System for converting coal seam in-situ plasma into heat energy
By stimulating the oxygen-containing component reaction medium in the conversion channel below the coal seam to produce living particles, efficiently convert coal into high-grade thermal energy, solving the problems of low conversion efficiency and low production intensity, and achieving stable thermal energy supply.
Patent Information
- Application Number
- CN202422519251.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-16
- Publication Date
- 2025-08-29
- Estimated Expiration
- 2034-10-16
AI Technical Summary
The existing coal seam in-situ thermal energy conversion methods have problems such as low conversion efficiency, low production intensity and difficulty in stably supplying heat.
High-energy devices are used to excite the reaction medium of oxygen-containing components in the conversion channel below the coal seam, producing active particles such as excited atoms or molecules, ground state atoms or molecules, positive ions, negative ions, etc., and efficiently convert coal resources into high-grade thermal energy products through the conversion components and the harvesting components, and the heat is harvested to the maximum extent through the insulation layer and the interlayer.
It improves conversion efficiency, enhances production intensity, reduces by-products, and achieves a stable supply of heat energy and is environmentally friendly.
Smart Images
Figure CN223276258U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of coal seam gasification, in particular to a coal seam in-situ plasma conversion thermal energy system. Background Art
[0002] In-situ coal seam conversion technology integrates well construction, coal mining, and conversion, significantly shortening the heating process and thus reducing carbon emissions and economic costs. Some studies have utilized in-situ coal seam conversion methods. After the well is constructed, the coal is ignited in the coal seam, oxygen-containing components are introduced, and the heat generated by the coal seam combustion is discharged to the surface. Alternatively, the heat energy is utilized by exchanging sensible heat from the coal gas based on in-situ coal seam gasification. This traditional in-situ coal seam combustion or gasification method involves a spontaneous reaction between dense underground coal seams and oxidants or gasifying agents. This is semi-naturally controlled, resulting in low conversion efficiency and low production intensity. Furthermore, the underground coal seam environment is complex. Coal seam intercalation, underground water inflow, and the expansion of the reaction chamber all have a serious impact on the conversion reaction. Flameout often causes production suspension, requiring the coal seam to be re-ignited and a fire zone to be established. The coal seam ignition takes 3 to 7 days, and the problem of stable heat supply is prominent.
[0003] Therefore, current methods of converting surface coal into thermal energy suffer from high carbon emissions, high economic costs, and solid waste accumulation. The more advanced method of in-situ thermal energy conversion in coal seams suffers from low conversion efficiency, low production intensity, and difficulty in providing a stable heat supply. Given these issues, there is an urgent need for an efficient and stable in-situ plasma thermal energy conversion system to convert underground coal seams into stable thermal products.
[0004] The above information disclosed in the background technology section is only used to enhance understanding of the background of the present invention and therefore may contain information that does not constitute the prior art known to ordinary technicians in this field. Utility Model Content
[0005] The purpose of the utility model is to provide a coal seam in-situ plasma conversion thermal energy system. In view of the problems of low conversion efficiency, low production intensity and difficulty in stable heat supply in the current coal seam in-situ thermal energy conversion method, the utility model excites and dissociates the reaction medium mainly composed of oxygen components to produce excited atoms or molecules, ground atoms or molecules, positive ions, negative ions and other active particles in the underground coal seam, and efficiently converts coal resources into high-grade thermal energy products on site. The system solves the problems of low conversion efficiency, low production intensity and difficulty in stable heat supply in conventional coal seam in-situ thermal energy conversion methods.
