CN216897882U - Geothermal utilization system for underground space of coal mine - Google Patents

Abstract

The utility model provides a geothermal utilization system for a coal mine underground space, wherein a coal mine underground space reservoir is arranged in the coal mine underground space, a circumferential side water-resisting layer and a lower end water-resisting layer are arranged in the coal mine underground space, and the circumferential side water-resisting layer and the lower end water-resisting layer are mutually connected to form a water-resisting space with water resisting at the side and the bottom, namely the coal mine underground space reservoir; geothermal water of the coal mine underground space reservoir is conveyed to the ground through a heat taking well, and conveyed to heat exchange equipment through a ground geothermal water conveying pipeline I, after heat exchange and heat taking, geothermal tail water after heat taking is conveyed to a recharging well through a ground geothermal water conveying pipeline II, and then the geothermal tail water enters the coal mine underground space reservoir through the recharging well for heat storage again; after geothermal water is subjected to heat taking and heat exchanging through heat exchanging equipment, the heat is taken away and applied to a heat supply pipe network, and finally the geothermal water enters a user side to realize geothermal development and utilization. So as to realize the combined development and comprehensive utilization of underground space and geothermal heat of the abandoned coal mine.

Description

Geothermal utilization system for underground space of coal mine

Technical Field

The utility model relates to the field of geothermal development and utilization, in particular to a geothermal utilization system for an underground space of a coal mine.

Background

Coal is the main energy in China, and a large number of coal mines are closed due to resource exhaustion after long-time high-intensity mining. According to incomplete statistics, from the end of the nineties to the end of 2019 of the twenty century, coal mines are closed in nearly 8 thousands nationwide. After the coal mine is closed, a large amount of residual coal, mine water, underground space, land, geothermal heat and other resources can be developed and utilized.

Coal mining in China is mainly underground mining, and a huge available special underground space is formed by long-term development, so that unique conditions are created for developing underground ecological cities. According to investigation, 139 hundred million m of current coal mine underground space in China is obtained through cultivation, and 241 million m of cultivation is expected to be achieved by 2030 years, the length is about 160 km, and 40 circles around the equator can be obtained. The underground space of the abandoned coal mine is developed and utilized, so that the great waste of the special underground space caused by the filling of the coal mine goaf can be avoided, the problems of land shortage and the like in the development of the ground city can be solved, a new path for transformation escaping and sustainable development can be provided for abandoned mine enterprises, and the transformation development of resource-exhausted cities is continuously promoted.

In addition, the geothermal resources of abandoned coal mines are also of interest. In recent years, as the coal mining depth is continuously deepened, the coal mining faces heat hazards, for example, the mining depth of a coal mine area in the province of Hebei reaches 600-800m, and some coal mines reach 1200 m or less. The terrestrial heat abnormity of the coal-saving mining area in Hebei is mainly distributed in the peak mining area in Handan, Yuanshi coal field in Shijiazhuan city, mining area in Tangshan city, coal-containing area in great city in Hebei plain, and the like. For example, 600 m of phoenix tree banker mine in a peak mining area, the ground temperature is 24.3-41.9 ℃, the ground temperature gradient of 16 drill holes in an exploration depth of 500-900 m is more than 3 ℃/100m, the Yangtong mine is 1500 m, and the temperature of geothermal water reaches 53.3 ℃. In most of the production periods of mines, geothermal heat is used as heat hazard treatment, and a small part of mines are also used as heat sources for development and utilization. Once the coal mine is closed, the geothermal energy is beneficial and harmless, and the development and the utilization of geothermal resources have double meanings of energy utilization and coal mine heat damage reduction and need to draw sufficient attention.

At present, the development and utilization of underground space resources and geothermal resources of abandoned mines in China are in the stage of just starting, and engineering cases and technical schemes for jointly developing and comprehensively utilizing underground spaces and geothermal resources of coal mines are lacked.

SUMMERY OF THE UTILITY MODEL

In order to solve the problems, the utility model provides a geothermal utilization system for underground space of a coal mine, so as to realize the combined development and comprehensive utilization of the underground space and geothermal heat of the abandoned coal mine.

