WO2018035734A1 - 用于煤炭地下气化过程的点火设备及其应用 - Google Patents

用于煤炭地下气化过程的点火设备及其应用 Download PDF

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Publication number
WO2018035734A1
WO2018035734A1 PCT/CN2016/096486 CN2016096486W WO2018035734A1 WO 2018035734 A1 WO2018035734 A1 WO 2018035734A1 CN 2016096486 W CN2016096486 W CN 2016096486W WO 2018035734 A1 WO2018035734 A1 WO 2018035734A1
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WIPO (PCT)
Prior art keywords
ignition
fuel
liner
coiled tubing
injection
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PCT/CN2016/096486
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English (en)
French (fr)
Inventor
闵振华
汪原理
伯格•卡斯珀•扬•亨德利克
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中为(上海)能源技术有限公司
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Application filed by 中为(上海)能源技术有限公司 filed Critical 中为(上海)能源技术有限公司
Priority to AU2016420954A priority Critical patent/AU2016420954B2/en
Priority to US16/327,729 priority patent/US11021943B2/en
Priority to PCT/CN2016/096486 priority patent/WO2018035734A1/zh
Priority to RU2019103223A priority patent/RU2705662C1/ru
Publication of WO2018035734A1 publication Critical patent/WO2018035734A1/zh
Priority to ZA2018/08612A priority patent/ZA201808612B/en

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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B19/00—Handling rods, casings, tubes or the like outside the borehole, e.g. in the derrick; Apparatus for feeding the rods or cables
    • E21B19/22—Handling reeled pipe or rod units, e.g. flexible drilling pipes
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/11—Perforators; Permeators
    • E21B43/116—Gun or shaped-charge perforators
    • E21B43/1185—Ignition systems
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
    • E21B43/24—Enhanced recovery methods for obtaining hydrocarbons using heat, e.g. steam injection
    • E21B43/243—Combustion in situ
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
    • E21B43/24—Enhanced recovery methods for obtaining hydrocarbons using heat, e.g. steam injection
    • E21B43/243—Combustion in situ
    • E21B43/247—Combustion in situ in association with fracturing processes or crevice forming processes
    • E21B43/248—Combustion in situ in association with fracturing processes or crevice forming processes using explosives
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/25—Methods for stimulating production
    • E21B43/26—Methods for stimulating production by forming crevices or fractures
    • E21B43/2607—Surface equipment specially adapted for fracturing operations
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/295—Gasification of minerals, e.g. for producing mixtures of combustible gases
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/30—Specific pattern of wells, e.g. optimising the spacing of wells
    • E21B43/305—Specific pattern of wells, e.g. optimising the spacing of wells comprising at least one inclined or horizontal well

Definitions

  • the invention provides an ignition device for underground coal gasification process, and also provides the application of the ignition device in the ignition phase of underground coal gasification process.
  • the underground coal gasification (UCG or ISC) process is a process in which coal is directly converted into product gas (also called crude syngas) by combustion and gasification of underground coal seams in the presence of an oxidant, which can then be used in a variety of applications.
  • Applications include fuel production, chemical production and power generation.
  • the completion system typically includes for injecting various reagents such as an oxidant (such as air, oxygen-enriched air or pure oxygen), a gasifying agent, and a coolant (water, water vapor, and carbon dioxide can be used as both a gasifying agent and a coolant).
  • an oxidant such as air, oxygen-enriched air or pure oxygen
  • a gasifying agent such as air, oxygen-enriched air or pure oxygen
  • a coolant water, water vapor, and carbon dioxide can be used as both a gasifying agent and a coolant.
  • air can also be used as an injection well for coolants, etc., production wells for removing product gas, and various auxiliary wells for assisting operations, in which injection wells, production wells, and auxiliary wells are usually laid Casings and/or liners and in communication with each other as desired, wherein the auxiliary wells typically include an ignition well, a freezing well, a shielded well, a protective well, etc., wherein the injection well is typically a horizontal directional well, while the production well and the auxiliary well It can usually be a horizontal directional well or a vertical well.
  • the most basic completion system consists of injection and production wells that are connected to each other and have casing and/or inner liners inside, also known as underground coal gasification units or wells. Correct.
  • the relevant underground area includes a combustion zone, a gasification zone and a pyrolysis zone, wherein: the combustion zone generally extends from the injection point of the oxidant and the gasification agent, and in the combustion zone, the coal is in the presence of the oxidant and the gasification agent. Combustion and gasification occur; the gasification zone is located downstream of the combustion zone or radially around the combustion zone. In the gasification zone, the coal is mainly gasified and partially oxidized to form product gas; the pyrolysis zone is located downstream of the gasification zone, in pyrolysis Pyrolysis of coal occurs in the area. For an ideal underground coal gasification process, it is generally desirable to have as little pyrolysis as possible. With underground coal With the gradual advancement of the chemical process, the burning area formed in the coal seam gradually became larger, and finally the underground coal reservoir was completely consumed, leaving only the coal ash.
  • the product gas produced usually contains CO, CO 2 , H 2 , CH 4 and solid particles, water, coal tar and hydrocarbons, and a small amount of H 2 S, NH 4 and COS.
  • the specific composition of the product gas typically depends on a number of factors, including the oxidant used (eg, air, oxygen-enriched air or pure oxygen), the presence of water (coal water or water from the surrounding formation that penetrates the coal seam), the quality of the coal, and Process parameters used (temperature and pressure, etc.).
  • the underground coal gasification process begins, and the underground coal seam needs to be heated to the ignition point in the presence of an oxidant such as air, oxygen-enriched air or pure oxygen.
  • an oxidant such as air, oxygen-enriched air or pure oxygen.
  • the ignition points of various coals such as lignite, bituminous coal, anthracite, and coke are generally 400-700 °C.
  • the oxidant is sufficient and the temperature reaches the point of ignition, external heating is no longer needed and the coal seam can maintain its entire combustion/gasification process by self-combustion.
  • the coal to be gasified can be used as fuel, and the initial heat is usually from external sources, including the ignition of the ignition fuel.
  • the heat generated, such as air or oxygen, is usually also supplied externally.
  • ignition fuels commonly used in the prior art such as triethylboron (TEB, (C 2 H 5 ) 3 B) or silane (SiH 4 ) or they are associated with lower hydrocarbons such as methane, ethane, Mixtures of propane, etc., usually react when exposed to air or oxygen, and are not safe to use, and the interlayers that may be present in the underground coal seam are also detrimental to coal seam ignition; in terms of heat, injection into the well liner and/or The casing may affect the initial heat during ignition to focus on the target coal seam.
  • the wet coal seam requires more heat to evaporate the water and make ignition difficult.
  • Condensation (such as tar, bitumen, etc.) causes blockage of the production well; in addition, there are problems or defects in the introduction and use of the oxidant and the selection and configuration of the equipment.
  • the ignition fuel can be further improved to provide more initial heat and further It is necessarily advantageous to step improve or optimize the well system configuration to take advantage of the initial heat.
  • WO 2014/089603 A1 discloses an apparatus for underground coal seam ignition, as shown in Fig. 1, wherein the ignition device is a mixing chamber 40 between the inlet 15 and the outlet 17, which contains an ignition fuel and an oxidant mixture,
  • the ignition fuel may be a hydrocarbon gas such as methane, propane, butane, etc.
  • the oxidant may be air, oxygen-enriched air, an oxygen-rich gas mixture or pure oxygen
  • the ignition device further includes a combustible burner nozzle end 35
  • the flammable burner nozzle end is itself flammable and may further comprise a thermite in order to promote coal seam ignition by combustion or reaction exotherm. It can be seen that the patent achieves ignition mainly by low-carbon hydrocarbon aerobic combustion, although the use of the aluminothermic agent to promote low-carbon hydrocarbon combustion does not well solve the fuel and heat supply during the ignition phase of the underground coal gasification process.
  • the present invention further improves the ignition phase of the underground coal gasification process and the ignition equipment applied therein, and in particular improves the heat supply of the ignition and ignition phases of the ignition device, thereby enabling better underground coal seam ignition. .
  • the present invention provides an ignition device for a coal underground gasification process, and also provides an application of such an ignition device in an ignition phase of a coal underground gasification process.
  • the present invention provides an ignition device for a coal underground gasification process, wherein the ignition device includes a conveyor device, a disconnect device, an ignition fuse, and one or more fuel packages, which are sequentially connected to each other, wherein the plurality of fuel packages Connected to each other, and where:
  • the conveying device is a coiled tubing, a joint pipe or an integrated signal cable;
  • the ignition fuse passes through one or more fuel packs and serves to ignite one or more fuel packs from the end of the apparatus in a delayed manner;
  • the fuel pack includes an aluminothermic agent and a ignited underground coal seam for igniting, the aluminothermic agent being a particulate mixture of aluminum powder and a metal oxide capable of undergoing aluminothermic reaction therewith, the metal oxide Selected from the group consisting of ferric oxide, triiron tetroxide, copper oxide, nickel oxynitride, nickel oxide, vanadium pentoxide, chromium trioxide and manganese dioxide, preferably ferric oxide and triiron tetroxide, Wherein the mixing ratio of the aluminum powder to the metal oxide is from 0.5 to 2.0, preferably from 0.7 to 1.5, and more preferably from 0.8 to 1.2 times the stoichiometric ratio of the aluminothermic reaction, and wherein the amount of the thermite is sufficient to provide 20 Ignition time from seconds to 10 minutes, preferably from 30 seconds to 7 minutes.
  • the aluminothermic agent being a particulate mixture of aluminum powder and a metal oxide
  • the invention also provides a coal underground gasification method, wherein a completion system for underground coal gasification is provided in the underground coal seam, wherein the ignition device of the invention is used for ignition, and after the ignition is successful, the gasification process is started, wherein
  • the conveying device is a coiled tubing or a joint pipe
  • an annular gap between the coiled tubing or the joint pipe and the coiled tubing or the joint pipe and the injection liner is used as an oxidant passage in the ignition phase
  • the conveying device is an integrated signal cable
  • the injection liner is used as a fuel package to push the gas passage and the oxidant passage in the ignition phase.
