Hydrogen production system using geothermal water

Abstract

The application discloses a hydrogen production system of geothermal water source and belongs to the technical field of hydrogen production. The system comprises a geothermal fluid circulation unit, an electrolyte preheating unit and an electrolytic hydrogen production unit. The geothermal fluid circulation unit realizes the recycling of geothermal water through a geothermal well, a recharge well and a geothermal heat exchanger; the electrolyte preheating unit connects an electrolyte storage tank and the second side of the geothermal heat exchanger through a second circulation pipeline to form a preheating circulation; the electrolytic hydrogen production unit comprises an electrolytic tank and a hydrogen purification device and receives the preheated electrolyte to produce hydrogen by electrolysis. In the preferred scheme, a flash evaporation pressurization and heat supplement unit is further included, the geothermal tail water is subjected to waste heat recovery through a flash tank and a steam compressor to generate high-temperature steam for auxiliary heating of the electrolytic tank. The application uses geothermal energy to replace electric heating to preheat electrolyte, significantly reduces the energy consumption of hydrogen production, has the advantages of reasonable structure, high automation degree, environmental protection and water saving and is suitable for hydrogen production application in areas rich in geothermal resources.

Description

Technical Field

[0001] This invention relates to the field of hydrogen production technology, specifically to a hydrogen production system using geothermal water sources. Background Technology

[0002] Hydrogen energy, as a clean and efficient secondary energy source, is considered key to solving the energy crisis and environmental problems. Currently, water electrolysis is one of the main methods for obtaining high-purity hydrogen. However, traditional water electrolysis processes require heating the feed water to the optimal operating temperature to ensure electrolysis efficiency and reduce energy consumption.

[0003] In existing technologies, this heating process typically relies on additional electric heating equipment. This leads to two main problems: first, it increases the initial investment and operating electricity costs, raising the cost of hydrogen production; second, the process is complex, requiring additional temperature control units, and the energy utilization method is singular. Especially in areas rich in geothermal resources, this approach of "using high-grade electrical energy to heat low-grade thermal energy" results in energy waste. Although some existing technologies have attempted to utilize geothermal energy, they are often structurally complex or only serve as auxiliary heat sources, failing to effectively replace electric heating equipment, and their practicality needs improvement. Summary of the Invention

[0004] This invention provides a hydrogen production system using geothermal water. By incorporating a geothermal heat exchanger to preheat the electrolyte with geothermal water, the energy consumption of traditional electric heating methods is significantly reduced. The entire system has a rational structural design and high energy efficiency, making it particularly suitable for areas rich in geothermal resources, and possessing good economic benefits and application prospects.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a hydrogen production system based on a geothermal water source, comprising: a geothermal fluid circulation unit, including a geothermal well, a reinjection well, and a first circulation pipeline connecting the geothermal well and the reinjection well, wherein a first circulation pump and a primary side of a geothermal heat exchanger are provided on the first circulation pipeline; an electrolyte preheating unit, including an electrolyte storage tank, a second circulation pipeline, and a second circulation pump and a temperature control valve provided on the second circulation pipeline, wherein the second circulation pipeline connects the electrolyte storage tank and the secondary side of the geothermal heat exchanger to form an electrolyte preheating circulation; and an electrolytic hydrogen production unit, including an electrolytic cell, wherein the inlet of the electrolytic cell is connected to the outlet of the electrolyte preheating unit, and the outlet of the electrolytic cell is connected to a hydrogen purification device.

[0006] Preferably, it further includes a flash pressurization and reheating unit, which includes a flash tank and a steam compressor; the primary side outlet of the geothermal heat exchanger is connected to the inlet of the flash tank via a pipeline; the steam outlet of the flash tank is connected to the inlet of the steam compressor; the liquid outlet of the flash tank is connected to the reinjection well; and the outlet of the steam compressor is connected to the auxiliary heating interface of the electrolytic cell.

[0007] Preferably, the condensate formed by the steam from the outlet of the steam compressor after releasing latent heat in the auxiliary heating interface of the electrolytic cell is connected to the reinjection well through a return water pipeline.

[0008] Preferably, the auxiliary heating interface of the electrolytic cell is a jacketed heating layer inlet located on the shell of the electrolytic cell, or an aeration pipe extending into the electrolytic cell for direct heating of the electrolyte.

[0009] Preferably, a flow regulating valve is installed on the inlet pipeline between the electrolyte storage tank and the electrolytic cell.

