CN107939370B - Strip type coal underground gasification system and production method - Google Patents
Strip type coal underground gasification system and production method Download PDFInfo
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- CN107939370B CN107939370B CN201711308448.XA CN201711308448A CN107939370B CN 107939370 B CN107939370 B CN 107939370B CN 201711308448 A CN201711308448 A CN 201711308448A CN 107939370 B CN107939370 B CN 107939370B
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP 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
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
- E21B47/06—Measuring temperature or pressure
- E21B47/07—Temperature
Abstract
The invention belongs to the technical field of coal mining, and discloses a strip coal underground gasification system and a production method, wherein a narrow strip gasification furnace is constructed, the tail end of a directional gas injection channel is drilled and communicated to form a gas injection and exhaust channel, a firing pipe is advanced to a through point of the gas injection channel of the gasification furnace in a gas injection pipeline, high-calorific-value combustible gas and oxygen are input through the firing pipe, and a coal bed in the gasification furnace is ignited; gas injection control is carried out in a mode that hot-melt elastic connectors are arranged on gas injection pipelines at equal intervals in a gas injection channel, so that gas injection points retreat at intervals along with the directional movement of a flame working surface; the borehole is monitored by placement of the temperature and changes in temperature values are monitored. The invention utilizes the rock roadway of the coal bed bottom plate of the mine to carry out furnace building construction and operation of the gasification furnace, thereby not only reducing the interference and damage to the coal bed in the gasification area and ensuring the airtightness in the gasification furnace, but also reducing the furnace building cost of the gasification furnace and improving the furnace building efficiency of the gasification furnace.
Description
Technical Field
The invention belongs to the technical field of coal mining, and particularly relates to a strip type coal underground gasification system and a production method.
Background
The Underground Coal Gasification technology (UCG) is also called as in-situ Coal Gasification, and the process is to convert the Coal bed existing Underground from physical Coal mining to chemical Coal mining, and the essential thing is to convert the useful substances (volatile components, fixed carbon and the like) in the Coal into combustible gas through physical and chemical conversion modes such as pyrolysis, combustion, Gasification and the like. The UCG integrates three processes of well construction, coal mining and gasification into a whole, and has the advantages of low gas production cost, high safety and good environmental benefit. The cost of the gas produced by the UCG is only 25-50% of that of the ground gasification furnace, and the UCG can be used as the raw material gas for gas power generation, boiler fuel and synthetic chemical products, so that the cost of power generation or synthetic chemical products is obviously reduced. UCG still has apparent environmental benefit, reduces the emission of coal fired pollution, gangue and lime-ash greatly, effectively solves the atmosphere haze problem that present coal-fired arouses, and combines together with carbon entrapment and sequestration technique, can effectively reduce greenhouse gas and discharge. UCG has received wide attention worldwide, and a number of theoretical studies and industrial trials have been conducted in several countries in the former soviet union, europe, usa, japan, australia, china and asia. Therefore, underground coal gasification is firstly a coal development method, is an innovation of the traditional coal mining mode, and is known as a second-generation coal mining method; from the benefit, the method is a new technology for developing clean energy by low carbon of high carbon resources. The technology has wide application prospect in the aspects of mining and utilization of residual coal such as low-quality (high-sulfur and high-ash), steep inclined, thin coal bed, deep coal bed, coal pressing under the third coal bed, conventional technology economy, non-mining and the like.
In recent years, the industrial test and the industrialized popularization strength of underground coal gasification are increased in main coal producing countries in the world, a large number of field tests are carried out in the United states, Australia, Canada, south Africa, China and the like, and the sequence of the commercial popularization and industrialization of underground coal gasification is opened. The underground coal gasification test in China begins in the last 60 th century, and twenty field tests have been carried out so far, so that well-type and non-well-type underground coal gasification processes are formed.
At present, the coal underground gasification does not realize industrialized production, and one important reason is that the scale of the coal underground gasification is small and the gas production is unstable. On one hand, under the influence of external hydrological and geological environment, the conditions (coal thickness, coal quality and the like) and occurrence conditions (geology, hydrology, structure and the like) of a gasified coal bed are complex and variable, the difficulty is increased for the underground gasification process of the coal, and the factors needing manual regulation and control are more; secondly, the control means of the underground coal gasification process is limited, and is influenced by factors such as high temperature, gas, coal body thermal fracture, surrounding rock stress, overlying strata collapse, fissure zone development and the like of an underground gasification space, so that effective monitoring and control means are difficult to be adopted like an underground coal gas producer, and the difficulty of artificial regulation and control is increased.
Therefore, in order to solve the problems of the existing underground coal gasification furnace production system, the underground coal gasification furnace production system and the process which are adaptive to geological environment and have a controllable function need to be developed, and technical support is provided for further realizing the industrialization of underground coal gasification.
Prior art solutions
For different coal seam occurrence conditions, scholars at home and abroad put forward different types of coal underground gasification furnace type structures and gasification production methods. In the aspect of the construction of the gasification furnace type, from the distribution positions of the gas injection channel, the gasification channel and the exhaust channel, the underground gasification furnace can be divided into a plurality of furnace types, namely a blind hole furnace, a one-line furnace, a V-shaped furnace, a U-shaped furnace, an E-shaped furnace and the like, and then a porous furnace and a long fireplace capable of converting the gas injection and exhaust operations are invented. The research direction of overseas underground gasification is mainly a well-free coal underground gasification process, a coal underground gasification furnace is constructed by drilling on the ground, and the well-free gasification process which is relatively mature comprises a linear Injection Point retreat process (CRIP) and a parallel directional drilling CRIP process.
In the soviet union of the last century and forty years ago, firstly, a field underground gasification test is carried out, two adjacent vertical drilling wells are respectively used as an injection well and a gas production well of a gasification agent, then, the bottoms of the two vertical drilling wells are communicated in a coal bed by adopting various communication methods (such as firepower communication, electric power communication, reverse combustion, air fracturing and the like) to form a gasification channel, and then the gasification agent is blown in from a gas injection well, and gas is produced from the gas production well. The furnace building process of the gasification furnace has the defects of low penetration speed, poor penetration directionality, difficult penetration or impossible penetration when the vertical well spacing is large; the vertical drilling distance is small, the number of vertical drilling is large during continuous production, and the investment is large; a gas injection device is not arranged in the gasification furnace, and the gasification agent is diffused and combusted in the whole gasification furnace, so that the combustion range and the boundary can not be effectively controlled, and the gas production quality is low; the enlarged combustion range causes large area collapse of the overlying strata, and the stability control effect of the surrounding rocks is poor. Since the last seventies, the countries in the europe and the america, represented by the usa, mainly develop a wellless CRIP process, a drawtube type mobile gas injection point device is adopted in the aspect of gas injection control, the gas injection point is pulled back periodically, and the gas injection point is pulled back for a certain distance each time.