  • the ignition device combination employs a conveying device, a disconnecting device, an ignition fuse and one or more fuel packages, wherein the conveying device can accurately transport and position the fuel pack, the ignition fuze starting from the end of the device in a delayed manner Ignite one or more fuel packs (ie, starting from the fuel pack closest to the end of the apparatus or from the fuel pack furthest from the ignition fuze), the disconnecting device is disconnected after the ignition fuze is activated, thereby
  • the ignition device components, including the conveyor are withdrawn to at least a safe location for subsequent use, and the fuel package is specifically designed to provide sufficient initial heat to heat the subterranean coal seam to its point of ignition, thereby igniting the subterranean coal seam.
  • the ignition device of the present invention can be used for re-ignition, including secondary ignition and multiple ignitions, until the coal seam is re-ignited, thereby ensuring the final implementation of the underground coal gasification process.
  • the ignition apparatus of the present invention can safely and efficiently achieve underground coal seam ignition to start and/or continue the underground coal gasification process, which brings advances to the prior art.
  • FIG. 1 is a schematic view of an ignition device in an inner liner of an injection well in accordance with an embodiment of the present invention, wherein a coiled tubing or a joint pipe is used as a conveying device and a coiled tubing or An annular gap between the inside of the joint pipe and the coiled tubing or the joint pipe and the injection liner is used as an oxidant passage in the ignition phase;
  • FIG 2 is a complete schematic view of the embodiment of the ignition apparatus of the present invention shown in Figure 1 including the injection well and the ground portion;
  • FIG. 3 is a schematic view of an ignition device in an inner liner of an injection well liner according to another embodiment of the present invention, wherein an integrated signal cable is used as a conveying device, and a loop between the fuel pack and the injection liner is sealed by a pipe righting ring. Gap, whereby the injection well liner is used as a fuel pack to push the gas passage and the oxidant passage in the ignition phase, wherein three fuel packs are used, and plugs are provided at both ends of the three fuel packs and are set on both plugs.
  • a pipe righting circle There is a pipe righting circle;
  • FIG 4 is a complete schematic view of the embodiment of the ignition apparatus of the present invention shown in Figure 3 including the injection well and the surface portion.
  • the invention provides an ignition device for underground coal gasification process, and also provides the application of the ignition device in the ignition phase of underground coal gasification process.
  • the present invention provides an ignition device for a coal underground gasification process
  • the ignition device includes a delivery device, a disconnect device, an ignition fuse, and one or more fuel packages that are sequentially connected to each other, wherein the plurality of fuel packages are connected in series with each other, and wherein:
  • the conveying device is a coiled tubing, a joint pipe or an integrated signal cable;
  • the ignition fuse passes through one or more fuel packs and serves to ignite one or more fuel packs from the end of the apparatus in a delayed manner;
  • the fuel pack includes an aluminothermic agent and a ignited underground coal seam for igniting, the aluminothermic agent being a particulate mixture of aluminum powder and a metal oxide capable of undergoing aluminothermic reaction therewith, the metal oxide Selected from the group consisting of ferric oxide, triiron tetroxide, copper oxide, nickel oxynitride, nickel oxide, vanadium pentoxide, chromium trioxide and manganese dioxide, preferably ferric oxide and triiron tetroxide, wherein The mixing ratio of the aluminum powder to the metal oxide is 0.5 to 2.0, preferably 0.7 to 1.5, and more preferably 0.8 to 1.2 times the stoichiometric ratio of the aluminothermic reaction, and wherein the amount of the thermite is sufficient to provide 20 seconds. Ignition time to 10 minutes, preferably 30 seconds to 7 minutes.
  • the conveying device in the ignition device, can be a coiled tubing or a joint tube or an integrated signal cable, which can accurately transport and position the fuel pack.
  • an annular gap between the coiled tubing or the joint pipe and between the coiled tubing or the joint pipe and the injection liner can be used. Oxidizer passage in the ignition phase.
  • a high-concentration oxidant such as pure oxygen
  • the coiled tubing is a highly airtight component and can be avoided.
  • coiled tubing is typically wound on a coiled tubing, and the coiled tubing is wound and retracted by coiled tubing during operation.
  • the coiled tubing and its reel are selected to ensure The coiled tubing can reach the depth of the coal seam and the length of the wellbore inside the coal seam.
  • a joint pipe in the ignition device, can also be used as the conveying device, and in the case where a high-concentration oxidant such as air is not used, the ordinary joint pipe is very
  • a high-concentration oxidant such as air
  • the coiled tubing and the joint pipe as the conveying means can be connected to other components by a suitable connection means, for example, both can be operatively connected to other components through an external grapple connector.
  • the external grapple connector allows for a non-welded connection and provides a hermetic seal whereby other components of the ignition device can be easily replaced and repaired.
  • the joint tube can be connected to other components through a threaded interface.
  • the check valve when a coiled tubing or a joint pipe is used as the conveying device, one or more check valves may be connected between the coiled tubing or the joint pipe and the disconnecting device, mainly for Preventing reverse flow of air from entering the coiled tubing or engaging tube to keep the ignition device related components clean and providing safety when the ground wellhead is removed or retracted, the check valve may be known to those skilled in the art Any type of check valve may be, for example, a spring flapper valve or a ball + spring type.
  • the ignition device when an integrated signal cable is used as the conveying device, it is generally required to seal the annulus between the fuel pack and the injection liner by using the pipe righting ring, thereby using the injection well lining.
  • the tube acts as a fuel pack to push the gas passage and the oxidant passage in the ignition phase, and in the process of conveying the fuel pack, the fuel pack can be determined according to the degree of cable tension to determine whether the fuel pack reaches the predetermined ignition position, and the fuel pack push gas flow can be reduced after arrival.
  • the integrated signal cable can be connected to the disconnect device via a cable connector and cable length can be a limiting factor.
  • the disconnecting device is a self-breaking mechanism that can be activated by a pressure signal or an electric signal for disconnecting after starting the ignition fuze, thereby retracting the conveying device
  • the ignition equipment components are at least in a safe position for subsequent application, thereby reducing equipment losses in the underground coal gasification process to a certain extent.
  • the ignition fuze in the ignition device, is passed through one or more fuel packs, ie through all the fuel packs used, it can be activated with a pressure signal or an electrical signal, and used in a delayed manner
  • Starting one or more fuel packs from the end of the apparatus, wherein igniting the fuel pack in a delayed manner may utilize a disconnect device to disconnect and withdraw ignition device components including the transport device at least until the fuel pack is ignited Safe location.
  • starting from the end of the device refers to starting with a fuel pack that is closest to the end of the device, that is, starting from the fuel pack that is furthest from the ignition fuze. Specifically, when igniting a plurality of fuel packs, the ignition fuze begins to ignite from the fuel pack closest to the end of the apparatus (ie, the fuel pack furthest from the ignition fuze) and then ignites each fuel pack sequentially .
  • both the ignition fuze and the disconnecting device can be activated by using a pressure signal or an electric signal, and the selection of which signal to start is usually determined based on the conveying device used, and the determination principle is It may simplify process operation and control.
  • the ignition fuze and disconnect device are typically each independently activated with a pressure signal
  • the ignition fuze and disconnect device when an integrated signal cable is used as the delivery device
  • they are independently activated by an electric signal.
  • the pressure at which the disconnecting device is activated is usually slightly higher than the pressure at which the ignition fuze is activated to ensure that the two are successively started, for example, for a gasification process with an operating pressure of 45 barg.
  • the ignition ignition fuse and the 50 barg pressure start disconnect device are activated with a pressure of 47.5 barg, and when activated with an electrical signal, the ignition fuse and the disconnect device are successively activated by independent electrical signals, respectively.
  • a specially designed fuel pack is used to ignite the subterranean coal seam, wherein the fuel pack itself and the fuel contained therein are specifically designed.
  • the fuel pack in the ignition device, may be a single fuel pack or a plurality of fuel packs connected in series with each other, the fuel pack containing an aluminothermic agent and igniting the underground coal seam after being ignited.
  • the shape of the fuel pack is generally matched with the liner of the injection well.
  • the shape of the fuel pack may be cylindrical, and the outer diameter of the cylinder is matched with the inner diameter of the liner of the injection well to ensure the The fuel pack can be freely moved within the injection liner to be delivered to a predetermined ignition location.
  • the outer casing of the fuel pack is generally a high-pressure waterproof outer casing, preferably a metal outer casing having suitable strength and capable of being melted by thermal reaction of aluminum, more preferably an aluminum outer casing (aluminum melting point is about 680 ° C), so that the fuel package can be kept intact when transported in the injection liner, and can be completely burned after the fuel package is ignited; in addition, the outer casing of the fuel package optionally includes some random Weak points of distribution, such as not fully drilled Drilling, thereby facilitating the release of gases that may be generated in the aluminothermic reaction; further, after positioning at the ignition position, the fuel pack itself may also function to block the ignition front channel to force the injection to some extent. The oxidant stream enters the coal seam for ignition.
  • a plug for blocking the ignition leading edge passage is provided at the front end of one or more fuel packs from the end of the apparatus, and the same is provided for balancing at the end of the plurality of fuel packs.
  • the plug is generally made of carbon steel or a metal having a higher melting point than aluminum.
  • the material of the plug is generally carbon steel or a metal having a higher melting point than aluminum, whereby the ignition front channel can be blocked longer than the fuel pack itself to force more injected oxidant flow into the channel.
  • the coal seam is used for ignition, and when multiple fuel packs are used, the same plug for balancing is usually provided at the end of the plurality of fuel packs (ie, the end of the fuel pack closest to the ignition fuze), thereby making the plurality of fuel packs Balance is better maintained during travel.