[0010] Preferably, the electrolytic cell is an alkaline water electrolytic cell, and the electrolyte storage tank contains alkaline solution; or the electrolytic cell is a PEM pure water electrolytic cell, and the electrolyte storage tank contains pure water.

[0011] Preferably, the geothermal heat exchanger is a plate heat exchanger or a shell-and-tube heat exchanger.

[0012] Preferably, the system also includes a controller, which is connected to the first circulating pump, the second circulating pump, and the temperature control valve respectively, and is used to automatically control the preheating temperature of the electrolyte according to a preset temperature.

[0013] Preferably, when a flash evaporation pressurization and reheating unit is included, the controller is also signal-connected to the steam compressor for controlling the start and stop of the steam compressor according to the temperature of the electrolytic cell.

[0014] The beneficial effects of this invention are as follows: By integrating a geothermal fluid circulation unit, an electrolyte preheating unit, and an electrolytic hydrogen production unit, a hydrogen production system utilizing geothermal resources for electrolyte preheating is constructed, which has the following beneficial effects:

[0015] Significantly reduced energy consumption: By using geothermal water as a heat source and preheating the electrolyte through a geothermal heat exchanger, the use of traditional electric heating equipment is replaced or significantly reduced, effectively reducing the power consumption of the hydrogen production process and improving energy utilization efficiency.

[0016] Achieving tiered energy utilization: By setting up a flash evaporation pressurization and reheating unit, the tailwater at the outlet of the geothermal heat exchanger is flashed and compressed, converting low-temperature waste heat into high-temperature steam, which further provides auxiliary heating for the electrolytic cell, thus realizing the tiered and maximized utilization of geothermal energy.

[0017] The system has a compact structure and a high degree of automation: the system integrates a controller to monitor and adjust the operating status of the circulating pump, temperature control valve and steam compressor in real time, ensuring that the electrolyte temperature is always within the optimal operating range, thus improving the system's operational stability and intelligence level.

[0018] Wide range of applications and strong compatibility: The system can be adapted to both alkaline water electrolyzers and PEM pure water electrolyzers, and has good compatibility and promotion value, especially suitable for areas with abundant geothermal resources.

[0019] Environmental protection and water conservation, resource recycling: Through reinjection wells and condensate recovery pipelines, the full reinjection and recycling of geothermal water and steam condensate is realized, avoiding water waste and environmental pollution, which is in line with the green and low-carbon development direction. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0022] In the diagram: 1. Geothermal well; 2. Recharge well; 3. First circulation pipeline; 4. First circulation pump; 5. Geothermal heat exchanger; 6. Electrolyte storage tank; 7. Second circulation pipeline; 8. Second circulation pump; 9. Temperature control valve; 10. Electrolyte; 11. Hydrogen purification device; 12. Flash tank; 13. Steam compressor; 14. Flow regulating valve; 16. Return water pipeline; 17. Liquid inlet pipeline. Detailed Implementation

[0023] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] according to Figure 1 As shown, a hydrogen production system based on a geothermal water source aims to utilize geothermal resources to replace or partially replace electric heating equipment for preheating the electrolyte before it enters the electrolyzer, thereby reducing the overall energy consumption of the hydrogen production system. This geothermal water source hydrogen production system mainly includes: a geothermal fluid circulation unit, an electrolyte preheating unit, and an electrolysis hydrogen production unit.

[0025] The geothermal fluid circulation unit is used to extract and circulate geothermal water as the heat source for the system. It includes a geothermal well 1, a reinjection well 2, and a first circulation pipeline 3 connecting the geothermal well 1 and the reinjection well 2. A first circulation pump 4 and the primary side of a geothermal heat exchanger 5 are installed on the first circulation pipeline 3. During operation, the first circulation pump 4 drives the geothermal water to be extracted from the geothermal well 1, flows through the primary side of the geothermal heat exchanger 5, releases heat, and lowers in temperature. Finally, the water returns to the ground through the reinjection well 2, achieving sustainable utilization of the geothermal fluid.

