A geothermal water cascade utilization based cogeneration helium poly-generation system and method

Abstract

The application provides a geothermal water cascade utilization based combined production system and method of heat, electricity and helium, which comprises, in sequence, a geothermal exploitation pretreatment unit, a thermal energy cascade utilization unit, a water-soluble helium gas purification and storage unit, a tail water reinjection unit and a valve control unit, wherein the valve control unit is provided with valve groups matched with the units according to functions. According to the application, the geothermal exploitation pretreatment unit, the thermal energy cascade utilization unit, the water-soluble helium gas purification and storage unit and the tail water reinjection unit are connected in sequence to realize the collaborative operation of the geothermal water cascade utilization and the water-soluble helium extraction. The valve control unit matched according to functions and the system interlocking control logic are provided to provide a targeted control structure for each process unit, realize the accurate control of process parameters and the flexible switching of working conditions, provide a structural basis for the online maintenance of subsequent equipment and the recycling of helium extraction, improve the overall operation stability of the system and improve the comprehensive utilization efficiency of geothermal resources and water-soluble helium resources.

Description

Technical Field

[0001] This invention relates to the field of geothermal resource comprehensive utilization technology, specifically to a combined heat and power (CHP) system and method based on the cascade utilization of geothermal water. Background Technology

[0002] Geothermal resources, as a clean and stable renewable energy source, are seeing their comprehensive utilization technology gradually evolve from single power generation or heating to cascade utilization. During geothermal extraction, geothermal fluids typically carry a certain concentration of water-soluble helium, making it possible to extract helium while simultaneously achieving cascade utilization of geothermal energy. Currently, combined heat and power (CHP) systems for geothermal resources usually integrate geothermal extraction, cascade utilization of thermal energy, helium purification, and tailwater reinjection in series to maximize resource utilization. Cascade utilization of thermal energy often employs a combination of organic Rankine cycle (ORC) power generation and heating, while helium purification mainly relies on conventional gas separation technologies such as membrane separation and pressure swing adsorption.

[0003] However, existing combined heat and power (CHP) systems based on the cascade utilization of geothermal water suffer from poor connectivity between process units and lack a systematic valve control system in practical applications. This makes it difficult to flexibly switch operating modes according to actual working conditions, achieve online equipment maintenance, and accurately control process parameters. In particular, the lack of a supporting recycling control structure in the water-soluble helium purification stage leads to the ineffective recovery of residual helium in non-permeable and desorbed gases, resulting in resource waste. Therefore, this invention studies and designs a CHP system and method based on the cascade utilization of geothermal water. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the above-mentioned defects, thereby providing a combined heat and power (CHP) system and method based on the cascade utilization of geothermal water.

[0005] To address the aforementioned problems, this invention provides a combined heat and power (CHP) system based on the cascade utilization of geothermal water, comprising: The geothermal extraction pretreatment unit, the thermal energy cascade utilization unit, the water-soluble helium purification and pressure storage unit, the tailwater reinjection unit, and the valve control unit are connected in sequence. The valve control unit is equipped with valve groups according to the functions of each unit. The geothermal extraction pretreatment unit includes: a geothermal production well, a cyclone desander, a gas-liquid separator, and an extraction branch valve group. The extraction branch valve group includes a direct bypass valve installed on the main extraction route between the geothermal production well and the gas-liquid separator, and a pair of shut-off valves installed in parallel at the inlet and outlet of the cyclone desander. The thermal energy cascade utilization unit includes an ORC power generation unit and a geothermal heating subunit. The thermal energy cascade utilization unit is equipped with a seasonal switching valve group. The seasonal switching valve group includes a non-heating season direct valve located on the tailwater direct branch of the ORC power generation unit and a heating season branch valve located at the inlet of the geothermal heating subunit. A pair of temperature interlocking flow regulating valves are installed at the inlet and outlet ends of the plate heat exchanger on the hot side of the geothermal heating subunit. The water-soluble helium purification and storage unit includes: a buffer drying subunit, a gas compression subunit, a three-stage membrane separation subunit, a dehydrogenation subunit, a pressure swing adsorption purification subunit, and a high-pressure filling subunit connected in sequence. The water-soluble helium purification and storage unit is equipped with a purification process valve group, which includes: a reflux regulating valve group matched with the three-stage membrane separation subunit and a desorption gas reflux valve group matched with the pressure swing adsorption purification subunit. The tailwater reinjection unit includes: a reinjection relay pump, a reinjection filter and a geothermal reinjection well connected in sequence, and the tailwater reinjection unit is equipped with a corresponding reinjection valve group; The valve control unit is equipped with system interlock control logic to achieve automatic control of each valve group and system safety protection.

[0006] Preferably, the shut-off valve at the outlet of the cyclone desander is connected in series with a swing check valve, and the bottom of the cyclone desander is equipped with a pneumatic sand discharge valve that is linked to the mining branch valve group; the liquid phase outlet of the gas-liquid separator is equipped with a liquid level interlock regulating valve, the gas phase outlet is equipped with a pressure stabilizing valve group, and the top of the gas-liquid separator is also equipped with a spring-loaded full-opening safety valve.

[0007] Preferably, the ORC generator unit includes an evaporator, a turbine generator, a condenser, a working fluid pump, and a cooling tower. The hot-side inlet and outlet of the evaporator are respectively connected to the gas-water separator and the geothermal heating subunit. The heating season branch valve is connected in parallel with the hot side of the evaporator. The cold side of the evaporator, the turbine generator, one side of the condenser and the working fluid pump form a circuit. A main working fluid circulation valve is provided between the cold side outlet of the evaporator and the inlet of the turbine generator. A turbine bypass regulating valve is connected in parallel between the inlet and outlet of the turbine generator. The other side of the condenser, the cooling tower, and the cooling water circulation pump form another loop, and a flow regulating valve is installed on the cooling water circulation pipeline between the condenser and the cooling tower. The geothermal heating subunit includes a plate heat exchanger, a heating circulation pump, and heating terminals. The hot-side inlet of the plate heat exchanger is connected in parallel to the hot-side outlet of the evaporator and the heating season branch valve. The cold side of the plate heat exchanger, the heating terminals, and the heating circulation pump form a circulation loop. The inlet and outlet of the heating circulation pump are equipped with check valves and a first reflux regulating valve. Each heating terminal branch is equipped with an independent temperature control valve. The hot-side outlet of the plate heat exchanger is connected to the tailwater reinjection unit.

[0008] Preferably, the inlet end of the buffer drying subunit is connected to the gas phase outlet of the gas-liquid separator; The gas compression subunit includes: a first compressor and a water-soluble gas collecting bottle. The inlet of the first compressor is connected to the outlet of the buffer drying subunit. The outlet of the first compressor is connected to the inlet of the water-soluble gas collecting bottle. The outlet of the water-soluble gas collecting bottle is connected to the three-stage stepped membrane separation subunit. The three-stage cascade membrane separation subunit includes a primary membrane separation device, a secondary first-stage membrane separation device, and a secondary second-stage membrane separation device connected in sequence; the reflux regulating valve group includes a primary membrane reflux regulating valve, a secondary first-stage membrane reflux regulating valve, and a secondary second-stage membrane reflux regulating valve. The primary membrane reflux regulating valve is located on the pipeline between the non-permeable side of the primary membrane separation device and the inlet of the gas compression unit. The secondary first-stage membrane reflux regulating valve is located on the pipeline between the non-permeable side of the secondary first-stage membrane separation device and the inlet of the primary membrane separation device. The secondary second-stage membrane reflux regulating valve is located on the pipeline between the non-permeable side of the secondary second-stage membrane separation device and the inlet of the secondary first-stage membrane separation device.