The Chinese patent publication No. CN101382065A discloses a shaft-free underground gasification process to construct an L-shaped gasification furnace, which is mainly characterized in that a linear furnace is formed by penetrating a plurality of vertical drill holes through directional drills to serve as a linear furnaceAnd the fire power penetrates through the other vertical drill holes to form a linear furnace as a gasification line, and the linear furnace and the gasification line form an L-shaped furnace together. And in the stage of expanding reproduction, continuously supplementing the drilling hole expansion gasification furnace. The technology has the defects that the number of the drilled holes needed for constructing the gasification furnace is large, and the communication difficulty between the horizontal directional drilling well and a plurality of vertical drilling wells is large; the multiple vertical drilling wells need to be communicated by multiple batches of high-pressure firepower in the coal seam, and especially under the conditions that a combustion space area is formed by combustion of a gasification furnace and a caving zone and a fissure zone develop, the effectiveness of the high-pressure firepower communication is difficult to guarantee, and the communication difficulty is high. Therefore, the gasifier is complex in furnace building and operation mode and poor in reliability. The Chinese patent publication No. CN1121138A discloses that 'long-channel large-section underground coal gasification in mine' constructs a long-channel large-section underground gasification furnace, which is mainly characterized in that a gasification furnace can be constructed in a abandoned coal seam of a mine, a coal seam roadway needs to be manually tunneled to serve as a gasification roadway, the length of the gasification roadway is generally more than 150m, and the section of the gasification roadway is large (2.5-4 m)2). The technology has the defects that a tunnel needs to be constructed in the gasification furnace manually, the furnace building machinery is low in level, and potential safety hazards exist; after the personnel quit the construction of the gasification furnace tunnel, the gasification furnace needs to be constructed to be isolated and sealed, and the sealing of the gas in the gasification furnace is difficult to be effectively realized under the influence of severe environments such as high temperature, gas, overlying strata collapse and the like in the gasification furnace; the gasification tunnel is lack of an effective gas injection device, the gasification agent is diffused in the whole tunnel, a combustion gasification reaction interface is spread in the whole gasification tunnel, gas flow is disordered, and the combustion range and the boundary of the gasification furnace are difficult to effectively control. The invention discloses an E-shaped structure gasification furnace constructed according to a gas injection point retreating type coal underground gasification system and process in the Chinese patent of publication No. CN 103277082B. The construction mode of the gasification furnace has the defects that the inner laneway of the gasification furnace needs to be constructed and tunneled in the coal bed manually, and a separation wall needs to be constructed at one end of the ventilation laneway connected with three laneways after people quit. In the coal road, high-temperature pyrolysis and cracking are carried out under the environment of high-temperature pyrolysis and crackingThe coal gas conveying roadway and the gasifying agent injection roadway are spaced by 30m (15 m-50 m), but no corresponding design basis is given, when the length of the gasification channel reaches 60m (30m × 2), the spacing distance is far greater than the limit span of an overlying direct roof and an old roof, so that large-area collapse of overlying rocks and excessive development of fracture zones can be caused, the overlying water-bearing layer can be seriously communicated, the water in the gasification furnace is excessively burst to cause a furnace flooding accident, and even the fractures penetrate through the ground surface to cause coal gas leakage to cause safety accidents.
The prior art has the following defects:
the existing furnace building mode needs manual work to dig a coal seam tunnel in a gasification furnace to serve as a gasification agent injection tunnel, a gasification channel and a coal gas conveying tunnel, isolation and sealing of the gasification furnace and an external channel need to be built after personnel quit, effective sealing is difficult to build in a high-temperature pyrolysis dry cracking environment in the coal tunnel to completely isolate high-temperature gas, the larger the section of the channel is, the greater the difficulty of complete isolation is, and serious safety accidents such as toxic and harmful gas leakage and the like can be caused once the isolation fails.
An effective gas injection pipeline and a movable gas injection device are lacked in the gas injection roadway of the existing gasification furnace. If the gas injection channel is not provided with a gas injection pipeline, the gasification agent is transmitted by a naked hole (or a tunnel) in the coal layer, so that a combustion interface of a flame working surface is upwards against the gas injection air flow, the combustion range is expanded into the gas injection channel, the combustion range and the boundary in the gasification furnace are expanded, the gas flow in the gasification furnace is disturbed, the gasification agent and the coal gas are mixed and combusted, and the quality of the coal gas is reduced; if the gas injection device is not moved in the gas injection channel or the gas injection openings are reserved at large intervals, the injection point of the gasifying agent cannot move along with the directional movement of the flame working surface, the distance from the gasification agent to the flame working surface from the combustion space area is increased, the gas flow in the gasification furnace is disturbed, and the quality of the coal gas is also reduced.
The prior art has poor control on the surrounding rock stability of the gasification furnace, the size design of the gasification furnace does not meet the requirement of the surrounding rock stability control, the mining width of the designed gasification furnace is larger than the limit span of the overlying rock, so that the overlying rock collapses in a large area, a fissure zone develops excessively, a water-bearing layer is communicated, gas leakage in the furnace, gas pressure reduction and excessive inflow of underground water are caused, even the gasification furnace is submerged, and a major operation accident is caused.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a strip type coal underground gasification system and a production method thereof.
The invention is realized in such a way that the production method of the strip type coal underground gasification system comprises the following steps:
constructing a narrow strip gasification furnace by drilling a directional drilling well towards a coal seam in a rock roadway of a coal seam floor under a well, drilling the tail end of a directional gas injection channel of a gas exhaust channel and penetrating to form a gas injection and exhaust passage, and uniformly distributing the gas injection and exhaust passages at the bottom of the coal seam;
the coal bed in the gasification furnace is ignited by a way that a firing tube is advanced to a through point of an injection and exhaust channel in a gas injection pipeline of the gasification furnace, high-calorific-value combustible gas and oxygen are input through the firing tube, and the combustible gas is ignited by an electronic ignition device arranged at the front end of the firing tube;
gas injection control is carried out in a mode that hot-melt elastic connectors are arranged on gas injection pipelines at equal intervals in a gas injection channel, so that gas injection points retreat at intervals along with the directional movement of a flame working surface;
and determining whether the flame working surface moves to a mining stop line position or not by arranging temperature monitoring drill holes and monitoring the change of temperature values, and stopping the gasifier when the temperature values of the coal-rock junction point of the coal seam roof and the coal-rock junction point of the coal seam floor reach the high temperature of 800-1000 ℃ close to the high temperature of the flame working surface.