[0006] In order to achieve the above purpose, the present invention provides the following technical solutions:
[0007] A coal seam in-situ plasma conversion thermal energy system comprises: a conversion channel, a conversion assembly, and a recovery assembly; the conversion channel comprises: a first vertical channel, a second vertical channel, and a non-vertical channel; the first vertical channel and the second vertical channel are formed by vertically penetrating the overburden and the upper edge of the coal seam, respectively, and the non-vertical channel is formed by the first and second vertical channels gradually deflecting and penetrating in the horizontal direction; the conversion assembly penetrates from the first vertical channel and extends into the non-vertical channel, one end of the conversion assembly located in the non-vertical channel is connected to a high-energy device, and the assembly contains a reaction medium injection pipe for providing a reaction medium to the high-energy device; the high-energy device is used to generate high-temperature and highly active oxygen-containing component particles from the reaction medium to convert the coal seam into hot gas; the recovery assembly penetrates from the second vertical channel and extends into the non-vertical channel, and is separated from the high-energy device by a preset distance, and the end of the recovery assembly away from the non-vertical channel is used to connect to an external gas storage unit.
[0008] Optionally, the conversion assembly includes: a conversion tube, a conversion tube drive device and an injection device; the conversion tube is arranged in the conversion channel, one end of the conversion tube is located outside the first vertical channel and is connected to the conversion tube drive device and the injection device, and the other end of the conversion tube extends into the non-vertical channel and is connected to the high-energy device; a coaxial injection pipe is provided in the conversion tube, and a reaction medium injection pipe, a cooling medium injection pipe and a power cable are wrapped in the injection pipe; the conversion tube drive device is arranged on the surface to move the conversion tube in a controllable manner, and the injection device is used to control the reaction medium injection amount and the cooling medium inlet and outlet flow rate.
[0009] Optionally, the recovery assembly includes: a recovery pipe, a recovery device and a recovery pipe driving device; one end of the recovery pipe is connected to the recovery device and the recovery pipe driving device on the surface, and the other end of the recovery pipe extends into the coal seam through the second vertical channel and the end is open; the recovery pipe driving device is arranged on the ground to move the recovery pipe in a controllable manner, the recovery device is arranged in the recovery pipe driving device and is connected to the surface end outlet of the recovery pipe, and the recovery device is provided with a plurality of outlet valves for outputting the hot gas, and the outlet valves are connected to the gas storage unit through pipelines.
[0010] Optionally, the recovery assembly further comprises a temperature measuring device, which is disposed inside the recovery pipe and is used to monitor the temperature distribution of the coal seam and the hot gas in the recovery pipe.
[0011] Optionally, the recovery assembly further comprises a comprehensive testing device, which is arranged at the surface portion of the recovery pipe and is used to test the flow rate, composition and pressure parameters of the recovered hot gas.
[0012] Optionally, the high-energy device includes a plasma generator or a high-energy burner.
[0013] Optionally, the conversion tube driving device drives the conversion tube to perform forward and backward movements with a movement accuracy of 0.1 m; the recovery tube driving device drives the recovery tube to perform forward and backward movements with a movement accuracy of 0.1 m.
[0014] Optionally, the number of the outlet valves is 1 to 3, and the recovery pipe is lowered by the recovery pipe driving device to 0.5m to 2m below the upper edge of the coal seam.
[0015] Optionally, the outside of the recovery pipe is coated with a thermal insulation layer, and the inside of the recovery pipe is provided with a heating interlayer.
[0016] Optionally, the heating interlayer is a hot gas annulus interlayer or a heating wire interlayer wrapping a resistance heating wire.
[0017] Optionally, the temperature measuring device includes a single multi-point temperature measuring thermocouple, and the temperature measuring range of the thermocouple is 50°C to 1700°C.
[0018] Optionally, the length of the thermocouple is the same as that of the recovery tube, and the temperature measurement points of the thermocouple are distributed gradually and densely from away from the end of the recovery tube to close to the end of the recovery tube.