[0009] Preferably, the dehydrogenation subunit includes: a second compressor, a dehydrogenation reactor, an air cooler, and a drying filter connected in sequence; the inlet of the second compressor is connected in parallel to the permeate side of the first-stage membrane separation unit and the permeate side of the second-stage membrane separation unit; the outlet of the drying filter is connected to the non-permeate side of the second-stage membrane separation unit; a helium / oxygen ratio regulating valve is provided on the feed pipeline of the dehydrogenation subunit; and an automatic drain valve is provided on the gas-liquid separator at the bottom of the air cooler. The pressure swing adsorption purification subunit includes: a third compressor, a PSA concentration tower and a PSA purification tower connected in series. The inlet of the third compressor is connected to the permeate side of the secondary-stage membrane separation unit, and the outlet of the third compressor is connected to the PSA concentration tower. The desorption gas reflux valve assembly includes: a concentration tower desorption gas reflux valve and a purification tower desorption gas reflux valve. The concentration tower desorption gas reflux valve is located on the pipeline between the desorption gas outlet of the PSA concentration tower and the permeate side of the secondary-stage membrane separation unit, and the purification tower desorption gas reflux valve is located on the pipeline between the desorption gas outlet of the PSA purification tower and the permeate side of the secondary-stage membrane separation unit.

[0010] Preferably, the high-pressure filling subunit includes a fourth compressor and a product gas collector, the outlet of the fourth compressor is provided with a high-pressure shut-off valve and an overpressure reflux valve, and the main pipe of the product gas collector is provided with a filling main valve.

[0011] Preferably, the recharge valve assembly includes a shut-off valve located at the outlet of the recharge filter, a maintenance bypass valve connected in parallel at both ends of the recharge filter, a pressure regulating valve located at the outlet of the recharge relay pump, and an automatic air vent valve located at the high point of the recharge pipeline; the backwash pipeline of the recharge filter unit is equipped with a pneumatic backwash valve.

[0012] Preferably, the system interlock control logic of the valve control unit is configured to: execute liquid level interlock, temperature interlock, purity interlock and maintenance interlock control; the liquid level interlock adjusts the opening of the liquid phase outlet regulating valve according to the liquid level signal of the gas-liquid separator; the temperature interlock shuts off the corresponding feed valve and opens the bypass valve when the dehydrogenation reactor or turbine generator overheats; the purity interlock shuts off the product outlet valve and switches to the reflux pipeline when the helium purity at the outlet of the pressure swing adsorption purification subunit does not meet the standard; and the maintenance interlock shuts off the equipment inlet and outlet shut-off valves and opens the corresponding bypass valve during single equipment maintenance.

[0013] The present invention also provides a method for combined heat and power (CHP) and helium based on the cascade utilization of geothermal water, comprising the CHP and helium system described in any of the preceding claims, and including the following steps: Step S1: Geothermal extraction and pretreatment. Gas-containing geothermal water is extracted from the geothermal production well. The geothermal water is controlled by the extraction branch valve group to flow through the cyclone desander for desanding and then enters the gas-liquid separator to complete the gas-liquid two-phase separation, obtaining liquid geothermal water and helium-containing raw gas. Step S2: Geothermal heat energy is utilized in stages. The system operating conditions are switched by seasonal switching valve groups. During the non-heating season, the non-heating season direct valve is opened, and the liquid geothermal water enters the ORC power generation unit to generate electricity. During the heating season, the non-heating season direct valve is closed and the heating season branch valve is opened. After generating electricity through the ORC power generation unit, the liquid geothermal water enters the geothermal heating subunit to provide heating. Step S3: Purification of water-soluble helium. The helium-containing raw material gas is dried by the buffer drying subunit, then pressurized by the gas compression subunit and enters the three-stage membrane separation subunit for progressive enrichment. After enrichment, the gas is dehydrogenated by the dehydrogenation unit and dehydrated by the air cooler to obtain crude helium. The crude helium enters the pressure swing adsorption purification subunit for deep impurity removal to obtain high-purity helium. The high-purity helium is pressurized by the high-pressure filling subunit and then filled into the product gas collection grid. Step S4: Tailwater reinjection. The geothermal tailwater discharged from the ORC generator unit or geothermal heating subunit is purified by a reinjection filter and pressurized by a reinjection relay pump. Then, it is reinjected into the geothermal reinjection well through the adjustment parameters of the reinjection valve group to achieve closed-loop circulation of geothermal resources.

[0014] Preferably, in step S1, when the cyclone separator is under maintenance or sand discharge, the shut-off valves of the inlet and outlet of the cyclone separator are closed, and the main bypass valve is opened to realize the direct delivery of geothermal water and the continuous operation of the system without stopping. The gas-water separator maintains the stability of the liquid level in the tank through the liquid level interlock regulating valve. The helium-containing raw material gas is delivered to the water-soluble helium purification and storage unit after being stabilized by the gas phase pressure stabilizing valve group. In step S3, the non-permeable gas from the three-stage membrane separation subunit is returned to the corresponding process at the front end for recycling and concentration via a reflux regulating valve group. The desorbed gas from the pressure swing adsorption purification subunit is returned to the corresponding process at the front end for recycling and helium recovery via a desorbed gas reflux valve group. The dehydrogenation unit controls the oxygen injection amount through a helium / oxygen ratio regulating valve to ensure that the residual hydrogen amount reaches a preset threshold. When the purity of the helium produced by the pressure swing adsorption purification subunit is not up to standard, it is switched to the reflux pipeline for reprocessing through a purity interlock control.

[0015] The combined heat and power (CHP) system and method based on the cascade utilization of geothermal water provided by this invention has the following beneficial effects: 1. This invention constructs an integrated closed-loop combined heat and power (CHP) system for helium production by sequentially connecting a geothermal extraction pretreatment unit, a thermal energy cascade utilization unit, a water-soluble helium purification and storage unit, and a tailwater reinjection unit. This effectively solves the problem of poor connectivity between the various process units and realizes the coordinated operation of geothermal energy cascade utilization and water-soluble helium extraction. At the same time, by setting up valve control units matched to functions and system interlocking control logic, it provides a targeted control structure for each process unit, realizing precise control of process parameters and flexible switching of operating conditions. It also provides a structural foundation for subsequent online equipment maintenance and helium purification and recycling, improves the overall operational stability of the system, and enhances the comprehensive utilization efficiency of geothermal and water-soluble helium resources. 2. This invention also achieves online sand discharge and backflow prevention by connecting a check valve in series at the outlet of the cyclone desander and installing a pneumatic sand discharge valve at the bottom that is linked to the mining branch valve group. Combined with the liquid level interlocking regulating valve, pressure stabilizing valve group, and safety valve of the gas-liquid separator, it ensures the continuous and stable operation of the pretreatment unit. By setting a seasonal switching valve group, it achieves seamless switching between heating season and non-heating season operating conditions. With the bypass regulating valve of the ORC generator unit and the return regulating valve of the geothermal heating subunit, it improves the flexibility and stability of the cascade utilization of thermal energy. In terms of helium purification, the return regulating valve group matched with the three-stage cascade membrane separation subunit realizes the recycling of non-permeable gas, improving the enrichment efficiency and recovery rate of low-concentration geothermal helium. 3. This invention also constructs a geothermal extraction system by sequentially performing geothermal extraction and pretreatment, cascade utilization of geothermal energy, purification of water-soluble helium, and tailwater reinjection. Thermal energy utilization Helium purification The continuous process route for tailwater reinjection enables continuous operation of the combined heat and power (CHP) system, effectively improving production efficiency. Flexible switching of operating conditions is achieved through seasonal switching valve groups, maximizing geothermal power generation during the non-heating season and enabling coordinated power generation and heating during the heating season, thereby improving the overall utilization efficiency of geothermal energy. The linkage control of the extraction branch valve groups enables online maintenance and sand removal of the cyclone separator, ensuring continuous operation of the system without shutdown. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the system framework structure of the present invention.

