An underground ignition tool for underground coal gasification and its operation method

Abstract

This invention discloses an underground ignition tool and its operating method for underground coal gasification processes, comprising: a casing with a tool connector inside; an oxygen injection tool connected to the tool connector inside the casing, the oxygen injection tool having a water channel and an oxygen interface; a connector shell fixedly fitted onto the outer side of the tool connector; a hydraulic piston movably disposed within the inner cavity of the connector shell; a separation shell detachably connected to the bottom of the inner wall of the connector shell; and an oxygen pressure piston movably engaged within the inner cavity of the separation shell. This underground ignition tool and its operating method for underground coal gasification processes perfectly solve the technical problem of underground gasifiers being unable to operate continuously and requiring shutdown and closure, while also possessing significant advantages such as simple operation and convenient installation.

Description

Technical Field

[0001] This invention relates to the field of coal gasification technology, specifically to an underground ignition tool and its operating method for underground coal gasification processes. Background Technology

[0002] Underground coal gasification (ISC) is a process that directly converts coal into product gas through combustion and gasification reactions in underground coal seams in the presence of an oxidant. This product gas is commonly referred to as syngas, which can then be used as feedstock for a variety of applications, including fuel production, chemical production, and power generation. This underground coal gasification technology is applicable to most coal deposits, and given the increasingly stringent environmental requirements for the mining industry and considering the associated labor and infrastructure costs, this technology is undoubtedly very attractive.

[0003] The product gas (crude syngas) generated by underground coal gasification typically contains syngas (a mixture of CO, CO2, H2, CH4, and other gases) as well as other solid particles, water, coal tar, hydrocarbon vapors, and other trace components including H2S, NH4, COS, etc. The complexity of its composition depends on several factors: the oxidant used in underground coal gasification (air or other oxidants, such as oxygen, oxygen-enriched air, or a mixture of steam), the inherent water in the coal seam or water seeping into the coal seam from surrounding strata, the coal quality, and the operating parameters of the underground coal gasification process, including temperature and pressure. In conventional underground gasifiers, due to maintenance of surface equipment or target failure during well construction, the underground gasifier may be unable to continue production and needs to be shut down. Therefore, underground gasifiers require multiple ignitions. This invention provides a reliable solution for successfully achieving secondary or multiple ignitions in underground gasification processes. Summary of the Invention

[0004] The purpose of this invention is to provide an underground ignition tool and its operating method for underground coal gasification processes, so as to at least solve the problem in the prior art that the underground gasifier cannot continue to produce due to reasons such as target miss during the construction of the underground gasifier, and needs to be shut down and extinguished, thus requiring the underground gasifier to be ignited multiple times.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an underground ignition tool for underground coal gasification processes, comprising:

[0006] A sleeve, wherein a tool connector is provided in the inner cavity of the sleeve;

[0007] The oxygen injection tool is connected to the tool connector inside the sleeve, and the oxygen injection tool is provided with a water channel and an oxygen interface.

[0008] A connector housing, which is fixedly sleeved on the outer side of the outer wall of the tool connector;

[0009] A hydraulic piston, which is movably disposed within the inner cavity of the connector housing;

[0010] A separation shell, which is detachably connected to the bottom of the inner wall of the connector housing;

[0011] An oxygen pressure piston is movably engaged in the inner cavity of the separation shell and abuts against the separation shell.

[0012] Oxygen fusion tubes, a plurality of such oxygen fusion tubes are disposed in the inner cavity of the separation shell, one end of which is fixedly inserted into the oxygen pressure piston;

[0013] A zirconium thermo-oxygen lance igniter, wherein the zirconium thermo-oxygen lance igniter is fixedly installed at the other end of the plurality of oxygen melting tubes;

[0014] A deflector housing is fixedly connected to the other end of the separation housing, and a deflector is also provided in its inner cavity.

[0015] Preferably, the tool connector is also provided with multiple drainage holes at the connection point with the oxygen injection tool.

[0016] Preferably, the oxygen melt tube is hollow, and the oxygen pressure piston is provided with multiple through holes. The through holes on the oxygen pressure piston and the hollow inner cavity of the oxygen melt tube form an oxygen channel.

