Coal seam plasma gasification system and method

Abstract

A coal seam plasma gasification system and method, in which a conversion channel vertically passes through the overburden and the upper edge of the coal seam from the ground and then gradually deflects horizontally to form a non-vertical channel in the coal seam, and the non-vertical channel extends a certain distance in the coal seam, and the other side vertically passes through the overburden and the coal seam from the ground and is connected to the non-vertical channel; one end of the reaction tube is connected to the reaction tube driving device and the injection device on the ground, and the other end in the non-vertical channel is connected to the plasma generator, and the plasma generator generates high-temperature and high-activity particles through the reaction medium provided by the injection tube to convert the coal seam into coal gas; the collection and conversion channels are connected to collect coal gas, and a comprehensive testing device is arranged on the ground part of the collection pipe to test the composition, temperature and pressure of the collected coal gas, and a flow testing device is arranged on the ground part of the collection pipe to test the collected coal gas flow. This system realizes efficient and flexible in-situ gasification control of coal seams.

Description

Technical Field

[0001] The present invention relates to the technical field of coal bed gasification, and in particular to a coal bed plasma gasification system and method. Background Art

[0002] The in-situ coal seam gasification technology integrates well construction, coal mining and conversion, transforming physical coal mining into chemical coal mining, that is, converting high-molecular-weight solid coal into low-molecular-weight synthetic gas and methane, etc., eliminating the process of mechanical mining, transportation, washing and furnace construction during utilization, and thus has the advantages of good safety, low investment, high efficiency, low pollution and high benefits. At present, hydrogen, methane and other gases produced by coal seam gasification can be used as fuel after being purified and separated on the ground. More often, synthetic gas is used as the main raw material to synthesize coal-based high-value products such as methane, methanol and ethylene glycol, or the carbon monoxide in the synthetic gas is converted into hydrogen to produce hydrogen products. In this production process, a conversion device must be set up on the ground to control the ratio of hydrogen and carbon monoxide to meet the synthesis or production needs of the target product. This directly improves the process and complexity of the ground gas treatment system, increases investment and operating costs, and reduces the cost advantage of in-situ coal seam gasification.

[0003] In principle, coal seam in-situ gasification can adjust the composition of the outlet gas by changing the composition and flow rate of the injected gasifier. However, the traditional coal seam in-situ combustion or gasification method is the autothermal reaction and semi-natural force control of the underground dense coal seam and the oxygen-containing gasifier. At the same time, it is significantly affected by the influx of groundwater from the coal seam roof, resulting in large fluctuations in the gas composition and output, slow and difficult regulation, low conversion efficiency, and low production intensity, which has a serious impact on the synthesis of the target product on the ground, and may even make it impossible to stabilize production. Therefore, the traditional coal seam in-situ gasification adopts the method of adding a change device on the ground to adjust the gas composition to meet the synthesis requirements of the target product.

[0004] Therefore, the current coal seam in-situ gasification has the problems of long process, complex operation, high investment and operation costs for the synthesis of target products. Based on this, a new coal seam gasification method is urgently needed to efficiently and flexibly control the composition of coal gas to meet the stable production needs of modern coal-based high-value products.

[0005] The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0006] The purpose of the present invention is to provide a coal seam plasma gasification system and method, which can simultaneously input different types of gasifying agents, and control the injection flow and composition of the gasifying agents, produce high-temperature and high-activity particles in different proportions, and further cause controllable gas-solid reactions and gas-gas reactions in the coal seam to be converted into hydrogen and carbon monoxide gases in different proportions. It realizes efficient and flexible in-situ gasification regulation of coal seams, can directly produce coal gas that meets the synthesis needs of coal-based high-value products, shortens the process of the ground coal gas treatment system, reduces investment and operating costs, and further improves the cost advantage of in-situ coal seam gasification. In order to achieve the above purpose, the present invention provides the following technical solutions:

[0007] A coal seam plasma gasification system of the present invention comprises:

[0008] The conversion channel vertically passes through the overburden and the upper edge of the coal seam from the ground and then gradually deflects to the horizontal direction to form a non-vertical channel in the coal seam. The non-vertical channel extends a certain distance in the coal seam, and the other side is vertically passed through the overburden and the coal seam from the ground to communicate with the non-vertical channel;

[0009] React components, which include,

[0010] A reaction tube is arranged in the conversion channel, one end of the reaction tube is connected to a reaction tube driving device and an injection device on the ground, and the other end in the non-vertical channel is connected to a plasma generator, and a coaxial injection tube is arranged in the reaction tube.

[0011] A reaction tube driving device is arranged on the ground to controllably move the reaction tube.

[0012] The injection device is connected to the reaction tube driving device and the injection tube to control the injection amount of gaseous and liquid reaction media and the flow rate of the cooling medium inlet loop. The injection device is provided with a plurality of reaction medium injection ports, cooling medium injection ports, power cables and corresponding valves and switches.

[0013] A plasma generator, which generates high-temperature and high-activity particles through a reaction medium provided by an injection pipe to convert a coal seam into coal gas, the plasma generator comprising:

[0014] Plasma generator body;

[0015] The cathode assembly is arranged in the plasma generator body, and the cathode assembly includes:

[0016] The cathode head is a hollow metal part.

[0017] The cathode rod is a hollow tube for conducting electricity and cooling the cathode head. One end of the cathode rod is connected to the cathode terminal, and the other end is threadedly connected to the cathode head.

[0018] The cathode coolant injection pipe passes through the cathode rod and goes deep into the cathode head so that the cathode head is filled with coolant to reduce the temperature.

[0019] A cathode coolant return pipe connected to the cathode rod allows the coolant after heat exchange to return through the cathode coolant return pipe, thereby realizing coolant circulation injection;

[0020] The reaction medium injection assembly is arranged in the plasma generator body, and the reaction medium injection assembly includes:

[0021] The gaseous reaction medium chamber comprises an injection end located on the left side of the plasma generator body and an outlet end flush with the left side of the cathode head. The gaseous reaction medium chamber gradually narrows from the injection end to the outlet end and is in a bell-mouth shape, so that the pressure of the gaseous reaction medium in the gaseous reaction medium chamber gradually increases due to the gradual reduction in volume. The injection end is provided with a gaseous reaction medium injection port.

[0022] a medium outlet connected to the outlet end and causing the volume of the gaseous reaction medium from the gaseous reaction medium chamber to increase sharply and the gas pressure to decrease to generate a pressure difference,

[0023] The liquid medium cavity is located between the gaseous reaction medium cavity and the outer annulus of the anode, and is in the shape of a right triangle with the gaseous reaction medium cavity. The liquid medium cavity is provided with at least one liquid medium capillary on one side of the gaseous reaction medium cavity, and a liquid medium injection port for injecting liquid medium is provided on the left side of the liquid medium cavity. The liquid medium injection port is located on the upper and lower sides of the reaction medium injection assembly and is connected with the liquid medium cavity. The liquid medium from the liquid medium capillary is discharged from the medium outlet via the pressure difference.

[0024] An atomizing plate is fixed on the cathode rod and arranged at the medium outlet to cooperate with the gaseous reaction medium to atomize the liquid medium to form atomized droplets, and the atomized droplets diffuse between the cathode and the anode along with the gaseous reaction medium;

[0025] The anode assembly is arranged in the plasma generator body, and the anode assembly includes:

[0026] The anode head is connected to the right end of the plasma generator body by threads or bolts, and an annulus is arranged outside the anode head.

[0027] The anode terminal is electrically connected to the anode head, and the discharge between the anode head and the cathode head ionizes the gaseous reaction medium and the atomized droplets to generate high-temperature and high-activity plasma.

[0028] an anode coolant injection pipe connected to one side of the annulus to introduce coolant into the annulus to cool the anode head,

[0029] an anode coolant return pipe, which is connected to the other side of the annulus to reflux the coolant after heat exchange, so as to realize coolant circulation injection;

[0030] A harvesting assembly comprising,

[0031] A recovery pipe connected to the conversion channel to collect coal gas,

[0032] Comprehensive testing equipment, which is installed on the ground part of the recovery pipe to test the recovered gas composition, temperature and pressure,

[0033] The flow testing device is installed on the ground part of the recovery pipe to test the flow of recovered gas.

