A dry hot rock heat exchange device capable of local secondary heat exchange

Abstract

The present invention relates to a hot dry rock heat exchange device capable of local secondary heat exchange. The heat exchange device comprises an insulation pipe, a water supply pipe, a nozzle, a nozzle joint, an injection chamber, a diffuser, a return pipe and a water collector. The insulation pipe is provided with a water supply pipe, a nozzle, an injection chamber and a diffuser from top to bottom. The water collector is connected to the insulation pipe and is arranged at the bottom of the insulation pipe. The nozzle is located in the nozzle joint. The water supply pipe is connected to the nozzle. The upper part of the injection chamber is connected to the nozzle joint. The lower part of the injection chamber is connected to the upper part of the diffuser. The lower part of the diffuser is connected to the water collector. The bottom of the water collector is provided with a return pipe connected to the water collector. The present invention has a simple structure; economical and reasonable; safe and reliable; environmentally friendly; broad promotion prospects; high heat exchange efficiency; and good thermal insulation performance.

Description

Technical Field

[0001] The invention belongs to the technical field of dry hot rock heat exchange, and in particular relates to a dry hot rock heat exchange device capable of local secondary heat exchange. Background Art

[0002] Hot dry rock is an emerging energy source, which exists thousands of meters underground, with a temperature greater than 180℃. Its thermal energy is a rock mass that can be utilized under current technical and economic conditions. The global land-based hot dry rock resources are equivalent to 49.5 million tons of standard coal, which is 30 times the energy contained in all the oil, natural gas and coal in the world. my country's hot dry rock resources are widely distributed in the Qinghai-Tibet Plateau, Songliao Basin, Bohai Bay Basin, southeast coast and other places. The energy contained in the land-based hot dry rock resources of 3,000 to 10,000 meters is equivalent to 8.56 million tons of standard coal, accounting for about 17% of the world's resources, and has good development prospects.

[0003] The development principle of hot dry rock resources is to use a hot dry rock drill to drill a hole (injection well) underground, and then inject high-pressure water into the well after closing the wellhead for fracturing or use bottom hole blasting to create cracks in the rock mass. The cracks continue to increase, expand, and interconnect, eventually forming a roughly planar artificial hot dry rock thermal storage structure. Use a hot dry rock drill to drill several wells (production wells) at a reasonable location away from the injection well to recover high-temperature water and steam. The water injected from the injection well flows along the cracks and exchanges heat with the surrounding rock mass, extracting heat energy from the production well for irrigation, heating, power generation, etc. The existing hot dry rock underground heat exchange device has low heat exchange efficiency and low water temperature at the outlet. It is urgent to develop a device to reheat the water injected into the underground to improve the heat exchange efficiency and the water temperature at the outlet. Summary of the invention

[0004] In order to solve the technical problems of low heat exchange efficiency and low water temperature at the water outlet of the existing hot dry rock heat exchange technology, the present invention provides a hot dry rock heat exchange device capable of local secondary heat exchange.

[0005] The technical solution of the present invention is: the present invention is a hot dry rock heat exchange device that can perform local secondary heat exchange, and its special feature is that: the heat exchange device includes an insulating pipe, a water supply pipe, a nozzle, a nozzle joint, an injection chamber, a diffuser, a return pipe and a water collector. The insulating pipe is provided with a water supply pipe, a nozzle, a injection chamber, and a diffuser from top to bottom. The water collector is communicated with the insulating pipe and is arranged at the bottom of the insulating pipe. The nozzle is located in the nozzle joint, the water supply pipe is connected with the nozzle, the upper part of the injection chamber is connected with the nozzle joint, the lower part of the injection chamber is connected with the upper part of the diffuser, the lower part of the diffuser is connected with the water collector, and the bottom of the water collector is provided with a return pipe connected with the water collector.

[0006] Preferably, a mixing chamber, a throat and a water outlet channel are arranged in sequence from top to bottom in the diffuser, the mixing chamber is connected to the lower part of the injection chamber, the water outlet channel is connected to the water collector, a return water channel is arranged between the outside of the diffuser and the insulation tube, and the water collector is connected to the injection chamber through the return water channel.

[0007] Preferably, an upper head is provided above the outlet of the water outlet channel between the side surface of the diffuser and the insulation tube.

[0008] Preferably, the heat exchange device further comprises a water return port and a water return channel connected to the water return port, wherein the water return port is arranged at the bottom of the water collector, and the water collector is connected to the water return pipe through the water return channel.

[0009] Preferably, the return water channel is wound around the water collector and the insulation pipe in an external spiral shape.

[0010] Preferably, a middle partition is vertically arranged in the water collector.

[0011] Preferably, the heat-insulating tube is made of a high-temperature-resistant and corrosion-resistant material.

[0012] Preferably, the heat exchange device further comprises a reducer, through which the water supply pipe is connected to the nozzle. The reducer is used to connect the water supply pipe and the nozzle joint, the water supply pipe is directly connected to the upper part of the reducer, and the lower part of the reducer is connected to the nozzle joint through a certain taper.

[0013] Preferably, the nozzle is a conical structure with a wide upper portion and a narrow lower portion.