  • the pipe righting ring which can be in one or more fuel casings.
  • the upper sleeve is provided with a pipe righting ring, and/or the balance plug which is present when the plug is plugged and the plurality of fuel packs are sleeved with a pipe righting ring, thereby sealing the ring between the fuel pack and the injection liner.
  • the gap allows the injection well liner to be used as a fuel pack push gas passage and an oxidant passage in the ignition stage, wherein the pipe normalization ring generally has a low coefficient of friction and the material may be rubber, preferably high density polyethylene.
  • thermite is a mixture of aluminum powder and some metal oxides, and when ignited, the aluminum heat reaction causes the metal in the metal oxide to be reduced, the aluminum heat The reaction is vigorously carried out and a large amount of heat is released, and the temperature can reach 2000-3000 ° C.
  • the reaction heat of aluminum and ferric oxide is 945.4 cal/g and the temperature can reach about 2500 ° C, but the aluminothermic itself is very stable. , can be handled and used safely.
  • the aluminothermic reaction of the thermite is a safe and effective method of generating sufficient heat in a limited volume, and thus can cause some reactions requiring high temperature and high heat.
  • the present invention designs the fuel pack based on the characteristics of the thermite.
  • the fuel pack contains an aluminothermic agent and is used to ignite a subterranean coal seam after being ignited, the aluminothermic agent being an aluminum powder and a metal oxide capable of undergoing an aluminothermic reaction therewith.
  • a particulate mixture of the metal oxides which may be selected from the group consisting of iron oxides such as ferric oxide and ferric oxide, nickel oxides such as nickel oxynitride and nickel oxide, and copper oxide, vanadium pentoxide, and the like.
  • the chromium oxide and the manganese dioxide are preferably ferric oxide and triiron tetroxide, wherein the mixing ratio of the aluminum powder to the metal oxide is generally determined according to the stoichiometric ratio of the thermal reaction of the aluminum, and specifically may be an aluminothermic reaction.
  • the stoichiometric ratio is 0.5-2.0, preferably 0.7-1.5 and more preferably 0.8-1.2 times, and wherein the amount of the thermite agent can be appropriately selected based on the required ignition time, preferably should be sufficient to provide 20 seconds to 10 minutes.
  • the ignition time is from 30 seconds to 7 minutes.
  • the fuel pack may further comprise a diluent to reduce its burning speed and correspondingly extend the ignition time
  • the diluent may generally be a particulate solid fuel, preferably selected from solid hydrocarbons and The carbon powder, the amount of the diluent may also be appropriately selected, and may generally not exceed 40% by weight, preferably not more than 30% by weight, more preferably not more than 25% by weight of the mixture of the diluent and the thermite.
  • the thermite and the optional diluent in the fuel pack are both granular materials, and their particle size can be appropriately selected, but generally it is preferred to use a particle size smaller.
  • the contents are used to increase the heat efficiency of the fuel pack.
  • the particle size of the thermite and the diluent may each independently be from 200 nm to 5.0 mm, preferably from 300 nm to 4.0 mm, more preferably from 500 nm to 2.5 mm.
  • the ignition device when the fuel package is ignited, the aluminothermic agent undergoes an aluminothermic reaction, and the diluent fuel that may be present is burned, and the heat generated in these processes is sufficient to burn through.
  • the injection liner and the injection liner at the ignition location, the free water in the coal seam at the evaporative ignition location, and the elevated coal seam temperature to the point of ignition ultimately achieve coal seam ignition.
  • the design can be carried out by adjusting the mixing ratio of the aluminum powder to the metal oxide, changing the selection and amount of the diluent, and changing the particle size of the thermite and/or the diluent. , thereby changing the heat release and ignition time of the fuel pack, thereby optimizing the ignition process of underground coal gasification.
  • it can be formed from aluminum powder and ferric oxide in a stoichiometric ratio (ie, a molar ratio of 2:1).
  • the thermite is then mixed with the carbon powder (the amount of carbon powder is about 15% by weight of the total mixture), the particle size of the resulting mixture is controlled to be about 1 mm, and the mixture is then used in the fuel pack of the present invention.
  • the combustion time of this mixture (6.35 lbs) after the ignition reaction was about 30 seconds, which produced a total of about 11.4 MJ of heat, which was enough to achieve the following effects: melting the aluminum casing of the fuel pack; heating and evaporating the fuel Pack and inject water within 2 feet of the bore liner of the well; melt the 3 foot long aluminum liner; heat 237 Nm 3 /h of nitrogen to 650 ° C; and heat the coal seam to 650 ° C to the point of ignition.
  • the invention also provides a coal underground gasification method, wherein a completion system for underground coal gasification is provided in the underground coal seam, wherein the ignition device of the invention is used for ignition, and after the ignition is successful, the gasification process is started, wherein
  • the conveying device is a coiled tubing or a joint pipe
  • an annular gap between the coiled tubing or the joint pipe and the coiled tubing or the joint pipe and the injection liner is used as an oxidant passage in the ignition phase
  • the conveying device is an integrated signal cable
  • the injection liner is used as a fuel package to push the gas passage and the oxidant passage in the ignition phase.
  • the outside of the vertical section of the injection well, the outside of the injection liner, the production well, the outer liner of the production well, and the outer wall of the coiled tubing are respectively fixed.
  • Temperature, pressure and acoustic sensors are used to acquire temperature, pressure and acoustic signals from underground coal seams and feed back to the control system near the wellhead.
  • the temperature, pressure and acoustic wave sensors may each be a distributed sensing optical fiber based on Optical Time-Domain Reflectometry (OTDR), which may be from a wellhead or a coiled tubing.
  • OTDR Optical Time-Domain Reflectometry
  • the central axis of the barrel begins to extend to the target measurement point to obtain the corresponding temperature curve, pressure curve and acoustic curve for monitoring the ignition position, the location of the combustion zone, the consumption of underground coal seams, the temperature of the injection well, the production well and the gasification zone.
  • a dual metal sheathed K-type dual probe thermocouple is additionally or alternatively used with the temperature sensor.
  • the temperature, pressure and acoustic sensors fixed outside the casing of the vertical section of the injection well, the wellhead and the outside of the production well are mainly used as data sources for the safety protection system, where the temperature is too high and the pressure is too high (for example, The system operation can be automatically stopped when the position temperature and/or pressure reaches a critical value or exceeds the design safety value, and the control system can respond to relevant problems at any time based on the acoustic signals of these sensors to ensure the integrity of the well system;
  • the temperature, pressure and acoustic sensors fixed outside the liner of the injection well are generally extended to the gasification zone via the instrument port near the wellhead, and the measurement results are fed back to the control system and stored in a database, wherein the temperature and pressure sensors are mainly used for Monitoring the temperature and pressure in the underground coal seam, the temperature of the ignition position, and the pressure in the gasification zone in the underground coal seam, and wherein the acoustic wave sensor is mainly used to confirm the ignition position.
  • the gasification zone temperature is >600 ° C, for example, 600- At 1200 °C, it can be considered that the coal seam is being vaporized along the direction of the liner in the injection well, and when the temperature is higher than 1,200 °C, coal combustion mainly occurs.
  • the system can also be automatically stopped;
  • the temperature, pressure and sonic sensors fixed to the outer wall of the coiled tubing can extend from the central axis of the coiled tubing to the oxidant nozzles that may be used. These sensors are connected to the wireless transmission and will measure The results are fed back to the control system and stored in the database.
  • the inner liner of the well system may be joined together by any suitable connection method commonly used in the art, for example, Connections such as welds, threads, clamp grooves, flanges, ferrules or snaps are followed by the principle of ensuring the best performance of the final completion system.
  • the injection liner is an important component, and its function is an important guarantee for the smooth progress of the underground coal gasification process.
  • the function of injecting the liner in the well is mainly reflected in the following aspects:
  • the injection liner is an important passage for fluid flow and equipment movement during underground coal gasification;
  • the annulus between the injection liner and the coal seam bore can also be used as a flow channel after purging with inert gas.
  • an additional gasifying agent can be injected through the channel; again, in order to monitor the consumption position of the underground coal seam and related process parameters, a distributed temperature, pressure and acoustic wave sensor can be fixed on the outer wall of the injection liner to provide Corresponding temperature, pressure and acoustic signal distribution curves.
  • the material of the liner in the injection well can be generally selected according to the static rock pressure and the hydrostatic pressure of the underground formation; the inner diameter of the liner in the injection well is generally matched with the outer diameter of the fuel pack; the inner wall of the injection liner and the coiled tubing Or an annulus between the joint tubes can be used as a flow passage, for example as an oxidant passage for the ignition phase; and the injection liner can generally extend near the bottom of the underground coal seam and above the sandwich layer that may be present, in general,
  • the injection liner shall be as close as possible to the bottom of the underground coal seam, but shall not jump out of the coal seam into the underlying rock formation.
  • the inner liner and the interlayer shall be there is a sandwich layer, it shall be located above the interlayer layer, at which time the inner liner and the interlayer shall be There is preferably a continuous coal seam of about 1 meter thick, preferably no less than 15 centimeters, more preferably less than 10 centimeters.
  • the injection liner and the production well liner generally meet at the ends, and the injection liner and the production liner are required to be opened at the intersection to facilitate the production.
  • the product gas enters the production well liner through the injection liner and is finally removed from the production well.
  • the length of the opening section can be independently 1-3, preferably 2 complete sections, and the aperture of the opening is generally 5-35 mm.
  • the openings are 10-25 mm, the openings are generally arranged at a staggered interval, and the total area of the openings may be 5-35%, preferably 10-30% of the wall area of the open section; in addition, wherein the total length is generally in the distance
  • the coupling is opened at least 0.5 meters away to maintain the strength of the entire length of the pipe.
  • an ignition positioning baffle is generally disposed in the opening section of the in-line liner of the injection well, and under the condition that the perforated inner liner is provided on both sides of the ignition positioning baffle, the ignition positioning baffle is preferably disposed at a distance.