[0034] In the coal seam plasma gasification system, the plasma generator is a multi-media injection plasma generator that simultaneously inputs different types of gasifying agents and controls the injection flow and composition of the gasifying agents, which produces high-temperature and high-activity particles in different proportions to produce controllable gas-solid reactions and gas-gas reactions in the coal seam to be converted into hydrogen and carbon monoxide gases in different proportions.

[0035] In the coal seam plasma gasification system, a multi-media injection plasma generator injects carbon dioxide and liquid water, or hydrogen and liquid water.

[0036] In the coal seam plasma gasification system, the gaseous reaction medium injection port is evenly arranged in two or more groups with the cathode rod as the symmetry axis and is located on the left side of the gaseous reaction medium cavity for evenly inputting the gaseous reaction medium into the gaseous reaction medium cavity.

[0037] In the coal seam plasma gasification system, two or more capillaries from the liquid medium are evenly distributed along the gaseous reaction medium cavity, and a baffle is arranged between the left side of the liquid medium cavity and the liquid medium injection port to prevent liquid reflux.

[0038] In the coal seam plasma gasification system, the cathode coolant injection pipe, the cathode coolant return pipe, the anode coolant injection pipe and the anode coolant return pipe are connected to the cooling medium injection port, and the gaseous reaction medium injection port and the liquid medium injection port are respectively connected to the reaction medium injection port.

[0039] In the coal seam plasma gasification system, the injection device includes a gas medium injection device and a liquid medium injection device.

[0040] In the coal seam plasma gasification system, the reaction tube driving device is connected to one end of the reaction tube to move the reaction tube by extending and retracting, and the moving distance is accurate to 0.1m.

[0041] The conversion method of the coal seam plasma gasification system includes:

[0042] After vertically passing through the overburden and the upper edge of the coal seam from the ground, it gradually deflects horizontally to form a non-vertical channel in the coal seam. The non-vertical channel extends a certain distance in the coal seam. The other side vertically passes through the overburden and the coal seam from the ground and connects with the non-vertical channel to form a conversion channel. The reaction tube extends from the ground into the coal seam in the conversion channel. One end of the reaction tube is connected to the reaction tube driving device and the injection device on the ground, and the other end is connected to the plasma generator on the ground and lowered to the coal seam. The plasma generator is lowered to the conversion channel through the reaction tube driving device and extended to the coal seam until the horizontal distance of the recovery pipe is 5~50m;

[0043] A certain amount of carbon dioxide is injected by the gas medium injection device to start the plasma generator. When the volume percentage of carbon monoxide in the outlet gas is higher than 5%, it indicates that the coal seam has started to gasify. The gas medium injection device and the liquid medium injection device are used to control the gas medium and liquid medium injection flow rates respectively, and the gas medium and liquid medium injection amounts and the plasma generator power are gradually adjusted to keep the plasma generator load between 10% and 50%, and then the coal seam gasification production begins.

[0044] For example, after a period of normal production, when the flow test device feeds back that the outlet gas flow rate continues to decrease, it indicates that as the reaction cavity of the coal seam increases, the conversion reaction intensity decreases. The reaction medium injection flow rate and the plasma generator power are increased to increase the conversion reaction load to 60%~100%. After continuing production for a period of time, the flow test device feeds back that the flow rate further decreases, indicating that the conversion of the coal seam covered between the plasma generator and the recovery tube is complete. The plasma generator is kept started and the reaction tube is withdrawn 5~50m. After the reaction tube is withdrawn, the coal seam conversion production is continued. The production is adjusted in this cycle. When the moving distance of the reaction tube drive device is close to the non-vertical section distance of the conversion channel, the plasma generator power is turned off, the reaction medium injection is stopped, the cooling medium injection is maintained, and the reaction tube and the recovery tube are withdrawn to the ground respectively.

[0045] In the above technical scheme, a coal seam plasma gasification system and method provided by the present invention has the following beneficial effects: in view of the long process, complex operation, high investment and operation cost of the current coal seam in-situ gasification for the target product synthesis needs, a multi-media injection plasma generator for underground coal seam gasification conditions can simultaneously input different types of gasifying agents, and control the injection flow and composition of the gasifying agents to produce different proportions of high-temperature and high-activity particles, and further controllable gas-solid reaction and gas-gas reaction occur in the coal seam, which are converted into different proportions of hydrogen and carbon monoxide gas, with sensitive regulation, high conversion efficiency, high production intensity, few by-products, and environmental friendliness. In view of the underground coal seam gasification conditions, carbon dioxide and liquid water can be injected at the same time, and the injection ratio of carbon dioxide and liquid water can be flexibly regulated, so as to realize the efficient and flexible gasification regulation of the coal seam in-situ, and directly produce coal gas that meets the synthesis needs of coal-based high-value products, shorten the process of the ground coal gas treatment system, reduce investment and operation costs, have strong operability, can ensure the stable synthesis of coal-based high-value products, and further improve the cost advantage of coal seam in-situ gasification. It can be used for the development and utilization of carbon-based energy such as coal, peat, oil shale, and heavy oil layers. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. 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.

[0047] Figure 1 A schematic structural diagram of a plasma generator of a coal seam plasma gasification system provided in one embodiment of the present invention.

[0048] Figure 2 A schematic structural diagram of a coal seam plasma gasification system provided in accordance with an embodiment of the present invention.

[0049] Description of reference numerals:

[0050] 1. Plasma generator body; 2. Reaction medium injection assembly; 3. Cathode assembly; 4. Anode assembly; 5. Gaseous reaction medium cavity; 6. Medium outlet; 7. Liquid medium cavity; 8. Liquid medium capillary; 9. Gaseous reaction medium injection port; 10. Liquid medium injection port; 11. Atomizing plate; 12. Cathode rod; 13. Cathode head; 14. Cathode terminal; 15. Cathode coolant injection pipe; 16. Cathode coolant return pipe; 17. Anode head; 18. Anode terminal; 19. Anode coolant injection pipe; 20. Anode coolant return pipe; 21. Coal seam; 22. Conversion channel; 23. Covering layer; 24. Ground; 25. Reaction assembly; 26. Recovery assembly; 27. Reaction tube; 28. Injection pipe; 29. ​​Plasma generator; 30. Reaction tube drive device; 31. Gas medium injection device; 32. Liquid medium injection device; 33. Recovery tube; 34. Comprehensive testing device; 35. Flow testing device. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, 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 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 creative work are within the scope of protection of the present invention.

[0052] 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 invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0054] 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 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 referred device or element 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.

[0055] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0056] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0058] 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.

[0059] See also Figure 1-2 As shown, in one embodiment, a coal seam plasma gasification system of the present invention includes:

[0060] The conversion channel 22 vertically passes through the overburden 23 and the upper edge of the coal seam 21 from the ground 24 and then gradually deflects to the horizontal direction to form a non-vertical channel in the coal seam 21. The non-vertical channel extends a certain distance in the coal seam, and the other side is vertically passed through the overburden 23 and the coal seam by the ground 24 to communicate with the non-vertical channel;

[0061] A reaction assembly 25, comprising,

[0062] The reaction tube 27 is arranged in the conversion channel 22. One end of the reaction tube 27 is connected to the reaction tube driving device 30 and the injection device on the ground, and the other end in the non-vertical channel is connected to the plasma generator 29. A coaxial injection pipe 28 is arranged in the reaction tube 27. The injection pipe 28 contains a reaction medium injection pipe, a cooling medium injection pipe and a power cable.

[0063] The reaction tube driving device 30 is disposed on the ground to controllably move the reaction tube 27.

[0064] The injection device is connected to the reaction tube driving device 30 and the injection tube 28 to control the injection amount of gaseous and liquid reaction media and the flow rate of the cooling medium inlet loop. The injection device is provided with a plurality of reaction medium injection ports, cooling medium injection ports, power cables and corresponding valves and switches.