Further, the production method of the strip type coal underground gasification system specifically comprises the following steps:
igniting a coal bed in the gasification furnace: in the underground ventilation pedestrian lane, an ignition tube is advanced along a gas injection pipeline in a gas injection channel to the ignition point position at the tail end of the gas injection channel, high-calorific-value combustible gas and oxygen are input through the ignition tube, an electronic ignition device is arranged at the front end of the ignition tube to ignite the combustible gas, and a coal bed at the ignition point position is ignited to complete the ignition of the coal bed in the gasification furnace;
gasifying agent is injected and a gasification channel is formed: after the coal bed is ignited, the ignition tube exits from the gas injection channel; the combustion gasification position is gradually expanded from the connection point of the gas injection channel and the exhaust channel, and a gasification channel is formed between the gas injection channel and the exhaust channel to form a flame working surface;
the flame working surface moves backwards and the gas injection point moves backwards: during the normal operation of the gasification furnace, the flame working surface moves backwards along the length direction of the narrow strip gasification furnace, the hot-melt elastic connectors arranged at equal intervals in the gas injection pipeline in the gas injection channel are sequentially positioned at the flame working surface, the hot-melt elastic connectors are sequentially disconnected under the high-temperature action near the flame working surface, new gas injection ports are sequentially formed on the gas injection pipeline, and the new gas injection ports continue to provide gasification agents for the flame working surface; the gasification agent injection point moves backwards at intervals along with the backward movement of the flame working surface, so that the airflow state in the gasification furnace is smooth and the reaction interface form and structure of the flame working surface are stable;
and (3) gas discharge and transportation: the coal gas produced in the gasification furnace reaches a ground coal gas using point through a flame working surface, an exhaust passage, an exhaust pipeline, an exhaust road in a ventilation pedestrian lane, an exhaust drilling pipeline and a ground exhaust pipeline in sequence;
temperature monitoring and gasifier shutdown: monitoring temperature values of three temperature measuring points in the temperature monitoring drill hole in real time, and when the temperature values of coal-rock junction points of a coal seam roof and the coal-rock junction points of a coal seam floor reach a high temperature of 800-1000 ℃ close to a flame working surface, stopping injecting oxygen or air into the gasification furnace when the flame working surface reaches a gasification furnace mining stop line position, and changing the injection into steam; the operation of the gasification furnace is stopped.
And in the step of injecting the gasification agent and forming the gasification channel, after the coal bed is ignited, the ignition tube exits from the gas injection channel, and simultaneously, the gasification agent is input to the ignition point position through the ground gasification agent preparation station, the ground gas injection pipeline, the gas injection drilling pipeline, the gas injection pipeline in the ventilation pedestrian lane and the gas injection pipeline in the gas injection channel in sequence, so that the coal bed is continuously combusted and gasified.
Further, the gasifying agent is one or a mixture of two or more of air, oxygen and steam.
Further, after the gasifier stops operating, when the temperature values of the coal-rock junction point of the coal seam roof and the coal-rock junction point of the coal seam floor are reduced to be less than 100 ℃, and the concentration of the discharged gas component CO is monitored to be reduced to zero, the gasifier is completely extinguished;
after the gasification furnace is completely extinguished, the following steps are required:
filling a gasification furnace; after the gasifier stops operating, the filling slurry is conveyed to the gasifier combustion space area through a ground filling pump station, a ground filling pipeline, a filling drilling pipeline, a pedestrian ventilation roadway filling pipeline and a gasifier gas injection pipeline in sequence, and the whole gasifier combustion space area is filled with the filling slurry.
Another object of the present invention is to provide a strip type underground coal gasification system using the production method of the strip type underground coal gasification system, including:
a gas injection channel, an exhaust channel and a temperature monitoring borehole which are arranged in the coal seam;
the gas injection channel and the gas exhaust channel are directional drilling channels which drill from a gasification coal seam floor rock roadway to a coal seam;
the gas exhaust channel is parallel to the gas injection channel and tunnels linearly along the inclination of the coal seam, and when reaching the tail end point of the gas injection channel, the gas exhaust channel bends and tunnels towards the tail end point of the gas injection channel and is communicated with the tail end point of the gas injection channel, so that a through gas injection and exhaust channel is formed in the coal seam.
The temperature monitoring drill hole is positioned in the middle of the gas injection channel and the gas exhaust channel, is drilled in parallel with the gas injection channel and the gas exhaust channel, and stops until the coal-rock junction of the coal seam roof is reached; and a temperature thermocouple is respectively arranged at the coal seam roof coal rock junction point, the coal seam floor coal rock junction point and the position close to the wall surface of the ventilation pedestrian roadway in the temperature monitoring drilled hole.
Further, the gas injection channel comprises a rock horizontal section and a rock bending section outside the gasification furnace and a coal seam section in the gasification furnace;
in a coal seam section in the gasification furnace, the gas injection channel and the gas exhaust channel are coal seam drilling channels which are tunneled along a coal seam bottom plate, and the tunneling direction is from top to bottom along the coal seam;
in the coal seam section in the gasification furnace, the gas injection channel is tunneled linearly along the coal seam trend and reaches the length designed according to the actual condition;
the parallel distance between the gas injection channel and the gas exhaust channel is the mining width of the gasification furnace, and the length of the coal bed section gas injection channel in the gasification furnace is the length of the gasification furnace; the width of the gasification furnace is smaller than the length value of the gasification furnace.
The gas injection passage and the gas exhaust passage of the coal seam section in the gasification furnace are internally provided with passage protective pipes which are sieve pipes, and the surfaces of the passage protective pipes are provided with round holes with certain sizes. The channel protection pipes in the gas injection channel and the gas exhaust channel are common steel pipes at the horizontal rock section and the curved rock section outside the gasification furnace, and two adjacent steel pipes are connected together through flange bolts.
An air injection pipeline is arranged in the air injection channel protective pipe and serves as a conveying channel of a gasification agent. The gas injection pipeline has equidistant hot melt type elastic connector that has arranged on the way, moves when the flame working face during hot melt type elastic connector position, under high temperature and certain time effect, hot melt type elastic connector disconnection forms new gas injection mouth on the gas injection pipeline, makes the gasification agent that injects can directly carry the flame working face position nearby, guarantees the stability of flame working face reaction interface morphological structure. Along with the continuous directional movement of the flame working surface, the hot-melt elastic connector on the gas injection pipeline is sequentially disconnected to form a new gas injection port, so that the gas injection port on the gas injection pipeline retreats along with the directional movement of the flame working surface, and the control requirement of moving gas injection is met. The two adjacent gas injection pipelines are connected together by a buckle type connector at a coal layer section in the gasification furnace, a rock bending section outside the gasification furnace and a rock horizontal section, and are connected with an underground gas injection pipeline in a pedestrian ventilation roadway outside the gasification furnace by a flange bolt outside the gasification furnace.