[0014] Preferably, a bottom head is provided at the bottom of the water collector.

[0015] The structure adopted by the present invention is that when the water flow entering from the water supply pipe passes through the nozzle, since the inner cavity of the nozzle is conical and the cross-section of the nozzle mouth is small, the water flow is sprayed into the diffuser at a relatively high speed. Under the action of the high-speed water flow, a part of the water body around the injection chamber formed by the nozzle and the diffuser is taken away by the high-speed water flow to form a negative pressure area. Under the action of the pressure difference, part of the liquid in the water collector is sucked into the injection chamber, and the high-speed water flow and the sucked water body are mixed in the mixing chamber to transfer and exchange energy. The sucked water body can be partially heat exchanged for a second time; a middle partition is set in the water collector to extend the heat exchange time, improve the heat exchange efficiency and the return water temperature of the return pipe. Therefore, the present invention has the following advantages:

[0016] 1. Simple structure: The design structure of the present invention is simple, easy to manufacture, install, debug, operate, run and maintain, and has low operating difficulty.

[0017] 2. Economical and reasonable; the accessories used in the present invention are universal and easy to purchase and replace; the manufacturing, operation and maintenance costs are low.

[0018] 3. Safe and reliable: The heat exchange devices of the present invention are all operated underground and can be operated continuously after installation. There is no need to frequently lift and lower the heat exchange devices into the borehole, which can avoid accidents such as drill jamming and hole wall collapse caused by suction.

[0019] 4. Environmental protection: The heat exchange device of the present invention operates in a borehole with a diameter of 215.9 mm, occupies a small area, does not require large-scale excavation, leveling of the site, and destruction of surface vegetation. During operation, no substances that pollute the air, soil, and water are generated, and the noise generated during operation is low.

[0020] 5. Broad prospects for promotion; the present invention can be applied to geothermal wells of all strata and temperatures for heat exchange and is not affected by site environment and altitude.

[0021] 6. High heat exchange efficiency: Under the action of high-speed water flow, a part of the water around the injection chamber is taken away by the high-speed water flow to form a negative pressure area. Under the action of the pressure difference, part of the liquid in the water collector is pumped into the injection chamber to transfer and exchange energy, and the sucked water undergoes local secondary circulation. A middle partition is arranged in the water collector to extend the heat exchange time, improve the heat exchange efficiency and the return water temperature of the return pipe.

[0022] 7. Good thermal insulation performance; the spiral winding range of the return water channel of the present invention is in the hot dry rock area, and the area outside the hot dry rock is an insulation pipe. The whole heat exchange device has good thermal insulation performance and less energy loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the present invention.

[0024] The reference numerals are as follows:

[0025] 1. Water supply pipe; 2. Reducer; 3. Nozzle joint; 4. Spray chamber; 5. Diffuser; 6. Upper head; 7. Water collector; 8. Bottom head; 9. Return pipe; 10. Insulated pipe; 11. Nozzle; 12. Mixing chamber; 13. Throat; 14. Return water channel; 15. Outlet channel; 16. Middle partition; 17. Return water channel; 18. Return water port. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with specific embodiments:

[0027] See also Figure 1The arrow direction in the figure is the direction of water flow. The specific embodiment of the present invention comprises a water supply pipe 1, a reducer 2, a nozzle joint 3, a spray chamber 4, a diffuser 5, an upper head 6, a water collector 7, a bottom head 8, a return pipe 9, an insulation pipe 10, a nozzle 11, a mixing chamber 12, a throat 13, a return water channel 14, a water outlet channel 15, a middle partition 16, a return water channel 17 and a return water port 18. The water supply pipe 1, the nozzle 11, the injection chamber 4, and the diffuser 5 are sequentially arranged in the insulated pipe 10 from top to bottom. The water collector 7 is connected to the insulated pipe 10 and is arranged at the bottom of the insulated pipe 10. The water supply pipe 1 is connected to the nozzle 11 through the reducer 2, that is, the water supply pipe 1 is connected to the nozzle 11. The nozzle 11 is a tapered structure with a wide upper part and a narrow lower part, which is located in the nozzle joint 3. The space part of the nozzle 11 and the diffuser 5 forms the injection chamber 4. The upper part of the injection chamber 4 is connected to the nozzle joint 3, and the lower part of the injection chamber 4 is connected to the upper part of the diffuser 5. The lower part of the diffuser 5 is connected to the water collector 7. The diffuser 5 is sequentially provided with a mixing chamber 12, a throat 13, and a water outlet channel 15 from top to bottom. The mixing chamber 12 is connected to the lower part of the injection chamber 4, and the water outlet channel 15 is connected to the water collector 7. A return water channel 14 is provided between the outside of the diffuser 5 and the insulated pipe 10, and the return water channel 14 is connected to the mixing chamber 12 and the water collector 7. An upper head 6 is provided above the outlet of the water outlet channel 15 between the side of the diffuser 5 and the insulation tube 10. The water flowing out of the water channel 15 is blocked by the upper head 6 and can only flow into the water collector 7. A return water port 18 is provided at the bottom of the water collector 7, and the return water port 18 is connected to the return water channel 17. The water collector 7 is connected to the return water pipe 9 through the return water channel 17. The return water channel 17 is wound around the water collector 7 and the insulation tube 10 in an outer spiral shape. A middle partition 16 is vertically provided in the water collector 7, and the middle partition 16 can increase the circulation time and improve the heat exchange efficiency. The insulation tube 10 is a high temperature resistant and corrosion resistant steel material, and its function is to lower the present invention into the heat exchange layer in the borehole for heat exchange. In the process of sucking out the water and pumping it to the surface, the hot water after heat exchange is prevented from heat loss and separated by the insulation tube. A bottom head 8 is provided at the bottom of the water collector 7.