[0019] In the above technical solution, the utility model provides a coal seam in-situ plasma conversion thermal energy system, which has at least the following beneficial effects:
[0020] By setting high-energy devices in the conversion channel below the coal seam, including but not limited to plasma, high-energy burners, etc., to excite and dissociate the reaction medium mainly composed of oxygen-containing components, active particles such as excited atoms or molecules, ground-state atoms or molecules, positive ions, and negative ions are generated. In the underground coal seam, coal resources are efficiently converted into high-grade thermal energy products on site, with high conversion efficiency, high production intensity, few by-products, and environmental friendliness. This is based on the technical characteristics of underground in-situ conversion of coal seams. In addition, the outside of the recovery pipe is covered with an insulation layer and an interlayer is arranged inside to prevent the loss of heat from hot gas and maximize the heat recovery, thus solving the problems of low conversion efficiency, low production intensity and difficulty in stable heat supply. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.
[0022] Figure 1 A schematic structural diagram of a coal seam in-situ plasma conversion thermal energy system provided in one embodiment of the utility model.
[0023] Figure 2 A schematic cross-sectional view of a recovery pipe of a coal seam in-situ plasma conversion thermal energy system provided in one embodiment of the present invention. DETAILED DESCRIPTION
[0024] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0025] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without inventive effort are within the scope of protection of the present invention. It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.
[0026] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.
[0027] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this utility model, "plurality" means two or more, unless otherwise specifically defined.
[0028] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; they can refer to direct connection or indirect connection through an intermediate medium; they can refer to internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.
[0029] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.
[0030] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.
[0031] See also Figure 1-2 As shown, in one embodiment, the utility model provides a coal seam in-situ plasma conversion thermal energy system comprising: a conversion channel, a conversion component and a recovery component.
[0032] Specifically, the conversion channel 4 includes: a first vertical channel, a second vertical channel, and a non-vertical channel (which can be understood as a horizontal channel or a nearly horizontal channel). The first vertical channel and the second vertical channel are formed by vertically passing through the overburden and the upper edge of the coal seam, respectively. The non-vertical channel is formed by the first vertical channel and the second vertical channel gradually deflecting toward the horizontal direction and penetrating. Specifically, the first vertical channel of the conversion channel 4 is formed by the ground surface 3 vertically passing through the overburden 2 and the upper edge of the coal seam 1, and then gradually deflecting toward the horizontal direction to form a non-vertical channel in the coal seam 1. The coordinates of the non-vertical channel extending a predetermined distance in the coal seam 1 are used as the target point. The second vertical channel is also formed by the ground surface 3 vertically passing through the overburden 2 and the upper edge of the coal seam 1, and gradually deflecting from the coal seam toward the target point until the non-vertical channel is penetrated.
[0033] Specifically, the conversion component 5 penetrates from the first vertical channel and extends into the non-vertical channel. One end of the conversion component located in the non-vertical channel is connected to the high-energy device 9. The conversion component 5 is wrapped with a reaction medium injection pipe for providing the reaction medium to the high-energy device 9; the high-energy device 9 is used to generate high-temperature and high-activity oxygen-containing component particles from the reaction medium to convert the coal seam into hot gas, thereby realizing in-situ conversion of the coal seam.
[0034] Optionally, the conversion assembly 5 includes: a conversion tube, a conversion tube drive device, and an injection device. The conversion tube 7 is disposed within the conversion channel 4. One end of the conversion tube 7 is connected to the conversion tube drive device and the injection device 11 at the surface 3, and the other end in the non-vertical channel is connected to the high-energy device 9. A coaxial injection pipe 8 is disposed within the conversion tube 7, and the injection pipe 8 encloses a reaction medium injection pipe, a cooling medium injection pipe, and a power cable. The conversion tube drive device 10 is disposed at the surface 3 to controllably move the conversion tube 7. The injection device 11 is connected to the conversion tube drive device 10 and the injection pipe 8 to control the reaction medium injection amount and the cooling medium inlet loop flow rate. The injection device 11 is provided with multiple reaction medium injection ports, cooling medium injection ports, power cables, and corresponding valves and switches. The high-energy device 9 is used to convert the reaction medium provided by the injection pipe 8 into high-temperature, highly active oxygen-containing component particles to convert the coal seam into hot gas.