And the exhaust channel is provided with exhaust pipelines at the horizontal section of the rock outside the gasification furnace, the adjacent exhaust pipelines at two ends are connected together through flange bolts and finally connected with underground exhaust pipelines in the roadway of the ventilation people outside the gasification furnace.
In order to ensure the isolation of the space in the gasification furnace and the environment outside the gasification furnace, hole sealing is carried out on the gas injection channel, the exhaust channel and the temperature monitoring drilling rock section, and high-temperature-resistant cement sealing materials are filled.
The pedestrian's lane of ventilating is for arranging in the rock tunnel of gasification coal seam bottom plate, and this pedestrian's lane of ventilating level elevation is the same with gasifier upper end elevation to have certain horizontal distance with the gasifier upper end point, have certain vertical distance with the gasification coal seam, this horizontal distance and vertical distance can guarantee the pedestrian's lane of ventilating and the safe isolation of gasifier heat affected zone scope. The pedestrian ventilation roadway is a construction roadway of the gas injection channel and the exhaust channel, directional drilling is horizontally tunneled towards the coal bed by using a directional drilling machine arranged in the pedestrian ventilation roadway, the directional drilling machine is bent and drilled according to a certain curvature when approaching the bottom plate of the coal bed, and after entering the coal bed, the gas injection channel and the exhaust channel of the coal bed in the gasification furnace are tunneled along the bottom plate of the coal bed. An underground gas injection pipeline, an exhaust pipeline, an auxiliary gas injection pipeline, an auxiliary exhaust pipeline, a filling grouting pipeline and a drainage pipeline are laid in the ventilation pedestrian roadway. The pedestrian ventilation roadway is also a manual operation roadway during the operation of the gasification furnace, and the air supply quantity in the roadway meets the requirements of maximum air consumption quantity of drilling construction, gas emission, carbon dioxide emission, personnel and the like.
In order to provide gasification agents for an air injection pipeline and an auxiliary air injection pipeline in the underground ventilation pedestrian lane, a vertical air injection well is drilled from the ground and is connected with the underground ventilation pedestrian lane, and a pipeline is arranged in the air injection well and is connected with the air injection pipeline and the auxiliary air injection pipeline in the underground ventilation pedestrian lane.
In order to provide filling slurry for filling pipelines in the underground ventilation pedestrian lane, a vertical filling drilling well is drilled from the ground and is connected with the underground ventilation pedestrian lane, and pipelines are arranged in the filling drilling well and are connected with the filling pipelines in the underground ventilation pedestrian lane.
In order to convey coal gas in an underground exhaust pipeline in a pedestrian ventilation roadway to a ground coal gas pipeline, a vertical exhaust drilling well is drilled from the ground and connected with the underground pedestrian ventilation roadway, and a pipeline is arranged in the exhaust drilling well and connected with the underground exhaust pipeline in the underground pedestrian ventilation roadway.
The invention has the advantages and positive effects that:
the invention solves the problems that how to establish a narrow strip coal underground gasification furnace aiming at the geological structure and occurrence conditions of a gasification coal bed, the physical and mechanical parameters of overlying strata, and the stress distribution and the movement deformation rule of the surrounding rocks under thermal coupling, the mining width of the narrow strip coal underground gasification furnace is less than the limit span of the overlying strata, the overlying strata cannot collapse in a large area in the operation process of the gasification furnace, the fracture zone of the overlying strata has limited development, and the fracture zone of the overlying strata cannot communicate with a water-bearing layer, so that the narrow strip coal underground gasification furnace has better surrounding rock control effect;
the invention reasonably arranges the gas injection channel, the gasification channel and the exhaust channel: the method comprises the steps that a gas injection channel, a gasification channel and an exhaust channel are positioned at the bottom of a coal seam, the morphological structure of a flame working surface is a downward inclined interface structure, flame is positioned above a lower coal seam, the flame is used for baking a coal body at high temperature and heating the coal body, and the coal body is thermally cracked and collapsed on the bottom plate of the coal seam under the action of overlying strata stress, dead weight and thermal stress to form a structure favorable for gas seepage combustion gasification, so that the surface junction of the coal body and gas reaction is increased, the permeability is high, the gas seepage speed is high, and the combustion gasification reaction is favorably carried out; the gasification furnace also comprises a gas injection channel, a gasification channel and a gas exhaust channel which are arranged on the same plane, so that the gas flow in the gasification furnace forms a smooth gas flow state through the gas injection channel, the gasification channel and the gas exhaust channel in sequence, oxygen in the gas injection channel and the gasification channel is not mixed with the generated combustible gas, the combustion loss of the combustible gas is effectively avoided, and the quality of coal gas is reduced.
The invention provides a simple and effective movable gas injection method, wherein hot-melt elastic connectors are arranged on a gas injection pipeline in a gas injection channel at equal intervals, when a flame working surface sequentially passes through the hot-melt elastic connectors, the hot-melt elastic connectors are broken at high temperature, a new gas injection port is formed on the gas injection pipeline, and a gasification agent is continuously supplied to the flame working surface through the new gas injection port, so that the gasification agent can be directly and nearby conveyed to the position of the flame working surface, the disorder of gas flow is not caused, a stable gas flow state is formed, the stable operation of gasification reaction is facilitated, and a better combustion control effect is achieved.
The invention provides a narrow strip coal underground gasification furnace production system and a process, wherein two parallel directional drilling holes are drilled towards a coal bed in a rock roadway of a coal bed bottom plate to construct a gasification furnace injection and exhaust channel, the front end of the gasification furnace penetrates through the narrow strip coal underground gasification furnace, and the mining width of the gasification furnace is reasonably designed to be smaller than the limit span of overlying strata; the coal bed of the gasification furnace is ignited through an ignition tube which advances in the gas injection channel; the gas injection point is retracted at intervals along with the directional movement of the flame working surface through a hot-melt elastic connecting device on a gas injection pipeline in the gasification furnace, and a stable gas flow state and a stable reaction interface morphological structure are formed in the gasification furnace through moving gas injection control; judging whether the gasification furnace reaches the position of a stoping line or not by monitoring the temperature value of a thermocouple arranged in a drilled hole through temperature monitoring, and carrying out closing operation on the gasification furnace; the filling system is adopted to fill the mined-out gas burning-out area of the gasification furnace, the filling has a good rock stratum control effect, and the residual pollutants in the burning-out area can be solidified in the filling slurry. The narrow-strip gasification furnace production system and the narrow-strip gasification furnace production process can enable the gasification furnace to have good rock stratum control, movable gas injection control and pollutant control effects, do not damage the complete structure of overlying strata, do not pollute underground water, and realize ecological green mining and harmless mining of coal to the maximum extent.
