Geothermal heat utilization system for combined heat and power

Abstract

The application discloses a dry hot rock heat utilization system for combined heat and power generation and belongs to the technical field of power generation. The technical scheme is as follows: a water filtering device is arranged, a water inlet pipe of the water filtering device is connected with a water pool, a water outlet is connected with a siphon pipe, and an electromagnetic valve is arranged on the water inlet pipe, the water inlet end and the water outlet end of the siphon pipe; the siphon pipe is connected with a water guide bucket through a water guide pipe, the water guide pipe is connected with an exhaust pipe, and an electromagnetic valve is arranged on the water guide pipe and the exhaust pipe; the siphon pipe is inserted into a vertical shaft, and multiple water power generation mechanisms are arranged below the water outlet of the siphon pipe along the vertical shaft height direction; the water power generation mechanism comprises a water turbine generator, a water falling bucket is arranged below the water turbine generator, a water falling pipe is connected with the water outlet of the water falling bucket, and the water turbine generator is connected with a power transmission and transformation device through a cable. The application realizes the coupling of dry hot rock heat collection and gravity potential water power generation by using the siphon principle, the whole production process does not need external energy input and pump transportation, zero-carbon combined heat and power generation can be realized, and the energy consumption is greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of power generation technology, and more specifically to a dry hot rock heat utilization system for combined heat and power. Background Technology

[0002] Petrochemical mobile energy has been caught in a vicious cycle of energy crisis and environmental pollution, while common new energy sources such as wind power, solar power, and tidal power are extremely unstable energy forms. The development of hot dry rock—a natural energy source with abundant resources and stable output—has attracted attention from the energy sector. my country is rich in hot dry rock resources, with huge reserves. Currently proven hot dry rock resources are equivalent to 856 million tons of standard coal. Based on current energy consumption, these resources would be sufficient for self-sufficiency for 4,000 years. Hot dry rock is a typical renewable and clean energy source, therefore it will become one of the important resources in the future.

[0003] Hydropower is the safest and most environmentally friendly clean and renewable energy source, as well as a stable energy output. Therefore, if hot dry rock thermal energy and hydropower can be combined to achieve cogeneration of thermal and electrical energy, energy consumption can be greatly reduced. Summary of the Invention

[0004] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art and provide a dry hot rock heat utilization system for cogeneration. It realizes the coupling of dry hot rock heat extraction and gravitational potential energy hydropower generation by using the siphon principle. The entire production process has no external energy input and no pump transportation, which can realize zero carbon cogeneration and greatly reduce energy consumption.

[0005] The technical solution of this invention is as follows:

[0006] The combined heat and power (CHP) dry hot rock heat utilization system includes a water filtration device. The inlet pipe of the water filtration device is connected to a water tank, and the outlet is connected to a siphon pipe. Solenoid valves are installed at the inlet and outlet ends of the inlet and siphon pipes, respectively. The siphon pipe is connected to a water inlet bucket via a water inlet pipe, which is also connected to an exhaust pipe. Solenoid valves are installed on both the water inlet and exhaust pipes. The siphon pipe extends into a vertical shaft, and multiple hydroelectric power generation mechanisms are sequentially arranged along the height of the shaft below the outlet of the siphon pipe. Each hydroelectric power generation mechanism includes a turbine generator. A water dropper is located below the turbine generator, and its outlet is connected to a water dropper pipe. The turbine generator is connected to a power transmission and transformation system via a cable. The device is connected as follows: the outlet of the lowest water hopper is connected to a medium pipe, which extends through the bottom of the vertical shaft into the dry hot rock vertical shaft below. A well plug is installed at the junction of the vertical shaft and the dry hot rock vertical shaft. Inside the dry hot rock vertical shaft, several nozzles or spray holes are installed on the medium pipe. A steam inclined shaft is connected to the side of the dry hot rock vertical shaft. The steam outlet of the steam inclined shaft extends out of the ground and is connected to a steam pipe. The steam pipe is connected to a heat-using device through a steam outlet pipe, and a solenoid valve is installed on the steam outlet pipe. The condensate from the heat-using device is connected to a water storage tank through a condensate discharge pipe. A siphon pipe is connected to the water storage tank through a circulation pipe. Solenoid valves are installed on the condensate discharge pipe and the circulation pipe.

[0007] Preferably, the dry hot rock shaft is connected to multiple steam inclined shafts on its side.

[0008] Preferably, the steam pipe is connected to a vent pipe, and a steam vent valve is installed on the vent pipe.

[0009] Preferably, the bottom of the dry hot rock shaft is connected to multiple horizontal wells.