[0065] A plasma generator 29, which generates high-temperature and highly active particles from a reaction medium provided via an injection pipe 28 to convert the coal seam into coal gas;

[0066] The harvesting assembly 26 comprises,

[0067] The recovery pipe 33 is connected to the conversion channel 22 to collect coal gas.

[0068] The comprehensive testing device 34 is installed on the ground part of the recovery pipe 33 to test the composition, temperature and pressure of the recovered gas.

[0069] The flow rate testing device 35 is installed on the ground portion of the recovery pipe 33 to test the flow rate of the recovered gas.

[0070] In a preferred embodiment of the coal seam plasma gasification system, the plasma generator 29 is a multi-media injection plasma generator that simultaneously inputs different types of gasifying agents and controls the injection flow and composition of the gasifying agents, which produces high-temperature and high-activity particles in different proportions to produce controllable gas-solid reactions and gas-gas reactions in the coal seam to be converted into hydrogen and carbon monoxide gases in different proportions.

[0071] In a preferred embodiment of the coal seam plasma gasification system, the multi-media injection plasma generator injects carbon dioxide and liquid water, or hydrogen and liquid water.

[0072] In a preferred embodiment of the coal seam plasma gasification system, the plasma generator 29 comprises:

[0073] Plasma generator body 1;

[0074] The cathode assembly 3 is arranged in the plasma generator body 1, and the cathode assembly 3 includes:

[0075] The cathode head 13 is a hollow metal part.

[0076] The cathode rod 12 is a hollow tube for conducting electricity and cooling the cathode head 13. One end of the cathode rod 12 is connected to the cathode terminal 14, and the other end is threadedly connected to the cathode head 13.

[0077] The cathode coolant injection pipe 15 passes through the cathode rod 12 and penetrates into the cathode head 13 so that the cathode head 13 is filled with coolant to reduce the temperature.

[0078] A cathode coolant return pipe 16 connected to the cathode rod 12 allows the coolant after heat exchange to return through the cathode coolant return pipe 16 to achieve coolant circulation injection;

[0079] The reaction medium injection assembly 2 is arranged in the plasma generator body 1, and the reaction medium injection assembly 2 includes:

[0080] The gaseous reaction medium chamber 5 includes an injection end located on the left side of the plasma generator body 1 and an outlet end flush with the left side of the cathode head 13. The gaseous reaction medium chamber 5 gradually narrows from the injection end to the outlet end and is in a bell-mouth shape, so that the gaseous reaction medium in the gaseous reaction medium chamber 5 gradually increases in pressure due to the gradual reduction in volume. The injection end is provided with a gaseous reaction medium injection port 9.

[0081] The medium outlet 6 is connected to the outlet end and causes the volume of the gaseous reaction medium from the gaseous reaction medium chamber 5 to increase sharply and the gas pressure to decrease to generate a pressure difference.

[0082] The liquid medium chamber 7 is located between the gaseous reaction medium chamber 5 and the outer annulus of the anode, and is in the shape of a right triangle with the gaseous reaction medium chamber 5. The liquid medium chamber 7 is provided with at least one liquid medium capillary 8 on one side of the gaseous reaction medium chamber 5. A liquid medium injection port 10 for injecting liquid medium is provided on the left side of the liquid medium chamber 7. The liquid medium injection port 10 is located on the upper and lower sides of the reaction medium injection assembly 2 and is connected to the liquid medium chamber 7. The liquid medium from the liquid medium capillary 8 is discharged from the medium outlet 6 via the pressure difference.

[0083] Atomizing plate 11, which is fixed on cathode rod 12 and arranged at medium outlet 6 to cooperate with gaseous reaction medium to atomize liquid medium to form atomized droplets, and atomized droplets diffuse to between cathode and anode along with gaseous reaction medium;

[0084] The anode assembly 4 is arranged in the plasma generator body 1, and the anode assembly 4 includes:

[0085] The anode head 17 is connected to the right end of the plasma generator body 1 by threads or bolts, and an annulus is arranged outside the anode head 17.

[0086] The anode terminal 18 is electrically connected to the anode head 17. The anode head 17 and the cathode head 13 discharge and ionize the gaseous reaction medium and the atomized droplets to generate high-temperature and high-activity plasma.

[0087] Anode coolant injection pipe 19, which is connected to one side of the annulus to introduce coolant into the annulus to cool the anode head 17,

[0088] The anode coolant return pipe 20 is connected to the other side of the annulus to return the coolant after heat exchange to achieve coolant circulation injection.

[0089] In a preferred embodiment of the coal seam plasma gasification system, the gaseous reaction medium injection port 9 is evenly arranged in two or more groups with the cathode rod 12 as the symmetry axis and is located on the left side of the gaseous reaction medium chamber 5 for evenly inputting the gaseous reaction medium into the gaseous reaction medium chamber 5.

[0090] In a preferred embodiment of the coal seam plasma gasification system, two or more liquid medium capillaries 8 are evenly distributed along the gaseous reaction medium cavity 5, and a baffle is provided between the left side of the liquid medium cavity 7 and the liquid medium injection port 10 to prevent liquid reflux.

[0091] In a preferred embodiment of the coal seam plasma gasification system, the cathode coolant injection pipe 15, the cathode coolant return pipe 16, the anode coolant injection pipe 19 and the anode coolant return pipe 20 are connected to the cooling medium injection port, and the gaseous reaction medium injection port 9 and the liquid medium injection port 10 are respectively connected to the reaction medium injection port.

[0092] In a preferred embodiment of the coal seam plasma gasification system, the injection device includes a gas medium injection device 31 and a liquid medium injection device 32 .

[0093] In a preferred embodiment of the coal seam plasma gasification system, the reaction tube driving device 30 is connected to one end of the reaction tube 27 to move the reaction tube 27 by extending and retracting, and the moving distance is accurate to 0.1m.

[0094] The conversion method of the coal seam plasma gasification system includes:

[0095] After vertically passing through the overburden 23 and the upper edge of the coal seam 21 from the ground 24, it gradually deflects horizontally to form a non-vertical channel in the coal seam. The non-vertical channel extends a certain distance in the coal seam. On the other side, the ground 24 vertically passes through the overburden 23 and the coal seam 21 and communicates with the non-vertical channel to form a conversion channel 22. The reaction tube 27 extends from the ground into the coal seam in the conversion channel 22. One end of the reaction tube 27 is connected to the reaction tube driving device 30 and the injection device on the ground, and the other end is connected to the plasma generator 29 on the ground and lowered to the coal seam 21. The plasma generator 29 is lowered to the conversion channel 22 through the reaction tube driving device 30 and extends to the coal seam until the horizontal distance of the recovery pipe 33 is 5 to 50 m.

[0096] A certain amount of carbon dioxide is injected by the gas medium injection device 31, and the plasma generator 29 is started. When the volume percentage of carbon monoxide in the outlet coal gas is higher than 5%, it indicates that the coal seam has started to gasify. The gas medium injection device 31 and the liquid medium injection device 32 respectively control the injection flow of the gas medium and the liquid medium, and gradually adjust the injection amount of the gas medium and the liquid medium and the power of the plasma generator 29 to keep the load of the plasma generator 29 between 10% and 50%, and start the coal seam gasification production.

[0097] For example, after a period of normal production, when the flow test device 35 reports that the outlet gas flow rate continues to decrease, it indicates that as the reaction cavity of the coal seam increases, the conversion reaction intensity decreases. The reaction medium injection flow rate and the power of the plasma generator 29 are increased to increase the conversion reaction load to 60%~100%. After a period of continued production, the flow test device 35 reports that the flow rate further decreases, indicating that the coal seam covered between the plasma generator 29 and the recovery pipe 33 has been converted. The plasma generator 29 is kept started and the reaction pipe 27 is withdrawn for about 5~50m. After the reaction pipe 27 is withdrawn, the coal seam conversion production is continued. The production is adjusted in this cycle. When the movement distance of the reaction tube driving device 30 is close to the non-vertical section distance of the conversion channel 22, the power of the plasma generator 29 is turned off, the injection of the reaction medium is stopped, the injection of the cooling medium is maintained, and the reaction pipe 27 and the recovery pipe 33 are withdrawn to the ground respectively.