[0017] The reference numerals in the attached figures are as follows: 1. Geothermal production well; 2. Cyclone desander; 3. Gas-water separator; 4. Buffer drying subunit; 5. First compressor; 6. Water-soluble gas collecting bottle; 7. Evaporator; 8. Turbine generator; 10. Working fluid pump; 11. Condenser; 12. Cooling tower; 13. Heating terminal; 14. Heating circulation pump; 15. Plate heat exchanger; 16. Reinjection relay pump; 17. Reinjection filter; 18. Geothermal reinjection well; 19. Cooling water circulation pump; 20. Primary membrane separation unit; 21. Secondary membrane separation unit; 22. Secondary membrane separation unit; 23. Second compressor; 24. Dehydrogenation reactor; 25. Air cooler; 26. Drying filter; 27. Third compressor; 28. Pressure swing adsorption purification subunit; 29. ​​Fourth compressor; 30. Product gas collecting grid. Detailed Implementation

[0018] like Figure 1 As shown, the present invention provides a combined heat and power (CHP) system based on the cascade utilization of geothermal water, comprising: The geothermal extraction pretreatment unit, the thermal energy cascade utilization unit, the water-soluble helium purification and pressure storage unit, the tailwater reinjection unit, and the valve control unit are connected in sequence. The valve control unit is equipped with valve groups according to the functions of each unit. The geothermal extraction pretreatment unit includes: a geothermal production well 1, a hydrocyclone desander 2, a gas-liquid separator 3, and an extraction branch valve group. The extraction branch valve group includes a direct bypass valve located on the main extraction route between the geothermal production well 1 and the gas-liquid separator 3, and a pair of shut-off valves connected in parallel at the inlet and outlet of the hydrocyclone desander 2. The geothermal production well 1 is a medium-deep geothermal extraction well, equipped with a submersible pump downhole. The hydrocyclone desander 2 is made of carbon steel with rubber lining, with a tangential inlet velocity of 1520 m / s and a separation efficiency of not less than 95%. The gas-liquid separator 3 is a vertical atmospheric pressure tank, equipped with baffles and a wire mesh demister. The direct bypass valve is an electric regulating valve, and the shut-off valve is an electric ball valve.

[0019] The thermal energy cascade utilization unit includes an ORC power generation sub-unit and a geothermal heating sub-unit. A seasonal switching valve group is correspondingly arranged for the thermal energy cascade utilization unit. The seasonal switching valve group includes a non-heating season direct-through valve arranged on the tail water direct-through branch of the ORC power generation sub-unit and a heating season branch valve arranged at the inlet of the geothermal heating sub-unit. A pair of temperature-interlocked flow regulating valves are arranged at the inlet and outlet ends of the hot side of the plate heat exchanger 15 of the geothermal heating sub-unit; the ORC power generation sub-unit is a modular integrated direct-in type ORC power generation structure, the plate heat exchanger 15 of the geothermal heating sub-unit is a plate heat exchange unit, the non-heating season direct-through valve and the heating season branch valve are electric gate valves, and the temperature-interlocked flow regulating valves are electric temperature regulating valves with PID closed-loop regulation function.

[0020] The water-soluble helium gas purification and compression storage unit includes: a buffer drying sub-unit 4, a gas compression sub-unit, a three-stage cascade membrane separation sub-unit, a dehydrogenation sub-unit, a pressure swing adsorption purification sub-unit 28, and a high-pressure filling sub-unit, which are connected in sequence. A purification process valve group is correspondingly arranged for the water-soluble helium gas purification and compression storage unit. The purification process valve group includes: a reflux regulating valve group supporting the three-stage cascade membrane separation sub-unit and a desorbed gas reflux valve group supporting the pressure swing adsorption purification sub-unit 28; the buffer drying sub-unit 4 is an adsorption drying device with a double-tower structure, filled with coalescing filters made of glass fiber material; the gas compression sub-unit is a multi-stage compression structure; the membrane separation devices of the three-stage cascade membrane separation sub-unit all adopt polyimide hollow fiber membrane modules, and the membrane modules can be arranged in parallel; the dehydrogenation sub-unit is a catalytic dehydrogenation reaction structure; the pressure swing adsorption purification sub-unit 28 is a pressure swing adsorption structure with two towers connected in series; the high-pressure filling sub-unit is a high-pressure gas filling structure; both the reflux regulating valve group and the desorbed gas reflux valve group are electric regulating valves.

[0021] The tail water reinjection unit includes: a reinjection relay pump 16, a reinjection filter 17, and a geothermal reinjection well 18, which are connected in sequence. A reinjection valve group is correspondingly arranged for the tail water reinjection unit; the reinjection relay pump 16 is a centrifugal pump, the reinjection filter 17 is a bag filter, and the geothermal reinjection well 18 and the geothermal production well 1 form a geothermal resource circulation system.

[0022] The valve control unit is equipped with a system interlock control logic for realizing the automatic control of each valve group and system safety protection. The valve control unit takes the DCS control system as the core, and is equipped with a touch screen operation interface and on-site detection instruments. The valves of each valve group are all electric or pneumatic valves, which are electrically connected to the DCS control system.

[0023] Specifically, the geothermal extraction pretreatment unit, the thermal energy cascade utilization unit, the water-soluble helium purification and pressure storage unit, and the tailwater reinjection unit are connected sequentially through pipelines to form a closed-loop process system of geothermal extraction, thermal energy utilization, helium purification, and tailwater reinjection. The valve control unit is equipped with dedicated valve groups according to the functional requirements of each process unit. The valves of each valve group are electrically connected to the control system. Through the system interlock control logic, signals from field monitoring instruments are received to realize the automatic opening and closing of each valve and the flow regulation, thereby completing the parameter regulation and operating condition switching of each process unit. At the same time, when the system malfunctions, safety protection actions are triggered to enable the coordinated operation of each process unit and complete the entire process of cogeneration of heat, power, and helium.

[0024] In some embodiments, the shut-off valve at the outlet of the cyclone desander 2 is connected in series with a swing check valve, and a pneumatic sand discharge valve linked to the mining branch valve group is provided at the bottom of the cyclone desander 2; the swing check valve is a swing single-disc check valve made of 304 stainless steel and installed on the downstream pipeline of the shut-off valve; the pneumatic sand discharge valve is a pneumatic knife gate valve made of carbon steel lined with rubber and installed at the sand discharge port at the bottom of the cyclone desander 2; the liquid phase outlet of the gas-liquid separator 3 is provided with a liquid level interlock regulating valve, the gas phase outlet is provided with a pressure stabilizing valve group, and the top of the gas-liquid separator 3 is also provided with a spring-loaded full-lift safety valve; the liquid level interlock regulating valve is an electric float-type liquid level regulating valve electrically connected to the float level gauge inside the gas-liquid separator 3; the pressure stabilizing valve group is a self-operated pressure regulating valve and a filter connected in series; the spring-loaded full-lift safety valve is a spring-loaded low-lift safety valve installed at the top of the gas-liquid separator 3.

[0025] Specifically, the swing check valve utilizes the flow thrust of the fluid to achieve one-way opening, preventing the fluid in the gas-liquid separator 3 from flowing back into the cyclone desander 2 and avoiding backflow of accumulated sand in the desander; the pneumatic sand discharge valve is linked with the shut-off valve of the mining branch valve group, closing the shut-off valve and opening the sand discharge valve when sand discharge is required, realizing online sand discharge of the cyclone desander 2; the liquid level interlock regulating valve receives the liquid level signal of the gas-liquid separator 3, adjusts the valve opening of the liquid phase outlet in real time, controls the liquid phase output flow, and maintains a stable liquid level in the tank; the pressure stabilizing valve group automatically adjusts the valve opening of the gas phase outlet through the self-operated pressure regulating valve to offset pressure fluctuations and ensure stable output pressure of the gas phase raw material gas; the spring-loaded full-opening safety valve automatically releases pressure when the pressure in the gas-liquid separator 3 exceeds the set pressure, and automatically closes after reducing the pressure in the tank to a safe range.