[0035] Furthermore, one end of the collection component 6 penetrates from the second vertical channel and extends into the non-vertical channel, and is spaced a preset distance from the high-energy device 9, for collecting hot gas; the end of the collection component away from the non-vertical channel is used to connect to an external gas storage unit, thereby transmitting the collected hot gas to the external gas storage unit for storage and standby use.
[0036] Optionally, the recovery assembly 6 includes a recovery pipe 12, a recovery device 16, and a recovery pipe drive 17. One end of the recovery pipe 12 is connected to the recovery device 16 and the recovery pipe drive 17 at the surface 3, while the other end, which extends into the coal seam, is open. The recovery pipe drive 17 is installed on the surface to controllably move the recovery pipe 12. The recovery device 16 is installed within the recovery pipe drive 17 and connected to the surface 3 outlet of the recovery pipe 12. The recovery device 16 is equipped with multiple outlet valves for outputting hot gas, which are connected to the gas storage unit via pipelines.
[0037] Optionally, the temperature measuring device 14 is provided inside the recovery pipe 12 to monitor the temperature distribution of the hot gas in the coal seam and the recovery pipe 12, which is conducive to feedback of the underground thermal energy conversion situation and provides a basis for real-time regulation of the conversion reaction to ensure stable operation of thermal energy conversion production.
[0038] Optionally, a comprehensive testing device 15 is arranged on the surface part of the recovery pipe 12 to test the flow, composition and pressure parameters of the recovered hot gas, which is conducive to feedback on the underground thermal energy conversion situation and provides a basis for real-time regulation of the conversion reaction to ensure stable operation of thermal energy conversion production.
[0039] In a preferred embodiment of the coal seam in-situ plasma conversion thermal energy system, the reaction medium includes air, pure oxygen, a mixture of oxygen and nitrogen with different volume fractions, oxygen and carbon dioxide with different volume fractions, oxygen and water with different volume fractions, oxygen and combustible gas with different volume fractions, and a combination of the above gases.
[0040] In a preferred embodiment of the coal seam in-situ plasma conversion thermal energy system, the high-energy device 9 excites or dissociates the reaction medium to produce high-temperature and highly active oxygen-containing component particles, which include excited state atoms or molecules, ground state atoms or molecules, positive ions, and negative ions.
[0041] This embodiment sets high-energy devices in the conversion channel below the coal seam, including but not limited to plasma, high-energy burners, etc., to excite and dissociate the reaction medium mainly composed of oxygen-containing components, thereby generating active particles such as excited atoms or molecules, ground-state atoms or molecules, positive ions, and negative ions. In the underground coal seam, coal resources are efficiently converted into high-grade thermal energy products on site, with high conversion efficiency, high production intensity, few by-products, and environmental friendliness, and based on the technical characteristics of underground in-situ conversion of coal seams.
[0042] In a preferred embodiment of the coal seam in-situ plasma conversion thermal energy system, the high-energy device 9 includes a plasma generator or a high-energy burner.
[0043] In a preferred embodiment of the coal seam in-situ plasma conversion thermal energy system, the conversion tube driving device 10 drives the conversion tube 7 to perform forward and backward movements with a movement accuracy of 0.1m, and the recovery tube driving device drives the recovery tube 12 to perform forward and backward movements with a movement accuracy of 0.1m.
[0044] In a preferred embodiment of the coal seam in-situ plasma conversion thermal energy system, the recovery pipe 12 is coated with an insulation layer 13 on the outside and an interlayer 18 is provided on the inside.
[0045] In a preferred embodiment of the coal seam in-situ plasma conversion thermal energy system, the interlayer 18 is a hot gas annulus interlayer or a heating wire interlayer wrapped around a resistance heating wire.
[0046] In a preferred embodiment of the coal seam in-situ plasma conversion thermal energy system, the temperature measuring device 14 includes a single multi-point temperature measuring thermocouple, and the temperature measuring range of the thermocouple is 50°C to 1700°C.