[0098] In one embodiment, the multi-media injection plasma generator 29 can simultaneously input different types of gasifying agents, and control the injection flow and composition of the gasifying agents to produce high-temperature and highly active particles in different proportions, and further controllable gas-solid reaction and gas-gas reaction occur in the coal seam, which are converted into hydrogen and carbon monoxide gas in different proportions. It can realize efficient and flexible gasification control of the coal seam in situ, and directly produce coal gas that meets the synthesis requirements of coal-based high-value products.

[0099] The gas-solid reaction is mainly:

[0100] C + H 2O = CO + H 2 (1)

[0101] C + CO 2 = 2CO(2)

[0102] That is, the carbon element in the coal seam undergoes a gas-solid reaction with high-temperature and highly active water vapor and carbon dioxide particles, mainly converting into carbon monoxide and hydrogen.

[0103] The gas-gas reaction is mainly:

[0104] (3)

[0105] The gas-gas reaction is mainly a water-gas shift reaction as shown in formula (3), which is a reversible reaction and is affected by the concentrations of carbon monoxide and water vapor as well as carbon dioxide and hydrogen in the gas flow channel and the gasification cavity. Excess water vapor can be generated by injecting excess liquid water, so that carbon monoxide and water vapor react to generate carbon dioxide and hydrogen, and the reaction formula (3) continues to occur in the positive direction. In addition, gas-gas reactions are easier to occur than gas-solid reactions. Based on the above reaction characteristics, synthesis gas with different ratios of hydrogen and carbon monoxide can be produced by adjusting the ratio of carbon dioxide and liquid water injected into the multi-media plasma generator.

[0106] The plasma generator 29 includes a plasma generator body, a cathode assembly 3, an anode assembly 4 and a reaction medium injection assembly 2. The multi-media injection plasma generator can inject carbon dioxide and liquid water, or hydrogen and liquid water into the reaction medium injection assembly 2, and the gaseous reaction medium atomizes the liquid water and diffuses it between the cathode and the anode, and under the action of high-voltage ionization, high-temperature and high-activity active particles are generated, and active particles of different compositions react in series with the coal seam to produce synthesis gas with different hydrogen-carbon ratios.

[0107] The outer shell of the plasma generator body is made of steel, copper, alloy or other composite materials, and has high temperature resistance and corrosion resistance. According to the coal bed gasification process design, the diameter of the plasma generator body 1 can be 5-10 cm and the length can be 60-200 cm;

[0108] The reaction medium injection assembly 2 includes a gaseous reaction medium chamber 5, a medium outlet 6, a liquid medium chamber 7, a liquid medium capillary 8, a gaseous reaction medium injection port 9, a liquid medium injection port 10 and an atomizing plate 11. The gaseous reaction medium chamber 5 gradually shrinks from the injection end to the outlet end, and is in a trumpet shape. The injection end of the gaseous reaction medium chamber 5 is located on the left side of the plasma generator body 1, and the outlet end is flush with the left side of the cathode head 13. The pressure of the gaseous reaction medium gradually increases in the gaseous reaction medium chamber 5 due to the gradual reduction of the volume, and the volume rises sharply at the medium outlet 6 end, and the gas pressure decreases, thereby generating a pressure difference, and the liquid in the liquid medium chamber 7 can be discharged from the liquid medium capillary 8 to the medium outlet 6. The liquid medium chamber 7 is located between the gaseous reaction medium chamber 5 and the outer annulus of the anode, and is approximately in a right-angled triangle shape with the gaseous reaction medium chamber 5. A liquid medium capillary 8 is arranged on one side of the gaseous reaction medium chamber 5, and two or more liquid medium capillaries 8 are evenly distributed along the gaseous reaction medium chamber 5. A baffle is arranged between the left side of the liquid medium cavity 7 and the liquid medium injection port 10 to prevent liquid reflux. The gaseous reaction medium injection port 9 is evenly arranged in two or more groups with the cathode rod 12 as the symmetry axis, and is located on the left side of the gaseous reaction medium cavity 5, for evenly inputting the gaseous reaction medium into the gaseous reaction medium cavity 5. The liquid medium injection port 10 is located on the upper and lower sides of the reaction medium injection assembly 2, and is connected to the liquid medium cavity 7. The atomizing plate 11 is fixed on the cathode rod 12, located between the end of the cathode rod 12 and the cathode head 13, and arranged at the medium outlet 6, for cooperating with the gaseous reaction medium to atomize the liquid water medium. The gaseous reaction medium is injected from the gaseous reaction medium injection port 9, and is continuously pressurized in the gaseous reaction medium chamber 5 before being discharged from the medium outlet 6, causing a sudden drop in pressure to form a pressure difference zone; after the liquid medium is injected from the liquid medium injection port 10, it is affected by the pressure difference and is discharged toward the medium outlet 6 along the liquid medium capillary 8; the gaseous reaction medium discharged to the medium outlet 6 is blocked and reflected by the atomizing plate 11 and the anode head 17, and the discharged liquid medium is cut, so that the liquid medium forms atomized small droplets, which then diffuse to between the cathode and the anode along with the gaseous reaction medium.

[0109] The cathode assembly 3 includes a cathode rod 12, a cathode head 13, a cathode terminal 14, a cathode coolant injection pipe 15 and a cathode coolant return pipe 16. The cathode rod 12 is mainly used for conducting electricity and cooling the cathode head 13. One end of the cathode rod 12 is connected to the cathode terminal 14, and the other end is connected to the cathode head 13. The cathode rod 12 is configured as a hollow tube. The coolant is injected into the cathode coolant injection pipe 15 so that the cathode part is filled with coolant to cool the cathode head 13. The coolant after heat exchange flows back through the cathode coolant return pipe 16 to achieve coolant circulation injection. The cathode head 13 is configured as a hollow metal part, and the outer side is connected to the cathode rod 12 by a thread. The cathode coolant injection pipe 15 extends into the cathode head 13 to ensure the cooling effect of the cathode head 13.

[0110] The anode assembly 4 includes a cathode head 13, an anode coolant injection pipe 19, an anode terminal 18, an anode coolant injection pipe 19 and an anode coolant return pipe 20. The anode head 17 is located at the right end of the plasma generator body 1 and is connected by threads or bolts. An annulus is set outside the anode head 17, one side of which extends into the anode coolant injection pipe 19, close to the end of the anode head 17, and an outlet is set on the other side as the anode coolant return pipe 20. The coolant enters the annulus through the anode coolant injection pipe 19 to cool and protect the anode head 17. The coolant after heat exchange flows back through the anode coolant return pipe 20 to realize the circulation injection of the coolant. Discharge occurs between the anode head 17 and the cathode head 13, ionizing the gaseous reaction medium and the atomized droplets to produce high-temperature and high-activity plasma.

[0111] In one embodiment, the coal seam plasma gasification system includes a conversion channel 22, a reaction assembly 25 and a recovery assembly 26. After vertically passing through the overburden 23 and the upper edge of the coal seam from the ground, it gradually deflects to the horizontal direction to form a non-vertical channel in the coal seam, and the non-vertical channel extends a certain distance in the coal seam. On the other side, the ground vertically passes through the overburden 23 and the coal seam and is connected to the non-vertical channel, that is, a conversion channel 22 is formed. The reaction assembly 25 includes a reaction tube 27, an injection tube 28, a plasma generator 29, a reaction tube drive device 30, a gaseous reaction medium injection device and a liquid medium injection device 32. The reaction tube 27 is in the conversion channel 22 and extends from the ground into the coal seam. One end of the reaction tube 27 is connected to the reaction tube drive device 30 and the injection device on the ground, and the other end is connected to the plasma generator 29 on the ground, and is lowered to the coal seam 21. The injection pipe 28 is located in the reaction tube 27 and is coaxial with the injection pipe 28. The injection pipe 28 contains the reaction medium injection pipe, cooling medium injection pipe and power cable required by the plasma generator 29. The injection pipe 28 is connected to the reaction tube driving device 30 and the injection device, and the plasma generator 29 respectively with the reaction tube 27. The reaction tube driving device 30 is connected to one end of the reaction tube 27 and can be used to accurately move the reaction tube 27, including forward extension and backward movement, and the moving distance is accurate to 0.1m. The injection device is connected to the reaction tube driving device 30 and communicated with the injection pipe 28 in the reaction tube 27. The injection device is provided with multiple reaction medium injection ports, cooling medium injection ports, power cables and corresponding valves, switches, etc. Each medium valve and each power switch is manually or automatically adjusted. The injection device is used to accurately control the injection amount of gaseous and liquid reaction media, allocate reaction medium injection components, control the cooling medium inlet circuit flow, and control the start, shutdown and power of the plasma generator 29.