[0026] In some embodiments, the ORC power generation unit includes an evaporator 7, a turbine generator 8, a condenser 11, a working fluid pump 10, and a cooling tower 12. The hot-side inlet and outlet of the evaporator 7 are respectively connected to the gas-water separator 3 and the geothermal heating subunit. A branch valve for the heating season is connected in parallel with the hot side of the evaporator 7. The cold side of the evaporator 7, the turbine generator 8, one side of the condenser 11, and the working fluid pump 10 form a loop. A main working fluid circulation valve is provided between the cold-side outlet of the evaporator 7 and the inlet of the turbine generator 8. A turbine bypass regulating valve is connected in parallel between the inlet and outlet of the turbine generator 8. The other side of the condenser 11, the cooling tower 12, and the cooling water circulation pump 19 form a loop. A flow regulating valve is provided on the cooling water circulation pipeline between the condenser 11 and the cooling tower 12.

[0027] The geothermal heating subunit includes a plate heat exchanger 15, a heating circulation pump 14, and heating terminals 13. The hot-side inlet of the plate heat exchanger 15 is connected in parallel to the hot-side outlet of the evaporator 7 and a heating season branch valve. The cold side of the plate heat exchanger 15, the heating terminals 13, and the heating circulation pump 14 form a loop. Check valves and a first reflux regulating valve are installed at the inlet and outlet of the heating circulation pump 14. Each branch of the heating terminals 13 is equipped with an independent temperature control valve. The hot-side outlet of the plate heat exchanger 15 is connected to the tailwater reinjection unit.

[0028] Specifically, during the non-heating season, the heating season branch valve is closed, and geothermal water completes heat exchange on the hot side of evaporator 7, heating the organic working fluid on the cold side. The organic working fluid enters the turbine generator 8 through the organic working fluid circulation main valve to drive it to generate electricity. After doing work, the organic working fluid enters the condenser 11, where it is condensed by cooling water from the cooling tower 12, which is supplied by the cooling water circulation pump 19. The condensed organic working fluid returns to the evaporator 7 via the working fluid pump 10, completing the organic working fluid circulation. The cooling water is cooled by the cooling tower 12 and then recycled. The turbine bypass regulating valve adjusts the flow rate during system start-up, shutdown, and load shedding to ensure the turbine generator 8... Stable operation; During the heating season, the heating season branch valve is opened, and the geothermal water can directly enter the plate heat exchanger 15, or enter the plate heat exchanger 15 after being generated by the evaporator 7. The plate heat exchanger 15 transfers the heat energy of the geothermal water to the heating circulating water on the cold side. The heating circulating pump 14 drives the heating circulating water to circulate between the plate heat exchanger 15 and the heating terminal 13. The first return regulating valve maintains the pressure of the circulating pipeline stable. The independent temperature control valve of each heating terminal 13 adjusts the branch flow according to the temperature demand to complete the residential heating. The geothermal tailwater after heat exchange enters the tailwater reinjection unit through the hot side outlet of the plate heat exchanger 15.

[0029] Specifically, the connection structure between the ORC power generation unit and the geothermal heating subunit enables the cascade utilization of geothermal heat energy. During the non-heating season, geothermal heat is fully utilized for power generation, while during the heating season, power generation and heating are coordinated, improving the utilization efficiency of geothermal heat energy. Precise control of the organic working fluid circulation in the ORC power generation unit is achieved through the main valve of the organic working fluid circulation and the turbine bypass regulating valve, ensuring the stable operation of the turbine generator 8. The flow regulating valve on the cooling water circulation pipeline controls the cooling water flow, ensuring the condensing effect of the condenser 11. Stable control of the circulating water pressure and flow rate in the geothermal heating subunit is achieved through the check valve and the first return regulating valve. Independent temperature control valves at each heating terminal 13 enable independent temperature control, improving the heating effect. Seamless connection between each valve group and the heat exchange and power generation components enables coordinated control of the heat energy utilization unit, improving the overall operational stability of the unit.

[0030] In some embodiments, the inlet of the buffer drying subunit 4 is connected to the gas phase outlet of the gas-water separator 3; the gas compression subunit includes a first compressor 5 and a water-soluble gas collecting bottle 6, the inlet of the first compressor 5 is connected to the outlet of the buffer drying subunit 4, the outlet is connected to the inlet of the water-soluble gas collecting bottle 6, and the outlet of the water-soluble gas collecting bottle 6 is connected to the three-stage stepped membrane separation subunit.

[0031] The three-stage cascade membrane separation subunit includes a first-stage membrane separation unit 20, a second-stage membrane separation unit 22, and a second-stage membrane separation unit 21 connected in sequence. The reflux regulating valve assembly includes a first-stage membrane reflux regulating valve, a second-stage membrane separation unit 22, and a second-stage membrane reflux regulating valve. The first-stage membrane reflux regulating valve is located on the pipeline between the non-permeable side of the first-stage membrane separation unit 20 and the inlet of the gas compression unit; the second-stage membrane separation unit 22 is located on the pipeline between the non-permeable side of the second-stage membrane separation unit 22 and the inlet of the first-stage membrane separation unit 20; and the second-stage membrane reflux regulating valve is located on the pipeline between the non-permeable side of the second-stage membrane separation unit 21 and the inlet of the second-stage membrane separation unit 22.

[0032] Specifically, the helium-containing feed gas from gas-liquid separator 3 enters buffer drying subunit 4 for deep drying, removing water vapor and minor impurities. The dried feed gas then enters the first compressor 5 for pressurization. The pressurized feed gas enters the water-soluble gas collecting bottle 6 for buffer storage, ensuring stable feed pressure and flow rate for subsequent membrane separation units. The helium-containing feed gas in the water-soluble gas collecting bottle 6 enters the first-stage membrane separation unit 20 for preliminary enrichment. Helium and hydrogen, as fast gas components, are enriched on the permeate side, while slow gas components such as methane and nitrogen remain on the non-permeate side. The non-permeate gas is returned to the inlet of the gas compression subunit via the first-stage membrane reflux regulating valve, re-participating in pressurization and membrane separation. The permeate gas from the first-stage membrane separation unit 20... The gas enters the second-stage membrane separation unit 22 for secondary concentration. The non-permeable gas is returned to the inlet of the first-stage membrane separation unit 20 via the second-stage membrane reflux regulating valve to participate in the initial concentration again. The permeable gas from the second-stage membrane separation unit 22 enters the second-stage membrane separation unit 21 for deep concentration. The non-permeable gas is returned to the inlet of the first-stage membrane separation unit 20 via the second-stage membrane reflux regulating valve, completing the three-stage gradient concentration, gradually increasing the concentration of helium-containing gas, reducing the processing load of subsequent purification processes, and realizing the recycling of non-permeable gas from each membrane separation unit through the reflux regulating valve group, avoiding the loss caused by the direct discharge of helium with non-permeable gas, and improving the concentration efficiency and recovery rate of helium.

