029] A heat energy recycling system for producing hydrogen by electrolysis also includes a hydrogen scrubber 14 connected to the hydrogen heat exchanger 11 through a pipeline and an oxygen scrubber 15 connected to the oxygen heat exchanger 12 through a pipeline, wherein the hydrogen scrubber 14 is connected to a hydrogen exhaust pipe, and the oxygen scrubber 15 is connected to an oxygen exhaust pipe. The hydrogen produced by the electrolyzer 1 is washed by the hydrogen scrubber and then discharged from the hydrogen exhaust pipe, and the oxygen produced is washed by the oxygen scrubber and then discharged from the oxygen exhaust pipe, thereby obtaining pure hydrogen and oxygen for subsequent use.

[0030] The desalted water device also includes a water pump 16 and a filter device 17 arranged on the pipeline between the raw water tank 5 and the reverse osmosis element 6. In this embodiment, the filter device 17 specifically includes a sand filter arranged in parallel through the pipeline, which can filter the raw water while ensuring the water flow rate, facilitate the treatment of the reverse osmosis element 6, and also help to improve the service life of the reverse osmosis element. The water pump is conducive to improving the water production efficiency of the desalted water device.

[0031] The electrolytic hydrogen production heat energy recycling system further includes a control cabinet 18, and the regulating valve 13 is electrically connected to the control cabinet 18. By setting the control cabinet 18, the regulating valve 13 can be remotely controlled to realize automated remote operation.

[0032] The water outlet of the reverse osmosis element 6 is provided with a first flow meter 19, and the wastewater outlet of the reverse osmosis element 6 is provided with a second flow meter 20, and the first flow meter 19 and the second flow meter 20 are respectively electrically connected to the control cabinet 18. By monitoring the flow of the water outlet and the wastewater outlet of the reverse osmosis element 6 and adjusting the opening of the regulating valve, the temperature of the reverse osmosis element can be accurately controlled by adjusting the opening of the regulating valve according to the water production of the reverse osmosis element, thereby ensuring that the desalted water device is not affected by the external environment and always maintains a high water production efficiency.

[0033] A temperature sensor is provided at the water outlet of the reverse osmosis element 6, and the temperature sensor is electrically connected to the control cabinet 18. By providing a temperature sensor at the water outlet of the reverse osmosis element 6, the water outlet temperature of the reverse osmosis element is further confirmed, the misjudgment of the control cabinet is avoided, and the stability of the system is improved.

[0034] A control method for a heat recycling system for producing hydrogen by electrolysis is applied to the above-mentioned heat recycling system for producing hydrogen by electrolysis, and comprises the following steps: obtaining the amount of produced water of the reverse osmosis element 6 by a first flow meter 19 disposed at the water outlet of the reverse osmosis element 6; obtaining the amount of wastewater of the reverse osmosis element 6 by a second flow meter 20 disposed at the wastewater outlet of the reverse osmosis element 6; comparing the ratio of the produced water amount to the wastewater amount with a preset value; and controlling the regulating valve according to the comparison result.

[0035] In this embodiment, the ratio of water production and wastewater of the first flow meter 19 and the second flow meter 20 is used to monitor whether the desalting water device meets the production requirements. The preset value is usually 3, that is, the designed water production of the desalting water device is about 3 times the wastewater production. At this time, the desalting water device is in good working condition and no intervention is required. When this ratio changes, it is necessary to adjust the regulating valve in time to adjust the temperature of the reverse osmosis element so that the ratio of the water production and the wastewater volume meets the preset requirements.

[0036] A control method for a heat energy recycling system for electrolytic hydrogen production, controlling the regulating valve according to the comparison result specifically includes: when the ratio is less than a preset value, increasing the opening of the regulating valve 13; when the ratio is greater than the preset value, reducing the opening of the regulating valve 13. Specifically, when the opening of the regulating valve is increased, the water flow rate increases, the temperature of the reverse osmosis element increases, and the water production increases; when the opening of the regulating valve is decreased, the water flow rate decreases, the temperature of the reverse osmosis element decreases, and the water production decreases.

[0037] A control method for a heat energy recycling system for producing hydrogen by electrolysis also includes obtaining the produced water temperature of the reverse osmosis element 6 by means of a temperature sensor disposed at the water outlet of the reverse osmosis element 6; comparing the produced water temperature with a preset temperature, and when the produced water temperature is lower than the preset temperature, increasing the opening of the regulating valve; and when the produced water temperature is lower than the preset temperature, reducing the opening of the regulating valve.

[0038] Specifically, the preset temperature is 25℃, and the reverse osmosis element outlet water temperature of 25℃ is used as the temperature control point to control the opening of the regulating valve. When the reverse osmosis element outlet water temperature is 25℃, the regulating valve is opened by 50%. When the temperature is lower than 25℃, the regulating valve is appropriately opened. When the regulating valve temperature is higher than 25℃, the valve is appropriately closed. This ensures that the water production rate of the desalted water device is not affected by the ambient temperature. This not only ensures the production capacity, but also reduces the discharge of concentrated brine industrial wastewater; secondly, it also shares part of the heat exchange work of the circulating cooling tower, reducing the energy consumption of the device.