[0112] The collection assembly 26 includes a collection pipe 33, a comprehensive test device 34 and a flow test device 35. The collection pipe 33 is connected to the conversion channel 22, and the collection pipe 33 is provided with a comprehensive test device 34 and a flow test device 35 on the ground. The comprehensive test device 34 is arranged on the ground part of the collection pipe 33, and is used to test the composition, temperature and pressure of the collected coal gas. The comprehensive test device 34 can be used to feedback the underground reaction situation and provide a basis for the regulation of coalbed gasification reaction. The process test device is arranged on the ground part of the collection pipe 33, and is used to test the collected coal gas flow rate, so as to feedback the underground coal seam reaction situation, judge the coal seam reaction situation, and provide a basis for the movement of the reaction tube 27. According to the construction and installation method, the conversion channel 22 is processed and the components are installed. The plasma generator 29 is debugged on the ground, and the reaction medium in and out and the cooling medium in and out circulation are tested. The power is turned on to test the startup and the reaction medium flow and power adjustment are normal. The plasma generator 29 is lowered to the conversion channel 22 through the reaction tube driving device 30, and extended to the coal seam, until the horizontal distance of the recovery pipe 33 is 5 to 50 m. The gas medium injection medium and liquid medium injection device 32 controls the gas medium and liquid medium injection flow rate, starts the plasma generator 29, starts the coal seam gasification reaction, and controls the gas medium and liquid medium injection amount according to the feedback of the outlet coal gas composition from the comprehensive testing device 34, and controls the movement of the reaction tube 27 according to the feedback of the outlet coal gas flow rate from the flow testing device 35.

[0113] In one embodiment, the conversion method comprises,

[0114] 1) Installation

[0115] After vertically passing through the overburden 23 and the upper edge of the coal seam 21 from the ground 24, it gradually deflects to the horizontal direction to form a non-vertical channel in the coal seam. The non-vertical channel extends a certain distance in the coal seam, and the other side vertically passes through the overburden 23 and the coal seam from the ground to connect with the non-vertical channel, thus forming a conversion channel 22 unit.

[0116] The reaction tube 27 extends from the ground into the coal seam in the conversion channel 22. One end of the reaction tube 27 is connected to the reaction tube driving device 30 and the injection device on the ground, and the other end is connected to the plasma generator 29 on the ground and lowered into the coal seam. The injection pipe 28 is located in the reaction tube 27 and is coaxial with the injection pipe 28. The injection pipe 28 contains the reaction medium injection pipe, the cooling medium injection pipe and the power cable required by the plasma generator 29. The injection pipe 28 is connected to the reaction tube driving device 30 and the injection device, and the plasma generator 29 along with the reaction tube 27.

[0117] The reaction tube 27 is in the conversion channel 22, extending from the ground into the coal seam. One end of the reaction tube 27 is connected to the reaction tube driving device 30 and the injection device on the ground, and the other end is connected to the plasma generator 29 on the ground and lowered into the coal seam. The injection pipe 28 is located in the reaction tube 27 and is coaxial with the injection pipe 28. The injection pipe 28 contains the reaction medium injection pipe, the cooling medium injection pipe and the power cable required by the plasma generator 29. The injection pipe 28 is connected to the reaction tube driving device 30 and the injection device, and the plasma generator 29 respectively along with the reaction tube 27. The reaction tube driving device 30 is connected to one end of the reaction tube 27, and the injection device is connected to the reaction tube driving device 30 and communicated with the injection pipe 28 in the reaction tube 27. The injection device is provided with a plurality of reaction medium injection ports, cooling medium injection ports, power cables and corresponding valves, switches, etc.

[0118] The recovery pipe 33 is located in the conversion channel 22. One end of the recovery pipe 33 is connected to the recovery device and the recovery pipe 33 driving device on the ground, and the other end extends into the coal seam. The comprehensive testing device 34 and the flow testing device 35 are arranged on the ground part of the recovery pipe 33 and connected to the ground end outlet of the recovery pipe 33. The recovery pipe 33 is provided with 1 to 3 outlet valves, which can be adjusted manually or automatically.

[0119] According to the construction and installation method, the conversion channel 22 is processed and all components are installed. The plasma generator 29 is debugged on the ground, and the reaction medium in and out and the cooling medium in and out circulation are tested. The power is turned on to test the start-up and reaction medium flow and power adjustment. The plasma generator 29 is lowered to the conversion channel 22 through the reaction tube drive device 30 and extended to the coal seam until the horizontal distance of the recovery pipe 33 is 5 to 50 meters.

[0120] 2) Initiation of conversion reaction

[0121] A certain amount of carbon dioxide is injected by the gas medium injection device 31 to start the plasma generator 29. According to the feedback of the outlet gas composition by the comprehensive testing device 34, when the volume percentage of carbon monoxide in the outlet gas is higher than 5%, it indicates that the coal seam has started gasification reaction. The gas medium injection device 31 and the liquid medium injection device 32 are used to control the gas medium and liquid medium injection flow rates respectively, and the gas medium and liquid medium injection amounts and the plasma generator 29 power are gradually adjusted to keep the plasma generator 29 load between 10% and 50%, and start coal seam gasification production.

[0122] 3) Main operations of gas composition control

[0123] The multi-media injection plasma generator simultaneously inputs different flow rates of carbon dioxide and liquid water to produce high-temperature and high-activity particles in different proportions, which can further control the gas-solid reaction and gas-gas reaction occurring in the coal seam to convert them into hydrogen and carbon monoxide gases in different proportions, directly producing coal gas that meets the synthesis needs of coal-based high-value products.

[0124] The gas-solid reaction is mainly:

[0125] C + H 2 O = CO + H 2 (1)

[0126] C + CO 2 = 2CO(2)

[0127] That is, the carbon element in the coal seam undergoes a gas-solid reaction with high-temperature and highly active water vapor and carbon dioxide particles, mainly converting into carbon monoxide and hydrogen.

[0128] The gas-gas reaction is mainly:

[0129] (3)

[0130] The gas-gas reaction is mainly a water-gas shift reaction as shown in formula (3), which is a reversible reaction and is affected by the concentrations of carbon monoxide and water vapor as well as carbon dioxide and hydrogen in the gas flow channel and the gasification cavity. Excess water vapor can be generated by injecting excess liquid water, so that carbon monoxide and water vapor react to generate carbon dioxide and hydrogen, and the reaction formula (3) continues to occur in the positive direction. In addition, gas-gas reactions are easier to occur than gas-solid reactions. Based on the above reaction characteristics, synthesis gas with different ratios of hydrogen and carbon monoxide can be produced by adjusting the ratio of carbon dioxide and liquid water injected into the multi-media plasma generator.