[0033] In some embodiments, the dehydrogenation subunit includes: a second compressor 23, a dehydrogenation reactor 24, an air cooler 25, and a drying filter 26 connected in sequence. The inlet of the second compressor 23 is connected in parallel to the permeate side of the primary membrane separation unit 20 and the permeate side of the secondary two-stage membrane separation unit 21. The outlet of the drying filter 26 is connected to the non-permeate side of the secondary one-stage membrane separation unit 22. A helium / oxygen ratio regulating valve is provided on the feed pipeline of the dehydrogenation subunit, and an automatic drain valve is provided on the gas-liquid separator at the bottom of the air cooler 25. The pressure swing adsorption purification subunit 28 includes: a second compressor 23, a dehydrogenation reactor 24, an air cooler 25, and a drying filter 26. The system consists of three compressors 27, a PSA concentration tower and a PSA purification tower connected in series. The inlet of the third compressor 27 is connected to the permeate side of the secondary-stage membrane separation unit 22, and the outlet of the third compressor is connected to the PSA concentration tower. The desorption gas reflux valve assembly includes a concentration tower desorption gas reflux valve and a purification tower desorption gas reflux valve. The concentration tower desorption gas reflux valve is located on the pipeline between the desorption gas outlet of the PSA concentration tower and the permeate side of the secondary-stage membrane separation unit 22, and the purification tower desorption gas reflux valve is located on the pipeline between the desorption gas outlet of the PSA purification tower and the permeate side of the secondary-stage membrane separation unit 22. In the dehydrogenation subunit, the second compressor 23 is a reciprocating compressor. Its inlet is connected to the permeate side of the primary membrane separation unit 20 and the permeate side flange of the secondary membrane separation unit 21 via a three-way pipe. It performs secondary pressurization on the helium-containing gas after membrane separation to meet the working pressure requirements of the dehydrogenation reactor 24. The dehydrogenation reactor 24 is a fixed-bed catalytic reactor filled with a precious metal catalyst, suitable for the catalytic oxidation reaction of hydrogen and oxygen. The air cooler 25 is a finned air cooler, which cools and condenses the gas after the dehydrogenation reaction. The gas-liquid separator at the bottom is a horizontal gas-liquid separator, which can separate the condensed liquid water. The automatic drain valve is a float-type automatic drain valve, which can realize the automatic discharge of liquid water without manual operation. The dryer filter 26 is a precision filter filled with adsorbent, which performs deep drying and filtration on the dehydrated gas. The helium / oxygen ratio regulating valve is an electric proportional regulating valve, which is installed on the feed pipe of the dehydrogenation reactor 24 and electrically connected to the oxygen delivery branch and the gas concentration analyzer, which can accurately control the ratio of helium and oxygen. In the pressure swing adsorption (PSA) purification subunit 28, the third compressor 27 is a reciprocating high-pressure compressor. Its inlet is connected to the permeate-side flange of the second-stage membrane separation unit 22 to pressurize the concentrated helium-containing gas to meet the working pressure requirements of PSA. The PSA concentration tower and the PSA purification tower are vertical PSA towers. The PSA concentration tower is filled with a mixed adsorbent of activated carbon and 5A zeolite, and the PSA purification tower is filled with carbon molecular sieve adsorbent. The two are connected in series by a pipeline flange. The outlet of the third compressor 27 is connected to the inlet flange of the PSA concentration tower. The desorption gas reflux valve of the concentration tower and the desorption gas reflux valve of the purification tower are both electric regulating valves, which are connected to the desorption gas outlets of the PSA concentration tower and the PSA purification tower and the permeate-side flange of the second-stage membrane separation unit 22 by pipelines, respectively.

[0034] Specifically, the permeate from the primary membrane separation unit 20 and the secondary membrane separation unit 21 enters the second compressor 23 for pressurization. The pressurized helium-containing gas, after the oxygen injection ratio is precisely controlled by the helium / oxygen ratio regulating valve, enters the dehydrogenation reactor 24. Hydrogen and oxygen undergo a catalytic oxidation reaction under the action of a catalyst to produce water. The gas after the reaction enters the air cooler 25 for cooling and condensation. The liquid water is separated in the gas-liquid separator and automatically discharged through the automatic drain valve. The dehydrated gas enters the dryer filter 26 for deep drying. The dried gas returns to the non-permeate side of the secondary membrane separation unit 22 to participate in the secondary process again. Concentration: The permeate gas from the second-stage membrane separation unit 22 enters the third compressor 27 for high-pressure boosting. The boosted gas then enters the PSA concentration tower, where the adsorbent selectively adsorbs impurities such as nitrogen and methane to obtain helium-rich gas. This helium-rich gas enters the PSA purification tower for deep purification, yielding high-purity helium. The desorbed gas from the PSA concentration tower is returned to the permeate side of the second-stage membrane separation unit 22 via the concentration tower desorbed gas reflux valve, and the desorbed gas from the PSA purification tower is also returned to the permeate side of the second-stage membrane separation unit 22 via the purification tower desorbed gas reflux valve, re-participating in subsequent pressurization and purification processes to achieve the recycling of residual helium in the desorbed gas. In some embodiments, the high-pressure filling subunit includes a fourth compressor 29 and a product gas collector 30. The outlet of the fourth compressor 29 is equipped with a high-pressure shut-off valve and an overpressure reflux valve. The main pipe of the product gas collector 30 is equipped with a filling main valve. The product gas collector 30 is a high-pressure gas storage cylinder group, which is composed of multiple high-pressure steel gas storage cylinders connected in parallel. The design pressure of the cylinders is matched with the storage pressure of high-purity helium. The filling main valve is a high-pressure electric gate valve, which is installed on the main pipe of the product gas collector 30 to control the filling of high-purity helium into the cylinder group.

[0035] Specifically, the high-purity helium produced by the pressure swing adsorption purification subunit 28 enters the fourth compressor 29, and after multi-stage pressurization, it reaches the pressure requirements for high-pressure storage. The high-pressure shut-off valve controls the flow of the pressurized high-purity helium according to the filling requirements. When the outlet pressure of the fourth compressor 29 exceeds the design storage pressure of the product gas collection grid 30, the overpressure reflux valve automatically opens, returning the overpressurized helium to the compressor inlet, reducing the outlet pressure, and realizing overpressure protection. After the pressurization, the high-purity helium passes through the high-pressure shut-off valve and then through the filling main valve of the main pipe of the product gas collection grid 30, and enters the high-pressure gas storage cylinder group to complete the storage.

[0036] In some embodiments, the reinjection valve assembly includes a shut-off valve located at the outlet of the reinjection filter 17, a maintenance bypass valve connected in parallel across the reinjection filter 17, a pressure regulating valve located at the outlet of the reinjection relay pump 16, and an automatic air vent valve located at a high point in the reinjection pipeline; the backwash pipeline of the reinjection filter unit is equipped with a pneumatic backwash valve; the shut-off valve is an electric gate valve, installed on the outlet pipeline of the reinjection filter 17, controlling the flow of water from the reinjection filter 17; the maintenance bypass valve is an electric gate valve, connected in parallel to the inlet and outlet pipelines of the reinjection filter 17 via a pipeline, and is opened during maintenance of the reinjection filter 17 to achieve... The tailwater is directly conveyed; the pressure regulating valve is an electric self-operated pressure regulating valve, installed on the outlet pipeline of the reinjection relay pump 16, and electrically connected to the pressure detection element. It can adjust the valve opening in real time according to the pressure of the reinjection pipeline to control the tailwater reinjection pressure; the automatic air vent valve is a composite automatic air vent valve, installed at the high point of the reinjection pipeline, which can automatically vent the gas accumulated in the pipeline and automatically close after venting to prevent tailwater leakage; the pneumatic backwash valve is a pneumatic ball valve, installed on the backwash pipeline of the reinjection filter 17, and used in conjunction with the backwash water pump to realize online backwashing of the reinjection filter 17.

[0037] Specifically, the geothermal tailwater enters the reinjection filter 17 to complete impurity filtration. The filtered tailwater then enters the reinjection relay pump 16 through the outlet shut-off valve. The reinjection relay pump 16 provides pressure power for tailwater reinjection. The outlet pressure regulating valve adjusts the valve opening in real time according to the pressure signal of the reinjection pipeline to maintain stable reinjection pressure and ensure tailwater reinjection effect. The automatic air vent valve at the high point of the reinjection pipeline automatically discharges the gas accumulated in the pipeline to avoid air blockage affecting tailwater transportation. When the reinjection filter 17 becomes clogged and requires maintenance, the inlet and outlet shut-off valves are closed, the maintenance bypass valve is opened to realize direct transportation of tailwater, and the pneumatic backwash valve is opened at the same time to cooperate with the backwash water pump to perform online backwashing of the reinjection filter 17 to remove impurities on the filter element.

