Deep coal seam coaxial sleeve gas-heat co-mining system
The deep coal seam coaxial casing gas-heat co-extraction system utilizes low-temperature water to absorb geothermal energy and separate gas, solving the problem of high-temperature heat hazards in deep coal mines and realizing the coordinated extraction and efficient utilization of coalbed methane and geothermal resources.
Patent Information
- Application Number
- CN202520160103.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-23
- Publication Date
- 2025-11-28
- Estimated Expiration
- 2035-01-23
AI Technical Summary
In the process of deep coal mining, high temperature heat hazard seriously affects safe and efficient mining, and existing technologies are unable to effectively utilize geothermal resources and coal resources for coordinated mining, resulting in low resource utilization efficiency.
A deep coal seam coaxial casing gas-heat co-extraction system is adopted. By drilling holes on the ground and installing coaxial casing heat exchangers, low-temperature water is used to absorb geothermal energy. Combined with electric submersible pumps and gas-liquid separation devices, gas and hot water are separated and recycled, thus realizing gas-heat co-extraction.
By extracting geothermal resources while simultaneously extracting coal seam gas, we can improve the efficiency of comprehensive resource utilization, reduce carbon emissions, and achieve the efficient use of clean energy.
Smart Images
Figure CN223608514U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model belongs to the deep coal bed gas and geothermal coordinated exploitation technical field, concretely relates to deep coal bed coaxial casing gas heat co-mining system. BACKGROUND
[0002] Coal resources belong to non-renewable primary energy, with the high intensity exploitation of coal resources in China, shallow coal resources gradually reduce, and the mine exploitation in China gradually shifts to deep part. However, with the increase of the depth of mine exploitation, the number of high ground temperature mine gradually increases, and the high temperature heat damage has a great influence, which seriously restricts the safe and efficient exploitation of deep coal resources. Therefore, the geothermal problem of deep mine has been the target of heat damage control for many years. Under this background, the idea of deep coal bed gas heat co-mining emerges as the times require. On the one hand, the high temperature environment of mine can be alleviated by exploiting geothermal resources in the process of coal mining. On the other hand, geothermal energy as a kind of clean energy can realize efficient utilization of resources, reduce carbon emission and meet the requirements of sustainable development through the coordinated exploitation with coal. Therefore, it is urgent to develop a gas heat co-mining system which can carry out gas extraction while exploiting geothermal resources and improve economic benefits. CONTENT OF UTILITY MODEL
[0003] In order to solve the above technical problems in the prior art, the utility model provides a deep coal bed coaxial casing gas heat co-mining system which is suitable for hot and waterless heat storage rock layer and can carry out gas extraction while exploiting geothermal resources.
[0004] In order to solve the above technical problems, the utility model adopts the following technical scheme: the deep coal bed coaxial casing gas heat co-mining system comprises an extraction pipeline, an electric submersible pump, a gas-liquid separation device, a heat pump unit and a water injection pipeline arranged on the ground, a plurality of extraction holes are vertically drilled from the ground, the extraction holes pass through the pre-mining coal seam and enter the rock layer at a certain depth below, and a coaxial casing extraction heat exchanger is vertically installed in each extraction hole; the coaxial casing extraction heat exchanger is arranged on the ground, and the coaxial casing extraction heat exchanger is arranged in the rock layer; the inlet of the electric submersible pump is connected with the outlet of the coaxial casing extraction heat exchanger through the extraction pipeline, the outlet of the electric submersible pump is connected with the inlet of the gas-liquid separation device, the water outlet of the gas-liquid separation device is connected with the hot water inlet of the heat pump unit, the gas outlet of the gas-liquid separation device is connected with the exhaust pipe, and the cold water outlet of the heat pump unit is connected with the inlet of the coaxial casing extraction heat exchanger through the water injection pipeline.