[0131] Taking methane or methanol as the target synthetic product as an example, the production process generally requires a hydrogen-carbon ratio (volume of hydrogen and carbon monoxide) of about 3. According to production requirements, the molar ratio of carbon dioxide and liquid water injected by the plasma generator 29 needs to be regulated. The carbon dioxide injection flow rate is controlled by the gas medium injection device 31, and the liquid medium injection device 32 controls the liquid water injection flow rate, so that the molar ratio of the injected liquid water and carbon dioxide is about 3. At this time, the gas components produced mainly include hydrogen, carbon monoxide and carbon dioxide, and the volume ratio is about 3:1:2. After the gas is discharged from the ground, it can be separated to obtain a synthesis gas with a hydrogen-carbon ratio of about 3, and the separated carbon dioxide is injected into the plasma generator 29 as a gasifying agent to continue to participate in the reaction. During the production process, according to the feedback of the outlet gas composition by the comprehensive testing device 34, it is judged whether the hydrogen-carbon ratio is about 3, and the hydrogen-carbon ratio of 2.8~3.2 is a stable production process. If the hydrogen-carbon ratio is lower than 2.8, the molar ratio of liquid water and carbon dioxide can be slowly increased until the comprehensive test device 34 shows that the hydrogen-carbon ratio is close to 3. If the hydrogen-carbon ratio is higher than 3.2, the molar ratio of liquid water and carbon dioxide can be slightly reduced and slowly reduced until the comprehensive test device 34 shows that the hydrogen-carbon ratio is close to 3. When the hydrogen-carbon ratio of the outlet gas is stable at about 3, the molar ratio of liquid water and carbon dioxide is kept unchanged, and the injection flow of liquid water and carbon dioxide and the power of the plasma generator 29 are slowly adjusted to stabilize the production load at about 60%, and a stable coalbed gasification reaction is carried out. After a period of normal production, when the flow test device 35 feedbacks that the outlet gas flow continues to decrease, it indicates that the coal seam has a lower conversion reaction intensity as the reaction cavity increases. At this time, the reaction medium injection flow and the power of the plasma generator 29 need to be increased to increase the conversion reaction load to 60%~100%, and continue production. After a period of time, when the feedback flow of the flow test device 35 further decreases, it indicates that the coal seam covered between the plasma generator 29 and the recovery pipe 33 has been converted. Keep the plasma generator 29 started, withdraw the mobile reaction tube 275~50m, and continue the coal seam conversion production after the reaction tube 27 is withdrawn.

[0132] Taking the Fischer-Tropsch synthesis of a wax as an example, the production process generally requires a hydrogen-carbon ratio of about 1.4 to 1.8. The gas medium injection device 31 and the liquid medium injection device 32 are respectively controlled to make the molar ratio of the injected liquid water and carbon dioxide about 5:3. At this time, the gas components produced mainly include hydrogen, carbon monoxide and carbon dioxide, and the volume ratio is about 5:3:4. After the gas is discharged from the ground, it can be separated to obtain a synthesis gas with a hydrogen-carbon ratio of about 5:3, and the separated carbon dioxide is injected into the plasma generator 29 as a gasifying agent to continue to participate in the reaction. According to the feedback of the outlet gas composition by the comprehensive test device 34, it is judged whether the hydrogen-carbon ratio is about 1.7, and the hydrogen-carbon ratio of 1.4 to 1.8 is a stable production process. If the hydrogen-carbon ratio is lower than 1.4, the molar ratio of liquid water and carbon dioxide can be slowly increased until the comprehensive test device 34 shows that the hydrogen-carbon ratio is close to 1.7. If the hydrogen-carbon ratio is higher than 1.8, the molar ratio of liquid water and carbon dioxide can be slightly reduced and slowly reduced until the comprehensive test device 34 shows that the hydrogen-carbon ratio is close to 1.7. When the hydrogen-carbon ratio of the outlet coal gas is stable at about 1.7, the molar ratio of liquid water and carbon dioxide is kept unchanged, and the injection flow of liquid water and carbon dioxide and the power of plasma generator 29 are slowly adjusted to stabilize the production load at about 10%~50%, and the coalbed gasification reaction begins to stabilize. After a period of normal production, when the flow test device 35 feedbacks that the outlet coal gas flow continues to decrease, it indicates that the coal seam has a lower conversion reaction intensity as the reaction cavity increases. At this time, it is necessary to increase the reaction medium injection flow and the power of plasma generator 29 to increase the conversion reaction load to 60%~100% and continue production. After a period of time, the feedback flow of the flow test device 35 further decreases, indicating that the coal seam covered between the plasma generator 29 and the recovery pipe 33 has been converted. Keep the plasma generator 29 started, withdraw the mobile reaction tube 275~50m, and continue the coal seam conversion production after the reaction tube 27 is withdrawn.

[0133] 4) Production end operation

[0134] The production is adjusted in this way. According to the statistics of the moving distance of the reaction tube driving device 30, when the moving distance is close to the non-vertical section distance of the conversion channel 22, it indicates that the coal seam covered by the unit has been converted. Turn off the power supply of the plasma generator 29, stop the injection of the reaction medium, maintain the injection of the cooling medium, and withdraw the reaction tube 27 and the recovery tube 33 to the ground respectively. Perform the well closing operation. According to the above method, construction, installation and gasification production are carried out in another target coal seam block.

[0135] Example 1: (Coal bed gasification to produce methanol)

[0136] The coal seam gasification method for producing methanol proposed in the embodiment of the present invention has a coal seam resource buried at a depth of about 1020m, an average coal seam thickness of 8m, anthracite as the coal type, a conversion unit is designed to cover a coal seam horizontal distance of 1000m, and the ground synthesis target product is methanol.

[0137] After vertically passing through the overburden 23 and the upper edge of the coal seam from the ground, it gradually deflects to the horizontal direction, forming a non-vertical channel in the coal seam. The non-vertical channel extends 1000m in the coal seam, and on the other side, the ground vertically passes through the overburden 23 and the coal seam and is connected to the non-vertical channel, thus forming a conversion channel 22.

[0138] The reaction tube 27 extends from the ground into the coal seam in the conversion channel 22. One end of the reaction tube 27 is connected to the reaction tube driving device 30 and the injection device on the ground, and the other end is connected to the plasma generator 29 on the ground and lowered into the coal seam. The injection pipe 28 is located in the reaction tube 27 and is coaxial with the injection pipe 28. The injection pipe 28 contains the reaction medium injection pipe, the cooling medium injection pipe and the power cable required by the plasma generator 29. The injection pipe 28 is connected to the reaction tube driving device 30 and the injection device, and the plasma generator 29 along with the reaction tube 27.

[0139] The reaction tube 27 is in the conversion channel 22, extending from the ground into the coal seam. One end of the reaction tube 27 is connected to the reaction tube driving device 30 and the injection device on the ground, and the other end is connected to the plasma generator 29 on the ground and lowered into the coal seam. The injection pipe 28 is located in the reaction tube 27 and is coaxial with the injection pipe 28. The injection pipe 28 contains the reaction medium injection pipe, the cooling medium injection pipe and the power cable required by the plasma generator 29. The injection pipe 28 is connected to the reaction tube driving device 30 and the injection device, and the plasma generator 29 respectively along with the reaction tube 27. The reaction tube driving device 30 is connected to one end of the reaction tube 27, and the injection device is connected to the reaction tube driving device 30 and communicated with the injection pipe 28 in the reaction tube 27. The injection device is provided with a plurality of reaction medium injection ports, cooling medium injection ports, power cables and corresponding valves, switches, etc.

[0140] The recovery pipe 33 is located in the conversion channel 22. One end of the recovery pipe 33 is connected to the recovery device and the recovery pipe 33 driving device on the ground, and the other end extends into the coal seam. The comprehensive testing device 34 and the flow testing device 35 are arranged on the ground part of the recovery pipe 33 and connected to the ground end outlet of the recovery pipe 33. The recovery pipe 33 is provided with an outlet valve, which can be adjusted manually or automatically.

[0141] According to the construction and installation method, the conversion channel 22 is processed and all components are installed. The plasma generator 29 is debugged on the ground, and the reaction medium in and out and the cooling medium in and out circulation are tested. The power is turned on to test the startup and reaction medium flow and power adjustment. The plasma generator 29 is lowered to the conversion channel 22 through the reaction tube drive device 30 and extended to the coal seam until the horizontal distance of the recovery pipe 33 is 20m.

[0142] 100 Nm is injected by the gas medium injection device 31 3 / h carbon dioxide, start the plasma generator 29. According to the feedback of the outlet gas composition by the comprehensive testing device 34, when the volume percentage of carbon monoxide in the outlet gas is higher than 5%, it indicates that the coal seam has started gasification reaction. The gas medium injection device 31 adjusts the carbon dioxide flow rate to 200 Nm 3 / h, the liquid water injection flow rate of the liquid medium injection device 32 is about 480 kg / h, the power of the plasma generator 29 is adjusted to about 1000 kW, and the load of the plasma generator 29 is maintained between 10% and 50%. According to the feedback of the export gas composition from the comprehensive testing device 34, the hydrogen-carbon ratio is stabilized between 2.8 and 3.2, the molar ratio of liquid water and carbon dioxide is kept unchanged, the injection flow rates of liquid water and carbon dioxide and the power of the plasma generator 29 are slowly adjusted to stabilize the production load at about 10% to 50%, and the coalbed gasification reaction begins to stabilize.