[0047] In a preferred embodiment of the coal seam in-situ plasma conversion thermal energy system, the length of the thermocouple is consistent with the recovery pipe 12, the temperature measuring points are distributed more densely at the end of the recovery pipe 12, and the temperature measuring points are gradually distributed sparsely in the direction away from the end, which is conducive to improving the temperature measurement accuracy.
[0048] The conversion process of the coal seam in-situ plasma conversion thermal energy system specifically includes:
[0049] A non-vertical channel is formed in the coal seam 1 after vertically passing through the overburden 2 and the upper edge of the coal seam 1 from the ground surface 3, and then gradually deflecting in the horizontal direction. The coordinates of the non-vertical channel extending a predetermined distance in the coal seam are used as the target point. Similarly, the ground surface 3 vertically passes through the overburden 2 and the upper edge of the coal seam 1, and gradually deflects from the coal seam 1 toward the target point until the non-vertical channel is penetrated to form a conversion channel 4.
[0050] The conversion tube 7 extends from the surface 3 into the coal seam within the conversion channel 4. One end of the conversion tube 7 is connected to the conversion tube drive device 10 and the injection device 11 at the surface 3, and the other end is connected to the high-energy device 9 at the surface 3 and lowered into the coal seam. The injection pipe 8 is located within the conversion tube 7 and is coaxial with the injection pipe 8. The injection pipe 8 encloses the reaction medium injection pipe 8, the cooling medium injection pipe 8, and the power cable. The injection pipe 8 is connected to the conversion tube drive device 10, the injection device 11, and the high-energy device 9 respectively along the conversion tube 7. One end of the recovery pipe 12 is connected to the recovery device 16 and the recovery pipe drive device 17 at the surface 3, and the other end extends into the coal seam. The recovery device 16 is located within the recovery pipe drive device and connected to the surface 3 end outlet of the recovery pipe 12.
[0051] The reaction medium is injected by the injection device 11, and the flow data of the comprehensive testing device 15 is fed back to check whether the conversion channel 4 and the recovery pipe 12 are unobstructed. After confirming that the conversion channel 4 and the recovery pipe 12 are unobstructed, the reaction medium and the cooling medium are injected by the injection device 11, and the high-energy device 9 is started. The reaction medium flow and the power of the high-energy device 9 are gradually adjusted to keep the load of the high-energy device 9 between 10% and 50%, and the normal conversion production of the coal seam conversion begins. During the conversion production process, when the temperature feedback of the temperature measuring device 14 is 1000°C and the flow feedback of the comprehensive testing device 15 is more than 1.1 times the reaction medium injection flow, it indicates that the coal seam conversion production is normal and the distance between the recovery pipe 12 and the high-energy device 9 is normal. If the temperature feedback of the temperature measuring device 14 is lower than 1000°C and the flow feedback of the comprehensive testing device 15 is kept more than 1.1 times the reaction medium injection flow, the recovery pipe 12 is moved toward the high-energy device 9. 12, until the feedback temperature of the temperature measuring device 14 is around 1000°C, stop moving. When the feedback temperature of the temperature measuring device 14 is at 1000°C, but the feedback flow of the comprehensive testing device 15 continues to decrease, increase the reaction medium injection flow and the power of the high-energy device 9 to increase the conversion reaction load to 60% to 100%. After the feedback temperature of the temperature measuring device 14 and the feedback flow of the comprehensive testing device 15 begin to decrease, keep the high-energy device 9 in the started state, retreat the conversion tube 75 to 50m, and after the conversion tube 7 is retreated, extend the recovery tube 125 to 50m and continue the coal seam conversion production. Repeat this cycle to adjust the production. When the moving distance of the conversion tube drive device 10 and the recovery tube drive device 17 is close to the non-vertical channel distance, turn off the power of the high-energy device 9, stop the reaction medium injection, maintain the cooling medium injection, and withdraw the conversion tube 7 and the recovery tube 12 to the surface 3 respectively.