[0028] When the present invention is working, the water supply pipe 1 is first connected to the pressure pump on the ground, and the return pipe 9 is connected to the suction pump on the ground. The water in the water supply pipe 1 passes through the circulation system of the present invention and is discharged to the ground through the return pipe 9.

[0029] The heat exchange device of the present invention is lowered into the heat exchange layer in the borehole, and the water flow of the water supply pipe 1 flows into the nozzle joint 3 through the reducer 2. The nozzle 11 in the nozzle joint 3 is a conical structure with a wide upper part and a narrow lower part. When the water flows through the nozzle 11, it is sprayed into the diffuser 5 at a high speed through the spray chamber 4. Under the action of the high-speed water flow, part of the water in the spray chamber 4 is taken away to form a negative pressure area. Under the action of the pressure difference, part of the water in the water collector 7 is sucked into the spray chamber 4 through the return water channel 14. The water sprayed out from the nozzle 11 and part of the water in the spray chamber 4 are mixed in the mixing chamber 12 and passed through the throat. 13 and the water outlet channel 15 to the water collector 7, the upper head 6 separates the diffuser 5 and the water collector 7, the water in the water collector 7 flows into the injection chamber 4 through the return water channel 14, and mixes with the water sprayed from the nozzle 11. The water collector 7 is provided with a middle partition 16 to extend the path of the water flow, which can extend the heat exchange time; finally, the water enters the return water channel 17 (the length of the return water channel 17 is buried according to the thickness of the dry hot rock) which is externally spirally wound around the water collector 7 and the insulation pipe 10 through the return water port 18 at the bottom of the water collector 7, and is discharged into the return water pipe 9, and is sucked out by the suction pump to complete the heat exchange process.

[0030] The above are only specific embodiments disclosed in the present invention, but the protection scope of the present invention is not limited thereto. The protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A hot dry rock heat exchange device capable of local secondary heat exchange, characterized in that: The heat exchange device includes an insulated tube, a water supply pipe, a nozzle, a nozzle joint, an injection chamber, a diffuser, a return pipe and a water collector. The insulated tube is provided with a water supply pipe, a nozzle, an injection chamber and a diffuser from top to bottom in sequence. The water collector is connected to the insulated tube and is arranged at the bottom of the insulated tube. The nozzle is located in the nozzle joint. The water supply pipe is connected to the nozzle. The upper part of the injection chamber is connected to the nozzle joint, the lower part of the injection chamber is connected to the upper part of the diffuser, the lower part of the diffuser is connected to the water collector, and a return pipe connected to the water collector is arranged at the bottom of the water collector. The diffuser is provided with a mixing chamber, a throat and a water outlet channel which are connected from top to bottom in sequence. The mixing chamber is connected to the lower part of the injection chamber, and the water outlet channel is connected to the water collector. A return water channel is arranged between the outside of the diffuser and the insulated tube, and the water collector is connected to the injection chamber through the return water channel.

2. The hot dry rock heat exchange device capable of local secondary heat exchange according to claim 1, characterized in that: An upper sealing head is arranged above the outlet of the water outlet channel between the side surface of the diffuser and the insulation pipe.

3. The hot dry rock heat exchange device capable of local secondary heat exchange according to claim 2, characterized in that: The heat exchange device also includes a water return port and a water return channel connected to the water return port. The water return port is arranged at the bottom of the water collector, and the water collector is connected to the water return pipe through the water return channel.

4. The hot dry rock heat exchange device capable of local secondary heat exchange according to claim 3 is characterized in that: The water return channel is wound around the water collector and the heat insulation pipe in an external spiral shape.

5. The hot dry rock heat exchange device capable of local secondary heat exchange according to claim 4, characterized in that: A middle partition is vertically arranged in the water collector.

6. The hot dry rock heat exchange device capable of local secondary heat exchange according to any one of claims 1 to 5, characterized in that: The heat-insulating pipe is made of high-temperature-resistant and corrosion-resistant material.

7. The hot dry rock heat exchange device capable of local secondary heat exchange according to claim 6, characterized in that: The heat exchange device also includes a reducing joint, and the water supply pipe is connected to the nozzle via the reducing joint.

8. The hot dry rock heat exchange device capable of local secondary heat exchange according to claim 7, characterized in that: The nozzle is a conical structure with a wide upper portion and a narrow lower portion.

9. The hot dry rock heat exchange device capable of local secondary heat exchange according to claim 8, characterized in that: A bottom seal is provided at the bottom of the water collector.

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