[0010] Preferably, the water storage tank and the steam pipe are provided with a first insulation layer.

[0011] Preferably, the first insulation layer is made of silica aerogel.

[0012] Preferably, the upper and lower surfaces of the well plug are composite with a thermal insulation layer.

[0013] Preferably, the thermal insulation layer on the upper surface of the well plug is made of PU foam composite board, and the thermal insulation layer on the lower surface of the well plug is made of thermal insulation aerogel.

[0014] Preferably, a second insulation layer is provided on the outside of the circulation pipe.

[0015] Preferably, the second insulation layer is made of PU material.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The cogeneration dry hot rock heat utilization system of the present invention realizes the coupling of dry hot rock heat extraction and gravitational potential energy hydropower generation by utilizing the siphon principle. The entire production process has no external energy input and no pump transportation, which can realize zero-carbon cogeneration and greatly reduce energy consumption. Attached Figure Description

[0017] 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, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of the present invention.

[0019] Figure 2 This is a schematic diagram of the structure of the vertical shaft, hot dry rock vertical shaft and steam inclined shaft of the present invention.

[0020] In the diagram, 1. Water filtration device; 2. Inlet pipe; 3. Water tank; 4. Siphon pipe; 5. Solenoid valve; 6. Water intake pipe; 7. Water intake bucket; 8. Exhaust pipe; 9. Vertical shaft; 10. Water turbine generator; 11. Water dropper; 12. Downpipe; 13. Cable; 14. Power transmission and transformation equipment; 15. Medium pipe; 16. Dry hot rock vertical shaft; 17. Well plug; 18. Nozzle; 19. Steam inclined shaft; 20. Steam pipe; 21. Steam outlet pipe; 22. Heat-using device; 23. Condensate discharge pipe; 24. Water storage tank; 25. Circulation pipe; 26. Drain pipe; 27. Steam vent valve; 28. Horizontal well. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0022] like Figure 1-2As shown, this invention provides a combined heat and power (CHP) system for utilizing hot dry rock heat, including a water filtration device 1. The inlet pipe 2 of the water filtration device 1 is connected to a water tank 3, and the outlet is connected to a siphon pipe 4. Solenoid valves 5 are installed at the inlet and outlet ends of the inlet pipe 2 and the siphon pipe 4, respectively. The water filtration device 1 filters and purifies the water source in the water tank 3. It can employ equipment such as anion and cation exchange resins or electronic ultrasonic filters, which are relatively mature devices in the prior art. The specific structure is not described in detail here. The processing capacity of the water filtration device 1 is determined according to the evaporation rate of the hot dry rock shaft 16 heating zone. For example, after physical filtration using multi-layer steel mesh and quartz sand and ceramsite, followed by ultrasonic composite filtration, the processing flow rate is 25,000 T / h; or, using a filter combining anion and cation exchange resins with activated carbon, molecular sieves, and other adsorption materials, the purification flow rate is 15,000 T / h.

[0023] The siphon pipe 4 is connected to a water inlet hopper 7 via a water inlet pipe 6. The water inlet pipe 6 is connected to an exhaust pipe 8, and solenoid valves 5 are installed on both the water inlet pipe 6 and the exhaust pipe 8. The main function of the water inlet mechanism, consisting of the water inlet hopper 7, the water inlet pipe 6, and the exhaust pipe 8, is to fill the siphon pipe 4, the water filter device 1, and all the devices and pipelines up to the water tank 3 with water, expelling any air, while keeping the solenoid valve 5 at the outlet of the siphon pipe 4 closed, in preparation for subsequent siphoning. The water inlet hopper 7 is positioned higher than all related devices. The water inlet hopper 7 can be made of engineering plastics, metal, etc., with a specification of DN1500 and a height of 3000mm; the water inlet pipe 6 can be a DN76 SUS304 pipe.