The technical scheme of the utility model is as follows: a geothermal utilization system for coal mine underground space comprises a coal mine underground space reservoir, a heat taking well, a recharging well, a ground geothermal water conveying pipeline, a heat exchanger, a heat supply pipe network, a user side and the like; the coal mine underground space reservoir is arranged in a coal mine underground space, a circumferential side water-resisting layer and a lower end water-resisting layer are arranged in the coal mine underground space, and the circumferential side water-resisting layer and the lower end water-resisting layer are connected with each other to form a water-resisting space with water resisting at the side and the bottom, namely the coal mine underground space reservoir; the lower ends of the heat taking well and the recharging well are respectively communicated with a coal mine underground space reservoir, the upper end of the heat taking well is connected with a ground geothermal water conveying pipeline I, the upper end of the recharging well is connected with a ground geothermal water conveying pipeline II, the geothermal water conveying pipeline I is connected with heat exchange equipment, and the geothermal water conveying pipeline II is connected with the heat exchange equipment; a water pump is arranged in the heat taking well; geothermal water of the coal mine underground space reservoir is conveyed to the ground through a heat taking well, and conveyed to heat exchange equipment through a ground geothermal water conveying pipeline I, after heat exchange and heat taking, geothermal tail water after heat taking is conveyed to a recharging well through a ground geothermal water conveying pipeline II, and then the geothermal tail water enters the coal mine underground space reservoir through the recharging well for heat storage again; after geothermal water is subjected to heat taking and heat exchange through heat exchange equipment, heat is taken away and applied to a heat supply pipe network, and finally the geothermal water enters a user end to realize geothermal development and utilization; wherein, heat supply pipe network connects indirect heating equipment and user respectively, realizes the hydrologic cycle.

Specifically, the coal mine underground space reservoir is a reservoir which is formed by transforming waste coal mine underground spaces and is used for storing geothermal water and storing the geothermal water, and specifically comprises underground spaces such as a goaf or/and a roadway project. Specifically, the method comprises the following steps: the lateral waterproof layer around the underground space of the coal mine comprises a grouting reinforced waterproof coal pillar, the lower end waterproof layer is a grouting reinforced waterproof bottom plate layer of the underground space of the coal mine, a grouting plugging side top plate is arranged at the upper end of the grouting reinforced waterproof coal pillar, and the lower end of the grouting reinforced waterproof coal pillar is connected with the grouting reinforced waterproof bottom plate layer through a grouting plugging side direct bottom plate. The grouting reinforced waterproof coal pillar and the grouting reinforced waterproof floor layer are formed by grouting and reinforcing the waterproof coal pillar and the waterproof floor layer, and the grouting blocked side top plate and the grouting blocked side direct bottom plate are formed by grouting and reinforcing and blocking the upper end and the lower end of the grouting reinforced waterproof coal pillar, so that the grouting blocked side top plate, the grouting reinforced waterproof coal pillar, the grouting blocked side direct bottom plate, the grouting reinforced waterproof floor layer and the grouting reinforced waterproof floor layer are isolated and integrated into a large underground space of the coal mine by the water-resisting measures of isolating the whole connected underground space of the coal mine into a mutually communicated large underground space, the underground space is isolated from the surrounding underground water by the waterproof coal pillar on the lower part of the waterproof floor and the side of the waterproof coal pillar and the grouting reinforced area, and the circulation between water and the surrounding underground water in the underground space is avoided, potential pollution to underground water in the process of geothermal development is avoided.

Preferably, the coal seam of the coal mine is a gentle coal seam, and the fault of the mining area does not develop, so that all underground spaces such as the goaf and the shaft and tunnel engineering are conveniently integrated into a large underground coal mine space with good external tightness, and a underground coal mine space reservoir with good tightness is formed. In the utility model, the inclination angle of the coal seam of the coal mine is required not to exceed 25 degrees.

The ground temperature of the underground space of the coal mine mainly depends on the buried depth, the ground temperature gradient and the like. Generally, the average geothermal gradient is about 2 to 3 ℃/100 m. Therefore, as can be readily appreciated by those skilled in the art, the deeper the burial depth, the higher the ground temperature of the coal mine underground space; the larger the ground temperature gradient is, the higher the ground temperature of the underground space of the coal mine is.

Preferably, the underground coal mine space has a certain burial depth, and the depth of the underground coal mine space is not smaller than 300m so as to generate sufficient geothermal heat.

Preferably, the coal mine is suitable for being positioned in an earth heat flow value, a high-temperature-gradient abnormal area or a deep broken heat conduction band so as to form a geothermal resource with higher than average geothermal gradient of the area. Preferably, geothermal resources with development value are preferably distributed in the coal mine with the underground space temperature gradient of the coal mine higher than the average underground temperature gradient of the local area by 1-3 ℃/100 m.