[0052] In one embodiment, by exciting and dissociating a reaction medium mainly composed of oxygen-containing components through methods including but not limited to plasma and high-energy burners, active particles such as excited atoms or molecules, ground-state atoms or molecules, positive ions, and negative ions are generated, and coal resources are efficiently converted into high-grade thermal energy products in situ in underground coal seams.
[0053] In one embodiment, the conversion process specifically includes:
[0054] 1) Installation
[0055] After vertically passing through the overburden 2 and the upper edge of the coal seam 1 from the ground surface 3, it gradually deflects horizontally, forming a non-vertical channel in the coal seam 1. The coordinates of the non-vertical channel extending a certain distance in the coal seam 1 are used as the target point. Similarly, the ground surface 3 vertically passes through the overburden 2 and the upper edge of the coal seam, and gradually deflects from the coal seam toward the target point until it penetrates, thus forming a conversion channel 4.
[0056] The conversion tube 7 extends from the surface 3 into the coal seam within the conversion channel 4. One end of the conversion tube 7 is connected to the conversion tube drive unit 10 and injection unit 11 at the surface 3, while the other end is connected to the high-energy device 9 at the surface 3 before being lowered into the coal seam. An injection pipe 8 is located within the conversion tube 7 and is coaxial with the injection pipe 8. The injection pipe 8 houses the reaction medium injection pipe 8, the cooling medium injection pipe 8, and the power cables required by the high-energy device 9. The injection pipe 8, along with the conversion tube 7, connects to the conversion tube drive unit 10 and injection unit 11, as well as the high-energy device 9.
[0057] The conversion tube drive device 10 is connected to one end of the conversion tube 7, and the injection device 11 is connected to the conversion tube drive device 10 and communicates with the injection pipe 8 in the conversion tube 7. The injection device 11 is provided with multiple reaction medium injection ports, cooling medium injection ports, power cables and corresponding valves, switches, etc.
[0058] The recovery pipe 12 is located within the conversion channel 4. One end of the recovery pipe 12 is connected to a recovery device 16 and a recovery pipe drive 17 at the surface (3). The other end extends into the coal seam. A comprehensive testing device 15 is located within the surface portion of the recovery pipe 12. The recovery device 16 is located within the recovery pipe drive and connected to the outlet at the surface (3) end of the recovery pipe 12. The recovery device 16 is equipped with one to three outlet valves, which can be adjusted manually or automatically. The recovery pipe drive 17 is integrated with the recovery device 16 and connected to the surface (3) end of the recovery pipe 12.
[0059] After the conversion channel 4 is machined and all components are installed according to the construction and installation methods, the high-energy device 9 is debugged at the surface 3, testing the flow of reaction medium and cooling medium. The power is turned on to test startup and the reaction medium flow and power adjustments for normal operation. The high-energy device 9 is lowered into the conversion channel 4 via the conversion tube drive device 10 and extended into the coal seam, extending 5 to 50 meters horizontally from the vertical section on one side of the recovery pipe 12. The recovery pipe 12 is then lowered by the recovery pipe drive device 17 to the upper edge of the coal seam, 0.5 to 2 meters below.
[0060] 2) Initiation of conversion reaction
[0061] A predetermined flow rate of reaction medium is injected through injection device 11, and flow rate data is fed back from integrated testing device 15 to confirm whether conversion channel 4 and recovery pipe 12 are unobstructed. After confirming that conversion channel 4 and recovery pipe 12 are unobstructed, injection device 11 injects reaction medium and cooling medium, and the power switch of high-energy device 9 is turned on to start the high-energy device 9.
[0062] Feedback from the integrated testing device 15 indicates that when the volume percentage of CO2 in the gas at the outlet of the recovery pipe 12, excluding the injected inert gases (N2, CO2, etc.), exceeds 10%, the coal seam conversion reaction has begun. The reaction medium flow rate and the power of the high-energy device 9 are gradually adjusted to maintain the load of the high-energy device 9 between 10% and 50%, and normal coal seam conversion production begins.