[0017] Preferably, the inner cavity of the separation shell is further provided with a sliding guide rail, which is located at the far end of the oxygen pressure piston, and the sliding guide rail is movably connected to the oxygen melting tube.

[0018] Preferably, the deflector corresponds to the position of the plurality of oxygen fusible tubes.

[0019] Preferably, the separating shell and the connector shell are fixedly connected by a shear pin, wherein the shearing portion of the shear pin is located at the connection between the separating shell and the connector shell.

[0020] Preferably, the inner and outer sides of the hydraulic piston are provided with multiple first sealing rings, and the separation shell and the oxygen injection tool are sealed and connected by a second sealing ring.

[0021] Preferably, the operation method of an underground ignition tool for underground coal gasification process according to the above technical solution includes the following steps:

[0022] S1. Before using this tool, the underground gasifier well needs to be cleaned and drained and dried. The well conditions must meet the ignition requirements.

[0023] S2. The oxygen injection tool is tested at the wellhead. The oxygen interface and water channel conditions are met before the tool is installed.

[0024] S3. Install the ignition tool inside the working window of the coiled tubing equipment, and utilize the coiled tubing equipment...

[0025] Deliver the ignition tool to the designed ignition point;

[0026] S4. Inject oxygen through the oxygen channel of the continuous tubing equipment. When the oxygen reaches the zirconium thermo-oxygen lance igniter, the oxygen fusion tube is ignited.

[0027] S5. Gradually increase the flow rate and pressure of injected oxygen to create a pressure difference between the front and rear ends of the oxygen melt tube, which will push the oxygen pressure piston and push the ignited oxygen melt tube into the deflector housing.

[0028] S6. Under the action of the deflector, the oxygen melting tube is driven to bend outward, and the high temperature combustion burns through the deflector shell and sleeve, and ignites the target coal seam.

[0029] S7. After the underground coal gasification monitoring system detects that the coal seam has been ignited, the disengagement operation begins.

[0030] S8. Water is injected into the water channel of the coiled tubing equipment. Under the action of water pressure, the water pressure piston is pushed and the shear pin is cut off, so that the joint shell and the separation shell are separated.

[0031] S9. Pull out the coiled tubing equipment, check for the ignition tool being lost, and lower the oxygen injection tool again to a distance of 10-20 meters from the secondary ignition position.

[0032] S10. Gradually increase the capacity of the underground gasifier to normal operating conditions and start production using the underground coal gasification controlled combustion process.

[0033] The present invention provides an underground ignition tool and its operating method for underground coal gasification processes, which has the following advantages:

[0034] 1. This invention, when used in conjunction with an oxygen injection tool, effectively utilizes the air and water flow it provides to meet the underground ignition operation requirements of the underground coal gasification process. It perfectly solves the technical problem that underground gasifiers cannot continue production and need to be shut down due to reasons such as target miss during the construction of underground gasifiers.

[0035] 2. This invention uses the combined action of an oxygen fusion tube, a zirconium thermo-oxygen igniter, and a deflector to achieve a stable and reliable lateral ignition effect. The oxygen fusion tube provides the oxygen needed for ignition and is movable, allowing it to extend to the designed ignition point in conjunction with external oxygen supply pressure. Its material is also combustible to a certain extent, thus extending the ignition time and ensuring the ignition effect.

[0036] 3. This invention flexibly utilizes the combined effect of the water pressure piston, oxygen injection tool, separation shell and shear pin to achieve a low-cost, structurally stable, and highly safe ignition source extension structure with flexible movement space, while also having the significant advantages of simple operation and convenient installation. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the structure of the present invention;

[0038] Figure 2 This is a schematic diagram of the structure of the present invention in the state of being dropped.

[0039] In the accompanying drawings, the same reference numerals refer to the same parts.