The invention utilizes the rock tunnel of the coal bed floor of the mine to carry out the construction of the gasifier and the operation of the gasifier, thereby not only reducing the interference and the damage to the coal bed in the gasification area and ensuring the airtightness in the gasifier, but also reducing the construction cost of the gasifier by more than 40 percent, simultaneously obviously shortening the construction time of the gasifier and improving the construction efficiency of the gasifier by more than 30 percent compared with the construction of the gasifier by manually digging the coal bed tunnel.
Drawings
FIG. 1 is a flow chart of a production method of a strip type coal underground gasification system provided by the embodiment of the invention.
FIG. 2 is a schematic diagram of a strip coal underground gasification system provided by the embodiment of the invention.
In the figure: 1. a gas injection channel; 1-1, a gas injection channel rock horizontal section; 1-2, gas injection channel rock bending section; 1-3, gas injection channel coal seam section; 2. an exhaust passage; 2-1, a rock horizontal section of the exhaust passage; 2-2, an exhaust passage rock bending section; 2-3, an exhaust passage coal seam section; 3. temperature monitoring and drilling; 4. ventilating pedestrian lanes; 5, a coal seam; 6. a temperature thermocouple; 7. a channel protection pipe; 8. an air injection pipeline; 9. a hot-melt elastic connector; 10. a snap-in connector; 11. a downhole gas injection line; 12. an exhaust line; 13. an underground exhaust pipeline; 14. sealing high-temperature-resistant cement; 15. filling a grouting pipeline; 16. a drain line; 17. gas injection well drilling; 18. filling and drilling; 19. exhausting and drilling; 20. an igniter tube; 21. stopping production line of the gasification furnace.
Fig. 3 is a sectional view a-a of a narrow strip underground gasification furnace production system provided by an embodiment of the present invention.
Fig. 4 is an enlarged view of the ignition point structure of the narrow strip underground gasification furnace provided by the embodiment of the invention.
Fig. 5 is a sectional view of a narrow strip underground gasification furnace according to an embodiment of the present invention during normal operation.
Fig. 6 is a sectional view B-B of a narrow strip underground gasification furnace production system according to an embodiment of the present invention.
FIG. 7 is a sectional view of a narrow strip underground gasifier production system C-C of the present invention.
FIG. 8 is a D-D cross-sectional view of a narrow strip underground gasifier production system provided in an embodiment of the present invention.
Fig. 9 is a sectional view of a narrow strip underground gasification furnace production system E-E according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In the prior art, a narrow strip coal underground gasification furnace model is not established aiming at the geological structure and occurrence conditions of a gasified coal bed, the physical and mechanical parameters of overlying strata, and the stress distribution and the movement deformation rule of surrounding rocks under thermal coupling, so that the narrow strip coal underground gasification furnace model has a better surrounding rock control effect; the production can not meet the production requirement of controllable, efficient and stable gas production of underground coal gasification.
The application of the principles of the present invention will be further described with reference to the accompanying drawings and specific embodiments.
FIG. 1 shows a production method of a strip coal underground gasification system provided by the embodiment of the invention, which comprises the following steps:
s101: igniting a coal bed in the gasification furnace: in the underground ventilation pedestrian lane, an ignition tube is advanced along a gas injection pipeline in a gas injection channel to the ignition point position at the tail end of the gas injection channel, high-calorific-value combustible gas and oxygen are input through the ignition tube, an electronic ignition device is arranged at the front end of the ignition tube to ignite the combustible gas, and a coal bed at the ignition point position is ignited to complete the ignition of the coal bed in the gasification furnace;
s102: gasifying agent is injected and a gasification channel is formed: after the coal bed is ignited, the ignition tube exits from the gas injection channel; meanwhile, gasifying agents are input to the ignition point position through a ground gasifying agent preparation station, a ground gas injection pipeline, a gas injection drilling pipeline, a ventilation pedestrian lane gas injection pipeline and a gas injection pipeline in a gas injection channel in sequence, and the coal bed is continuously combusted and gasified; the combustion gasification position is gradually expanded from the connection point of the gas injection channel and the exhaust channel, and a gasification channel is formed between the gas injection channel and the exhaust channel to form a flame working surface;
s103: the flame working surface moves backwards and the gas injection point moves backwards: during the normal operation of the gasification furnace, the flame working surface moves backwards along the length direction of the narrow strip gasification furnace, the hot-melt elastic connectors arranged at equal intervals in the gas injection pipeline in the gas injection channel are sequentially positioned at the flame working surface, the hot-melt elastic connectors are sequentially disconnected under the high-temperature action near the flame working surface, new gas injection ports are sequentially formed on the gas injection pipeline, and the new gas injection ports continue to provide gasification agents for the flame working surface; the gasification agent injection point moves backwards at intervals along with the backward movement of the flame working surface, so that the airflow state in the gasification furnace is smooth and the reaction interface form and structure of the flame working surface are stable;
s104: and (3) gas discharge and transportation: the coal gas produced in the gasification furnace reaches a ground coal gas using point through a flame working surface, an exhaust passage, an exhaust pipeline, an exhaust road in a ventilation pedestrian lane, an exhaust drilling pipeline and a ground exhaust pipeline in sequence;
s105: temperature monitoring and gasifier shutdown: monitoring temperature values of three temperature measuring points in the temperature monitoring drill hole in real time, and when the temperature values of coal-rock junction points of a coal seam roof and the coal-rock junction points of a coal seam floor reach a high temperature of 800-1000 ℃ close to a flame working surface, stopping injecting oxygen or air into the gasification furnace when the flame working surface reaches a gasification furnace mining stop line position, and changing the injection into steam; the operation of the gasification furnace is stopped.
Meanwhile, gasifying agents are input to the ignition point position through a ground gasifying agent preparation station, a ground gas injection pipeline, a gas injection drilling pipeline, a ventilation pedestrian lane gas injection pipeline and a gas injection pipeline in a gas injection channel in sequence, and the coal bed is continuously combusted and gasified; after the gasifier stops operating, when the temperature values of coal-rock junction points of the coal seam roof and the coal-rock junction points of the coal seam floor are reduced to be less than 100 ℃, and the concentration of the discharged gas components CO is monitored to be reduced to zero, the gasifier is completely extinguished;
s106, filling a gasification furnace; after the gasifier stops operating, the filling slurry is conveyed to the gasifier combustion space area through a ground filling pump station, a ground filling pipeline, a filling drilling pipeline, a pedestrian ventilation roadway filling pipeline and a gasifier gas injection pipeline in sequence, and the whole gasifier combustion space area is filled with the filling slurry.
The gasifying agent is one or more than two mixed gases of air, oxygen and water vapor.