  • the ignition positioning baffle may be a welded baffle or a reduced diameter clamp for pre-setting the ignition position and running
  • the auxiliary fuel pack is finally positioned, and the fuel pack blocks the ignition positioning baffle after positioning, thereby blocking the ignition front channel and forcing the injected oxidant flow into the coal seam through the opening in the injection liner to enter the coal seam for ignition .
  • the ignition device of the present invention optionally has a plug for blocking the ignition front channel at the front end of the one or more fuel packets from the end of the device, when the ignition positioning baffle is used,
  • the plugging plug is used to block the ignition positioning baffle, thereby blocking the ignition front passage to force the injected oxidant flow through the opening in the injection liner to enter the coal seam for ignition.
  • drilling and rinsing and drainage and air drying are usually included in the preparation of the completion system, wherein the drilling and drainage include removing cuttings and drilling fluid, and pumping the free water in the well. Draining, air drying involves injecting air from the injection well and entraining or purging the residual water from the production well, and then gradually pressurizing to the target operating pressure and injecting air until ignition to maintain the circulation of the well system. And dry.
  • ignition and gasification can be further performed as follows:
  • the starting conveying device transports one or more fuel packs to the ignition positioning baffle, and when the conveying device is an integrated signal cable, air is used as a fuel pack to push the gas;
  • the ignition device component including the delivery device is at least to a safe position, the safety position being at least 10 meters away from the ignition position, preferably at least 20 meters;
  • the temperature rise rate is generally controlled based on the oxidant, i.e., the air flow rate, does not exceed 20 ° C / h, preferably does not exceed 15 ° C / h and finally stabilizes at 120 - 150 ° C
  • the output well exit temperature is controlled to ensure that the volatiles of the coal and the pyrolysis products of the coal can be entrained by the product gas stream to the surface without clogging the production well after condensation. At the same time, the integrity of the well system will not be destroyed. If the production well is blocked, the ignition will be stopped, and the oxygen leakage can be monitored based on the oxygen content in the product gas. When the oxygen content in the product gas is within the explosion limit, oxygen leakage can be determined. The ignition should also be suspended.
  • the present invention in the underground coal gasification method, when gasification is performed using a high-purity oxidant having an oxygen concentration of more than 35 vol%, it is necessary to simultaneously inject a coolant, and it is also possible to utilize between the injection well liner and the coal seam drilling hole.
  • the annulus is injected with a gasifying agent which typically needs to be purged with an inert gas prior to ignition.
  • re-ignition (including secondary ignition and multiple ignition) is generally required in the case where the coal seam is not ignited during the ignition phase or the coal seam is interrupted during the gasification process.
  • the coiled tubing acts as a conveyor to reload and transport the fuel pack in place, and uses a coiled tubing as an oxidant passage to inject an oxidant with an oxygen concentration of 35-50 vol% to reignite the coal seam.
  • the coiled tubing used here is due to its operational flexibility and more importantly Due to its high air tightness, it is guaranteed that the oxidant will not leak.
  • the ignition is stopped. At this time, it is usually determined whether the coal seam is ignited, and if it is not ignited, re-ignition is performed. Specifically, if an oxygen leak occurs, the coal seam is generally not completely ignited at this time, and usually needs to be re-ignited; if the production well is blocked, such as the coal tar and other condensation causes the production well to be clogged, it is generally necessary to first clear the plug and clear the production. Exit the well and then confirm that the coal seam is ignited. If it is already ignited, only increase the oxidant flow rate to continue the ignition. If it is not ignited, ignite again. For re-ignition in the ignition phase, the oxidant with an oxygen concentration of 35-50 vol% is mainly used to ensure that the injected liner in the well after the previous ignition can be quickly burned off to ignite the new coal seam.