[0039] In the present application, the flow sensor is mainly used for monitoring the water production and the amount of brine produced and wasted, and the temperature at the outlet of the reverse osmosis element is used as an auxiliary to determine whether the desalting water device has insufficient heat exchange in the reverse osmosis element, resulting in too low water temperature and affecting the production. If the monitored production is abnormal, it will be fed back to the control system. The control system will transmit a signal to the regulating valve, and the regulating valve will execute the signal instruction to adjust the switching amount of the regulating valve, so as to adjust the temperature of the reverse osmosis element, thereby achieving efficient operation of the device, reducing the amount of brine (wastewater) produced and wasted, and reducing operating costs.

[0040] It should be noted that, in the description of this application, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of this application, unless otherwise specified, the meaning of "plurality" is two or more.

[0041] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0042] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0043] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A heat energy recycling system for hydrogen production by electrolysis, characterized in that: The invention comprises an electrolyzer, a hydrogen separator and an alkaline liquid cooler connected end to end through pipelines to form a first circulation loop, an oxygen separator, the oxygen separator is connected end to end with the alkaline liquid cooler and the electrolyzer through pipelines to form a second circulation loop, a desalted water device, the desalted water device comprises a raw water tank, a reverse osmosis element and a produced water tank connected in sequence through pipelines, the raw water tank is used to inject raw water, and a cooling water system, the cooling water of the cooling water system passes through the alkaline liquid cooler and the reverse osmosis element in sequence to perform heat exchange on the reverse osmosis element; The desalted water device also includes a water pump and a filter device disposed on the pipeline between the raw water tank and the reverse osmosis element; The cooling water system comprises a circulation pipeline passing through the alkali liquid cooler and the reverse osmosis element, wherein in the direction from the reverse osmosis element to the alkali liquid cooler, a cooling tower and a pneumatic membrane regulating valve are sequentially arranged on the circulation pipeline; in the direction from the alkali liquid cooler to the reverse osmosis element, a regulating valve is arranged on the circulation pipeline; It also includes a control cabinet, and the regulating valve is electrically connected to the control cabinet; The water outlet of the reverse osmosis element is provided with a first flow meter, and the wastewater outlet of the reverse osmosis element is provided with a second flow meter. The first flow meter and the second flow meter are electrically connected to the control cabinet respectively.

2. The heat energy recycling system for hydrogen production by electrolysis according to claim 1, characterized in that: It also includes a hydrogen heat exchanger connected to the hydrogen separator through a pipeline and an oxygen heat exchanger connected to the oxygen separator through a pipeline. The cooling water inlets of the hydrogen heat exchanger and the oxygen heat exchanger are connected to the circulation pipeline between the pneumatic diaphragm regulating valve and the alkali liquid cooler through a pipeline, and the cooling water outlets of the hydrogen heat exchanger and the oxygen heat exchanger are connected to the circulation pipeline between the alkali liquid cooler and the regulating valve.

3. The heat energy recycling system for producing hydrogen by electrolysis according to claim 2, characterized in that: It also includes a hydrogen scrubber connected to the hydrogen heat exchanger through a pipeline and an oxygen scrubber connected to the oxygen heat exchanger through a pipeline, the hydrogen scrubber is connected to a hydrogen exhaust pipe, and the oxygen scrubber is connected to an oxygen exhaust pipe.

4. The heat energy recycling system for hydrogen production by electrolysis according to claim 1, characterized in that: A temperature sensor is provided at the water outlet of the reverse osmosis element, and the temperature sensor is electrically connected to the control cabinet.

5. A control method for a heat energy recycling system for electrolytic hydrogen production, characterized in that: The heat energy recycling system for producing hydrogen by electrolysis as described in any one of claims 1 to 4 above comprises the following steps: obtaining the amount of produced water of the reverse osmosis element by a first flow meter disposed at a water outlet of the reverse osmosis element; obtaining the amount of wastewater of the reverse osmosis element by a second flow meter disposed at a wastewater outlet of the reverse osmosis element; comparing the ratio of the produced water amount to the wastewater amount with a preset value; and controlling the regulating valve according to the comparison result.

6. The control method of the electrolytic hydrogen production heat energy recycling system according to claim 5, characterized in that: Controlling the regulating valve according to the comparison result specifically includes: when the ratio is less than a preset value, increasing the opening of the regulating valve; when the ratio is greater than the preset value, reducing the opening of the regulating valve.

7. The control method of the electrolytic hydrogen production heat energy recycling system according to claim 5, characterized in that: The method further includes obtaining the produced water temperature of the reverse osmosis element by means of a temperature sensor disposed at the water outlet of the reverse osmosis element; comparing the produced water temperature with a preset temperature, and when the produced water temperature is lower than the preset temperature, increasing the opening of the regulating valve; When the produced water temperature is lower than the preset temperature, the opening of the regulating valve is reduced.

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