As shown in fig. 2 to 9, the strip coal underground gasification system provided by the embodiment of the invention,
comprises a gas injection channel 1, a gas exhaust channel 2 and a temperature monitoring borehole 3 which are arranged in a coal seam. The gas injection channel 1 and the gas exhaust channel 2 are directional drilling channels which are drilled from a gasification coal seam floor rock roadway (namely a ventilation pedestrian roadway 4) to a coal seam 5, and comprise rock horizontal sections (1-1 and 2-1) and rock bending sections (1-2 and 2-2) outside the gasification furnace and coal layer sections (1-3 and 2-3) inside the gasification furnace. In the coal seam section in the gasifier, gas injection leads to 1 and exhaust passage 2 and is the coal seam drilling passageway of drivage along the coal seam bottom plate, and the direction of drivage is from top to bottom for following the coal seam tendency. In the coal seam section in the gasification furnace, the gas injection channel 1 is tunneled linearly along the coal seam inclination and reaches the designed length; the exhaust channel 2 is parallel to the gas injection channel 1 and tunnels linearly along the inclination of the coal seam, and when the exhaust channel approaches to the tail end point of the gas injection channel 1, the exhaust channel bends and tunnels towards the tail end point of the gas injection channel 1 and is communicated with the tail end point of the gas injection channel 1, so that a through gas injection and exhaust channel is formed in the coal seam. The parallel distance between the gas injection channel 1 and the gas exhaust channel 2 is the designed sampling width of the gasification furnace, the length of the coal seam section gas injection channel 1 in the gasification furnace is the designed length of the gasification furnace, the sampling width of the gasification furnace is smaller than the length ratio of the gasification furnace, and the whole gasification furnace is similar to a narrow strip and is called as a narrow strip gasification furnace.
In this embodiment, the design basis of the gasifier design width is that the gasifier width is smaller than the limit span of the coal seam overburden rock. And (3) after calculating the limit span of the overlying strata according to the geological structure and occurrence conditions of the gasified coal seam, the physical and mechanical parameters of the overlying strata, the stress distribution of the surrounding rocks under thermal coupling and the movement deformation rule, considering the influence of the temperature field and the boundary expansion of two sides, and drawing up a safety coefficient, wherein the limit span of the overlying strata is divided by the safety coefficient to obtain the design mining width of the gasifier. The design width of a common gasification furnace is 20-30 m, the design length of the gasification furnace is 300-600 m, and the length-width ratio of the gasification furnace is 10: 1-30: 1.
The temperature monitoring drill hole 3 is positioned in the middle of the gas injection channel 1 and the exhaust channel 2 and is parallel to the gas injection channel 1 and the exhaust channel
And drilling the channel 2, and stopping until the coal-rock junction of the top plate of the coal seam is exposed. 1 temperature thermocouples 6 are respectively arranged at coal seam roof coal rock junction points and coal seam floor coal rock junction points in the drill holes and positions close to the wall surface of a ventilation pedestrian roadway, the total number is 3, and temperature values of the 3 positions are respectively monitored.
The gas injection passage 1 and the exhaust passage 2 of the coal seam section in the gasification furnace are internally provided with a passage protective pipe 7, the passage protective pipe 7 is a sieve pipe, and the surface of the passage protective pipe is provided with a round hole with a certain size, the passage protective pipe 7 not only plays a role in supporting the coal wall of the gas injection passage 1 and the exhaust passage 2, but also is beneficial to the diffusion of a gasification agent to a flame working surface and the collection of coal gas to the exhaust passage. The channel protection pipes in the gas injection channel and the gas exhaust channel are common steel pipes at the rock horizontal section and the rock bending section outside the gasification furnace.
An air injection pipeline 8 is arranged in the air injection channel protection pipe 7, and the air injection pipeline 8 is used as a conveying channel of a gasification agent. Equidistant hot melt formula elastic connector 9 has been arranged on gas injection pipeline 8, moves as the flame working face during the hot melt formula elastic connector 9 position, under high temperature and certain time effect, hot melt formula elastic connector 9 disconnection forms new gas injection mouth on gas injection pipeline 8, makes the gasification agent of pouring into can directly carry the flame working face position nearby, guarantees the stability of flame working face reaction interface morphological structure. Along with the continuous directional movement of the flame working surface, the hot-melt elastic connector 9 on the gas injection pipeline 8 is sequentially disconnected to form a new gas injection port, so that the gas injection port on the gas injection pipeline 8 retreats along with the directional movement of the flame working surface, and the control requirement of moving gas injection is met. Two adjacent gas injection pipelines 8 are connected together by a buckle type connector 10 at a coal layer section in the gasification furnace, a rock bending section outside the gasification furnace and a rock horizontal section, and are connected with a downhole gas injection pipeline 11 in a ventilation roadway outside the gasification furnace by flange bolts.
And the exhaust channel 2 is provided with exhaust pipelines 12 at the horizontal section of the rock outside the gasification furnace, the exhaust pipelines 12 adjacent to two ends are connected together through flange bolts and finally connected with an underground exhaust pipeline 13 in a pedestrian roadway for ventilation outside the gasification furnace.
In order to ensure the isolation of the space in the gasification furnace from the environment outside the gasification furnace, hole sealing is carried out on the gas injection channel, the exhaust channel and the temperature monitoring drilling rock section, and a high-temperature-resistant cement sealing material 14 is filled.
The pedestrian's lane of ventilating 4 is for arranging in the rock tunnel of gasification coal seam bottom plate, and this pedestrian's lane of ventilating 4 horizontal elevation is the same with gasifier upper end elevation to have certain horizontal distance with the gasifier upper end point, have certain vertical distance with the gasification coal seam, this horizontal distance and vertical distance can guarantee the pedestrian's lane of ventilating and the safe isolation of gasifier heat affected zone scope. The ventilation pedestrian lane 4 is a construction lane of the gas injection channel 1, the exhaust channel 2 and the temperature monitoring drill hole 3, a directional drilling machine arranged in the ventilation pedestrian lane 4 is used for horizontally tunneling directional drill holes towards the coal seam, the directional drilling machine is bent and drilled according to a certain curvature when approaching the coal seam bottom plate, and after entering the coal seam, the coal seam gas injection channel 1 and the exhaust channel 2 in the gasification furnace are tunneled along the coal seam bottom plate. And an underground gas injection pipeline 11, an exhaust pipeline 13, a filling and grouting pipeline 15 and a drainage pipeline 16 are laid in the ventilating pedestrian lane 4. The pedestrian ventilation lane 4 is also a manual operation lane during the operation of the gasification furnace, and the transportation and ventilation in the lane meet the requirements of equipment transportation, drilling construction, gas emission, carbon dioxide emission, personnel respiration and the like of the existing coal mining.