[0038] In some embodiments, the system interlock control logic of the valve control unit is configured to: execute liquid level interlock, temperature interlock, purity interlock, and maintenance interlock control; the liquid level interlock adjusts the opening of the liquid phase outlet regulating valve according to the liquid level signal of the gas-liquid separator 3; the temperature interlock shuts off the corresponding feed valve and opens the bypass valve when the dehydrogenation reactor 24 or the turbine generator 8 exceeds the temperature limit; the purity interlock shuts off the product outlet valve and switches to the reflux pipeline when the helium purity at the outlet of the pressure swing adsorption purification subunit 28 is substandard; and the maintenance interlock shuts off the equipment inlet and outlet shut-off valves and opens the corresponding bypass valve during single equipment maintenance; the liquid level interlock control is implemented through a DCS control system. The liquid level gauge in the gas-liquid separator 3 transmits the liquid level signal to the control system in real time. When the liquid level is higher than the set upper limit, the control system sends a signal to increase the opening of the liquid phase outlet regulating valve and increase the liquid phase output flow rate; when the liquid level is lower than the set lower limit, the control system sends a signal to decrease the opening of the liquid phase outlet regulating valve and decrease the liquid phase output flow rate, maintaining the liquid level within the set range. Temperature interlock control is implemented through the DCS control system. Temperature sensors in the dehydrogenation reactor 24 and turbine generator 8 transmit temperature signals to the control system in real time. When the temperature exceeds the set upper limit, the control system immediately shuts off the feed valve of the corresponding equipment and simultaneously opens the bypass valve, allowing fluid to be transported via the bypass valve to prevent damage from overheating. Purity interlock control is also implemented through the DCS control system. The gas concentration analyzer at the outlet of the pressure swing adsorption purification subunit 28 transmits the helium purity signal to the control system in real time. When the helium purity does not meet the set standard, the control system immediately closes the product outlet valve and simultaneously opens the valve in the return pipeline, allowing the substandard helium to return to the upstream process for reprocessing. Maintenance interlock control is implemented through manual triggering or automatic detection by the DCS control system. When a single unit requires maintenance or a fault is detected, the control system immediately shuts off the inlet and outlet valves of that unit and simultaneously opens the corresponding bypass valve, enabling offline maintenance and ensuring the normal operation of other process units in the system.

[0039] Specifically, the system's interlocking control logic is centered on the DCS control system, integrating field detection signals such as liquid level, temperature, purity, and equipment status. According to preset programs and parameter thresholds, it sends automatic control signals to the valves of each valve group to achieve closed-loop control of liquid level, temperature, and purity. When the system malfunctions or equipment needs maintenance, it quickly triggers corresponding safety protection and operating condition switching actions, shutting off the feed and discharge of the faulty / maintained equipment, and opening the bypass valve to ensure the normal transport of fluids in the system. This enables the system to achieve safety protection under abnormal conditions and achieve non-stop operation during equipment maintenance.

[0040] The thermoelectric helium poly-generation system based on the cascaded utilization of geothermal water in this application constructs an integrated thermoelectric helium tri-generation closed-loop system by connecting a geothermal exploitation pretreatment unit, a thermal energy cascaded utilization unit, a water-soluble helium gas purification and compression storage unit, and a tail water reinjection unit in sequence. It effectively solves the problem of poor connectivity between process units and realizes the coordinated operation of the cascaded utilization of geothermal water and the extraction of water-soluble helium gas. At the same time, by setting a valve control unit and a system interlock control logic that match the functions, a targeted control structure is provided for each process unit, realizing the precise control of process parameters and the flexible switching of operating conditions, and providing a structural basis for the subsequent online maintenance of equipment and the recycling of helium gas purification, improving the overall operation stability of the system and the comprehensive utilization efficiency of geothermal resources and water-soluble helium gas resources.

[0041] In this application, an on-line sand removal and anti-backflow are achieved by connecting a check valve in series at the outlet of the hydrocyclone separator 2 and setting a pneumatic sand discharge valve at the bottom that联动 with the exploitation branch valve group. Combined with the liquid level interlock regulating valve, pressure stabilizing valve group and safety valve of the gas-liquid separation tank 3, the continuous and stable operation of the pretreatment unit is ensured. By setting a seasonal switching valve group, a seamless switching between the heating season and non-heating season operating conditions is achieved.配合 the bypass regulating valve of the ORC power generation sub-unit and the return regulating valve of the geothermal heating sub-unit, the flexibility and stability of the cascaded utilization of thermal energy are improved. In terms of helium gas purification, the recycling of non-permeate gas is achieved through the return regulating valve group supporting the three-stage cascaded membrane separation sub-unit, improving the concentration efficiency and recovery rate of low-concentration geothermal helium gas. Through the helium / oxygen ratio regulating valve of the dehydrogenation sub-unit and the desorbed gas return valve group of the pressure swing adsorption purification sub-unit 28, the dehydrogenation accuracy and the total helium gas recovery rate are further improved. Structures such as the overpressure return valve of the high-pressure filling sub-unit, the maintenance bypass valve, backwashing valve and automatic exhaust valve of the tail water reinjection unit respectively ensure the filling safety and the continuous and stable reinjection.

[0042] This invention also provides a thermoelectric helium poly-generation method based on the cascaded utilization of geothermal water, including the thermoelectric helium poly-generation system based on the cascaded utilization of geothermal water described in any one of the preceding items, and including the following steps: Step S1: Geothermal exploitation and pretreatment. Extract the gas-containing geothermal water from the geothermal production well 1, and control the geothermal water to flow through the hydrocyclone separator 2 for sand removal through the exploitation branch valve group and then enter the gas-liquid separation tank 3 to complete the gas-liquid two-phase separation, obtaining liquid-phase geothermal water and helium-containing raw gas. Step S2: Cascaded utilization of geothermal water thermal energy. Switch the system operating conditions through the seasonal switching valve group. In the non-heating season, open the non-heating season direct-through valve, and the liquid-phase geothermal water enters the ORC power generation sub-unit to complete power generation. In the heating season, close the non-heating season direct-through valve and open the heating season branch valve. After the liquid-phase geothermal water generates power through the ORC power generation sub-unit, it enters the geothermal heating sub-unit to complete heating. Step S3: Purification of water-soluble helium. The helium-containing raw gas is dried by the buffer drying subunit 4, then pressurized by the gas compression subunit and enters the three-stage membrane separation subunit for progressive enrichment. After enrichment, the gas is dehydrogenated by the dehydrogenation unit and dehydrated by the air cooler 25 to obtain crude helium. The crude helium enters the pressure swing adsorption purification subunit 28 for deep impurity removal to obtain high-purity helium. The high-purity helium is pressurized by the high-pressure filling subunit and then filled into the product gas collection grid 30. Step S4: Tailwater reinjection. The geothermal tailwater discharged from the ORC generator unit or geothermal heating subunit is purified by the reinjection filter 17 and pressurized by the reinjection relay pump 16. Then, it is reinjected into the geothermal reinjection well 18 through the adjustment parameters of the reinjection valve group to realize the closed-loop circulation of geothermal resources.

[0043] Specifically, in step S1, the submersible pump in the geothermal production well 1 extracts medium-deep gas-bearing geothermal water. The shut-off valve of the extraction branch valve group is opened and the direct bypass valve is closed. The geothermal water passes through the cyclone desander 2 to remove solid sand particles and impurities. The desandered geothermal water enters the gas-liquid separator 3. The gas and liquid phases are separated by the baffle plate and wire mesh demister in the tank. The liquid phase is geothermal water and the gas phase is helium-containing raw material gas, which are respectively transported to the subsequent process units. In step S2, the seasonal switching valve group switches operating conditions according to seasonal needs. During the non-heating season, the non-heating season direct valve is opened and the heating season branch valve is closed. The liquid geothermal water directly enters the ORC generator unit, completes heat exchange through the evaporator 7, and drives the turbine generator 8 to generate electricity. The geothermal tailwater after power generation directly enters the tailwater reinjection unit. During the heating season, the non-heating season direct valve is closed and the heating season branch valve is opened. The liquid geothermal water first enters the ORC generator unit to generate electricity. The geothermal tailwater after power generation enters the geothermal heating subunit, completes heat exchange through the plate heat exchanger 15, and provides heating for residents. The geothermal tailwater after heating enters the tailwater reinjection unit. In step S3, the helium-containing raw material gas from the gas-water separator 3 enters the buffer drying subunit 4 to remove water vapor and minor impurities, completing deep drying. The dried raw material gas then enters the gas compression subunit for pressurization. The pressurized raw material gas then enters the three-stage cascade membrane separation subunit, sequentially passing through the first-stage membrane separation device 20, the second-stage membrane separation device 22, and the second-stage membrane separation device 21 for cascade enrichment. The enriched helium-hydrogen mixture enters the dehydrogenation subunit, where hydrogen is removed by catalytic oxidation. It then passes through the air cooler 25 and the drying filter 26 to obtain crude helium. The crude helium enters the pressure swing adsorption purification subunit 28, where it undergoes deep impurity removal through the PSA enrichment tower and the PSA purification tower to obtain high-purity helium. The high-purity helium enters the high-pressure filling subunit for multi-stage pressurization, and is finally filled into the high-pressure gas storage cylinder group of the product gas collection grid 30 for storage. In step S4, the geothermal tailwater discharged from the ORC generator unit or the geothermal heating subunit enters the reinjection filter 17 to remove solid impurities and complete purification. The purified tailwater enters the reinjection relay pump 16, which provides pressure and power. The reinjection pressure is regulated by the pressure regulating valve of the reinjection valve group, and the automatic air vent valve discharges the accumulated air in the pipeline. Finally, the geothermal tailwater is reinjected into the geothermal reinjection well 18, forming a closed loop of geothermal resources with the geothermal production well 1.