Further, the thermal conductivity of a solid is mainly evaluated by thermal conductivity, and thermal conductivity = thermal diffusivity × specific heat × density, so that increasing the density, thermal diffusivity, and the like of a solid contributes to improving the thermal conductivity thereof.

Preferably, the utility model requires comprehensive grouting reinforcement and grouting plugging of the waterproof coal pillar, the waterproof bottom plate, the rock layers above and below the waterproof coal pillar and the like for constructing the reservoir of the underground space of the coal mine, improves the compactness of the surrounding rock of the underground space of the coal mine, further improves the heat conductivity of the waterproof coal pillar, the waterproof bottom plate, the rock layers above and below the waterproof coal pillar and the like, and improves the heat storage effect of the reservoir of the underground space of the coal mine. The grouting process is required to adopt the principle of comprehensive grouting reinforcement and key grouting of leakage points, high-pressure grouting is adopted, grout is diffused in a seepage mode, the grouting depth in a preset water-resisting rock stratum or a water-resisting rock body is not less than 10m, and the grouting end standard is as follows: the designed final pressure is reached, the flow rate of the slurry is below 40 l/min and lasts for more than 20 minutes.

Because the coal mine underground space reservoir is a semi-sealed space with the bottom and the side sealed and the top unsealed, and the coal bed generally has a certain inclination angle, the absolute elevation of the top of the water-proof coal pillar in the upstream direction of the groundwater runoff is higher than the absolute elevation of the top of the water-proof coal pillar in the downstream direction of the groundwater runoff, so as to prevent the water body of the coal mine underground space reservoir from overflowing from the upper part of the water-proof coal pillar to enter the peripheral underground rock mass to cause the loss of the water in the coal mine underground space reservoir, the rock stratum above the water-proof coal pillar in the downstream direction of the groundwater runoff needs to be grouted, reinforced and grouted and plugged, and the height of the grouting area of the rock stratum above the water-proof coal pillar is not lower than the height of the overflow of the groundwater runoff. Preferably, the height of the stratum grouting area above the water-resisting coal pillar in the downstream direction of the groundwater runoff is the top of the water-resisting coal pillar in the upstream direction of the groundwater runoff, so that the absolute elevation of the top of the whole side water-resisting layer is kept consistent.

Preferably, the coal mine can adopt a high-water material or ultrahigh-water material filling mining mode, and the goaf is filled with the high-water material, so that the goaf is prevented from being filled with a top plate to reduce the volume of an underground space; meanwhile, because the high-water material or the ultrahigh-water material contains a large amount of free water, the high-water material filling body can be used for storing water, and further the storage capacity of the coal mine underground space reservoir is improved.

Compared with the defects that the water quantity is less and the underground water is possibly polluted in the heat taking process in the traditional geothermal use directional drilling heat taking technology, the water-resisting property of the reservoir in the underground space of the coal mine disclosed by the utility model realizes the isolation between the reservoir and the surrounding underground water, so that the circulation between a water body in the underground space and the surrounding underground water is avoided or reduced, and the potential pollution to the underground water in the geothermal development process is avoided. Therefore, the underground reservoir formed by transforming the underground space of the coal mine, which is provided by the utility model, has the characteristics of good tightness, excellent space stability and huge space. The water body of the reservoir in the coal mine underground space forms geothermal water through the action of geothermal heat.

In addition, the pumping and heat-taking channel is communicated with the underground space reservoir of the coal mine through the coal mine shaft or the inclined shaft, and the recharging power generation channel is communicated with the underground space reservoir of the coal mine through the coal mine shaft or the inclined shaft, so that the punching construction process is reduced, and the construction is greatly reduced.

Generally, a vertical shaft or an inclined shaft is required to be arranged as a main shaft and an auxiliary shaft for transportation, and after a coal mine is closed, the function of the vertical shaft or the inclined shaft as a transportation channel does not exist, so that a water pumping heat extraction channel (namely, a heat extraction well) can be communicated with a coal mine underground space reservoir through the coal mine vertical shaft or the inclined shaft, and a recharge channel (namely, a recharge well) can be communicated with the coal mine underground space reservoir through the coal mine vertical shaft or the inclined shaft.