In order to provide gasification agent for the gas injection pipeline 11 in the underground ventilation pedestrian lane 4, a vertical gas injection well 17 is drilled from the ground and connected with the underground ventilation pedestrian lane 4, and a pipeline is arranged in the gas injection well and connected with the gas injection pipeline 11 in the underground ventilation pedestrian lane.
In order to provide filling slurry for a filling grouting pipeline 15 in the underground ventilation pedestrian lane 4, a vertical filling well 18 is drilled from the ground and connected with the underground ventilation pedestrian lane 4, and a pipeline is arranged in the filling well and connected with the filling pipeline 15 in the underground ventilation pedestrian lane.
In order to convey coal gas in the underground exhaust pipeline 13 in the ventilation pedestrian lane to a ground coal gas pipeline, a vertical exhaust well 19 is drilled from the ground and connected with the underground ventilation pedestrian lane 4, and a pipeline is arranged in the exhaust well and connected with the underground exhaust pipeline 13 in the underground ventilation pedestrian lane.
The invention is further described below with reference to specific assays.
The hole diameters and directional drilling parameters of the gas injection channel drilling hole, the gas exhaust channel drilling hole and the temperature monitoring drilling hole are determined according to specific coal seam occurrence states (such as coal seam inclination angles, thicknesses and the like), the geological storage capacity of a gasification furnace, the gasification scale, the service life, the gas production scale and the like, and the reasonable size interval is generally between 100 and 300 mm.
The tunneling positions of the gas injection channel and the gas exhaust channel are not limited to the positions close to the bottom plate rock stratum at the bottom of the coal bed, and can be positioned at the lower part, the middle lower part or the middle position of the bottom plate of the coal bed according to design requirements and have a certain distance from the bottom plate rock stratum of the coal bed; or the drilling parts of the gas injection channel and the gas exhaust channel are positioned in the rock of the coal seam floor under the influence of the corrugation fluctuation of the coal seam floor.
The lengths of the single sections of the channel protection pipe, the gas injection pipeline and the gas exhaust pipeline are determined according to drilling parameters and field installation conditions, different installation positions can be different, and the generally reasonable length range of the single section is 3-6 m.
The installation distance of the hot-melt elastic connector is influenced by parameters of a gasification furnace (such as the thickness of a gasification coal bed, the storage capacity of the gasification furnace, the moving speed of a flame working surface and the length of a gasification channel) and the control effect of interval moving gas injection, and when the gasification coal bed is thick, the storage capacity is large, the moving speed of the flame working surface is slow, the gasification channel is long, and the control effect of moving gas injection needs to be improved, the distance of the hot-melt elastic connector can be properly increased; the reverse is true.
The invention is further described below in connection with the innovative points.
The invention constructs the narrow strip gasification furnace by drilling the directional drilling towards the coal seam in the rock roadway of the underground coal seam floor, the tail end of the directional gas injection channel of the gas exhaust channel drilling is drilled and communicated to form a gas injection and exhaust channel, and the gas injection and exhaust channels are uniformly distributed at the bottom of the coal seam.
The ignition of the coal bed in the gasification furnace is realized by the way that the ignition tube is used for inputting high-calorific-value combustible gas and oxygen to the through point of the gas injection and exhaust channel, and the front end of the ignition tube is provided with the electronic ignition device for igniting the combustible gas.
The mode of arranging the hot-melt elastic connectors at equal intervals in the gas injection pipeline in the gas injection channel realizes gas injection control, so that gas injection points retreat at intervals along with the directional movement of the flame working surface, and the smoothness of the gas flow state in the gasification furnace and the stability of the morphological structure of the reaction interface of the flame working surface are ensured.
Whether the flame working face moves to the position of a mining stop line is determined by arranging temperature monitoring drill holes and monitoring the change of temperature values, and when the temperature values of coal-rock junction points of a coal seam roof and the coal-rock junction points of a coal seam floor successively reach the high temperature (800-1000 ℃) close to the flame working face, the gasifier can be stopped.
Compared with the prior art scheme, its advantage is as follows:
the invention relates to a method for constructing a gasification furnace by drilling a directional well towards a coal bed and communicating the directional well by utilizing a bottom plate rock roadway of the underground coal bed. The furnace building method does not need to manually dig a coal seam tunnel in the gasification furnace to be used as a gasification agent injection tunnel, a gasification channel and a coal gas conveying tunnel, and does not need to build a large-scale isolation seal of the gasification furnace and an external tunnel after people quit. The coal bed is not tunneled and damaged, the integrity and the tightness of the coal bed are not damaged, the coal bed is disclosed and interfered as little as possible, and the gasifier has better tightness and pressure bearing performance in the operation process.
The length-width ratio of the narrow strip gasification furnace constructed by the invention is 10: 1-30: 1, the mining width of the gasification furnace is less than the limit span of the overlying strata, the complete structure of the overlying strata is not damaged, the large-area collapse of the overlying strata is not caused, the development height of the overlying strata fracture zone is effectively controlled, and the air tightness and the pressure-bearing property of the gasification furnace are ensured; and the method is combined with the combustion space area filling, so that the method has good rock stratum control effect and combustion space area pollutant control effect.