[0044] In some embodiments, in step S1, when the hydrocyclone desander 2 needs maintenance or sand discharge, the control system of the valve control unit sends a signal to close the shut-off valves at the inlet and outlet of the hydrocyclone desander 2, and at the same time opens the direct bypass valve of the main line. The geothermal water enters the gas-water separator 3 directly through the direct bypass valve, realizing the continuous operation of the system without stopping. The level gauge of the gas-water separator 3 transmits the level signal to the control system, and the liquid phase outlet flow rate is adjusted in real time through the level interlock regulating valve to maintain the stability of the liquid level in the tank. The helium-containing raw material gas automatically adjusts the pressure through the pressure stabilizing valve group at the gas phase outlet, and after pressure stabilization, it is delivered to the water-soluble helium purification and pressure storage unit.

[0045] In step S3, the non-permeable gas generated by the first-stage membrane separation unit 20, the second-stage membrane separation unit 22, and the second-stage membrane separation unit 21 of the three-stage cascade membrane separation subunit is returned to the inlet of the corresponding gas compression subunit, the inlet of the first-stage membrane separation unit 20, and the inlet of the first-stage membrane separation unit 20, respectively, through the first-stage membrane reflux regulating valve, the second-stage membrane reflux regulating valve, and the second-stage membrane reflux regulating valve, respectively, to re-participate in the pressurization and membrane separation process, thereby achieving the cyclic concentration of the non-permeable gas; the desorption gas generated by the PSA concentration tower and the PSA purification tower of the pressure swing adsorption purification subunit 28 is returned to the inlet of the corresponding gas compression subunit, the inlet of the first-stage membrane separation unit 20, and the inlet of the first-stage membrane separation unit 21, respectively, through the concentration tower desorption gas reflux valve, The desorbed gas from the purification tower is returned to the permeate side of the secondary membrane separation unit 22 via the reflux valve, where it re-participates in subsequent pressurization and purification processes, achieving the recycling of residual helium in the desorbed gas. The helium / oxygen ratio regulating valve of the dehydrogenation subunit receives signals from the gas concentration analyzer and precisely controls the oxygen injection amount, ensuring that the residual hydrogen in the gas after the dehydrogenation reaction reaches a preset threshold. The gas concentration analyzer at the outlet of the pressure swing adsorption purification subunit 28 monitors the helium purity in real time. When the purity does not meet the preset standard, the purity interlock control immediately closes the product outlet valve and simultaneously opens the reflux pipeline valve, returning the substandard helium to the upstream process for reprocessing.

[0046] This application constructs a continuous process route for geothermal energy extraction, utilization of helium, and tailwater reinjection by sequentially executing the steps of geothermal extraction and pretreatment, cascade utilization of geothermal energy, purification of water-soluble helium, and tailwater reinjection. This enables continuous operation of a combined heat and power (CHP) system, effectively improving production efficiency. Flexible switching of operating conditions is achieved through seasonal switching valve groups, maximizing geothermal power generation during the non-heating season and enabling coordinated power generation and heating during the heating season, thereby improving the comprehensive utilization efficiency of geothermal energy. The linkage control of the extraction branch valve groups enables online maintenance and sand removal of the cyclone desander 2, ensuring continuous operation of the system without shutdown. The reflux regulating valve group and desorbed gas reflux valve group enable the recycling of non-permeable gas and desorbed gas, maximizing the recovery of residual helium and significantly improving the helium recovery rate. Precise control of the helium / oxygen ratio regulating valve and purity interlocking control ensure the stability of dehydrogenation effect and helium product purity.

[0047] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A combined heat and power (CHP) system based on the cascade utilization of geothermal water, characterized in that, include: The geothermal extraction pretreatment unit, the thermal energy cascade utilization unit, the water-soluble helium purification and pressure storage unit, the tailwater reinjection unit, and the valve control unit are connected in sequence. The valve control unit is equipped with valve groups according to the functions of each unit. The geothermal extraction pretreatment unit includes: a geothermal production well, a cyclone desander, a gas-liquid separator, and an extraction branch valve group. The extraction branch valve group includes a direct bypass valve installed on the main extraction route between the geothermal production well and the gas-liquid separator, and a pair of shut-off valves installed in parallel at the inlet and outlet of the cyclone desander. The thermal energy cascade utilization unit includes an ORC power generation unit and a geothermal heating subunit. The thermal energy cascade utilization unit is equipped with a seasonal switching valve group. The seasonal switching valve group includes a non-heating season direct valve located on the tailwater direct branch of the ORC power generation unit and a heating season branch valve located at the inlet of the geothermal heating subunit. A pair of temperature interlocking flow regulating valves are installed at the inlet and outlet ends of the plate heat exchanger on the hot side of the geothermal heating subunit. The water-soluble helium purification and storage unit includes: a buffer drying subunit, a gas compression subunit, a three-stage membrane separation subunit, a dehydrogenation subunit, a pressure swing adsorption purification subunit, and a high-pressure filling subunit connected in sequence. The water-soluble helium purification and storage unit is equipped with a purification process valve group, which includes: a reflux regulating valve group matched with the three-stage membrane separation subunit and a desorption gas reflux valve group matched with the pressure swing adsorption purification subunit. The tailwater reinjection unit includes: a reinjection relay pump, a reinjection filter and a geothermal reinjection well connected in sequence, and the tailwater reinjection unit is equipped with a corresponding reinjection valve group; The valve control unit is equipped with system interlock control logic to achieve automatic control of each valve group and system safety protection.

2. The combined heat and power (CHP) system based on geothermal water cascade utilization according to claim 1, characterized in that: The shut-off valve at the outlet of the cyclone desander is connected in series with a swing check valve, and the bottom of the cyclone desander is equipped with a pneumatic sand discharge valve that is linked to the mining branch valve group; the liquid phase outlet of the gas-liquid separator is equipped with a liquid level interlock regulating valve, the gas phase outlet is equipped with a pressure stabilizing valve group, and the top of the gas-liquid separator is also equipped with a spring-loaded full-opening safety valve.

3. The combined heat and power (CHP) system based on the cascade utilization of geothermal water according to claim 1, characterized in that: The ORC power generation unit includes an evaporator, a turbine generator, a condenser, a working fluid pump, and a cooling tower. The hot-side inlet and outlet of the evaporator are respectively connected to the gas-water separator and the geothermal heating subunit. The heating season branch valve is connected in parallel with the hot side of the evaporator. The cold side of the evaporator, the turbine generator, one side of the condenser and the working fluid pump form a circuit. A main working fluid circulation valve is provided between the cold side outlet of the evaporator and the inlet of the turbine generator. A turbine bypass regulating valve is connected in parallel between the inlet and outlet of the turbine generator. The other side of the condenser, the cooling tower, and the cooling water circulation pump form another loop, and a flow regulating valve is installed on the cooling water circulation pipeline between the condenser and the cooling tower. The geothermal heating subunit includes a plate heat exchanger, a heating circulation pump, and heating terminals. The hot-side inlet of the plate heat exchanger is connected in parallel to the hot-side outlet of the evaporator and the heating season branch valve. The cold side of the plate heat exchanger, the heating terminals, and the heating circulation pump form a circulation loop. The inlet and outlet of the heating circulation pump are equipped with check valves and a first reflux regulating valve. Each heating terminal branch is equipped with an independent temperature control valve. The hot-side outlet of the plate heat exchanger is connected to the tailwater reinjection unit.