The heat extraction well is a channel for extracting geothermal water from a reservoir in the underground space of the coal mine and lifting the geothermal water to the ground, namely a vertical well for extracting and conveying the geothermal water. The method is realized by modifying a coal mine vertical shaft or inclined shaft. The heat extraction well needs to extract and lift geothermal water of the coal mine underground space reservoir, so that a water suction pump needs to be arranged in the heat extraction well so as to extract and lift the geothermal water of the coal mine underground space reservoir to the ground, and the quantity, the model, the power and the like of the water suction pump can be determined according to the buried depth, the lift, the water delivery quantity and the like; the installation position of the water suction pump comprises the lower end of the heat taking well, and the water suction pump is arranged in the middle of the heat taking well, at the upper end of the heat taking well and on a ground geothermal water conveying pipeline according to requirements.

The heat extraction well can be realized by laying and installing pipelines made of large-caliber, high-temperature-resistant, corrosion-resistant and high-strength materials in a vertical shaft or an inclined shaft, namely pumping heat extraction well pipelines, wherein the pipelines can be steel pipes or integral steel-lined reinforced concrete water pipes, the water pipe frames are fixed by the rock walls of the vertical shaft, and the design and construction of the pumping energy storage power station water pipe construction are required to be executed according to the requirements of the specifications of NB/T35056-2015 hydropower station pressure steel pipe design specification and the like; the lower end of the water pumping and heat taking well pipeline extends into the water body of the coal mine underground space reservoir so as to be capable of pumping geothermal water of the coal mine underground space reservoir; the upper end of the water pumping and heat taking well pipeline is connected to the ground and is connected with a ground geothermal water conveying pipeline I. The heat-taking well pipeline is wrapped with a heat-insulating layer, and the heat-insulating material can be hard polyurethane foam plastic.

The recharging well is a channel for recharging geothermal water tail water (namely cold water obtained after geothermal water is subjected to heat exchange and is heated) which is subjected to heat exchange on the ground to the reservoir of the underground space of the coal mine, namely a vertical shaft for recharging the geothermal water tail water. The method is realized by modifying a coal mine vertical shaft or inclined shaft. The lower end of the recharging well is connected with a reservoir of the underground space of the coal mine, and the upper end of the recharging well extends to the ground and is connected with a ground geothermal water conveying pipeline on the ground.

The recharging well has two forms: firstly, the geothermal water tail water after heat exchange directly enters a coal mine underground space reservoir through a vertical shaft or an inclined shaft by gravity flow without additionally laying a pipeline, the lower end of the vertical shaft or the inclined shaft of the coal mine directly enters the coal mine underground space reservoir, and the upper end of the vertical shaft or the inclined shaft is connected with a ground geothermal water conveying pipeline; and the second installation pipeline is a recharging well pipeline which is connected with a ground geothermal water conveying pipeline II, the recharging well pipeline is wrapped by a heat-insulating layer, and the heat-insulating material can be hard polyurethane foam plastic. The recharging well pipeline can be made of the same material as the water pumping and heat taking well pipeline.

The heat taking well and the recharging well can be formed by transforming a main well and an auxiliary well in a vertical well or an inclined well respectively, the lower end of the heat taking well needs to be located in the downstream direction of groundwater runoff, and the lower end of the recharging well needs to be located in the upstream direction of the groundwater runoff, so that geothermal water tail water (namely cold water after being subjected to heat exchange and heat removal) recharged into a reservoir in the underground space of the coal mine flows to the heat taking well direction along the groundwater runoff direction under the action of gravity, and is heated into geothermal water by geothermal heat in the migration process, and the heat storage process of the geothermal water is completed. Therefore, the heat taking well is formed by modifying a vertical well or an inclined well in the downstream direction of the groundwater runoff, and the recharging well is formed by modifying a vertical well or an inclined well in the upstream direction of the groundwater runoff.

The ground geothermal water conveying pipeline is a pipeline for conveying geothermal water pumped to a coal mine underground space reservoir behind the ground to a heat exchanger for heat extraction and further conveying tail water of the geothermal water after heat exchange to a recharging well from the heat exchanger, and comprises a ground geothermal water conveying pipeline I and a ground geothermal water conveying pipeline II which are respectively connected with the upper ends of the heat extraction well and the recharging well; the pipeline is made of a large-caliber, high-temperature-resistant, corrosion-resistant and high-strength material, the pipeline can be a steel pipe or an integral steel-lined reinforced concrete water delivery pipe, the water delivery pipe frame is fixed by a vertical shaft rock wall, the design and construction of the water delivery pipe construction of the pumped storage power station are implemented according to the standard requirements of NB/T35056-2015 hydropower station pressure steel pipe design standard and the like, and a plurality of pump stations are arranged according to actual requirements to pressurize geothermal water through pumped pressure pumps so as to smoothly deliver the geothermal water. And a heat-insulating layer is arranged outside the ground geothermal water conveying pipeline. The heat insulating material may be hard foamed polyurethane plastic.