[0143] After 10 days of continuous production, the comprehensive testing device 34 reported that the hydrogen-carbon ratio of the exported coal gas was higher than 3.2. This might be due to the high water content in the coal seam. The molar ratio of liquid water and carbon dioxide was slowly reduced through the injection device until the comprehensive testing device 34 showed that the hydrogen-carbon ratio was close to 3.

[0144] After 15 days of normal production, the flow test device 35 reported that the outlet gas flow rate continued to decrease, indicating that the conversion reaction intensity of the coal seam decreased with the increase of the reaction cavity. The molar ratio of liquid water and carbon dioxide was kept unchanged, and the carbon dioxide injection flow rate was increased to 400 Nm 3 / h, the liquid water injection flow rate is about 960 kg / h, and the power of plasma generator 29 is about 2000kW, which increases the conversion reaction load to 60%~100% and continues production.

[0145] After 6 days, the flow rate feedback from the flow test device 35 further decreased, indicating that the coal seam covered between the plasma generator 29 and the recovery pipe 33 was completely converted. The plasma generator 29 was kept started, and the mobile reaction tube 27 was withdrawn by 2720m. After the reaction tube 27 was withdrawn, the coal seam conversion production continued.

[0146] The production is adjusted in this way. According to the statistics of the movement distance of the reaction tube driving device 30, it is close to 1000m, indicating that the coal seam covered by the unit has been converted. The power supply of the plasma generator 29 is turned off, the injection of the reaction medium is stopped, the injection of the cooling medium is maintained, and the reaction tube 27 and the recovery tube 33 are withdrawn to the ground respectively. The well is shut in. According to the above method, construction, installation and gasification production are carried out in another target coal seam block.

[0147] Example 2: (Coal bed gasification combined with Fischer-Tropsch synthesis to produce wax products)

[0148] The coal seam gasification combined with Fischer-Tropsch synthesis to produce wax products is proposed in the embodiment of the present invention. The coal seam resource is buried at a depth of about 1260m, the coal seam thickness is 9m on average, the coal type is lignite, a conversion unit is designed to cover a horizontal distance of 1500m in the coal seam, and the target product of the ground synthesis is wax products.

[0149] After vertically passing through the overburden 23 and the upper edge of the coal seam from the ground, it gradually deflects to the horizontal direction, forming a non-vertical channel in the coal seam. The non-vertical channel extends 1500m in the coal seam, and on the other side, the ground vertically passes through the overburden 23 and the coal seam and is connected with the non-vertical channel, thus forming a conversion channel 22.

[0150] The reaction tube 27 extends from the ground into the coal seam in the conversion channel 22. One end of the reaction tube 27 is connected to the reaction tube driving device 30 and the injection device on the ground, and the other end is connected to the plasma generator 29 on the ground and lowered into the coal seam. The injection pipe 28 is located in the reaction tube 27 and is coaxial with the injection pipe 28. The injection pipe 28 contains the reaction medium injection pipe, the cooling medium injection pipe and the power cable required by the plasma generator 29. The injection pipe 28 is connected to the reaction tube driving device 30 and the injection device, and the plasma generator 29 along with the reaction tube 27.

[0151] The reaction tube 27 is in the conversion channel 22, extending from the ground into the coal seam. One end of the reaction tube 27 is connected to the reaction tube driving device 30 and the injection device on the ground, and the other end is connected to the plasma generator 29 on the ground and lowered into the coal seam. The injection pipe 28 is located in the reaction tube 27 and is coaxial with the injection pipe 28. The injection pipe 28 contains the reaction medium injection pipe, the cooling medium injection pipe and the power cable required by the plasma generator 29. The injection pipe 28 is connected to the reaction tube driving device 30 and the injection device, and the plasma generator 29 respectively along with the reaction tube 27. The reaction tube driving device 30 is connected to one end of the reaction tube 27, and the injection device is connected to the reaction tube driving device 30 and communicated with the injection pipe 28 in the reaction tube 27. The injection device is provided with a plurality of reaction medium injection ports, cooling medium injection ports, power cables and corresponding valves, switches, etc.

[0152] The recovery pipe 33 is located in the conversion channel 22. One end of the recovery pipe 33 is connected to the recovery device and the recovery pipe 33 driving device on the ground, and the other end extends into the coal seam. The comprehensive testing device 34 and the flow testing device 35 are arranged on the ground part of the recovery pipe 33 and connected to the ground end outlet of the recovery pipe 33. The recovery pipe 33 is provided with two outlet valves, which can be adjusted manually or automatically.

[0153] According to the construction and installation method, the conversion channel 22 is processed and all components are installed. The plasma generator 29 is debugged on the ground, and the reaction medium in and out and the cooling medium in and out circulation are tested. The power is turned on to test the startup and reaction medium flow and power adjustment. The plasma generator 29 is lowered to the conversion channel 22 through the reaction tube drive device 30 and extended to the coal seam until the horizontal distance of the recovery pipe 33 is 50m.

[0154] 100 Nm is injected by the gas medium injection device 31 3 / h carbon dioxide, start the plasma generator 29. According to the feedback of the outlet gas composition by the comprehensive testing device 34, when the volume percentage of carbon monoxide in the outlet gas is higher than 5%, it indicates that the coal seam has started gasification reaction. The gas medium injection device 31 adjusts the carbon dioxide flow rate to 200 Nm 3 / h, the liquid water injection flow rate of the liquid medium injection device 32 is about 480 kg / h, the power of the plasma generator 29 is adjusted to about 1000 kW, and the load of the plasma generator 29 is maintained between 10% and 50%. According to the feedback of the export gas composition from the comprehensive testing device 34, the hydrogen-carbon ratio is stabilized between 1.4 and 1.8, the molar ratio of liquid water and carbon dioxide is kept unchanged, the injection flow rates of liquid water and carbon dioxide and the power of the plasma generator 29 are slowly adjusted to stabilize the production load at about 10% to 50%, and the coalbed gasification reaction begins to stabilize.

[0155] After 6 days of continuous production, the comprehensive testing device 34 reported that the hydrogen-carbon ratio of the export coal gas was lower than 1.4, and the molar ratio of liquid water and carbon dioxide was slowly increased through the injection device until the comprehensive testing device 34 showed that the hydrogen-carbon ratio was close to 1.7.

[0156] After 17 days of normal production, the flow test device 35 reported that the outlet gas flow rate continued to decrease, indicating that the conversion reaction intensity of the coal seam decreased with the increase of the reaction cavity. The molar ratio of liquid water and carbon dioxide was kept unchanged, and the carbon dioxide injection flow rate was increased to 400 Nm 3 / h, the liquid water injection flow rate is about 960 kg / h, and the power of plasma generator 29 is about 2000kW, which increases the conversion reaction load to 60%~100% and continues production.

[0157] After 7 days, the flow rate feedback from the flow test device 35 further decreased, indicating that the coal seam covered between the plasma generator 29 and the recovery pipe 33 was completely converted. The plasma generator 29 was kept started, and the mobile reaction tube 2750m was withdrawn. After the reaction tube 27 was withdrawn, the coal seam conversion production continued.

[0158] The production is adjusted in this way. According to the statistics of the movement distance of the reaction tube driving device 30, it is close to 1500m, indicating that the coal seam covered by the unit has been completely converted. The power supply of the plasma generator 29 is turned off, the injection of the reaction medium is stopped, the injection of the cooling medium is maintained, and the reaction tube 27 and the recovery tube 33 are withdrawn to the ground respectively. The well is shut in. According to the above method, construction, installation and gasification production are carried out in another target coal seam block.

[0159] Finally, it should be noted that the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making any creative work are within the scope of protection of the present application.