[0026] The electrolyte preheating unit is used to heat the electrolyte to be introduced into the electrolytic cell. It includes an electrolyte storage tank 6, a second circulation pipeline 7, and a second circulation pump 8 and a temperature control valve 9 installed on the second circulation pipeline 7. The second circulation pipeline 7 connects the electrolyte storage tank 6 to the secondary side of the geothermal heat exchanger 5, forming a closed preheating loop. Driven by the second circulation pump 8, the electrolyte in the electrolyte storage tank 6 enters the secondary side of the geothermal heat exchanger 5, where it exchanges heat with the high-temperature geothermal water on the primary side, absorbing heat and increasing its temperature. The temperature control valve 9 controls the flow rate into the geothermal heat exchanger 5 or adjusts the bypass flow, thereby precisely controlling the temperature of the preheated electrolyte. A portion or all of the preheated electrolyte is returned to the electrolyte storage tank 6 or directly output to the next unit.

[0027] The electrolysis hydrogen production unit is the core component for generating hydrogen through water electrolysis. It includes an electrolytic cell 10, whose inlet is connected to the outlet of the electrolyte preheating unit. The preheated electrolyte, reaching a suitable temperature, is drawn from the electrolyte storage tank 6 or the preheating circulation pipeline and enters the electrolytic cell 10 for electrolysis. The hydrogen and oxygen mixture produced by electrolysis is discharged from the outlet of the electrolytic cell 10 and connected to a hydrogen purification device 11. After purification, high-purity hydrogen is obtained.

[0028] In order to more accurately control the flow rate of electrolyte entering the electrolytic cell, a flow regulating valve 14 can be installed on the inlet pipe 17 between the electrolyte storage tank 6 and the electrolytic cell 10 to match the needs of the electrolytic cell 10 under different operating conditions.

[0029] This system is applicable to various types of electrolytic hydrogen production technologies. Preferably, the electrolyzer 10 can be an alkaline water electrolyzer, in which case the electrolyte storage tank 6 stores alkaline solution. Alternatively, the electrolyzer 10 can also be a PEM pure water electrolyzer, in which case the electrolyte storage tank 6 stores pure water. To improve heat exchange efficiency, the geothermal heat exchanger 5 is preferably a plate heat exchanger, which features high heat exchange efficiency and a compact structure; under special operating conditions, a shell-and-tube heat exchanger can also be used.

[0030] To achieve automated control, the system may also include a controller. The controller is connected to the first circulating pump 4, the second circulating pump 8, and the temperature control valve 9 via signal connections. This controller can automatically adjust the operating frequencies of the first and second circulating pumps 4 and the second circulating pump 8, as well as the opening degree of the temperature control valve 9, based on a preset optimal operating temperature range for the electrolyte. This allows for precise control of the electrolyte preheating temperature, ensuring the system always operates in its optimal state.

[0031] In a preferred improved embodiment, where the geothermal heat exchanger alone cannot heat the electrolyte to a sufficiently high temperature, or to further improve energy efficiency, the system may further include a flash pressurization and reheating unit. This unit includes a flash tank 12 and a steam compressor 13. The connection is as follows: the primary outlet of the geothermal heat exchanger 5 is connected to the inlet of the flash tank 12 via a pipeline. After passing through the geothermal heat exchanger 5, the geothermal water temperature decreases but still contains a large amount of residual heat. This portion of the hot water enters the flash tank 12 and flashes under low pressure, producing low-temperature, low-pressure steam and even lower-temperature hot water. The liquid outlet at the bottom of the flash tank 12 is connected to the reinjection well 2 to reinject the geothermal water. The steam outlet at the top of the flash tank 12 is connected to the inlet of the steam compressor 13. The steam compressor 13 compresses the low-temperature, low-pressure steam, increasing its pressure and saturation temperature, transforming it into medium-pressure steam with a certain degree of superheat. The outlet of the steam compressor 13 is connected to the auxiliary heating interface of the electrolytic cell 10.

[0032] In this way, the waste heat from the previously discarded low-temperature geothermal water is converted into usable high-quality steam through flash evaporation and compression. This steam can be used for direct or indirect auxiliary heating of the electrolytic cell 10. For example, the auxiliary heating interface of the electrolytic cell 10 can be an inlet of the jacketed heating layer on the shell of the electrolytic cell, where steam enters the jacket to insulate or heat the inside of the electrolytic cell; or, the interface can also be an aeration pipe extending into the electrolytic cell for direct heating of the electrolyte, where steam mixes directly with the electrolyte through aeration, resulting in extremely high heat exchange efficiency.

[0033] Furthermore, the steam exiting the steam compressor 13 releases latent heat in the auxiliary heating interface of the electrolysis cell 10, and then condenses to form high-temperature condensate. This condensate still has a high temperature and purity, and can be connected to the reinjection well 2 by setting a return water pipeline 16. It can then be mixed with the hot water discharged from the bottom of the flash tank 12 and reinjected together, realizing the recycling of all water resources and avoiding water waste and environmental pollution.