The gasification furnace gas injection roadway is internally provided with the gas injection pipeline and the effective movable gas injection device, the hot-melt elastic connectors are arranged on the gas injection pipeline at equal intervals, and when the flame working surface moves to the positions of the hot-melt elastic connectors, the hot-melt elastic connectors are sequentially disconnected and new gas injection ports are sequentially formed on the gas injection pipeline, so that the injection points of the gasification agent retreat at intervals along with the retreat movement of the flame working surface, and the smoothness of the gas flow state in the gasification furnace and the stability of the reaction interface morphological structure of the flame working surface are ensured.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (3)
1. The production method of the strip type underground coal gasification is characterized by comprising the following steps:
constructing a narrow strip gasification furnace by drilling a directional drilling well towards a coal seam in a rock roadway of a coal seam floor under a well, drilling the tail end of a directional gas injection channel of a gas exhaust channel and penetrating to form a gas injection and exhaust passage, and uniformly distributing the gas injection and exhaust passages at the bottom of the coal seam;
the coal bed in the gasification furnace is ignited by a way that a firing tube is advanced to a through point of an injection and exhaust channel in a gas injection pipeline of the gasification furnace, high-calorific-value combustible gas and oxygen are input through the firing tube, and the combustible gas is ignited by an electronic ignition device arranged at the front end of the firing tube;
gas injection control is carried out in a mode that hot-melt elastic connectors are arranged on gas injection pipelines at equal intervals in a gas injection channel, so that gas injection points retreat at intervals along with the directional movement of a flame working surface;
determining whether the flame working surface moves to a mining stop line position or not by arranging temperature monitoring drill holes and monitoring the change of temperature values, and stopping the gasifier when the temperature values of the coal-rock junction point of the coal seam roof and the coal-rock junction point of the coal seam floor sequentially reach the high temperature of 800-1000 ℃ close to the flame working surface;
the production method of the strip type coal underground gasification system specifically comprises the following steps:
igniting a coal bed in the gasification furnace: in the underground ventilation pedestrian lane, an ignition tube is advanced along a gas injection pipeline in a gas injection channel to the ignition point position at the tail end of the gas injection channel, high-calorific-value combustible gas and oxygen are input through the ignition tube, an electronic ignition device is arranged at the front end of the ignition tube to ignite the combustible gas, and a coal bed at the ignition point position is ignited to complete the ignition of the coal bed in the gasification furnace;
gasifying agent is injected and a gasification channel is formed: after the coal bed is ignited, the ignition tube exits from the gas injection channel; the combustion gasification position is gradually expanded from the connection point of the gas injection channel and the exhaust channel, and a gasification channel is formed between the gas injection channel and the exhaust channel to form a flame working surface;
the flame working surface moves backwards and the gas injection point moves backwards: during the normal operation of the gasification furnace, the flame working surface moves backwards along the length direction of the narrow strip gasification furnace, the hot-melt elastic connectors arranged at equal intervals in the gas injection pipeline in the gas injection channel are sequentially positioned at the flame working surface, the hot-melt elastic connectors are sequentially disconnected under the high-temperature action near the flame working surface, new gas injection ports are sequentially formed on the gas injection pipeline, and the new gas injection ports continue to provide gasification agents for the flame working surface; the gasification agent injection points are retracted at intervals along with the backward movement of the flame working surface;
and (3) gas discharge and transportation: the coal gas produced in the gasification furnace reaches a ground coal gas using point through a flame working surface, an exhaust passage, an exhaust pipeline, an exhaust road in a ventilation pedestrian lane, an exhaust drilling pipeline and a ground exhaust pipeline in sequence;
temperature monitoring and gasifier shutdown: monitoring temperature values of three temperature measuring points in the temperature monitoring drill hole in real time, and when the temperature values of coal-rock junction points of a coal seam roof and the coal-rock junction points of a coal seam floor reach the high temperature of 800-1000 ℃ of a flame working surface, stopping injecting oxygen or air into the gasification furnace when the flame working surface reaches a gasification furnace mining stop line position, and changing the injection into steam; stopping the operation of the gasification furnace;
in the step of injecting the gasification agent and forming the gasification channel, after the coal seam is ignited, the ignition tube exits from the gas injection channel, and simultaneously, the gasification agent is input to the ignition point position through a ground gasification agent preparation station, a ground gas injection pipeline, a gas injection drilling pipeline, a ventilation pedestrian lane gas injection pipeline and a gas injection pipeline in the gas injection channel in sequence, so that the coal seam is continuously combusted and gasified;
the gasifying agent is one or more than two mixed gases of air, oxygen and water vapor;
after the gasifier stops operating, when the temperature values of coal-rock junction points of the coal seam roof and the coal-rock junction points of the coal seam floor are reduced to be less than 100 ℃, and the concentration of the discharged gas components CO is monitored to be reduced to zero, the gasifier is completely extinguished;
after the gasification furnace is completely extinguished, the following steps are required:
filling a gasification furnace; after the gasifier stops operating, the filling slurry is conveyed to the gasifier combustion space area through a ground filling pump station, a ground filling pipeline, a filling drilling pipeline, a pedestrian ventilation roadway filling pipeline and a gasifier gas injection pipeline in sequence, and the whole gasifier combustion space area is filled with the filling slurry.
2. A strip coal underground gasification system using the production method of strip coal underground gasification according to claim 1, characterized by comprising:
a gas injection channel, an exhaust channel and a temperature monitoring borehole which are arranged in the coal seam;
the gas injection channel and the gas exhaust channel are directional drilling channels which drill from a gasification coal seam floor rock roadway to a coal seam;
the exhaust channel is parallel to the gas injection channel and tunnels linearly along the inclination of the coal seam, and when reaching the tail end point of the gas injection channel, the exhaust channel tunnels towards the tail end point of the gas injection channel in a bending way and is communicated with the tail end point of the gas injection channel, so that a through gas injection and exhaust channel is formed in the coal seam;
the temperature monitoring drill hole is positioned in the middle of the gas injection channel and the gas exhaust channel, is drilled in parallel with the gas injection channel and the gas exhaust channel, and stops until the coal-rock junction of the coal seam roof is reached; and a temperature thermocouple is respectively arranged at the coal seam roof coal rock junction point, the coal seam floor coal rock junction point and the position close to the wall surface of the ventilation pedestrian roadway in the temperature monitoring drilled hole.
3. The strip coal underground gasification system according to claim 2, wherein the gas injection channel comprises a rock horizontal section and a rock bending section outside the gasification furnace and a coal bed section inside the gasification furnace;
in a coal seam section in the gasification furnace, the gas injection channel and the gas exhaust channel are coal seam drilling channels which are tunneled along a coal seam bottom plate, and the tunneling direction is from top to bottom along the coal seam;
in the coal seam section in the gasification furnace, the gas injection channel is tunneled linearly along the coal seam trend and reaches the length designed according to the actual condition;
the parallel distance between the gas injection channel and the gas exhaust channel is the mining width of the gasification furnace, and the length of the coal bed section gas injection channel in the gasification furnace is the length of the gasification furnace; the width of the gasification furnace is smaller than the length value of the gasification furnace.
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| CN112127866B (en) * | 2019-06-25 | 2022-08-30 | 中国石油天然气股份有限公司 | Process for developing deep coal bed by using underground coal gasification technology |
| CN110159245A (en) * | 2019-07-05 | 2019-08-23 | 山东科技大学 | Distribution note exhaust passage narrow strips coal underground gasifying furnace production system and method |
| CN110778301B (en) * | 2019-10-22 | 2020-07-14 | 中国矿业大学 | High-temperature high-pressure steam secondary fracturing device and method for coal seam drilling |
| CN112627791B (en) * | 2020-09-24 | 2023-04-25 | 山东科技大学 | Mobile ignition system, device and method for underground coal gasification |
| CN112096358B (en) * | 2020-09-25 | 2022-11-25 | 山东科技大学 | Underground coal gasification mining method for drilling blasting cracking loosening coal seam |
| CN112483063B (en) * | 2020-12-17 | 2022-12-23 | 西安科技大学 | Underground interlayer type coal in-situ gasification mining system and construction method thereof |
| CN114718543A (en) * | 2022-04-19 | 2022-07-08 | 山东科技大学 | Pipeline cutting device and method for realizing underground coal gasification mobile gas injection |
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