[0005] The coaxial sleeve extraction heat exchanger comprises an outer tube arranged vertically and an inner tube coaxially arranged inside the outer tube, the outer wall of the outer tube and the outer wall of the inner tube are connected by a plurality of radially arranged crossbars, a plurality of communication pipes are arranged between the outer tube and the inner tube in a section of the pre-mined coal seam, the two ends of the communication pipes are communicated with the pre-mined coal seam and the inside of the inner tube respectively, a one-way valve adjacent to the inner tube is arranged on the communication pipe, a blocking plate is arranged at the lower end of the outer tube, the lower end edge of the inner tube is higher than the upper surface of the blocking plate, the annular channel between the outer tube and the inner tube and the inner cavity of the inner tube form a baffle overwater channel, the upper end of the inner tube is the outlet of the coaxial sleeve extraction heat exchanger and is connected with the lower end of the extraction pipeline, the upper end of the outer tube is provided with an annular cover plate sleeved outside the inner tube, the upper side of the outer tube is provided with a water inlet hole, and the water inlet hole is the inlet of the coaxial sleeve extraction heat exchanger and is connected with the outlet of the water injection pipeline.
[0006] The diameter of the extraction hole in the section of the pre-mined coal seam is greater than the outer diameter of the outer tube, and the extraction hole in the section of the pre-mined coal seam and the outer tube forms an annular extraction cavity, and the diameter of the extraction hole in the section of the rock stratum is equal to the outer diameter of the outer tube.
[0007] The lower end of the inner tube is provided with a support, a rotating shaft is rotatably arranged between the support and the center of the blocking plate, a spiral blade located above the support in the inner tube and an anti-deposition scraper located below the support in the inner tube are arranged on the rotating shaft.
[0008] By adopting the technical scheme, the specific working process of the coaxial sleeve extraction heat exchanger is as follows: the electric submersible pump, the gas-liquid separation device and the heat pump unit are started, low-temperature water is injected into the outer tube through the water injection pipeline, the low-temperature water flows down along the outer tube, the low-temperature water fully absorbs the heat in the pre-mined coal seam and the rock stratum in the process of flowing downward, the heated water enters the inner tube upward from the blocking plate at the bottom of the outer tube, at the same time, the gas in the pre-mined coal seam is sucked upward by the negative pressure of the hot water in the inner cavity of the inner tube in the annular extraction cavity, the gas enters the inner tube and mixes with the hot water through the communication pipe and the one-way valve, the one-way valve prevents the hot water in the inner tube from entering the annular extraction cavity along the communication pipe, the electric submersible pump extracts the gas and the heat-exchanged hot water in the inner tube upward, the electric submersible pump sends the hot water into the gas-liquid separation device, the gas-liquid separation device separates the gas and the water, the separated gas is collected through the exhaust pipe, the separated high-temperature water enters the heat pump unit again, the heat pump unit stores or directly utilizes the heat extracted from the hot water, and the heat pump unit re-injects the low-temperature water into the coaxial sleeve extraction heat exchanger through the water injection pipeline for heat exchange, so that the gas and heat are extracted together and the water circulation flow is realized. After the water flow in the outer tube enters the inner cavity of the inner tube upward through the baffle overwater channel, the upward power of the water flow drives the spiral blade to rotate, the spiral blade drives the anti-deposition scraper below to rotate through the rotating shaft, so that the deposition or scale accumulated on the blocking plate is avoided.
[0009] Compared with the prior art, the innovation of the coaxial sleeve extraction heat exchanger mainly lies in the following aspects:
[0010] (1) The coaxial sleeve extraction heat exchanger mainly comprises an outer pipe and an inner pipe, the inner and outer sleeve pipes are fixed through cross-shaped flat-shaped crossbars to ensure that the inner pipe and the outer pipe are connected as a whole, and the structure is more stable; the inner pipe and the outer pipe are connected through a communication pipe inside the pre-mined coal seam, and a one-way valve is installed on each communication pipe near the inner pipe, the one-way valve only allows the gas to pass from outside to inside in the communication pipe, and prevents the water in the inner pipe from flowing into the communication pipe to affect the gas extraction effect; the outer pipe is made of a material with good heat conductivity (stainless steel, heat-conducting insulating plastic, etc.), so that heat can be fully conducted to the low-temperature water, and the inner pipe is made of a material with good heat preservation (PVC), to prevent heat loss.