[0040] Specifically, the meanings of the reference numerals in the accompanying drawings are as follows: 1. Sleeve; 2. Oxygen injection tool; 3. Water channel; 4. Tool connector; 5. Drain hole; 6. Connector housing; 7. Hydraulic piston; 8. Oxygen channel; 9. First sealing ring; 10. Separation shell; 11. Shear pin; 12. Second sealing ring; 13. Oxygen interface; 14. Oxygen pressure piston; 15. Oxygen fusion tube; 16. Sliding guide rail; 17. Zirconium thermo-oxygen lance igniter; 18. Deflector housing; 19. Deflector. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] Please see Figures 1 to 2 The present invention provides a technical solution: an underground ignition tool for underground coal gasification process, comprising: casing 1, oxygen injection tool 2, water channel 3, tool connector 4, connector shell 6, water pressure piston 7, separation shell 10, oxygen interface 13, oxygen pressure piston 14, oxygen melting tube 15, zirconium thermo-oxygen igniter 17, deflector shell 18, and deflector 19.

[0043] The inner cavity of the sleeve 1 is provided with a tool connector 4; the oxygen injection tool 2 is connected to the tool connector 4 inside the sleeve 1, and the oxygen injection tool 2 is provided with a water channel 3 and an oxygen interface 13; the connector housing 6 is fixedly sleeved on the outer side of the outer wall of the tool connector 4; the water pressure piston 7 is movably disposed in the inner cavity of the connector housing 6; the separation shell 10 is detachably connected to the bottom of the inner wall of the connector housing 6; the oxygen pressure piston 14 is movably snapped into the inner cavity of the separation shell 10 and abuts against the separation shell 10; multiple oxygen melt tubes 15 are disposed in the inner cavity of the separation shell 10, one end of which is fixedly inserted into the oxygen pressure piston 14; the zirconium thermo-oxygen igniter 17 is fixedly disposed at the other end of the multiple oxygen melt tubes 15; the deflector housing 18 is fixedly connected to the other end of the separation shell 10, and a deflector 19 is also provided in its inner cavity.

[0044] It should be noted that the function of tool connector 4 is to connect the secondary ignition tool to oxygen injection tool 2. The oxygen injection tool 2 utilizes its independently provided oxygen and water channels 3 to achieve ignition, combustion, and release functions. The oxygen channel provides oxygen directly into the separation shell 10 for ignition and combustion. Water supplied through the water channel 3 enters tool connector 4, and the water pressure pushes the water piston to cut off the pin, achieving the separation process of the separation shell 10 and releasing the device. After release, the water flows out of ignition tool connector 4 from drain hole 5. The composition of the water supplied by oxygen injection tool 2 can be adjusted according to actual needs; it can be water or a liquid material containing combustion-supporting components.

[0045] The deflector housing 18 is equipped with a zirconium thermo-oxygen lance igniter 17 and a deflector 19. The operator needs to reasonably control the ignition of the zirconium thermo-oxygen lance igniter 17 before the oxygen fusion tube 15 is pushed, according to the oxygen supply pressure. Then the oxygen fusion tube 15 is pushed into the deflector housing 18 and reaches the deflector 19. Under the limitation of the shape of the deflector 19 itself, the oxygen fusion tube 15 bends and continues to extend outward until it burns through the sleeve 1 and the deflector housing 18, so as to achieve the purpose of re-igniting the coal seam.

[0046] As a preferred option, the oxygen injection tool 2 connection of the tool connector 4 is further provided with multiple drain holes 5. The drain holes 5 can ensure the smooth flow of water and make its pressure act on the water pressure piston 7 to achieve the effect of pushing the water pressure piston 7.

[0047] As a preferred option, the oxygen fusion tube 15 is hollow, and the oxygen pressure piston 14 is provided with multiple through holes. The through holes on the oxygen pressure piston 14 and the hollow inner cavity of the oxygen fusion tube 15 form the oxygen channel 8.

[0048] Understandably, in application, the oxygen pressure provided by the oxygen channel 8 pushes the oxygen pressure piston 14, and with the support of the sliding guide block, the oxygen melt tube 15 steadily moves forward and enters the deflector 19 cavity. When the oxygen pressure piston 14 on the outer wall of the oxygen melt tube 15 reaches the sliding guide rail 16, it is stopped from moving. The oxygen melt tube 15 is made of a material with an inner hole, the size of which needs to be selected according to the gasifier pressure, and the pressure difference can be used to push the oxygen melt tube 15 to move.