[0024] A siphon pipe 4 extends into the vertical shaft 9, and multiple hydroelectric power generation mechanisms are sequentially arranged below the outlet of the siphon pipe 4 along the height direction of the vertical shaft 9. Each hydroelectric power generation mechanism includes a turbine generator 10. A dropper 11 is located below the turbine generator 10, and a drop pipe 12 is connected to the outlet of the dropper 11. The turbine generator 10 is connected to a power transmission and transformation device 14 via a cable 13. A medium pipe 15 is connected to the outlet of the lowest dropper 11. The medium pipe 15 passes through the bottom of the vertical shaft 9 and extends into the lower dry hot rock vertical shaft 16. A well plug 17 is installed at the junction of the vertical shaft 9 and the dry hot rock vertical shaft 16. Several nozzles 18 are installed on the medium pipe 15 inside the dry hot rock vertical shaft 16. The dry hot rock shaft 16 has multiple steam inclined shafts 19 connected to its side. The steam outlet of each steam inclined shaft 19 extends above the ground and is connected to a steam pipe 20. The steam pipe 20 is connected to a vent pipe 26, and a steam vent valve 27 is installed on the vent pipe 26. The steam pipe 20 is connected to a heat-using device 22 through a steam outlet pipe 21, and a solenoid valve 5 is installed on the steam outlet pipe 21. The condensate from the heat-using device 22 is connected to a water storage tank 24 through a condensate drain pipe 23. A siphon pipe 4 is connected to the water storage tank 24 through a circulation pipe 25. A second insulation layer is provided on the outside of the circulation pipe 25, which can be made of PU material. Solenoid valves 5 are installed on the condensate drain pipe 23 and the circulation pipe 25.

[0025] The water turbine generator 10 is the device for generating electrical energy according to this invention. Multiple water turbine generators 10 can be installed vertically within the shaft 9. Because the water turbine generators 10 are installed within the shaft 9, their installation is constrained by the shaft diameter. Therefore, water turbine generators 10 with high head, low flow rate, and a slender design can be selected, such as shaft 9 through-flow turbines, axial-flow turbines, bulb turbines, and bucket turbines. The shaft 9 is designed to be 1000m deep and 1000mm in diameter, allowing for the installation of four water turbine generators 10. These are axial-flow turbines with a head of 200m and a power output of 90kW, resulting in a total power output of 360kW and a daily electricity production of 8640kWh. The design includes nine vertical shafts, each 1200m deep and 1200mm in diameter. It can accommodate three vertical shaft 9-type axial-flow turbines and one bucket turbine, with installed capacities of 75kW, 200kW, and a total power of 425kW. The daily power generation is 10200kWh.

[0026] The bottom of the hot dry rock shaft 16 is connected to several branching horizontal shafts 28. Spray holes are machined on the medium pipe 15 within the horizontal shafts 28. The medium pipe 15 is DN200 and made of SUS 316 stainless steel. The medium pipe 15 within the horizontal shafts 28 is DN120 and also made of SUS316. The nozzles 18 on the medium pipes 15 are made of silicon carbide and stainless steel. The nozzles 18 at the top of the hot dry rock shaft 16 are made of stainless steel (SUS 310 S), with a flow rate of 200 kg / h, and are installed at a density of one nozzle every 8 meters. The nozzles 18 at the bottom of the hot dry rock shaft 16 are made of silicon carbide, with a flow rate of 220 kg / h, and are installed at a density of one nozzle every 5 meters. The spray holes on the medium pipes 15 within the horizontal shafts 28 have a flow rate of 250 kg / h and are installed at a density of one nozzle every 3 meters. The medium pipes 15 can be connected by screws or clamps. Elbows can be connected by corrugated metal pipes or high-strength flexible carbon fiber pipes.

[0027] The well plug 17 is the enclosure separating the vertical shaft 9 from the hot dry rock shaft 16. Due to the high temperature and steam pressure inside the hot dry rock shaft 16, in addition to high-strength material sealing, thermal insulation layers are laminated on the upper and lower surfaces of the well plug 17. For example, a 250mm thick PU foam composite board is laminated on the upper surface, and a 100mm thick thermal insulation aerogel is laminated on the lower surface of the well plug 17. The well plug 17 can be made of 50mm thick SUS 304 stainless steel plate, φ800×50 or φ700×50, or 500mm thick concrete.

[0028] Shaft 9 and dry hot rock shaft 16 are a single shaft structure. Shaft 9 is the upper section of the shaft, and dry hot rock shaft 16 is the lower section of the shaft. They are separated into two spaces by shaft plug 17. Shaft 9 is an open space, while dry hot rock shaft 16, steam inclined shaft 19, and steam pipe 20 form a closed space.

[0029] The diameter and depth of shaft 9 and hot dry rock shaft 16 depend on the temperature of the underground mine in the geographical location of the hot dry rock resource and the heat generated by the design.

[0030] In a certain area, the gradient of hot dry rock is 60℃ / km. Hot dry rock shaft 16 is designed with a diameter of 500mm and a depth of 5500m, with a bottom temperature of 330℃. Shaft 9 has a diameter of 1000mm and a depth of 1000m. There are two horizontal shafts 28 at the bottom of hot dry rock shaft 16, each 400m long, for a total length of 800m. A steam inclined shaft intersects with hot dry rock shaft 16 at 1100m, with a diameter of 400mm.