[0011] (2) Before the gas and heat co-extraction is implemented, a plurality of extraction holes are drilled vertically downward to the pre-mined coal seam on the ground, the extraction holes pass through the pre-mined coal seam and enter the rock layer to a certain depth, and then the coaxial sleeve extraction heat exchanger is arranged in the hole; low-temperature water is injected into the outer pipe through the water injection pipeline, and the water flows down along the outer pipe and fully absorbs the heat in the coal seam and the rock layer; when the extraction starts, the gas enters the inner pipe along the communication pipeline through the one-way valve, and the electric submersible pump extracts the gas and water together along the extraction pipeline to the ground; the other end of the electric submersible pump is connected to a gas-liquid separation device to separate the gas and water, thereby realizing the gas and heat co-extraction.
[0012] The gas-liquid separation device adopts a cyclone type gas-liquid separator, the mixture of the gas and the water rotates at high speed in the device, the water is thrown to the inner wall of the cyclone type gas-liquid separator and flows out from the lower water outlet due to the relatively large density, and the separated gas moves upward along the central shaft and is discharged from the gas outlet; the water outlet is connected to a heat pump unit, the separated hot water enters the heat pump for heat exchange, and finally is re-injected into the outer pipe of the coaxial sleeve extraction heat exchanger along the water injection pipeline, thereby realizing the circulation of the whole gas and heat co-extraction system.
[0013] (3) A spiral blade is arranged inside the lower end of the inner pipe, when the hot water flows upward from the lower end of the inner pipe, the spiral blade is driven to rotate, the rotation shaft drives the anti-deposition scraper above the baffle to rotate, the water at the dead angle position of the lower end of the outer pipe is always kept in an agitated state, the deposition and scaling at the position will not be deposited again, thereby avoiding the deposition and scaling accumulation to block the baffle passage.
[0014] In summary, the principle of the utility model is scientific, the coal seam gas can be extracted while the geothermal resources are exploited, and the gas and heat co-extraction of the deep coal seam is realized; the coal bed gas and the geothermal resources belong to the clean energy category, and the deep coal bed gas and the geothermal resources are co-mined, thereby improving the resource comprehensive utilization efficiency and the resource comprehensive development benefit. BRIEF DESCRIPTION OF DRAWINGS
[0015] Figure 1 is a structural schematic view of the utility model.
[0016] Figure 2 isFigure 1 Figure 1 is a schematic diagram of the overall structure of the coaxial casing extraction heat exchanger;
[0017] Figure 3 is Figure 2 Figure 2 is a schematic diagram of the cross-sectional structure between the outer tube and the inner tube; DETAILED DESCRIPTION
[0018] The embodiments of the present application will be further described in detail below with reference to the accompanying drawings and examples.
[0019] As Figures 1-3 shown, the deep coal seam coaxial casing gas-heat co-extraction system of the present application comprises an extraction pipeline 6, an electric submersible pump 7, a gas-liquid separation device 8, a heat pump unit 9 and a water injection pipeline 10 arranged on the ground 1, a plurality of extraction holes 2 vertically drilled downward from the ground 1, the extraction holes 2 passing through the pre-mining coal seam 3 and entering the rock stratum 4 at a certain depth, and a coaxial casing extraction heat exchanger 5 vertically installed in each extraction hole 2; the coaxial casing extraction heat exchanger 5 has its upper end protruding out of the ground 1 and its lower end extending into the rock stratum 4; the inlet of the electric submersible pump 7 is connected with the outlet of the coaxial casing extraction heat exchanger 5 through the extraction pipeline 6, the outlet of the electric submersible pump 7 is connected with the inlet of the gas-liquid separation device 8, the water outlet of the gas-liquid separation device 8 is connected with the hot water inlet of the heat pump unit 9, the gas outlet of the gas-liquid separation device 8 is connected with an exhaust pipe, and the cold water outlet of the heat pump unit 9 is connected with the inlet of the coaxial casing extraction heat exchanger 5 through the water injection pipeline 10.