  • the gasification process is terminated, and generally it is necessary to restart
  • the location of the coal seam is determined for re-ignition, wherein an oxidant with an oxygen concentration of 35-50 vol% is used primarily to ensure that the new coal seam can be ignited quickly.
  • FIG. 1-2 One embodiment of the ignition device of the present invention is illustrated in Figures 1-2, in which a coiled tubing or a joint tube is utilized as the delivery device.
  • a coiled tubing or a joint tube As shown in Figure 1-2, where the coiled tubing or joint tube 12
  • the external grapple connector 10 is connected to the check valve 9 and further connected to the ignition fuse 6 and the fuel pack 5 via the disconnecting device 7.
  • Distributed temperature, pressure and acoustic wave sensors 8 are respectively attached to the outside of the injection liner and to the outer wall of the coiled tubing.
  • the fuel pack 5 contains an aluminothermic agent and a diluent, and the ignition fuze 6 runs through the fuel pack (three fuel packs are shown in Fig.
  • the fuel pack farthest from the fuel pack in a delayed manner and then sequentially backwards. Ignite each fuel pack.
  • the fuel pack is ignited to release heat, and the oxidant passage 11 (in this case, the coiled tubing or the annulus between the joint pipe 10 and the injection liner) injects low-flow air that carries the heat.
  • the opening in the injection liner 3 enters the coal seam 1 in the surrounding annular region and transfers heat to the coal seam 1.
  • a plug 4 is disposed at a front end portion of the fuel pack for sealing the casing clamp 2 (the reduced diameter clamp is simultaneously used as an ignition positioning baffle) provided in the injection liner 3 after the fuel pack is positioned, thereby The injected low flow air is forced into the coal seam through the openings in the injection liner to enter the coal seam for ignition.
  • FIG. 3-4 Another embodiment of the ignition device of the present invention is illustrated in Figures 3-4, wherein an integrated signal cable is utilized as the delivery device.
  • the integrated signal cable 21 is connected at its ends to the disconnecting means 7 and the ignition fuse 6 via the cable connector 22, wherein both the disconnecting means 7 and the ignition fuse 6 are activated by electrical signals.
  • the arrangement and function of the fuel pack 5 in Fig. 3 is the same as in Fig. 1, except that the electrical signal control and activation disconnecting means 7 and the ignition fuze 6 are transmitted through the integrated signal cable 21.
  • the integrated signal cable 21 must inject fuel pack push air through the oxidant passage 11 to deliver the fuel pack 5 to a predetermined ignition position.
  • a plug for plugging 4 is provided at the front end of the fuel pack, and a plug 4 for balancing is provided at the end of the fuel pack, and a pipe righting ring 23 is sleeved on both plugs, thereby achieving close contact with the inner wall of the inner liner of the injection well.

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Abstract

一种用于煤炭地下气化过程的点火设备及利用其点火的煤炭地下气化方法。点火设备包括彼此按顺序连接的输送装置、断开装置（7）、点火引信（6）和一个或多个燃料包（5），其中多个燃料包彼此串联，和其中：所述输送装置为连续油管/接合管（12）或集成信号电缆（21）；所述点火引信贯穿通过一个或多个燃料包和用于以延迟方式从设备端部开始引燃一个或多个燃料包；所述断开装置在启动点火引信后断开，由此回撤包括输送装置在内的点火设备部件至少至安全位置；和所述燃料包中包含铝热剂和用于被引燃后点燃地下煤层（1）。

Description

用于煤炭地下气化过程的点火设备及其应用 技术领域
本发明提供了一种用于煤炭地下气化过程的点火设备，还提供了这种点火设备在煤炭地下气化过程点火阶段中的应用。
背景技术
煤炭地下气化(UCG或ISC)过程是在氧化剂存在下通过地下煤层的燃烧和气化将煤直接转化为产品气(也称为粗合成气)的过程，所述产品气随后可以用于多种应用，包括燃料生产、化学品生产和发电等。鉴于采矿业越来越严格的环保要求和考虑到相关的人工成本和基建成本，这种适用于大多数煤藏的煤炭地下气化技术无疑是很有吸引力的。
在煤炭地下气化过程中，通常要在地下煤层中设有相应的完井系统。所述完井系统通常包括用于注入各种试剂如氧化剂(如空气、富氧空气或纯氧)、气化剂和冷却剂(水、水蒸汽和二氧化碳可同时用作气化剂和冷却剂，空气亦可用作冷却剂)等的注入井、用于移除产品气的产出井和用于起辅助作用的各种辅助井，其中注入井、产出井和辅助井内通常均铺设有套管和/或内衬管且按需要彼此连通，其中所述辅助井通常包括点火井、冷冻井、屏蔽井和防护井等，其中注入井通常为水平定向井，而产出井和辅助井通常可以为水平定向井或垂直井。
因此，在煤炭地下气化过程中，最基本的完井系统由彼此连通且内部铺设有套管和/或内衬管的注入井和产出井组成，亦称为煤炭地下气化单元或井对。
在煤炭地下气化过程中，相关地下区域包括燃烧区、气化区和热解区，其中：燃烧区一般从氧化剂和气化剂注入点开始延伸，在燃烧区中煤在氧化剂和气化剂存在下发生燃烧和气化；气化区位于燃烧区下游或以放射状围绕在燃烧区周围，在气化区中煤主要被气化和部分氧化生成产品气；热解区位于气化区下游，在热解区发生煤的热解。对于理想的煤炭地下气化过程来说，一般希望煤的热解尽可能少。随着煤炭地下气 化过程的逐渐推进，煤层中形成的燃空区逐渐变大，最终地下煤藏完全被消耗，仅留下煤灰。
在煤炭地下气化过程中，所生成的产品气通常包含CO、CO2、H2、CH4及固体颗粒、水、煤焦油和烃以及少量H2S、NH4和COS等。所述产品气的具体组成通常取决于多个因素，包括所使用的氧化剂(例如空气、富氧空气或纯氧)、水的存在(煤层水或周边地层渗入煤层的水)、煤的质量以及所采用的工艺参数(温度和压力等)。
为了点燃地下煤层开始煤炭地下气化过程，需要在氧化剂如空气、富氧空气或纯氧存在下，将地下煤层加热到着火点。各种煤如褐煤、烟煤、无烟煤、焦炭的着火点一般为400-700℃。当氧化剂充足且温度达到着火点后，不再需要外部供热，煤层可通过自身燃烧来维持整个燃烧/气化过程。
因此，在煤炭地下气化过程的点火阶段，点燃地下煤层并使之持续燃烧需要燃料、热量和氧化剂，其中待气化的煤炭自身可以作为燃料，初始热量通常来自外部来源，包括外加点火燃料燃烧产生的热量，氧化剂如空气或氧气通常也由外部供给。
在煤炭地下气化过程中，在保持井系统完整性的情况下安全高效地点燃地下煤层非常重要，但在现有技术中，煤炭地下气化过程的点火阶段在多个方面仍存在问题和需要改进。
具体地，在燃料方面，现有技术中常用的点火燃料如三乙基硼(TEB,(C2H5)3B)或硅烷(SiH4)或者它们与低碳烃如甲烷、乙烷、丙烷等的混合物通常在暴露于空气或氧气时会发生反应，使用起来安全性不够，而地下煤层中可能存在的夹矸层也不利于煤层点火；在热量方面，注入井内衬管和/或套管可能影响点火时的初始热量聚焦到目标煤层，较湿煤层需要更多热量蒸发水分而使点火困难，点火过程中还要保持产出井温度以防止煤挥发分和煤热解产物重组分(如焦油、沥青等)冷凝导致产出井堵塞；另外，在氧化剂的引入和使用以及设备的选择和配置方面也存在问题或缺陷。