[0031] In a region rich in hot dry rock resources, with a hot dry rock gradient of 80℃ / km, a hot dry rock shaft 16 is designed with a diameter of 600mm and a depth of 5000m, achieving a bottom temperature of 400℃. Shaft 9 has a depth of 800m and a diameter of 1200mm. At the bottom of hot dry rock shaft 16, there are three branching horizontal shafts 28, each with a diameter of 500mm and a length of 500m, for a total length of 1500m. Two steam inclined shafts 19, with a diameter of 400mm, intersect with hot dry rock shaft 16 at 900m and 950m respectively. An EGS energy storage area will be established within the hot dry rock shaft 16 and horizontal shaft 28 heating zones.

[0032] Steam pipe 20 is installed at the wellhead of steam inclined shaft 19 and is a sealed connection. An air vent valve is installed at the top of steam pipe 20 for use during equipment maintenance. Steam pipe 20 has a first insulation layer to prevent heat loss. Steam pipe 20 is the transmission pipeline between the high-temperature steam coming from steam inclined shaft 19 and the heat-using device 22. Steam pipe 20 can be made of DN300 SUS304 pipe, with an 80mm thick silica aerogel layer.

[0033] The steam used in the heat-using device 22 can be industrial steam, steam for turbine power generation, steam for equipment and building heating, etc. The power of the heat-using device 22 can be designed according to the temperature, pressure and volume of the steam.

[0034] Water storage tank 24 collects and stores the condensate generated after the heating device 22 operates, and can also serve as a water source for the siphon pipe 4. When used as a water source for the siphon pipe 4, water storage tank 24 is subjected to negative pressure due to the siphon force. For example, if the water head height of the siphon pipe 4 is 300m, it is subjected to a negative pressure of 3MPa. Water storage tank 24 can be 30000m... 2 The domed tank is made of carbon steel with a wall thickness of 80mm. The inside of the tank is coated with an epoxy coating for corrosion protection, and the outside is insulated with 50mm thick PU flame-retardant foam insulation material. In addition, since the condensate has a high temperature, this heat can be reused in a heat exchanger and then siphoned into the vertical shaft 9 to fully utilize the heat energy.

[0035] 1. Operating Instructions:

[0036] (1) Close the solenoid valve 5 on the inlet pipe 2 of the water filter device 1; close the solenoid valve 5 at the outlet end of the siphon pipe 4 and open the solenoid valve 5 at the inlet end; open the solenoid valve 5 on the water inlet pipe 6 and the exhaust pipe 8.

[0037] (2) Add fresh water to the water inlet 7 so that the gas in the device and pipeline is vented through the exhaust pipe 8 and the water level in the water inlet no longer drops. Then close the solenoid valve 5 on the water inlet pipe 6.

[0038] (3) Open the solenoid valve 5 on the inlet pipe 2 of the water filter device 1 and the solenoid valve 5 at the outlet of the siphon pipe 4.

[0039] 2. Working principle

[0040] After the above operations, when the water in the siphon pipe 4 flows out of the outlet, it is automatically drawn from the pool 3 into the water filtration device 1 by the siphon force for filtration and purification. The filtered water flows into the siphon pipe 4 and falls from the outlet of the siphon pipe 4 onto the water turbine generator 10 below, using the gravitational potential energy of the water to drive the water turbine generator 10. Subsequently, the water falls downward into the drop hopper 11 and through the drop pipe 12 into the next stage water turbine generator 10, driving the next stage water turbine generator 10 to work. In this way, multiple stages of water turbine generators 10 can be driven to generate electricity. Finally, the water falling into the lowest drop hopper 11 passes through the medium pipe 15 and the well plug 17 into the dry hot rock shaft 16. The medium pipe 15 extends all the way to the bottom of the dry hot rock shaft 16. If a horizontal well 28 is set at the bottom of the dry hot rock shaft 16, the medium pipe 15 extends into the horizontal well 28. A nozzle 18 or nozzle hole is installed on the corresponding medium pipe 15 entering the heating area of ​​the hot dry rock shaft 16 (generally, nozzle 18 is installed in the hot dry rock shaft 16, and nozzle hole is installed in the horizontal shaft 28). The medium water is sprayed into the heating area for heat exchange, and the water phase changes into steam. Driven by the upward movement of heat and the expansion pressure of steam, it rises along the steam inclined shaft 19 to the steam pipe 20 on the ground, and finally enters the heat-using device 22 (the heat-using device 22 can be a thermal power plant, industrial heat, food processing, steam drying, building heat, etc.). After heat exchange in the heat-using device 22, the steam phase changes into condensate, which is discharged into the water storage tank 24 through the condensate discharge pipe 23.