4. The combined heat and power (CHP) system based on geothermal water cascade utilization according to claim 1, characterized in that: The inlet end of the buffer drying subunit is connected to the gas phase outlet of the gas-liquid separator; The gas compression subunit includes: a first compressor and a water-soluble gas collecting bottle. The inlet of the first compressor is connected to the outlet of the buffer drying subunit, the outlet of the first compressor is connected to the inlet of the water-soluble gas collecting bottle, and the outlet of the water-soluble gas collecting bottle is connected to the three-stage stepped membrane separation subunit. The three-stage cascade membrane separation subunit includes a primary membrane separation device, a secondary first-stage membrane separation device, and a secondary second-stage membrane separation device connected in sequence; the reflux regulating valve group includes a primary membrane reflux regulating valve, a secondary first-stage membrane reflux regulating valve, and a secondary second-stage membrane reflux regulating valve. The primary membrane reflux regulating valve is located on the pipeline between the non-permeable side of the primary membrane separation device and the inlet of the gas compression unit. The secondary first-stage membrane reflux regulating valve is located on the pipeline between the non-permeable side of the secondary first-stage membrane separation device and the inlet of the primary membrane separation device. The secondary second-stage membrane reflux regulating valve is located on the pipeline between the non-permeable side of the secondary second-stage membrane separation device and the inlet of the secondary first-stage membrane separation device.

5. The combined heat and power (CHP) system based on the cascade utilization of geothermal water according to claim 4, characterized in that: The dehydrogenation subunit includes: a second compressor, a dehydrogenation reactor, an air cooler, and a drying filter connected in sequence. The inlet of the second compressor is connected in parallel to the permeate side of the first-stage membrane separation unit and the permeate side of the second-stage membrane separation unit. The outlet of the drying filter is connected to the non-permeate side of the second-stage membrane separation unit. A helium / oxygen ratio regulating valve is provided on the feed pipeline of the dehydrogenation subunit. An automatic drain valve is provided on the gas-liquid separator at the bottom of the air cooler. The pressure swing adsorption purification subunit includes: a third compressor, a PSA concentration tower and a PSA purification tower connected in series. The inlet of the third compressor is connected to the permeate side of the secondary-stage membrane separation unit, and the outlet of the third compressor is connected to the PSA concentration tower. The desorption gas reflux valve assembly includes: a concentration tower desorption gas reflux valve and a purification tower desorption gas reflux valve. The concentration tower desorption gas reflux valve is located on the pipeline between the desorption gas outlet of the PSA concentration tower and the permeate side of the secondary-stage membrane separation unit, and the purification tower desorption gas reflux valve is located on the pipeline between the desorption gas outlet of the PSA purification tower and the permeate side of the secondary-stage membrane separation unit.

6. The combined heat and power (CHP) system based on geothermal water cascade utilization according to claim 1, characterized in that: The high-pressure filling subunit includes a fourth compressor and a product gas collection grid. The outlet of the fourth compressor is equipped with a high-pressure shut-off valve and an overpressure reflux valve, and the main pipe of the product gas collection grid is equipped with a filling main valve.

7. The combined heat and power (CHP) system based on geothermal water cascade utilization according to claim 1, characterized in that: The recharge valve assembly includes a shut-off valve located at the outlet of the recharge filter, a maintenance bypass valve connected in parallel at both ends of the recharge filter, a pressure regulating valve located at the outlet of the recharge relay pump, and an automatic air vent valve located at the high point of the recharge pipeline; the backwash pipeline of the recharge filter unit is equipped with a pneumatic backwash valve.

8. The combined heat and power (CHP) system based on geothermal water cascade utilization according to claim 1, characterized in that: The system interlock control logic of the valve control unit is configured to: execute liquid level interlock, temperature interlock, purity interlock and maintenance interlock control; the liquid level interlock adjusts the opening of the liquid phase outlet regulating valve according to the liquid level signal of the gas-liquid separator; the temperature interlock shuts off the corresponding feed valve and opens the bypass valve when the dehydrogenation reactor or turbine generator is overheated; the purity interlock shuts off the product outlet valve and switches to the reflux pipeline when the helium purity at the outlet of the pressure swing adsorption purification subunit is not up to standard; and the maintenance interlock shuts off the equipment inlet and outlet shut-off valves and opens the corresponding bypass valve when a single equipment is under maintenance.

9. A method for combined heat and power (CHP) and helium production based on the cascade utilization of geothermal water, characterized in that: The combined heat and power (CHP) system based on the cascade utilization of geothermal water, as described in any one of claims 1-8, comprises the following steps: Step S1: Geothermal extraction and pretreatment. Gas-containing geothermal water is extracted from the geothermal production well. The geothermal water is controlled by the extraction branch valve group to flow through the cyclone desander for desanding and then enters the gas-liquid separator to complete the gas-liquid two-phase separation, obtaining liquid geothermal water and helium-containing raw gas. Step S2: Geothermal heat energy is utilized in stages. The system operating conditions are switched by seasonal switching valve groups. During the non-heating season, the non-heating season direct valve is opened, and the liquid geothermal water enters the ORC power generation unit to generate electricity. During the heating season, the non-heating season direct valve is closed and the heating season branch valve is opened. After generating electricity through the ORC power generation unit, the liquid geothermal water enters the geothermal heating subunit to provide heating. Step S3: Purification of water-soluble helium. The helium-containing raw material gas is dried by the buffer drying subunit, then pressurized by the gas compression subunit and enters the three-stage membrane separation subunit for progressive enrichment. After enrichment, the gas is dehydrogenated by the dehydrogenation unit and dehydrated by the air cooler to obtain crude helium. The crude helium enters the pressure swing adsorption purification subunit for deep impurity removal to obtain high-purity helium. The high-purity helium is pressurized by the high-pressure filling subunit and then filled into the product gas collection grid. Step S4: Tailwater reinjection. The geothermal tailwater discharged from the ORC generator unit or geothermal heating subunit is purified by a reinjection filter and pressurized by a reinjection relay pump. Then, it is reinjected into the geothermal reinjection well through the adjustment parameters of the reinjection valve group to achieve closed-loop circulation of geothermal resources.

10. The combined heat and power (CHP) method based on the cascade utilization of geothermal water according to claim 9, characterized in that: In step S1, when the hydrocyclone desander is under maintenance or sand discharge, the shut-off valves of the hydrocyclone desander inlet and outlet are closed, and the main bypass valve is opened to realize direct delivery of geothermal water and continuous operation of the system without stopping. The gas-water separator maintains the stability of the liquid level in the tank through the liquid level interlock regulating valve. The helium-containing raw material gas is delivered to the water-soluble helium purification and storage unit after being stabilized by the gas phase pressure stabilizing valve group. In step S3, the non-permeable gas from the three-stage membrane separation subunit is returned to the corresponding process at the front end for recycling and concentration via a reflux regulating valve group. The desorbed gas from the pressure swing adsorption purification subunit is returned to the corresponding process at the front end for recycling and helium recovery via a desorbed gas reflux valve group. The dehydrogenation unit controls the oxygen injection amount through a helium / oxygen ratio regulating valve to ensure that the residual hydrogen amount reaches a preset threshold. When the purity of the helium produced by the pressure swing adsorption purification subunit is not up to standard, it is switched to the reflux pipeline for reprocessing through a purity interlock control.

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