The utilization of the terrestrial heat refers to the fact that a ground source heat pump technology (HP) is adopted for extracting heat in geothermal water of a reservoir in an underground space of a coal mine and transferring the heat to a heating pipe network, a heat exchanger in the HP technology is adopted as the heat exchanger, and the structure of the heat exchanger is the prior art. May include an evaporator, a condenser, a compressor, an expansion valve, piping, etc. The heat exchanger is the heat exchange equipment.

Preferably, the configuration of the type, the number, the power and the like of the heat exchangers is required to be carried out according to actual requirements, and when a plurality of heat exchangers work together, a parallel mode is adopted to carry out heat taking and heat exchanging work simultaneously.

The heat supply pipe network is a pipe network system for heating urban life. The heating network is a conventional arrangement of the prior art. The heat supply pipe network can be laid again according to the requirements in the prior art, and the heat exchange equipment and the heat supply pipe network can be connected through a pipeline.

Specifically, the heating pipe network of urban residents adopts water as a heating medium, and when heating, ventilation and air conditioning heat loads are main loads and the production process needs to adopt steam for heating, the two heating media of water and steam can be adopted when the technical and economic comparison shows that the heating pipe network is reasonable. The urban resident heat supply pipe network preferably adopts a closed double-pipe system, the heat supply pipeline is laid in a direct burial mode, and the direct burial pipeline adopts an integral prefabricated direct burial heat preservation pipe formed by tightly combining a steel pipe, a heat preservation layer and an outer protection layer into a whole; the pipe is made of seamless steel pipes and connected in a welding mode, the heat-insulating material is made of hard polyurethane foam plastics, and the protective shell is made of a polyethylene outer sheath. Other matters of the heat supply pipe network need to meet the requirements related to the design code of urban heat supply pipe network (CJJ 34-2010).

The heating network connects the heating user end, and the heating user end is the heating system who is used for resident's indoor heating demand, is prior art's conventional setting. The heat-radiating type heat-radiating device mainly comprises indoor floor heating, a radiator and other heat-radiating equipment, a heat-supplying pipeline, accessories and the like. The selection and the quantity of heat dissipation equipment such as floor heating, radiators and the like need to be designed according to the heat dissipation capacity. The indoor heat supply pipeline needs to select a single-pipe crossing type or double-pipe type heat supply system according to the actual situation of a user. Other matters of indoor heat supply user terminals need to meet the requirements of the standards of residential design standard GB50096-2011 and the like.

In addition, it is understood that the whole geothermal utilization system of the underground space of the coal mine needs to carry out power transmission and distribution on various electric devices (including a water suction pump and a pressure pump in a water suction and heat extraction well, a pressure pump of a ground geothermal water conveying pipeline and the like), and the power transmission and distribution system is a conventional arrangement in the prior art.

The utility model has the advantages that in the traditional geothermal development and utilization project, drilling is needed to enter a preset heat-taking layer, and then a horizontal drilling method is adopted to carry out heat flow heat-taking, so that the heat-taking technology is labor-consuming, time-consuming and huge in consumption; secondly, the bore hole diameter is small, and the geothermal water flow is limited, so that the heat extraction is small; and thirdly, the underground water is polluted in the heat taking process. The utility model integrates the underground space of the abandoned mine (including the goaf and the shaft tunnel engineering), constructs the underground space of the coal mine into an underground reservoir with good tightness, excellent space stability and huge space, the huge underground reservoir is positioned under the deep underground and becomes a huge heat storage pool under the heat transfer action of the deep geothermal heat, and the heat of the surrounding geological structure is used for storing the heat of the water in the underground reservoir, thereby providing a continuous heat source for the geothermal utilization system of the whole underground space of the coal mine. In addition, due to the sealing property of the underground space of the coal mine, the pollution to the surrounding underground water is avoided or greatly reduced in the operation process.