[0034] In embodiments including a flash pressurization and reheating unit, the controller can also be connected to the steam compressor 13 via a signal connection. The controller automatically controls the start and stop of the steam compressor 13 based on temperature data fed back from temperature sensors installed on the electrolytic cell 10. When the internal temperature of the electrolytic cell 10 is lower than a set value, the steam compressor 13 is started for reheating; when the required temperature is reached, reheating is stopped, thereby achieving precise management of the electrolytic cell temperature.

[0035] This invention significantly reduces energy consumption compared to traditional electric heating methods by using a geothermal heat exchanger to preheat the electrolyte with geothermal water. Simultaneously, by adding a flash evaporation pressurization and reheating unit, waste heat from the geothermal tailwater is further recovered and converted into high-temperature steam that can be directly used for heating the electrolytic cell, achieving the graded and maximized utilization of geothermal energy. The entire system has a rational structural design and high energy efficiency, making it particularly suitable for areas rich in geothermal resources, and possessing good economic benefits and application prospects.

[0036] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A hydrogen production system using geothermal water source, characterized in that, include: A geothermal fluid circulation unit includes a geothermal well (1), a reinjection well (2), and a first circulation pipeline (3) connecting the geothermal well (1) and the reinjection well (2). The first circulation pipeline (3) is equipped with a first circulation pump (4) and the primary side of a geothermal heat exchanger (5). The electrolyte preheating unit includes an electrolyte storage tank (6), a second circulation pipeline (7), a second circulation pump (8) and a temperature control valve (9) installed on the second circulation pipeline (7). The second circulation pipeline (7) connects the electrolyte storage tank (6) to the secondary side of the geothermal heat exchanger (5) to form an electrolyte preheating cycle. An electrolytic hydrogen production unit includes an electrolytic cell (10), the inlet of which is connected to the outlet of the electrolyte preheating unit, and the outlet of which is connected to a hydrogen purification device (11).

2. The hydrogen production system based on a geothermal water source according to claim 1, characterized in that, It also includes a flash pressurization and reheating unit, which includes a flash tank (12) and a steam compressor (13); the primary outlet of the geothermal heat exchanger (5) is connected to the inlet of the flash tank (12) through a pipeline; the steam outlet of the flash tank (12) is connected to the inlet of the steam compressor (13); the liquid outlet of the flash tank (12) is connected to the reinjection well (2); and the outlet of the steam compressor (13) is connected to the auxiliary heating interface of the electrolytic cell (10).

3. A hydrogen production system based on a geothermal water source according to claim 2, characterized in that, The steam from the outlet of the steam compressor (13) releases its latent heat in the auxiliary heating interface of the electrolysis cell (10), forming condensate, which is then connected to the reinjection well (2) through the return water pipeline (16).

4. A hydrogen production system based on a geothermal water source according to claim 2, characterized in that, The auxiliary heating interface of the electrolytic cell (10) is either a jacketed heating layer inlet on the shell of the electrolytic cell or an aeration pipe that extends into the electrolytic cell to directly heat the electrolyte.

5. A hydrogen production system based on a geothermal water source according to claim 1, characterized in that, A flow regulating valve (14) is provided on the inlet pipe (17) between the electrolyte storage tank (6) and the electrolytic cell (10).

6. A hydrogen production system based on a geothermal water source according to claim 1, characterized in that, The electrolytic cell (10) is an alkaline water electrolytic cell, and the electrolyte storage tank (6) contains alkaline solution; or the electrolytic cell (10) is a PEM pure water electrolytic cell, and the electrolyte storage tank (6) contains pure water.

7. A hydrogen production system based on a geothermal water source according to claim 1, characterized in that, The geothermal heat exchanger (5) is a plate heat exchanger or a shell-and-tube heat exchanger.

8. A hydrogen production system based on a geothermal water source according to claim 1 or 2, characterized in that, It also includes a controller, which is connected to the first circulating pump (4), the second circulating pump (8), and the temperature control valve (9) respectively, and is used to automatically control the preheating temperature of the electrolyte according to the preset temperature.

9. A hydrogen production system based on a geothermal water source according to claim 8, characterized in that, When the flash evaporation pressurization and reheating unit is included, the controller is also signal-connected to the steam compressor (13) for controlling the start and stop of the steam compressor (13) according to the temperature of the electrolytic cell (10).

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