因此，如果能够进一步改进点火燃料以提供更多初始热量以及进一 步改进或优化井系统配置以充分利用所述初始热量必然是有利的。
WO2014/089603A1公开了一种用于地下煤层点火的设备，如其附图1所示，其中点火设备在入口15和出口17之间为混合腔40，该混合腔中包含点火燃料和氧化剂混合物，所述点火燃料可以为烃类气体如甲烷、丙烷、丁烷等，氧化剂可以为空气、富氧空气、富含氧的气体混合物或纯氧，所述点火设备还包括可燃的燃烧器喷嘴端35，该可燃的燃烧器喷嘴端自身可燃并且可进一步包含铝热剂，目的是通过燃烧或反应放热来促进煤层点火。可知该专利中主要通过低碳烃有氧燃烧来实现点火，尽管其中利用铝热剂来促进低碳烃燃烧，但并没有很好地解决煤炭地下气化过程点火阶段的燃料和热量供应。
针对现有技术，本发明进一步改进了煤炭地下气化过程的点火阶段及其中所应用的点火设备，尤其是改进了点火设备的燃料和点火阶段的热量供应，从而可以更好地实现地下煤层点火。
发明内容
针对现有技术，本发明提供了一种用于煤炭地下气化过程的点火设备，还提供了这种点火设备在煤炭地下气化过程点火阶段中的应用。
本发明提供了一种用于煤炭地下气化过程的点火设备，其中所述点火设备包括彼此按顺序连接的输送装置、断开装置、点火引信和一个或多个燃料包，其中多个燃料包彼此串联，和其中：
所述输送装置为连续油管、接合管或集成信号电缆；
所述点火引信贯穿通过一个或多个燃料包和用于以延迟方式从设备端部开始引燃一个或多个燃料包；
所述断开装置在启动点火引信后断开，由此回撤包括输送装置在内的点火设备部件至少至安全位置；和
所述燃料包中包含铝热剂和用于被引燃后点燃地下煤层,所述铝热剂为铝粉和能够与之发生铝热反应的金属氧化物的颗粒状混合物，所述金属氧化物选自三氧化二铁、四氧化三铁、氧化铜、三氧化二镍、氧化镍、五氧化二钒、三氧化二铬和二氧化锰，优选为三氧化二铁和四氧化三铁， 其中铝粉与所述金属氧化物的混合比为铝热反应化学计量比的0.5-2.0、优选为0.7-1.5和更优选为0.8-1.2倍，和其中所述铝热剂的用量足以提供20秒至10分钟、优选30秒到7分钟的点火时间。
本发明还提供了一种煤炭地下气化方法，其中在地下煤层中设有用于煤炭地下气化的完井系统，其中利用本发明的点火设备进行点火，和点火成功后开始气化过程，其中当输送装置为连续油管或接合管时，连续油管或接合管内部及连续油管或接合管与注入井内衬管之间的环隙用作点火阶段的氧化剂通道，和当输送装置为集成信号电缆时，用管道扶正圈密封燃料包与注入井内衬管之间环隙后使用注入井内衬管作为燃料包推送气体通道及点火阶段的氧化剂通道。
按照本发明，所述点火设备组合应用了输送装置、断开装置、点火引信和一个或多个燃料包，其中输送装置可以准确地输送和定位燃料包，点火引信以延迟方式从设备端部开始引燃一个或多个燃料包(即从最接近所述设备端部的燃料包开始或从与点火引信距离最远的燃料包开始)，断开装置在启动点火引信后断开，由此可以回撤包括输送装置在内的点火设备部件至少至安全位置以供后续应用，而所述燃料包经具体设计后可以提供足够的初始热量加热地下煤层至其着火点，由此点燃地下煤层。
按照本发明，在所述煤炭地下气化方法中，在点火阶段发生故障如发生产出井堵塞和/或氧泄漏而未点燃煤层的情况下，或者在气化过程中发生煤层中断不能继续气化的情况下，可以利用本发明的点火设备进行再次点火，包括二次点火及多次点火，直到再次点燃煤层，从而保证了煤炭地下气化过程的最终实施。
因此，利用本发明的点火设备可以安全高效地实现地下煤层点火以开始和/或继续煤炭地下气化过程，为现有技术带来了进步。
附图说明
下面参考附图来进一步描述本发明，其中：
图1为按照本发明一种实施方案的点火设备在注入井内衬管内部分的示意图，其中利用连续油管或接合管作为输送装置和利用连续油管或 接合管内部及连续油管或接合管与注入井内衬管之间的环隙作为点火阶段的氧化剂通道；
图2给出了图1所示本发明点火设备实施方案在包括注入井和地面部分时的完整示意图；
图3为按照本发明另一实施方案的点火设备在注入井内衬管内部分的示意图，其中利用集成信号电缆作为输送装置,和利用管道扶正圈密封燃料包与注入井内衬管之间的环隙，由此使用注入井内衬管作为燃料包推送气体通道及点火阶段的氧化剂通道，其中使用了3个燃料包，在3个燃料包两端均设有塞子和在两个塞子上都套有管道扶正圈；
图4给出了图3所示本发明点火设备实施方案在包括注入井和地面部分时的完整示意图。
在各附图中，相同的附图标记指相同部件。具体地，各附图中涉及的附图标记含义如下：
1、煤层；2、套管卡箍(缩径卡箍兼作点火定位挡板)；3、注入井内衬管；4、塞子(前端塞子用于封堵和尾端塞子用于平衡)；5、燃料包(3个燃料包彼此串联)；6、点火引信(点火引信贯穿通过3个燃料包)；7、断开装置；8、分布式温度、压力和声波传感器(固定在注入井内衬管外部和使用连续油管时亦固定在连续油管外壁上)；9、止回阀(球+弹簧型)；10、外部抓钩连接器；11、氧化剂通道；12、连续油管/接合管；13、气化区方向；14、注入井套管；15、井口冷却剂/空气注入口；16、井口备用冷却剂注入口；17、井口控制设备；18、连续油管卷筒(中心轴内连接仪表和数据传输线路)；19、旋转接头；20、地面氧化剂源管线；21、集成信号电缆；22、电缆连接器；23、管道扶正圈；24、电缆服务车。
具体实施方式
本发明提供了一种用于煤炭地下气化过程的点火设备，还提供了这种点火设备在煤炭地下气化过程点火阶段中的应用。
具体地，本发明提供了一种用于煤炭地下气化过程的点火设备，其 中所述点火设备包括彼此按顺序连接的输送装置、断开装置、点火引信和一个或多个燃料包，其中多个燃料包彼此串联，和其中：
所述输送装置为连续油管、接合管或集成信号电缆；
所述点火引信贯穿通过一个或多个燃料包和用于以延迟方式从设备端部开始引燃一个或多个燃料包；
所述断开装置在启动点火引信后断开，由此回撤包括输送装置在内的点火设备部件至少至安全位置；和
所述燃料包中包含铝热剂和用于被引燃后点燃地下煤层,所述铝热剂为铝粉和能够与之发生铝热反应的金属氧化物的颗粒状混合物，所述金属氧化物选自三氧化二铁、四氧化三铁、氧化铜、三氧化二镍、氧化镍、五氧化二钒、三氧化二铬和二氧化锰，优选为三氧化二铁和四氧化三铁，其中铝粉与所述金属氧化物的混合比为铝热反应化学计量比的0.5-2.0、优选为0.7-1.5和更优选为0.8-1.2倍，和其中所述铝热剂的用量足以提供20秒至10分钟、优选30秒到7分钟的点火时间。
按照本发明，在所述点火设备中，所述输送装置可以为连续油管或接合管或集成信号电缆，该输送装置可以准确地输送和定位燃料包。
按照本发明，在所述点火设备中，当采用连续油管或接合管作为输送装置时，连续油管或接合管内部及连续油管或接合管与注入井内衬管之间的环隙均可用作点火阶段的氧化剂通道。
按照本发明，在所述点火设备中，当采用连续油管作为输送装置时，可通过连续油管向地下煤层注入高浓度氧化剂如纯氧，这是因为连续油管为高度气密性部件，可以避免应用高浓度氧化剂如纯氧时可能存在的安全问题。
如本领域中所公知的，连续油管通常卷绕在连续油管卷筒上，在作业状态下通过连续油管卷筒卷绕实现连续油管的释放和回撤，连续油管及其卷筒的选择应确保连续油管可以抵达煤层所在深度及煤层内部井孔延伸长度。
按照本发明，在所述点火设备中，还可以采用接合管作为输送装置，对于不采用高浓度氧化剂如空气气化的情况，采用普通接合管是非常经 济的方案，不足之处是在插入地下煤层及回撤过程中耗时较多且劳动强度较大。
按照本发明，在所述点火设备中，作为输送装置的连续油管和接合管可以通过合适的连接方式与其它部件相连，例如二者均可以通过外部抓钩连接器与其它部件有效连接，所述外部抓钩连接器可以实现非焊接连接和提供气密性密封，由此可以容易地更换和维修点火设备的其它部件，另外，接合管还可以通过螺纹接口与其它部件相连。
按照本发明，在所述点火设备中，当采用连续油管或接合管作为输送装置时，所述连续油管或接合管与断开装置之间还可以连接有一个或多个止回阀，主要用于阻止逆向气流进入所述连续油管或接合管，以使点火设备相关部件保持清洁并在地面井口移除或回撤设备时提供安全保护，所述止回阀可以是本领域技术人员已知适用的任何类型的止回阀，例如可以为弹簧挡板阀或球+弹簧型等。
按照本发明，在所述点火设备中，当采用集成信号电缆作为输送装置时，一般需要利用管道扶正圈密封燃料包与注入井内衬管之间的环隙，由此可以使用注入井内衬管作为燃料包推送气体通道及点火阶段的氧化剂通道,而在输送燃料包的过程中，可以根据电缆绷紧程度确定燃料包是否到达预定点火位置，和可以在到达后减小燃料包推送气体流量以在保持燃料包定位的同时避免电缆过度紧绷，其中集成信号电缆可以通过电缆连接器与断开装置相连和电缆长度可能成为限制因素。
按照本发明，在所述点火设备中，所述断开装置为一种自断机构，可以利用压力信号或电信号启动，用于在启动点火引信后断开，由此可以回撤包括输送装置在内的点火设备部件至少至安全位置以供后续应用，从而在一定程度上减少了煤炭地下气化过程中的设备损耗。
按照本发明，在所述点火设备中，所述点火引信贯穿通过一个或多个燃料包，即贯穿通过所使用的全部燃料包，它可以利用压力信号或电信号启动，和用于以延迟方式从设备端部开始引燃一个或多个燃料包，其中以延迟方式引燃燃料包可以在燃料包被引燃之前利用断开装置断开和回撤包括输送装置在内的点火设备部件至少至安全位置。
如这里所应用的，“从设备端部开始”指的是从最接近所述设备端部的燃料包开始，也就是说，从与点火引信距离最远的燃料包开始。具体地，当引燃多个燃料包时，点火引信从最接近所述设备端部的燃料包(即与点火引信距离最远的燃料包)开始引燃和然后依次向后引燃各燃料包。
按照本发明，在所述点火设备中，所述点火引信和断开装置均可以利用压力信号或电信号启动，而选择利用何种信号启动通常基于所使用的输送装置来确定，确定原则是尽可能简化过程操作和控制。
具体地，当使用连续油管或接合管作为输送装置时，所述点火引信和断开装置通常各自独立地利用压力信号启动，当使用集成信号电缆作为输送装置时，所述点火引信和断开装置通常各自独立地利用电信号启动，当利用压力信号启动时，启动断开装置的压力通常要略高于启动点火引信的压力以确保二者相继启动，例如对于操作压力为45barg的气化过程，可采用47.5barg的压力启动点火引信和50barg的压力启动断开装置，而当利用电信号启动时，点火引信和断开装置分别通过独立的电信号相继启动。
按照本发明，在所述点火设备中，采用具体设计的燃料包来点燃地下煤层，其中具体设计了所述燃料包本身及其内部所包含的燃料。
按照本发明，在所述点火设备中，所述燃料包可以为单个燃料包或彼此串联的多个燃料包，所述燃料包中包含铝热剂和用于被引燃后点燃地下煤层,所述燃料包的形状一般要与注入井内衬管匹配，例如，所述燃料包的形状可以为圆筒状，所述圆筒的外径要与注入井内衬管内径匹配，以保证所述燃料包可以在注入井内衬管中自由移动，从而被输送到预定点火位置。