Therefore, the utility model provides the geothermal utilization system for the underground space of the coal mine, which changes waste into valuable, has low cost, simple process and huge heat source, and realizes the combined development and comprehensive utilization of the underground space and the terrestrial heat of the abandoned coal mine.

Drawings

Fig. 1 is a schematic structural view of the present invention.

In the figure: 1. a geothermal water delivery pump; 2. a geothermal water delivery pipe; 3. a tail water delivery pipe of geothermal water; 4. an evaporator; 5. an expansion valve; 6. a heat exchanger; 7. a compressor; 8. a condenser; 9. a heat supply pipeline water delivery pump; 10. a heat supply pipeline; 11. a user side; 12. a user; 13. a ground surface unconsolidated formation; 14. a heat extraction well; 15. a secondary well; 16. grouting a plugged side top plate; 17. waterproof coal pillars; 18. a base plate; 19. grouting the side of the plug to directly connect the bottom plate; 20. a bottom plate water-resisting layer; 21. a water pump of an underground reservoir in the underground space of the coal mine; 22. an underground reservoir of the coal mine underground space; 23. recharging the well; 24. and (4) a main well.

Detailed Description

While the present invention will be described in detail and with reference to the embodiments, it is to be understood that the present invention is not limited to the details of construction and the arrangements of the components set forth in the following description, but is capable of numerous modifications and variations within the spirit and scope of the utility model as defined by the claims. In the present invention, unless otherwise specifically defined and limited, technical terms used in the present application should have the ordinary meaning as understood by those skilled in the art to which the present invention pertains.

As shown in fig. 1, the present embodiment is modified based on the geological formation of a certain coal mine and the coal mining situation. The coal seam of the coal mine is flat (about 6 degrees at the most), the burial depth is large (the mining depth is 600-800 m), and the fault does not develop, so that the working faces of the mining area are arranged in parallel and can be connected into a whole. Because the coal mine is located in a plain town belt, the 'third lower' coal pressing is serious, so the mining mode is filling mining, and the filling is a high-water material and an ultrahigh-water material. The net diameter of the main mine well is 5.5m, and the depth of the well bore is 666 m; the net diameter of the auxiliary well is 7.0m, the depth of the shaft is 690m, and the direction of groundwater runoff is from the direction of the main well to the direction of the auxiliary well. In addition, the plots of the coal mines belong to geothermal abnormal areas, the geothermal gradient is more than 3 ℃/100m, and the geothermal temperature of the underground space of the mine is 24.3-41.9 ℃.

The coal mine underground space reservoir 22 is formed by reconstructing coal mine underground space. In the embodiment, the utility model provides that underground spaces such as all underground goafs, roadway projects, mountains and the like are integrated together to form a huge underground space. Reserving waterproof coal pillars around the huge underground space, and performing comprehensive grouting reinforcement on the waterproof coal pillars and a water-resisting bottom plate rock stratum (also called a bottom plate water-resisting rock stratum which is a water-resisting bottom plate rock stratum formed by water-resisting rocks) of the whole mining area to form a grouting-reinforced waterproof coal pillar 17 and a grouting-reinforced water-resisting bottom plate layer 20; grouting and plugging the top plate above the waterproof coal pillar to manufacture a grouting and plugging side top plate 16, and grouting and plugging the direct bottom plate below the waterproof coal pillar 17 to manufacture a grouting and plugging side direct bottom plate 19. A huge underground space area can be commonly enclosed by the grouting reinforced waterproof bottom plate layer 20, the grouting reinforced waterproof coal pillar 17, the grouting plugged side top plate 16 above the waterproof coal pillar 17 and the grouting plugged side direct bottom plate 19 below the waterproof coal pillar 17.

In addition, because this ore deposit adopts high water material and ultrahigh water material to fill and exploit, the moisture content of ultrahigh water material is up to more than 90%, and inside moisture is mostly combination water and free water, is equivalent to whole collecting space area and still has a large amount of free water inside after being filled by high water material, consequently, the water capacity of this underground space improves greatly. In addition, because the geothermal energy of the underground space of the coal mine is obvious, and the heat conductivity of the surrounding rock after grouting plugging treatment is good, the underground space reservoir 22 of the coal mine is positioned in the deep underground and becomes a huge heat storage pool under the heat transfer action of the deep geothermal energy, and the water in the underground reservoir is stored by the heat of the surrounding geological structure, so that a continuous heat source is provided for the underground space geothermal utilization system of the whole coal mine. In summary, the coal mine underground space reservoir 22 provided by the utility model has the characteristics of good tightness, excellent space stability, huge water storage space, high heat source quality, huge heat source and the like.