[0049] As a preferred embodiment, the inner cavity of the separation shell 10 is further provided with a sliding guide rail 16, which is located at the far end of the oxygen pressure piston 14, and the sliding guide rail 16 is movably connected to the oxygen melting tube 15.

[0050] The sliding guide rail 16 is designed to ensure that multiple oxygen melting tubes 15 can be movably connected in the inner cavity of the separation shell 10, and also to limit the displacement of the oxygen pressure piston 14.

[0051] As a preferred option, the deflector 19 is positioned to correspond to the positions of the multiple oxygen fuse tubes 15, ensuring the reliability of the outward extension combustion operation of the oxygen fuse tubes 15.

[0052] As a preferred embodiment, the separation shell 10 and the connector shell 6 are further fixedly connected by a shear pin 11, wherein the shearing part of the shear pin 11 is located at the connection between the separation shell 10 and the connector shell 6.

[0053] It is understandable that the setting of the shear pin 11 allows the separation shell 10 to be temporarily fixed to the inside of the connector shell 6. When the separation shell 10 is pushed by the water pressure piston 7, the shear point of the shear pin 11 is forced to break and separate under the effect of the thrust, thereby releasing the temporary fixed connection between the separation shell 10 and the connector shell 6, realizing a reliable release operation and reducing the risk of downhole ignition.

[0054] As a preferred option, multiple first sealing rings 9 are provided on the inner and outer sides of the hydraulic piston 7, and the separation shell 10 and the oxygen injection tool 2 are sealed together by a second sealing ring 12, so that the hydraulic piston 7 and the separation shell 10 can have a more reliable sealing effect, ensuring the steady advancement of the hydraulic piston 7.

[0055] As a preferred embodiment, and further, the operating method of an underground ignition tool for underground coal gasification technology provided by the above technical solution includes the following steps:

[0056] S1. Before using this tool, the underground gasifier well needs to be cleaned and drained and dried. The well conditions must meet the ignition requirements.

[0057] S2. Debug the oxygen injection tool 2 at the wellhead. After the conditions of its oxygen interface 13 and water channel 3 are met, start installing the tool.

[0058] S3. Install the ignition tool inside the working window of the coiled tubing equipment, and use the coiled tubing equipment to deliver the ignition tool to the designed ignition point.

[0059] S4. Inject oxygen through the oxygen channel 8 of the continuous tubing equipment. When the oxygen reaches the zirconium thermo-oxygen lance igniter 17, ignite the oxygen melting tube 15.

[0060] S5. Gradually increase the flow rate and pressure of injected oxygen to create a pressure difference between the front and rear ends of the oxygen melt tube 15, which will push the oxygen pressure piston 14 and push the ignited oxygen melt tube 15 into the deflector housing 18.

[0061] S6. Under the action of the deflector 19, the oxygen melting tube 15 is driven to bend outward, and the high-temperature combustion burns through the deflector shell 18 and the casing 1, and ignites the target coal seam.

[0062] S7. After the underground coal gasification monitoring system detects that the coal seam has been ignited, the disengagement operation begins.

[0063] S8. Water is injected into the water channel 3 of the coiled tubing equipment. Under the action of water pressure, the water pressure piston 7 is pushed and the shear pin 11 is cut off, so that the outer shell of the connector 4 and the separation shell are separated.

[0064] S9. Remove the coiled tubing equipment, check for the ignition tool being lost, and lower the oxygen injection tool 2 again to a distance of 10-20 meters from the secondary ignition position.

[0065] S10. Gradually increase the capacity of the underground gasifier to normal operating conditions and start production using the underground coal gasification controlled combustion process.