按照本发明，在所述点火设备中，所述燃料包的外壳通常为高压防水型外壳，优选为具有合适强度并且能够被铝热反应熔化的金属外壳，更优选为铝外壳(铝熔点约为680℃)，从而可以保持燃料包在注入井内衬管内被输送时结构完整，又可以在燃料包被引燃后被完全烧掉；另外，所述燃料包的外壳上任选还包括一些随机分布的薄弱点例如未完全钻通 的钻孔，从而有利于释放铝热反应中可能产生的气体；进一步，在点火位置定位后，所述燃料包本身还可以起到封堵点火前沿通道的作用，以在一定程度上迫使注入的氧化剂流进入煤层用于点火。
按照本发明，在所述点火设备中，任选从设备端部开始在一个或多个燃料包前端设有用于封堵点火前沿通道的塞子和在多个燃料包尾端设有用于平衡的相同塞子,所述塞子的材料一般为碳钢或熔点高于铝的金属。
具体地，在本发明的点火设备中，从最接近所述设备端部开始，任选在一个或多个燃料包前端(即与点火引信距离最远的燃料包端部)设有用于封堵点火前沿通道的塞子，所述封堵用塞子的材料一般为碳钢或熔点高于铝的金属，由此可以比燃料包本身更久地封堵点火前沿通道，以迫使更多注入的氧化剂流进入煤层用于点火，而当使用多个燃料包时通常还在多个燃料包尾端(即与点火引信距离最近的燃料包端部)设有用于平衡的相同塞子，由此使多个燃料包在行进过程中较好地保持平衡。
另外，如前面已经提到的，当使用集成信号电缆作为输送装置时，需要利用管道扶正圈密封燃料包与注入井内衬管之间的环隙，此时可以在一个或多个燃料包外壳上套有管道扶正圈，和/或在所述封堵用塞子和多个燃料包时存在的平衡用塞子上套有管道扶正圈，由此密封燃料包与注入井内衬管之间的环隙，使注入井内衬管可以用作燃料包推送气体通道及点火阶段的氧化剂通道，其中所述管道扶正圈一般具有低摩擦系数，其材料可以为橡胶，优选为高密度聚乙烯。
如现有技术中已知的，所述铝热剂为铝粉与一些金属氧化物的混合物，当被引燃后二者发生铝热反应使金属氧化物中的金属被还原，所述铝热反应剧烈进行并放出大量的热，温度可达2000-3000℃，例如铝与三氧化二铁的反应热为945.4cal/g和温度可达约2500℃，但所述铝热剂本身又非常稳定，可以安全地处理和使用。
因此，铝热剂的铝热反应是在有限体积内产生足够热量的安全有效方法，并由此可以引发一些需要高温高热的反应。本发明就基于铝热剂的特点设计了所述燃料包。
按照本发明，在所述点火设备中，所述燃料包中包含铝热剂和用于被引燃后点燃地下煤层，所述铝热剂为铝粉和能够与之发生铝热反应的金属氧化物的颗粒状混合物，所述金属氧化物可以选自铁氧化物如三氧化二铁和四氧化三铁、镍氧化物如三氧化二镍和氧化镍、以及氧化铜、五氧化二钒、三氧化二铬和二氧化锰，优选为三氧化二铁和四氧化三铁，其中铝粉与所述金属氧化物的混合比一般按照铝热反应的化学计量比来确定，具体可以为铝热反应化学计量比的0.5-2.0、优选为0.7-1.5和更优选为0.8-1.2倍，和其中所述铝热剂的用量可以基于所需要的点火时间适当选择，优选应足以提供20秒至10分钟、优选30秒到7分钟的点火时间。
按照本发明，在所述点火设备中，所述燃料包中还可以包含稀释剂以降低其燃烧速度和相应延长点火时间，所述稀释剂通常可以为颗粒状固体燃料，优选选自固态烃和炭粉，所述稀释剂的用量通常也可以适当选择，一般可以不超过稀释剂与铝热剂混合物的40wt％，优选不超过30wt％，更优选不超过25wt％。
按照本发明，在所述点火设备中，所述燃料包中的铝热剂和任选的稀释剂均为颗粒状物质，它们的颗粒粒度可以适当选择，但一般倾向于使用颗粒粒度较小的内容物来提高燃料包发热效率，例如，所述铝热剂和所述稀释剂的颗粒粒度可以各自独立地为200nm-5.0mm，优选为300nm-4.0mm，更优选为500nm-2.5mm。
按照本发明，在所述点火设备中，当所述燃料包被引燃后，其中的铝热剂发生铝热反应，可能存在的稀释剂燃料则发生燃烧，这些过程中产生的热量足以烧穿燃料包外壳和点火位置处的注入井内衬管、蒸发点火位置处煤层内的自由水和提升煤层温度到着火点，最终实现煤层点火。
因此，按照本发明，在所述点火设备中，可以通过调节铝粉与金属氧化物的混合比、改变稀释剂的选择和用量以及改变铝热剂和/或稀释剂的颗粒粒度等来进行设计，由此改变燃料包的放热量和点火时间等，从而优化煤炭地下气化的点火过程。
例如，可以由铝粉和三氧化二铁以化学计量比(即摩尔比为2:1)形成 铝热剂，然后与炭粉混合(炭粉用量为总混合物的约15wt％)，控制所形成的混合物的颗粒粒度为约1mm，然后将所述混合物用于本发明的燃料包中。
根据实验测量，这种混合物(6.35磅)引燃反应后的燃烧时长为约30秒，共产生约11.4MJ的热量，而这足以达到如下效果：使燃料包的铝外壳熔融；加热并蒸发燃料包和注入井内衬管环隙内2英尺距离内的水；使3英尺长的铝制内衬管熔融；加热237Nm3/h的氮气至650℃；和加热煤层到达到着火点650℃。
这样，在组合使用10个这种规格的燃料包和逐个依次引燃后，则可提供5分钟的燃烧时长和约114MJ的热量，从而足以点燃地下煤层。这表明，本发明的燃料包可以很好地用于在煤炭地下气化过程中点燃煤层。
本发明还提供了一种煤炭地下气化方法，其中在地下煤层中设有用于煤炭地下气化的完井系统，其中利用本发明的点火设备进行点火，和点火成功后开始气化过程，其中当输送装置为连续油管或接合管时，连续油管或接合管内部及连续油管或接合管与注入井内衬管之间的环隙用作点火阶段的氧化剂通道，和当输送装置为集成信号电缆时，用管道扶正圈密封燃料包与注入井内衬管之间环隙后使用注入井内衬管作为燃料包推送气体通道及点火阶段的氧化剂通道。
按照本发明，在所述煤炭地下气化方法中，在注入井垂直段套管外部、注入井内衬管外部、产出井井口、产出井内衬管外部和连续油管外壁上分别固定有温度、压力和声波传感器，用于获取地下煤层的温度、压力和声波信号并反馈给井口附近的控制系统。
按照本发明，所述温度、压力和声波传感器均可以为基于光纤时域反射测量技术(Optical Time-Domain Reflectometry--OTDR)的分布式感应光纤，所述光纤均可以由井口附近或连续油管卷筒的中心轴开始一直延伸到目标测量点，以获取相应的温度曲线、压力曲线和声波曲线用于监测点火位置、燃烧区位置、地下煤层消耗情况、注入井、产出井和气化区的温度和压力以及井系统完整性等，从而控制煤炭地下气化过程， 和温度传感器附加或替代地使用双金属护套K型双探头热电偶。
具体地，按照本发明，各温度、压力和声波传感器的功能描述如下：
固定在注入井垂直段套管外部、产出井井口及产出井内衬管外部的温度、压力和声波传感器主要作为安全保护系统的数据来源，在温度过高、压力过高(例如当所述位置温度和/或压力达到临界值或超过设计安全值时)时可自动停止系统运行，和控制系统可基于这些传感器的声波信号随时应对相关问题以确保井系统完整；
固定在注入井内衬管外部的温度、压力和声波传感器一般经井口附近的仪表端口一直延伸到气化区，和将测量结果反馈给控制系统并储存到数据库，其中温度和压力传感器主要用于监测地下煤层内的温度和压力、点火位置的温度和地下煤层内气化区的压力，和其中声波传感器主要用来确认点火位置，一般地，当气化区温度>600℃，例如为600-1200℃时，可以认为沿着注入井内衬管方向煤层正在被气化，而该温度高于1,200℃时则主要发生煤燃烧，另外，当沿着注入井内衬管的地下煤层全部被消耗时，亦可自动停止系统运行；
当使用连续油管作为输送装置时，固定在连续油管外壁上的温度、压力和声波传感器可以从连续油管卷筒的中心轴一直延伸到可能使用的氧化剂喷嘴，这些传感器与无线传输设备连接，将测量结果反馈给控制系统并储存到数据库。
按照本发明，基于如上所述设计的温度、压力和声波信号采集系统，可以实现对包括点火阶段在内的整个煤炭地下气化过程的良好控制。
按照本发明，对于设在地下煤层内的完井系统来说，井系统(包括注入井和产出井)的内衬管可以采用本领域通常应用的任何合适连接方式连接在一起，例如可以采用焊接、螺纹、卡箍沟槽、法兰、卡套或卡压等连接方式，所遵循的原则是确保最终完井系统性能最好。
按照本发明，对于所述完井系统来说，注入井内衬管是很重要的组成部分，它的功能完好是整个煤炭地下气化过程顺利进行的重要保证。
具体地，注入井内衬管的功能主要体现在以下方面：首先，注入井内衬管是煤炭地下气化过程中用于流体流动和设备移动的重要通道；其 次，注入井内衬管和煤层钻孔之间的环隙在用惰性气体吹扫后亦可用作流动通道，例如，在点火成功后，若煤层非常干燥和/或气化过程需要更多气化剂时，可以通过该通道注入附加气化剂；再次，为了监控地下煤层的消耗位置和相关工艺参数，可以在注入井内衬管外壁上固定分布式温度、压力和声波传感器，以提供相应的温度、压力和声波信号分布曲线。
按照本发明，注入井内衬管的材料一般可以依据地下地层静岩压和静水压选择；注入井内衬管的内径一般与燃料包外径相匹配；注入井内衬管内壁与连续油管或接合管之间的环隙可用作流动通道，例如用作点火阶段的氧化剂通道；和注入井内衬管通常延伸到地下煤层的底部附近和在可能存在的夹矸层上方，一般地，注入井内衬管要尽可能接近地下煤层的底部，但不能跃出煤层进入下伏岩层，当存在夹矸层时，要位于夹矸层上方，此时在所述内衬管和夹矸层之间优选有约1米厚的连续煤层，无煤层厚度优选要小于15厘米，更优选小于10厘米。
按照本发明，注入井内衬管和产出井内衬管在端部一般要彼此交汇，并且在交汇段注入井内衬管和产出井内衬管都要开孔，以利于所产生的产品气通过注入井内衬管进入产出井内衬管和最后由产出井移除。
在这种情况下，对于注入井内衬管和产出井内衬管来说，开孔段长度可以各自独立地为1-3、优选2个完整管段，开孔孔径一般为5-35mm、优选10-25mm，所述开孔一般交错间隔排布，和开孔总面积可以为开孔段管壁面积的5-35％、优选10-30％；另外，其中以完整管段计一般在距离接箍至少0.5米远处开始开孔，以保持整个管段的强度。
按照本发明，其中在注入井内衬管开孔段内通常设置点火定位挡板，在保证点火定位挡板两侧均有开孔内衬管的条件下，优选将点火定位挡板设在距注入井内衬管端部1-2个完整管段处，以辅助燃料包最终定位，其中所述点火定位挡板可以为焊接挡板或缩径卡箍，用于预先设定点火位置和在运行过程中辅助燃料包最终定位，且燃料包在定位后封堵所述点火定位挡板，由此封堵点火前沿通道迫使注入的氧化剂流通过注入井内衬管上的开孔进入煤层用于点火。
另外，如前面所提到的，本发明的点火设备从所述设备端部开始任选在一个或多个燃料包前端设有用于封堵点火前沿通道的塞子，当使用点火定位挡板时，所述封堵用塞子就用于封堵点火定位挡板，由此封堵点火前沿通道迫使注入的氧化剂流通过注入井内衬管上的开孔进入煤层用于点火。
另外，与现有技术的煤炭地下气化过程类似，在准备完井系统时通常包括钻井冲洗和排水及空气干燥，其中钻井冲洗和排水包括除去钻屑和钻井液等以及用泵把井内自由水抽干，空气干燥包括由注入井注入空气和从产出井放空把井内的残余水夹带或吹扫出来，和之后逐渐加压至目标操作压力并直到点火前一直注入空气以保持井系统的流通和干燥。
按照本发明，在所述煤炭地下气化方法中，可以进一步按如下步骤进行点火和气化：
在注入空气保持井系统流通和干燥的条件下，启动输送装置将一个或多个燃料包输送到点火定位挡板处定位，当输送装置为集成信号电缆时采用空气作为燃料包推送气体；