The mine is provided with a primary well and a secondary well.

Wherein, lay the seamless steel pipe in the auxiliary shaft 15 and form the well pipeline 14 of heat extraction of pumping water, fix the well pipeline 14 of heat extraction of pumping water on the side wall of auxiliary shaft 15, the well pipeline 14 bottom of heat extraction of pumping water is provided with the underground reservoir suction pump 21 of colliery underground space.

Wherein, a recharging well pipeline 23 is laid in the main well 24, the recharging well pipeline 23 is fixed on the side wall of the main well 24, and the recharging well pipeline 23 recharges the geothermal tail water into the underground space reservoir 22 of the coal mine in a gravity flowing mode.

Because the underground water runoff direction of the underground space of the coal mine is from the direction of the main well 24 to the direction of the auxiliary well 15, the recharging well pipeline 23 is arranged in the main well 24, the geothermal tail water which is recharged into the underground space reservoir 22 of the coal mine can automatically flow to the direction of the water pumping and heat taking well pipeline 14 under the action of gravity, and the heat storage is completed through the action of geothermal heat in the transportation process.

Geothermal water pipeline in this application draws water including setting up in auxiliary well 15 and gets hot well pipeline 14, the lower extreme that draws water and get hot well pipeline 14 is equipped with suction pump 21, draw water and get hot well pipeline 14 upper end and pass through I-geothermal water pipeline 2 connection heat exchanger 7 of ground geothermal water pipeline, be equipped with geothermal water delivery pump 1 on geothermal water pipeline 2, geothermal water after the cooling passes through II-geothermal water pipeline 2 of ground geothermal water pipeline and connects the recharge well pipeline 23 that sets up in main well 24, when power is not enough, be equipped with geothermal water tail water pipeline force (forcing) pump on geothermal water tail water pipeline 2.

The heat exchanger 6 and the heat exchanger 7 adopt heat exchangers commonly used in ground source heat pump technology (HP), and are conventional technology. The ground source heat pump which can be provided by the chinese patent CN200520040921.7 comprises an evaporator 4, a condenser 8, a compressor 7, an expansion valve 5, a pipeline and the like.

Wherein, the heat supply pipe network includes heat supply pipeline water pump 9 and heat supply pipeline 10.

The user side is a heating system for the indoor heating demand of residents, and comprises a user side 11, a user side 12 and the like, wherein the user side comprises indoor floor heating, radiators and other heat dissipation equipment, heat supply pipelines, accessories and the like, and the conventional technology is adopted.

Therefore, the utility model provides a technical scheme for transforming the underground space of the abandoned coal mine into a geothermal development system, and provides a geothermal utilization system of the underground space of the coal mine, which changes waste into valuable, has low cost, simple process and huge heat source, so as to realize the combined development and comprehensive utilization of the underground space of the abandoned coal mine and geothermy.

The above description is only a preferred embodiment of the present invention, not all embodiments, and the scope of the present invention is not limited thereto, and each feature of the above-described embodiments may be arbitrarily combined, and for the sake of brevity, all possible combinations of each feature of the above-described embodiments are not described, however, as long as there is no contradiction between these combinations of features, the scope of the present invention should be considered as being described in the present specification. When combinations of technical solutions are mutually inconsistent or cannot be realized, such combinations should not be considered to exist and are not within the scope of the claimed invention. It should be noted that those skilled in the art and any person skilled in the art can equally substitute or change the technical solution of the present invention and the inventive concept thereof, and make several changes and improvements without departing from the spirit of the present invention and the general concept thereof, and these should be considered as the protection scope of the present invention.

Claims (9)

1. A colliery underground space geothermol power utilization system which characterized in that: the system comprises a coal mine underground space reservoir, a heat taking well, a recharging well, a ground geothermal water conveying pipeline, a heat exchanger, a heat supply pipe network, a user side and the like; the coal mine underground space reservoir is arranged in a coal mine underground space, a circumferential side water-resisting layer and a lower end water-resisting layer are arranged in the coal mine underground space, and the circumferential side water-resisting layer and the lower end water-resisting layer are connected with each other to form a water-resisting space with water resisting at the side and the bottom, namely the coal mine underground space reservoir; the lower ends of the heat taking well and the recharging well are respectively communicated with a coal mine underground space reservoir, the upper end of the heat taking well is connected with a ground geothermal water conveying pipeline I, the upper end of the recharging well is connected with a ground geothermal water conveying pipeline II, the geothermal water conveying pipeline I is connected with heat exchange equipment, and the geothermal water conveying pipeline II is connected with the heat exchange equipment; a water pump is arranged in the heat taking well;