[0160] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions 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 conversion method using a coal bed plasma gasification system, characterized in that: The coal seam plasma gasification system comprises: The conversion channel vertically passes through the overburden and the upper edge of the coal seam from the ground and then gradually deflects to the horizontal direction to form a non-vertical channel in the coal seam. The non-vertical channel extends a certain distance in the coal seam, and the other side is vertically passed through the overburden and the coal seam from the ground to communicate with the non-vertical channel; React components, which include, A reaction tube is arranged in the conversion channel, one end of the reaction tube is connected to a reaction tube driving device and an injection device on the ground, and the other end in the non-vertical channel is connected to a plasma generator, and a coaxial injection tube is arranged in the reaction tube. A reaction tube driving device is arranged on the ground to controllably move the reaction tube. The injection device is connected to the reaction tube driving device and the injection tube to control the injection amount of gaseous and liquid reaction media and the flow rate of the cooling medium inlet loop. The injection device is provided with a plurality of reaction medium injection ports, cooling medium injection ports, power cables and corresponding valves and switches. A plasma generator, which generates high-temperature and high-activity particles through a reaction medium provided by an injection pipe to convert a coal seam into coal gas, the plasma generator comprising: Plasma generator body; The cathode assembly is arranged in the plasma generator body, and the cathode assembly includes: The cathode head is a hollow metal part. The cathode rod is a hollow tube for conducting electricity and cooling the cathode head. One end of the cathode rod is connected to the cathode terminal, and the other end is threadedly connected to the cathode head. The cathode coolant injection pipe passes through the cathode rod and goes deep into the cathode head so that the cathode head is filled with coolant to reduce the temperature. A cathode coolant return pipe connected to the cathode rod allows the coolant after heat exchange to return through the cathode coolant return pipe, thereby realizing coolant circulation injection; The reaction medium injection assembly is arranged in the plasma generator body, and the reaction medium injection assembly includes: The gaseous reaction medium chamber comprises an injection end located on the left side of the plasma generator body and an outlet end flush with the left side of the cathode head. The gaseous reaction medium chamber gradually narrows from the injection end to the outlet end and is in a bell-mouth shape, so that the pressure of the gaseous reaction medium in the gaseous reaction medium chamber gradually increases due to the gradual reduction in volume. The injection end is provided with a gaseous reaction medium injection port. a medium outlet connected to the outlet end and causing the volume of the gaseous reaction medium from the gaseous reaction medium chamber to increase sharply and the gas pressure to decrease to generate a pressure difference, The liquid medium cavity is located between the gaseous reaction medium cavity and the outer annulus of the anode, and is in the shape of a right triangle with the gaseous reaction medium cavity. The liquid medium cavity is provided with at least one liquid medium capillary on one side of the gaseous reaction medium cavity, and a liquid medium injection port for injecting liquid medium is provided on the left side of the liquid medium cavity. The liquid medium injection port is located on the upper and lower sides of the reaction medium injection assembly and is connected with the liquid medium cavity. The liquid medium from the liquid medium capillary is discharged from the medium outlet via the pressure difference. An atomizing plate is fixed on the cathode rod and arranged at the medium outlet to cooperate with the gaseous reaction medium to atomize the liquid medium to form atomized droplets, and the atomized droplets diffuse between the cathode and the anode along with the gaseous reaction medium; The anode assembly is arranged in the plasma generator body, and the anode assembly includes: The anode head is connected to the right end of the plasma generator body by threads or bolts, and an annulus is arranged outside the anode head. The anode terminal is electrically connected to the anode head, and the discharge between the anode head and the cathode head ionizes the gaseous reaction medium and the atomized droplets to generate high-temperature and high-activity plasma. an anode coolant injection pipe connected to one side of the annulus to introduce coolant into the annulus to cool the anode head, an anode coolant return pipe, which is connected to the other side of the annulus to reflux the coolant after heat exchange, so as to realize coolant circulation injection; A harvesting assembly comprising, A recovery pipe connected to the conversion channel to collect coal gas, Comprehensive testing device, which is installed on the ground part of the recovery pipe to test the recovered gas composition, temperature and pressure, A flow testing device, which is installed on the ground part of the recovery pipe to test the flow rate of the recovered gas; The transformation method comprises: After vertically passing through the overburden and the upper edge of the coal seam from the ground, it gradually deflects horizontally to form a non-vertical channel in the coal seam. The non-vertical channel extends a certain distance in the coal seam. The other side vertically passes through the overburden and the coal seam from the ground and connects with the non-vertical channel to form a conversion channel. The reaction tube extends from the ground into the coal seam in the conversion channel. One end of the reaction tube is connected to the reaction tube driving device and the injection device on the ground, and the other end is connected to the plasma generator on the ground and lowered to the coal seam. The plasma generator is lowered to the conversion channel through the reaction tube driving device and extended to the coal seam until the horizontal distance of the recovery pipe is 5-50m; A certain amount of carbon dioxide is injected by the gas medium injection device to start the plasma generator. When the volume percentage of carbon monoxide in the outlet gas is higher than 5%, it indicates that the coal seam has started to gasify. The gas medium injection device and the liquid medium injection device are used to control the gas medium and liquid medium injection flow rates respectively, and the gas medium and liquid medium injection amounts and the plasma generator power are gradually adjusted to keep the plasma generator load between 10% and 50%, and then the coal seam gasification production begins. For example, after a period of normal production, when the flow test device feeds back that the outlet gas flow rate continues to decrease, it indicates that as the reaction cavity of the coal seam increases, the conversion reaction intensity decreases. The reaction medium injection flow rate and the plasma generator power are increased to increase the conversion reaction load to 60%-100%. After a period of continued production, the flow test device feeds back that the flow rate further decreases, indicating that the conversion of the coal seam covered between the plasma generator and the recovery tube is complete. The plasma generator is kept started and the reaction tube is withdrawn 5-50m. After the reaction tube is withdrawn, the coal seam conversion production is continued. The production is adjusted in this cycle. When the moving distance of the reaction tube drive device is close to the non-vertical section distance of the conversion channel, the plasma generator power is turned off, the reaction medium injection is stopped, the cooling medium injection is maintained, and the reaction tube and the recovery tube are withdrawn to the ground respectively.

2. The conversion method using coal bed plasma gasification system according to claim 1, characterized in that: The plasma generator is a multi-media injection plasma generator that simultaneously inputs different types of gasifying agents and controls the injection flow and composition of the gasifying agents. It produces high-temperature and high-activity particles in different proportions to produce controllable gas-solid reactions and gas-gas reactions in the coal seam to be converted into hydrogen and carbon monoxide gases in different proportions.

3. The conversion method using coal bed plasma gasification system according to claim 1, characterized in that: Multi-media injection plasma generators inject carbon dioxide and liquid water, or hydrogen and liquid water.

4. The conversion method using coal bed plasma gasification system according to claim 3, characterized in that: The gaseous reaction medium injection port is evenly arranged in two or more groups with the cathode rod as the symmetry axis and is located on the left side of the gaseous reaction medium cavity for evenly inputting the gaseous reaction medium into the gaseous reaction medium cavity.

5. The conversion method using coal bed plasma gasification system according to claim 3, characterized in that: Two or more capillaries of the liquid medium are evenly distributed along the gaseous reaction medium cavity, and a baffle is arranged between the left side of the liquid medium cavity and the liquid medium injection port to prevent liquid reflux.

6. The conversion method using coal bed plasma gasification system according to claim 3, characterized in that: The cathode coolant injection pipe, cathode coolant return pipe, anode coolant injection pipe and anode coolant return pipe are connected to the cooling medium injection port, and the gaseous reaction medium injection port and liquid medium injection port are respectively connected to the reaction medium injection port.

7. The conversion method using coal bed plasma gasification system according to claim 1, characterized in that: The injection device includes a gas medium injection device and a liquid medium injection device.

8. The conversion method using coal bed plasma gasification system according to claim 1, characterized in that: The reaction tube driving device is connected to one end of the reaction tube to move the reaction tube in a forward and backward motion, and the moving distance is accurate to 0.1m.

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