[0066] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An underground ignition tool for underground coal gasification processes, characterized in that, include: A sleeve (1) is provided with a tool connector (4) inside the sleeve (1); Oxygen injection tool (2), the oxygen injection tool (2) is connected to the tool connector (4) inside the sleeve (1), and the oxygen injection tool (2) is provided with a water channel (3) and an oxygen interface (13); The connector housing (6) is fixedly sleeved on the outer side of the outer wall of the tool connector (4); A water pressure piston (7) is movably disposed in the inner cavity of the connector housing (6); Separation shell (10), which is detachably connected to the bottom of the inner wall of the connector housing (6); Oxygen pressure piston (14), which is movably engaged in the inner cavity of the separation shell (10) and abuts against the separation shell (10); Oxygen fusion tube (15), a plurality of oxygen fusion tubes (15) are disposed in the inner cavity of the separation shell (10), one end of which is fixedly inserted into the oxygen pressure piston (14); Zirconium thermo-oxygen lance igniter (17), which is fixedly installed at the other end of the plurality of oxygen melting tubes (15); A deflector housing (18) is fixedly connected to the other end of the separation housing (10), and a deflector (19) is also provided in its inner cavity.

2. The downhole ignition tool for underground coal gasification process according to claim 1, characterized in that: The tool connector (4) is also provided with multiple drainage holes (5) at the connection with the oxygen injection tool (2).

3. The underground ignition tool for underground coal gasification process according to claim 1, characterized in that: The oxygen melt tube (15) is hollow, and the oxygen pressure piston (14) is provided with multiple through holes. The through holes on the oxygen pressure piston (14) and the hollow inner cavity of the oxygen melt tube (15) form an oxygen channel (8).

4. The downhole ignition tool for underground coal gasification process according to claim 1, characterized in that: The inner cavity of the separation shell (10) is also provided with a sliding guide rail (16), which is located at the far end of the oxygen pressure piston (14), and the sliding guide rail (16) is movably connected to the oxygen melting tube (15).

5. The underground ignition tool for underground coal gasification process according to claim 1, characterized in that: The deflector (19) corresponds to the position of the plurality of oxygen fused tubes (15).

6. The underground ignition tool for underground coal gasification process according to claim 1, characterized in that: The separation shell (10) and the connector shell (6) are fixedly connected by a shear pin (11), wherein the shearing part of the shear pin (11) is located at the connection between the separation shell (10) and the connector shell (6).

7. The underground ignition tool for underground coal gasification process according to claim 1, characterized in that: The water pressure piston (7) is provided with multiple first sealing rings (9) on its inner and outer sides, and the separation shell (10) and the oxygen injection tool (2) are sealed together by a second sealing ring (12).

8. The operating method of an underground ignition tool for underground coal gasification process according to any one of claims 1-7, characterized in that: Includes the following steps: S1. Before using this tool, the underground gasifier well needs to be cleaned and drained and dried. The well conditions must meet the ignition requirements. S2. The oxygen injection tool (2) is adjusted at the wellhead. The oxygen interface (13) and water channel (3) conditions are met before the tool is installed. S3. Install the ignition tool inside the working window of the coiled tubing equipment, and use the coiled tubing equipment to deliver the ignition tool to the designed ignition point. S4. Inject oxygen through the oxygen channel (8) of the coiled tubing equipment. When the oxygen reaches the zirconium thermo-oxygen igniter (17), ignite the oxygen fusion tube (15). S5. Gradually increase the flow rate and pressure of injected oxygen, so that a pressure difference is generated between the front and rear ends of the oxygen melt tube (15) and pushes the oxygen pressure piston (14) to push the ignited oxygen melt tube (15) into the deflector housing (18). S6. Under the action of the deflector (19), the oxygen melting tube (15) is driven to bend outward, and the high temperature combustion burns through the deflector shell (18) and the casing (1), and ignites the target coal seam. S7. After the underground coal gasification monitoring system detects that the coal seam has been ignited, the disengagement operation begins. S8. Water is injected through the water channel (3) of the coiled tubing equipment. Under the action of water pressure, the water pressure piston (7) is pushed and the shear pin (11) is cut off, so that the joint shell and the separation shell are separated. S9. Remove the coiled tubing equipment, check if the ignition tool is lost, and lower the oxygen injection tool (2) again to a distance of 10-20 meters from the secondary ignition position; S10. Gradually increase the capacity of the underground gasifier to normal operating conditions and start production using the underground coal gasification controlled combustion process.

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