在通过氧化剂通道注入低流量空气(如≤300Nm3/h的空气)的条件下,启动点火引信以延迟方式从设备端部开始引燃一个或多个燃料包，接着启动断开装置以回撤包括输送装置在内的点火设备部件至少至安全位置，所述安全位置远离点火位置至少10米，优选为至少20米；和
监测点火位置和产出井井口的温度，在注入井内衬管开始熔融后逐渐增加空气流量(如逐渐增加到≤1,000Nm3/h)直到产品气组成稳定，之后再逐渐增加空气流量直到产出井井口温度符合要求(例如达到预定值120-150℃)，在未发生产出井堵塞和/或氧泄漏的条件下，开始注入氧化剂和气化剂进行气化，其中如果光纤信号反馈显示点火位置温度超出测量范围且光纤长度缩短，则可以确定注入井内衬管开始熔融。
在本发明的上述方法中，对于产出井出口温度，一般基于氧化剂即空气流量控制其升温速率不超过20℃/h、优选不超过15℃/h和最后使其稳定在120-150℃，如此控制产出井出口温度是为了确保煤的挥发分和煤的热解产品可以被产品气流夹带到地面而不会在冷凝后堵塞产出井， 同时不会破坏井系统完整性，若发生产出井堵塞则中止点火，和可以基于产品气中的氧含量监控氧泄漏，当产品气中氧气含量在爆炸极限内则可以确定发生氧泄漏，此时亦应中止点火。
按照本发明，在所述煤炭地下气化方法中，当使用氧浓度大于35vol％的高纯度氧化剂进行气化时需同时注入冷却剂，其中还可以利用注入井内衬管与煤层钻孔之间的环隙注入气化剂，所述环隙在点火前一般需要用惰性气体吹扫。
按照本发明，在所述煤炭地下气化方法中，在点火阶段未点燃煤层或气化过程中煤层中断的情况下一般需要进行再次点火(包括二次点火和多次点火)，此时一般采用连续油管作为输送装置重新装载和输送燃料包就位，和利用连续油管作为氧化剂通道注入氧浓度为35-50vol％的氧化剂以重新点燃煤层，这里采用连续油管是由于其操作灵活性和更主要是由于其高度气密性可以保证不会泄漏所述氧化剂。
按照本发明，在所述煤炭地下气化方法中，如果在点火阶段发生产出井堵塞和/或氧泄漏则中止点火，此时通常要确定煤层是否点燃，如果未点燃则要进行再次点火。具体地，如果发生氧泄漏，此时煤层一般不会完全点燃，通常需要进行再次点火；如果发生产出井堵塞，如由于煤焦油等冷凝导致产出井堵塞，则一般要先清理堵塞物疏通产出井，然后再确认煤层是否点燃，如果已经点燃则只需要加大氧化剂流量继续点火，如果未点燃则要再次点火。对于在点火阶段进行再次点火，其中采用氧浓度为35-50vol％的氧化剂主要是为了确保可以快速烧掉前次点火后残留的注入井内衬管以点燃新煤层。
按照本发明，在所述煤炭地下气化方法中，如果在气化过程中发生煤层中断，例如碰到较厚的非煤层如夹矸、断层或褶皱等，导致气化过程中止，一般要重新确定煤层位置进行再次点火，其中采用氧浓度为35-50vol％的氧化剂主要是为了确保可以快速点燃新煤层。
下面参考附图进一步描述本发明的实施方案。
图1-2中给出了本发明的点火设备的一个实施方案，其中利用连续油管或接合管作为输送装置。如图1-2所示，其中连续油管或接合管12 通过外部抓钩连接器10与止回阀9相连，并进一步经断开装置7连接到点火引信6和燃料包5。分布式温度、压力和声波传感器8分别固定在注入井内衬管外部和连续油管外壁上。燃料包5内包含铝热剂和稀释剂，点火引信6贯穿通过燃料包(图1中示出3个燃料包)，并以延迟方式首先引燃与其相距最远的燃料包和然后依次向后引燃各燃料包。燃料包被引燃后释放热量，由氧化剂通道11(此时为连续油管或接合管10与注入井内衬管之间的环隙)注入低流量空气，所述低流量空气携带所述热量通过注入井内衬管3上的开孔进入周围环形区域内的煤层1和将热量传递给煤层1。在燃料包前端部设有塞子4，用于在燃料包定位后封堵设在注入井内衬管3内的套管卡箍2(缩径卡箍同时用作点火定位挡板)，从而可以迫使注入的低流量空气通过注入井内衬管上的开孔进入煤层用于点火。
图3-4中给出了本发明的点火设备的另一个实施方案，其中利用集成信号电缆作为输送装置。如图3-4所示，其中集成信号电缆21在其端部经电缆连接器22连接到断开装置7和点火引信6，其中断开装置7和点火引信6均用电信号启动。图3中燃料包5的设置和功能与图1中相同，只是通过集成信号电缆21传送电信号控制和启动断开装置7和点火引信6。另外，集成信号电缆21必须通过氧化剂通道11注入燃料包推送空气来输送燃料包5到达预定点火位置。在燃料包前端设有封堵用塞子4和在燃料包尾端设有平衡用塞子4，而且在两个塞子上均套有管道扶正圈23，由此与注入井内衬管内壁紧密接触实现气密性密封，以最大化燃料包推送空气流的推动力。
本发明并不局限于以上所述实施方案，对于本领域的技术人员来说，本发明还可以有各种变化和调整，只要不偏离本发明的精神和原则，所述变化和调整均应在本发明范围内。

Claims (17)

  1. 一种用于煤炭地下气化过程的点火设备，其中所述点火设备包括彼此按顺序连接的输送装置、断开装置、点火引信和一个或多个燃料包，其中多个燃料包彼此串联，和其中：
    所述输送装置为连续油管、接合管或集成信号电缆；
    所述点火引信贯穿通过一个或多个燃料包和用于以延迟方式从设备端部开始引燃一个或多个燃料包；
    所述断开装置在启动点火引信后断开，由此回撤包括输送装置在内的点火设备部件至少至安全位置；和
    所述燃料包中包含铝热剂和用于被引燃后点燃地下煤层,所述铝热剂为铝粉和能够与之发生铝热反应的金属氧化物的颗粒状混合物，所述金属氧化物选自三氧化二铁、四氧化三铁、氧化铜、三氧化二镍、氧化镍、五氧化二钒、三氧化二铬和二氧化锰，优选为三氧化二铁和四氧化三铁，其中铝粉与所述金属氧化物的混合比为铝热反应化学计量比的0.5-2.0、优选为0.7-1.5和更优选为0.8-1.2倍，和其中所述铝热剂的用量足以提供20秒至10分钟、优选30秒到7分钟的点火时间。
  2. 权利要求1所述的点火设备，其中从设备端部开始在一个或多个燃料包前端设有用于封堵点火前沿通道的塞子和在多个燃料包尾端设有用于平衡的相同塞子,所述塞子的材料为碳钢或熔点高于铝的金属。
  3. 权利要求1或2所述的点火设备，其中所述燃料包的外壳为具有合适强度并且能够被铝热反应熔化的金属外壳，优选为铝外壳，所述燃料包的外壳上任选包括一些随机分布的未完全钻通的钻孔从而有利于释放铝热反应中可能产生的气体。
  4. 权利要求1-3任一项所述的点火设备，其中所述燃料包中还包含选自固体燃料、优选选自固态烃和炭粉的颗粒状稀释剂，所述稀释剂的用量不超过稀释剂与铝热剂混合物的40wt％，优选不超过30wt％，更优选不超过25wt％，和其中所述铝热剂和所述稀释剂的颗粒粒度各自独立地为200nm-5.0mm，优选为300nm-4.0mm，更优选为500nm-2.5mm。
  5. 权利要求1-4任一项所述的点火设备，其中所述输送装置为连续油管或接合管，其中所述连续油管或接合管通过外部抓钩连接器与其它部件有效连接，所述外部抓钩连接器实现非焊接连接和提供气密性密封。
  6. 权利要求5所述的点火设备，其中所述点火引信和断开装置各自利用压力信号启动，和在所述连续油管或接合管与断开装置之间还连接有一个或多个止回阀，用于阻止逆向气流进入所述连续油管或接合管。
  7. 权利要求1-4任一项所述的点火设备，其中所述输送装置为集成信号电缆，所述集成信号电缆通过电缆连接器与断开装置相连，和在一个或多个燃料包外壳上套有管道扶正圈和/或在所述封堵用塞子和如果存在的平衡用塞子上套有管道扶正圈。
  8. 权利要求7所述的点火设备，其中所述点火引信和断开装置各自利用电信号启动，所述管道扶正圈的材料为橡胶，优选为高密度聚乙烯。
  9. 一种煤炭地下气化方法，其中在地下煤层中设有用于煤炭地下气化的完井系统，其中利用权利要求1-8任一项的点火设备进行点火，和点火成功后开始气化过程，其中当输送装置为连续油管或接合管时，连续油管或接合管内部及连续油管或接合管与注入井内衬管之间的环隙用作点火阶段的氧化剂通道，和当输送装置为集成信号电缆时，用管道扶正圈密封燃料包与注入井内衬管之间环隙后使用注入井内衬管作为燃料包推送气体通道及点火阶段的氧化剂通道。
  10. 权利要求9所述的方法，其中在注入井垂直段套管外部、注入井内衬管外部、产出井井口、产出井内衬管外部和连续油管外壁上分别固定有温度、压力和声波传感器，用于获取地下煤层的温度、压力和声波信号并反馈给井口附近的控制系统。
  11. 权利要求10所述的方法，其中所述温度、压力和声波传感器均为基于光纤时域反射测量技术的分布式感应光纤，所述光纤由井口附近或连续油管卷筒的中心轴开始一直延伸到目标测量点，和温度传感器附加或替代地使用双金属护套K型双探头热电偶。
  12. 权利要求9-11任一项所述的方法，其中注入井内衬管延伸到地下煤层的底部附近和可能存在的夹矸层上方，注入井内衬管和产出井内衬 管在端部交汇，和在交汇段注入井内衬管和产出井内衬管均开孔。
  13. 权利要求12所述的方法，其中所述注入井内衬管和产出井内衬管上的开孔段长度各自独立地为1-3、优选2个完整管段，开孔孔径为5-35mm、优选10-25mm，所述开孔交错间隔排布，开孔总面积为开孔段管壁面积的5-35％、优选10-30％，和其中在注入井内衬管开孔段内设置点火定位挡板以辅助燃料包最终定位。
  14. 权利要求13所述的方法，其中按如下步骤进行点火和气化：
    在注入空气保持井系统流通和干燥的条件下，启动输送装置将一个或多个燃料包输送到点火定位挡板处定位，当输送装置为集成信号电缆时采用空气作为燃料包推送气体；
    在通过氧化剂通道注入低流量空气的条件下启动点火引信以延迟方式从设备端部开始引燃一个或多个燃料包，接着启动断开装置以回撤包括输送装置在内的点火设备部件至少至安全位置；
    监测点火位置和产出井井口的温度，在注入井内衬管开始熔融后逐渐增加空气流量直到产品气组成稳定，之后再逐渐增加空气流量直到产出井井口温度符合要求，在未发生产出井堵塞和/或氧泄漏的条件下，开始注入氧化剂和气化剂进行气化。
  15. 权利要求14所述的方法，其中当使用氧浓度大于35vol％的高纯度氧化剂进行气化时需同时注入冷却剂，其中还利用注入井内衬管与煤层钻孔之间的环隙注入气化剂，所述环隙在点火前用惰性气体吹扫，和其中在煤层中断的情况下进行再次点火。
  16. 权利要求14所述的方法，其中基于空气流量控制产出井井口温度的升温速率不超过20℃/h、优选不超过15℃/h和最后使产出井出口温度稳定在120-150℃以避免产出井堵塞，和基于产品气中的氧含量监控氧泄漏，若发生产出井堵塞和/或氧泄漏则中止点火，其中在未点燃煤层的情况下进行再次点火。
  17. 权利要求15或16所述的方法，其中在进行再次点火时，采用连续油管作为输送装置重新装载和输送燃料包就位，和利用连续油管作为氧化剂通道注入氧浓度为35-50vol％的氧化剂以重新点燃煤层，和其中在 发生产出井堵塞时，还需要先疏通产出井和然后进行再次点火。
PCT/CN2016/096486 2016-08-24 2016-08-24 用于煤炭地下气化过程的点火设备及其应用 WO2018035734A1 (zh)

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