[0020] The coaxial casing extraction heat exchanger 5 comprises a vertically arranged outer tube 11 and an inner tube 12 coaxially arranged inside the outer tube 11, a plurality of radially arranged crossbars 13 connecting the inner wall of the outer tube 11 and the outer wall of the inner tube 12, a plurality of communication tubes 14 arranged between the outer tube 11 and the inner tube 12 in the pre-mining coal seam 3, the two ends of the communication tubes 14 respectively communicating with the pre-mining coal seam 3 and the inside of the inner tube 12, a one-way valve 15 arranged on the communication tube 14 adjacent to the inner tube 12, a blocking plate 16 arranged at the lower end of the outer tube 11, the lower end edge of the inner tube 12 being higher than the upper surface of the blocking plate 16, an annular passage between the outer tube 11 and the inner tube 12 and the inner cavity of the inner tube 12 forming a baffle overcurrent passage 17, the upper end of the inner tube 12 being the outlet of the coaxial casing extraction heat exchanger 5 and connected with the lower end of the extraction pipeline 6, and the upper end of the outer tube 11 being provided with an annular cover plate 18 sleeved on the outside of the inner tube 12, and the upper side of the outer tube 11 being provided with a water inlet hole which is the inlet of the coaxial casing extraction heat exchanger 5 and connected with the outlet of the water injection pipeline 10.
[0021] The diameter of the extraction hole 2 in the pre-mining coal seam 3 is greater than the outer diameter of the outer tube 11, an annular extraction cavity 19 is formed between the extraction hole 2 in the pre-mining coal seam 3 and the outer tube 11, and the diameter of the extraction hole 2 in the rock stratum 4 is equal to the outer diameter of the outer tube 11; the outer tube 11 is made of a material with good heat conductivity and corrosion resistance, and the inner tube 12 is made of a material with good heat preservation.
[0022] The inner tube 12 lower end port is provided with a support 20, the support 20 is rotatably arranged with a rotating shaft 21 between the center of the blocking plate 16, the rotating shaft 21 is provided with a spiral blade 22 located in the inner tube 12 inside the upper of the support 20 and a deposition prevention scraper 23 located in the inner tube 11 inside the lower of the support 20.
[0023] The specific working process of the utility model is: starting the electric submersible pump 7, the gas-liquid separation device 8 and the heat pump unit 9, injecting low-temperature water into the outer tube 11 through the water injection pipeline 10, the low-temperature water flows down along the outer tube 11, the low-temperature water fully absorbs the heat in the coal seam and the rock stratum 4 in the process of flowing down, the heat-absorbed hot water enters the inner tube 12 upwards from the blocking plate 16 at the bottom of the outer tube 11, at the same time, the gas in the pre-mining coal seam 3 is sucked upwards by the hot water in the inner tube 12 in the annular extraction cavity 19, the gas enters the inner tube 12 and mixes with the hot water through the communication pipe 14 and the one-way valve 15, the one-way valve 15 prevents the hot water in the inner tube 12 from entering the annular extraction cavity 19 along the communication pipe 14, the electric submersible pump 7 extracts the gas and the heat-exchanged hot water in the inner tube 12 upwards, the electric submersible pump 7 sends the hot water into the gas-liquid separation device 8, the gas-liquid separation device 8 separates the gas and the water, the separated gas is collected through the exhaust pipe, the separated high-temperature water enters the heat pump unit 9 again, the heat pump unit 9 stores or directly uses the heat in the hot water after extracting the heat, the heat pump unit 9 re-injects the low-temperature water into the coaxial sleeve pipe extraction heat exchanger 5 through the water injection pipeline 10 to exchange heat, so that the gas and heat are co-mined and the hot water circulates, after the water flows downwards through the baffle water passage 17 and enters the inner cavity of the inner tube 12 upwards, the upward power of the water flow drives the spiral blade 22 to rotate, the active rotating blade drives the deposition prevention scraper 23 at the lower part to rotate through the rotating shaft 21, so that the deposition or scale accumulated on the blocking plate 16 is avoided.