geothermal water of the coal mine underground space reservoir is conveyed to the ground through a heat taking well, and conveyed to heat exchange equipment through a ground geothermal water conveying pipeline I, after heat exchange and heat taking, geothermal tail water after heat taking is conveyed to a recharging well through a ground geothermal water conveying pipeline II, and then the geothermal tail water enters the coal mine underground space reservoir through the recharging well for heat storage again; after geothermal water is subjected to heat taking and heat exchange through heat exchange equipment, heat is taken away and applied to a heat supply pipe network, and finally the geothermal water enters a user end to realize geothermal development and utilization; wherein, heat supply pipe network connects indirect heating equipment and user respectively, realizes the hydrologic cycle.

2. The geothermal utilization system for the underground space of the coal mine according to claim 1, wherein: the coal mine underground space comprises a waste coal mine goaf or/and a roadway project, a side water-resisting layer around the coal mine underground space comprises a grouting reinforced waterproof coal pillar, a lower end water-resisting layer is a grouting reinforced water-resisting bottom plate layer of the coal mine underground space, a grouting plugging side top plate is arranged at the upper end of the grouting reinforced waterproof coal pillar, and the lower end of the grouting reinforced waterproof coal pillar is connected with the grouting reinforced water-resisting bottom plate layer through a grouting plugging side direct bottom plate.

3. The coal mine underground space geothermal utilization system of claim 1, wherein: the heat extraction well is arranged in a vertical well or an inclined well in the downstream direction of the groundwater runoff, and the recharge well is a vertical well or an inclined well in the upstream direction of the groundwater runoff.

4. The coal mine underground space geothermal utilization system of claim 3, wherein: the heat extraction well is a channel for extracting geothermal water from a reservoir of the coal mine underground space and lifting the geothermal water to the ground, the installation pipeline is laid in a vertical shaft or an inclined shaft to be a water pumping heat extraction well pipeline, the lower end of the water pumping heat extraction well pipeline extends into the water in the reservoir of the coal mine underground space, and the upper end of the water pumping heat extraction well pipeline is connected with a ground geothermal water conveying pipeline.

5. The coal mine underground space geothermal utilization system of claim 3, wherein: the recharging well is a channel for recharging ground hot water tail water subjected to heat exchange to the underground space reservoir of the coal mine, the lower end of the recharging well is connected with the underground space reservoir of the coal mine, the upper end of the recharging well is connected with a ground geothermal water conveying pipeline to the ground, and the recharging well has two forms: firstly, the geothermal water tail water after heat exchange directly enters a coal mine underground space reservoir through a vertical shaft or an inclined shaft by gravity flow without additionally laying a pipeline, the lower end of the vertical shaft or the inclined shaft of the coal mine directly enters the coal mine underground space reservoir, and the upper end of the vertical shaft or the inclined shaft is connected with a ground geothermal water conveying pipeline I; and secondly, laying a pipeline in the vertical shaft or the inclined shaft to form a recharging well pipeline, wherein the recharging well pipeline is connected with the ground geothermal water conveying pipeline II.

6. The coal mine underground space geothermal utilization system of claim 5, wherein: the pumping and heat taking well pipeline, the recharging well pipeline, the ground geothermal water conveying pipeline I and the ground geothermal water conveying pipeline II are externally wrapped with heat-insulating layers, and the heat-insulating materials are hard polyurethane foam plastics.

7. The coal mine underground space geothermal utilization system of claim 1, wherein: the coal seam of the coal mine is a gentle coal seam, the inclination angle of the coal seam is not more than 25 degrees, and the fault of the mining area is not developed.

8. The geothermal utilization system for the underground space of the coal mine according to claim 3, wherein: the depth of the underground space of the coal mine is more than or equal to 300 m.

9. The coal mine underground space geothermal utilization system of claim 3, wherein: the coal mine is suitable for being in a high-earth heat flow value, high-earth-temperature-gradient abnormal area or a deep-fracture heat conduction belt, and the earth-temperature gradient of the underground space of the coal mine is 1-3 ℃/100m higher than the average earth-temperature gradient of the local area.

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