[0063] 3) Main operations of the conversion process
[0064] According to the situation corresponding to the test data feedback in Table 1, the corresponding control method is operated to enable the underground coal to convert thermal energy efficiently and stably in situ.
[0065] During the conversion process, focus on the temperature feedback from the temperature measuring device 14 and the gas flow rate from the comprehensive testing device 15. When the temperature feedback from the temperature measuring device 14 is around 1000°C and the flow rate from the comprehensive testing device 15 is at least 1.1 times the reaction medium injection rate, this indicates normal coal seam conversion production and the proper distance between the recovery pipe 12 and the high-energy device 9.
[0066] During the production process, if the feedback temperature of the temperature measuring device 14 is lower than 1000°C, and the feedback flow rate of the comprehensive testing device 15 remains at least 1.1 times the reaction medium injection flow rate, it indicates that the recovery pipe 12 is too far away from the high-energy device 9. The recovery pipe 12 is moved toward the high-energy device 9 until the feedback temperature of the temperature measuring device 14 is around 1000°C. Then, the pipe 12 is stopped and normal coal seam conversion production begins.
[0067] For example, after a period of normal production, when the feedback temperature of the temperature measuring device 14 is still around 1000°C, but the feedback flow of the comprehensive testing device 15 continues to decrease, it indicates that the conversion reaction intensity of the coal seam decreases as the reaction cavity increases. At this time, it is necessary to increase the reaction medium injection flow rate and the power of the high-energy device 9 to increase the conversion reaction load to 60% to 100%;
[0068] If, after a period of normal production, the temperature feedback from the temperature measuring device 14 and the flow rate feedback from the comprehensive testing device 15 both begin to decrease, it indicates that the coal seam between the high-energy device 9 and the recovery pipe 12 has been converted. Keep the high-energy device 9 activated and move the conversion pipe 75 to 50 meters backward. After the conversion pipe 7 is completely withdrawn, the recovery pipe 12 is extended forward 125 to 50 meters accordingly to continue coal seam conversion production.
[0069] If the temperature feedback from the temperature measuring device 14 is above 1000°C and continues to rise, while the flow feedback from the comprehensive testing device 15 remains basically stable, it indicates that the recovery pipe 12 is too close to the high-energy device 9. To protect the recovery assembly 6, the recovery pipe 12 is gradually withdrawn until the temperature feedback from the temperature measuring device 14 stabilizes at around 1000°C, and coal seam conversion production can continue.
[0070] If the feedback temperature of the temperature measuring device 14 and the feedback flow of the comprehensive testing device 15 continue to increase, it indicates that the reaction intensity in this section is too large. In order to maintain a stable supply of thermal energy products, the reaction medium injection flow and the power of the high-energy device 9 are gradually reduced until the feedback temperature of the temperature measuring device 14 stabilizes at around 1000°C and the feedback flow of the comprehensive testing device 15 remains in the normal range, and the coal seam conversion production continues.
[0071] 4) Production end operation
[0072] Production is adjusted in this cycle. When the horizontal travel distance of the conversion tube drive unit 10 and the recovery tube drive unit 17 approaches the non-vertical distance of the conversion channel 4, conversion of the overlying coal seam in that unit is complete. The high-energy device 9 is powered off, reaction medium injection is stopped, while cooling medium injection is maintained. The conversion tube 7 and recovery tube 12 are then withdrawn to the surface 3. This completes production. Following the above procedure, construction, installation, and conversion production are continued in another target coal seam block.
[0073] Finally, it should be noted that the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making any creative work are within the scope of protection of this application.
[0074] The above description is merely illustrative of certain exemplary embodiments of the present invention. It goes without saying that those skilled in the art will be able to modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and description are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.