[0024] The extraction pipeline 6, the electric submersible pump 7, the gas-liquid separation device 8, the heat pump unit 9, the water injection pipeline 10 and the one-way valve 15 in the utility model are all existing equipment or components, which can be purchased or customized in the market.
[0025] The above embodiments illustrate the basic principles and characteristics of the utility model, but the above only illustrates the relatively optimal embodiment of the utility model, and is not limited by the described embodiments. Those skilled in the art can make many form variations and improvements under the inspiration of the patent without departing from the purpose of the utility model and the scope protected by the claims, which all belong to the protection scope of the utility model. Therefore, the utility model patent and the protection scope should be subject to the appended claims.
Claims
1. A coaxial casing gas-heat co-mining system for deep coal seams, characterized in that: The device comprises a pumping pipeline arranged on the ground, an electric submersible pump, a gas-liquid separation device, a heat pump unit and a water injection pipeline, a plurality of pumping holes are vertically drilled downward from the ground, the pumping holes pass through the pre-mining coal seam and enter the rock formation at a certain depth, a coaxial casing pumping heat exchanger is vertically installed in each pumping hole; the coaxial casing pumping heat exchanger extends out of the ground at the upper end, and extends into the rock formation at the lower end; the inlet of the electric submersible pump is connected with the outlet of the coaxial casing pumping heat exchanger through the pumping pipeline, the outlet of the electric submersible pump is connected with the inlet of the gas-liquid separation device, the water outlet of the gas-liquid separation device is connected with the hot water inlet of the heat pump unit, the gas outlet of the gas-liquid separation device is connected with an exhaust pipe, and the cold water outlet of the heat pump unit is connected with the inlet of the coaxial casing pumping heat exchanger through the water injection pipeline.
2. The deep coalbed coaxial casing gas and heat co-recovery system of claim 1, wherein: The coaxial casing pumping heat exchanger comprises an outer tube and an inner tube arranged coaxially in the outer tube, the inner wall of the outer tube and the outer wall of the inner tube are connected by a plurality of radial arranged cross bars, a plurality of communication pipes are arranged between the outer tube and the inner tube in the pre-mining coal seam, the two ends of the communication pipe are communicated with the pre-mining coal seam and the inner tube respectively, a one-way valve is arranged on the communication pipe close to the inner tube, a blocking plate is arranged at the lower end of the outer tube, the lower end edge of the inner tube is higher than the upper surface of the blocking plate, the annular channel between the outer tube and the inner tube and the inner cavity of the inner tube form a zigzag water passing channel, the upper end of the inner tube is the outlet of the coaxial casing pumping heat exchanger and is connected with the lower end of the pumping pipeline, the upper end of the outer tube is provided with an annular cover plate sleeved on the outer part of the inner tube, and a water inlet hole is arranged on the upper side of the outer tube, the water inlet hole is the inlet of the coaxial casing pumping heat exchanger and is connected with the outlet of the water injection pipeline.
3. The deep coalbed coaxial casing gas and heat co-recovery system of claim 2, wherein: The diameter of the pumping hole in the pre-mining coal seam is greater than the outer diameter of the outer tube, and the annular pumping cavity is formed between the pumping hole in the pre-mining coal seam and the outer tube, and the diameter of the pumping hole in the rock formation is equal to the outer diameter of the outer tube.
4. The deep coalbed coaxial casing gas and heat co-recovery system of claim 3, wherein: The lower end of the inner tube is provided with a support, a rotating shaft is rotatably arranged between the support and the center of the blocking plate, a spiral blade is arranged in the inner tube above the support, and an anti-deposition scraper is arranged in the inner tube below the support.