[0041] Furthermore, the cogeneration system of this invention has two circulation routes. During startup, a water intake and storage circulation is implemented using a water intake mechanism. After the water storage tank 24 reaches the required storage capacity for evaporation, the system switches to another circulation route, the normal operating circulation route. In this route, the solenoid valve 5 at the inlet of the siphon pipe 4 is closed, and the solenoid valve 5 on the circulation pipe 25 is opened, allowing the water stored in the storage tank 24 to circulate. When water consumption occurs in the normal operating circulation route, the water intake and storage circulation route can be activated appropriately. The siphon pipe 4 can draw water from the water tank 3 to replenish the water supply, thus meeting the water demand for evaporation during the operating cycle.

[0042] In the aforementioned combined heat and power process, carbon-free cogeneration was achieved by generating electricity through the hydro turbine generator 10 and producing heat through the dry hot rock shaft 16. There is no external energy consumption, it is environmentally friendly, and the output is safe and stable. This is extremely rare among all natural new energy sources.

[0043] Although the present invention has been described in detail with reference to the accompanying drawings and preferred embodiments, the invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the invention should also be covered within the protection scope of the invention. Therefore, the protection scope of the invention should be determined by the scope of the claims.

Claims

1. A combined heat and power (CHP) dry hot rock heat utilization system, characterized in that, The system includes a water filtration device (1), whose inlet pipe (2) is connected to a water tank (3), and whose outlet is connected to a siphon pipe (4). Solenoid valves (5) are installed at the inlet and outlet ends of the inlet pipe (2) and the siphon pipe (4), respectively. The siphon pipe (4) is connected to a water inlet bucket (7) via a water inlet pipe (6), which is connected to an exhaust pipe (8). Solenoid valves (5) are installed on the water inlet pipe (6) and the exhaust pipe (8). The siphon pipe (4) extends into a vertical shaft (9), and the siphon pipe (4)... Multiple hydroelectric power generation mechanisms are arranged sequentially along the height of the vertical shaft (9) below the outlet. The hydroelectric power generation mechanism includes a turbine generator (10). A drop hopper (11) is arranged below the turbine generator (10). The outlet of the drop hopper (11) is connected to a drop pipe (12). The turbine generator (10) is connected to the power transmission and transformation device (14) through a cable (13). The outlet of the lowest drop hopper (11) is connected to a medium pipe (15). The medium pipe (15) extends through the bottom of the vertical shaft (9) into the... Inside the lower hot dry rock shaft (16), a well plug (17) is installed at the junction of the shaft (9) and the hot dry rock shaft (16); inside the hot dry rock shaft (16), several nozzles (18) or nozzle holes are installed on the medium pipe (15); a steam inclined shaft (19) is connected to the side of the hot dry rock shaft (16); the steam outlet of the steam inclined shaft (19) extends out of the ground and is connected to a steam pipe (20); the steam pipe (20) is connected to a heat-using device (22) through a steam outlet pipe (21); on the steam outlet pipe (21) A solenoid valve (5) is installed; the condensate from the heating device (22) is connected to the water storage tank (24) through the condensate drain pipe (23), and the siphon pipe (4) is connected to the water storage tank (24) through the circulation pipe (25). A solenoid valve (5) is installed on the condensate drain pipe (23) and the circulation pipe (25); multiple steam inclined shafts (19) are connected to the side of the dry hot rock shaft (16); the steam pipe (20) is connected to the vent pipe (26), and a steam vent valve (27) is installed on the vent pipe (26).

2. The cogeneration dry hot rock heat utilization system as described in claim 1, characterized in that, The bottom of the dry hot rock shaft (16) is connected to multiple horizontal shafts (28).

3. The cogeneration dry hot rock heat utilization system as described in claim 1, characterized in that, The water storage tank (24) and the steam pipe (20) are provided with a first insulation layer on the outside.

4. The cogeneration dry hot rock heat utilization system as described in claim 3, characterized in that, The first insulation layer is made of silica aerogel.

5. The cogeneration dry hot rock heat utilization system as described in claim 1, characterized in that, The well plug (17) has a thermal insulation layer on its upper and lower surfaces.

6. The cogeneration dry hot rock heat utilization system as described in claim 5, characterized in that, The upper surface of the well plug (17) is made of PU foam composite board, and the lower surface of the well plug (17) is made of thermal insulation aerogel.

7. The cogeneration dry hot rock heat utilization system as described in claim 1, characterized in that, The circulation pipe (25) is provided with a second insulation layer on the outside.

8. The cogeneration dry hot rock heat utilization system as described in claim 7, characterized in that, The second insulation layer is made of PU material.

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