Claims
1. A coal seam in-situ plasma conversion thermal energy system, characterized in that: include: Conversion channel, conversion component and harvesting component; The conversion channel includes: a first vertical channel, a second vertical channel and a non-vertical channel; The first vertical channel and the second vertical channel are formed by passing through the overburden and the upper edge of the coal seam in a vertical direction respectively, and the non-vertical channel is formed by the first vertical channel and the second vertical channel gradually deflecting and penetrating in a horizontal direction; One end of the conversion assembly passes through the first vertical channel and extends into the non-vertical channel. The end of the conversion assembly located in the non-vertical channel is connected to a high-energy device. A reaction medium injection pipe for supplying reaction medium to the high-energy device is enclosed in the conversion assembly. The high-energy device is used to generate high-temperature and highly active oxygen-containing component particles from the reaction medium to convert the coal seam into hot gas. One end of the collection component passes through the second vertical channel and extends into the non-vertical channel, and is spaced a preset distance from the high-energy device for collecting hot gas; the other end of the collection component is used to connect to an external gas storage unit.
2. The coal seam in-situ plasma conversion thermal energy system according to claim 1, characterized in that: The conversion assembly includes: a conversion tube, a conversion tube driving device and an injection device; The conversion tube is arranged in the conversion channel, one end of the conversion tube is located outside the first vertical channel and is connected to the conversion tube driving device and the injection device, and the other end of the conversion tube extends into the non-vertical channel and is connected to the high-energy device; A coaxial injection pipe is provided in the conversion tube, and the reaction medium injection pipe, the cooling medium injection pipe and the power cable are wrapped in the injection pipe; the conversion tube drive device is provided on the surface to controllably move the conversion tube, and the injection device is used to control the injection amount of the reaction medium and the inlet and outlet flow of the cooling medium.
3. The coal seam in-situ plasma conversion thermal energy system according to claim 2, characterized in that: The recovery assembly includes: a recovery pipe, a recovery device and a recovery pipe driving device; One end of the recovery pipe is connected to the recovery device and the recovery pipe driving device on the surface, and the other end of the recovery pipe extends into the coal seam through the second vertical channel and has an open end. The recovery pipe drive device is installed on the ground to controllably move the recovery pipe. The recovery device is installed in the recovery pipe drive device and is connected to the surface outlet of the recovery pipe. The recovery device is provided with a plurality of outlet valves for outputting the hot gas. The outlet valves are connected to the gas storage unit through pipelines.
4. The coal seam in-situ plasma conversion thermal energy system according to claim 3, characterized in that: The recovery assembly further comprises a temperature measuring device, which is arranged inside the recovery pipe and is used to monitor the temperature distribution of the coal seam and the hot gas in the recovery pipe.
5. The coal seam in-situ plasma conversion thermal energy system according to claim 4, characterized in that: The recovery assembly further comprises a comprehensive testing device, which is arranged at the surface portion of the recovery pipe and is used to test the flow rate, composition and pressure parameters of the recovered hot gas.
6. The coal seam in-situ plasma conversion thermal energy system according to claim 1, characterized in that: The high-energy device includes a plasma generator or a high-energy burner.
7. The coal seam in-situ plasma conversion thermal energy system according to claim 3, characterized in that: The conversion tube driving device drives the conversion tube to perform forward and backward movements with a moving accuracy of 0.1 m; the recovery tube driving device drives the recovery tube to perform forward and backward movements with a moving accuracy of 0.1 m.
8. The coal seam in-situ plasma conversion thermal energy system according to claim 3, characterized in that: The number of the outlet valves is 1 to 3, and the recovery pipe is lowered by the recovery pipe driving device to 0.5m to 2m below the upper edge of the coal seam.
9. The coal seam in-situ plasma conversion thermal energy system according to claim 3, characterized in that: The outside of the recovery pipe is covered with a heat-insulating layer, and the inside of the recovery pipe is provided with a heating interlayer.
10. The coal seam in-situ plasma conversion thermal energy system according to claim 9, characterized in that: The heating interlayer is a hot gas annular interlayer or a heating wire interlayer wrapping a resistance heating wire.