Movable ignition system, device and method for underground coal gasification

Abstract

The invention belongs to the technical field of underground coal gasification, and discloses a movable ignition system, device and method for underground coal gasification. The movable ignition system comprises a movable ignition device control module, a high-pressure combustible agent pipeline module, a temperature sensor module, a ventilation module, a power supply module, an electromagnetic heating igniter and a crawler belt moving module. According to the movable ignition system, device and method for underground coal gasification, ignition can be carried out in a movable mode as required under the condition that a large amount of underground water exists at the designed ignition position, and the problem that secondary ignition cannot be rapidly conducted after primary ignition fails in the traditional ignition technology is solved; an electromagnetic induction heating system can well protect an igniter structure and is stable in ignition, the ignition defect existing in electric ignition and other methods is effectively avoided, and the movable ignition device can be used repeatedly; under the dual action of a temperature control switch and a temperature sensor, fuel gas conveying is controlled, stable flames are formed, and the burning explosion phenomenon is eradicated; and a crawler-type moving system can pass through a complex structure in a drill hole or a sleeve, so that the operation is convenient.

Description

technical field [0001] The invention belongs to the technical field of underground coal gasification, and in particular relates to a mobile ignition system, device and method for underground coal gasification. Background technique [0002] At present, the foundation of today's world's energy composition is still dominated by fossil energy, and coal will occupy the dominant position for a long time. Traditional coal mining, transportation, and use methods will cause a lot of waste of coal resources. Due to the limitation of underground mining technology, about 50% of coal resources are abandoned underground, and the coal resources abandoned in old mines reach more than 30 billion tons; at the same time , Traditional coal mining and utilization methods have also brought many safety and environmental problems, such as coal mine safety accidents, occupational disease hazards, groundwater pollution, greenhouse gas emissions, surface subsidence, heavy metal pollution, and air poll...

AI Technical Summary

Problems solved by technology

In the wellless gasifier, the traditional ignition method is generally forced ignition. The commonly used forced ignition method is to put ignited coal into the borehole, and then supply air into the borehole to use the heat generated by the put in burning coal Ignite the coal seam to be gasified, but this method often causes ignition failure due to excessive heat absorption due to water evaporation in coal seams rich in water

Electric ignition is often used in wellless gasifiers, using electric heating to ignite combustibles arranged at the ignition point to generate high temperature and then ignite the coal seam. However, when this method is implemented, the electric heating device is prone to short circuit and cause failure.

When a well-type gasifier is ignited, an ignition device made of an electric heating plate is usually arranged manually in the gasification channel, and the wire is energized to heat and ignite. This method is different from the well-less electric ignition method. Similar, also prone to short-circuit problems

When gasification is carried out in deep coal seams, some special ignition methods are often used, such as silane ignition method, chemical solidification igniter ignition method, etc., but due to the poor observability and detectability of deep coal seams, such ignition methods There is also a greater chance of failure

[0008] In addition, scholars and institutions at home and abroad have also proposed a series of special ignition methods and ignition devices: the Chinese patent "An Underground Gasification Ignition Method" with the publication number CN103726818A proposes an underground gasification furnace for building directional drilling and vertical wells, The coal seam is pre-perforated by cold fracturing, and the method of igniting the coal seam and penetrating the gasification channel is achieved by exchanging the air holes at the end of the directional drilling in the vertical well at the end of the directional drilling. However, the process of this method is very complicated and requires additional vertical Drilling, the initial investment in furnace construction is large and there is no remedial measure after ignition failure; the Chinese patent "Ultra-deep Coal Underground Gasification Technology" with publication number CN101864941A proposes an underground gasification process and ignition method applicable at 800m to 3000m. After a passage in the deep combustion place, horizontal wells are drilled on both sides and a high-temperature-resistant retractable igniter is arranged, and the butane and electric ignition are used through the pressure of the air compressor

This method needs to drill a large number of wells in the deep coal seam in the early stage, which costs a lot, and the stability of electric ignition using butane in the deep coal seam is poor, the control is difficult, and it is easy to explode when ignited; the Chinese patent of publication number CN108729916A "An underground gasifier Coal Seam Ignition Device and Backward Repeated Ignition Gasification Method" proposes a gasifier ignition device suitable for horizontal wells with segmented gas injection point technology. The device uses a lifting coiler to drag the coal seam ignition device to compensate The cavity cannot trigger the next gas injection point, and the production cannot continue due to fire extinguishing. This device has a large defect in applicability. When used in a gasifier with a channel protection tube, the ignition device cannot pass through the protection tube smoothly. The connection buckle between the pipes and the possible coal bumps in the gasification channel, etc., the ignition device is likely to be stuck in the gasifier and cannot be used; the Chinese patent "Underground Coal Gasification Ignition" with publication number CN107461188A "Device and ignition method" proposes an ignition device, which is provided with a conveying pipe connecting the ground and the coal seam, using the conveying pipe to convey the self-combustible gas, and the annular space between the conveying pipe and the cementing casing conveys the combustion-supporting gas to the coal seam to realize ignition; The utility model patent "ignition device" with the publication number CN204327059U has improved the above-mentioned device, provided an inner tube and an outer tube, the outer tube is set outside the inner tube, the inner tube transports fuel gas, and the space between the inner tube and the outer tube transports Combustion-supporting gas, an ignition plate is set at the coal seam to realize gas mixing and ignition; the new patent "a coal underground gasification ignition device" with the publication number CN203614085U is also improved on the basis of the above-mentioned patent, and an ignition device is set at the bottom of the inner tube The mechanism can achieve the effect of igniting the ignition point and the nearby coal seam, but there are certain hidden dangers in the casing gas transmission method of the above-mentioned devices. There may be leakage and mixing of fuel gas and combustion-supporting gas during the transportation process, and ignition will cause explosion. Destroying the ignition device, the safety is poor; the Chinese patent "water-bearing coal seam water control igniter" with the publication number CN101382066B proposes a device for igniting by using resistance wire to energize and generate heat. Heating up and igniting, but the device needs to consume a large amount of electric energy when igniting the ignition point with a large water content, and the circuit is prone to short-circuit failure; the Chinese patent "Mobile Ignition Device for Underground Coal Gasification" with publication number CN102635346A proposes a portable mobile ignition device. The ignition system of the device has realized the separation of the combustion accelerant and the combustible agent, but the mobile device of the system is not perfect, and can only realize mobile ignition, and it is easy to get stuck in the casing when it is applied to the gasifier with gas injection casing technology buckle, and additional drilling is required for ignition and air supply, which increases the construction cost

[0009] The disadvantages of the traditional underground coal gasification coal seam ignition method are obvious: when the forced ignition method is applied in a coal seam rich in groundwater, a large amount of heat will be absorbed due to the evaporation of water, resulting in the extinguishment or insufficient temperature of the hot coal put into the borehole To ignite the gasified coal seam; electric ignition is to arrange heating devices such as electric heating plates in the gasification channel, and to raise the temperature of the heating plate through power supply to ignite the combustibles placed at the ignition place to ignite the coal seam. However, the electric igniter is easily damaged and short-circuit and other failures occur; the silane ignition method has extremely high safety requirements, and silane is very expensive and difficult to carry out large-scale underground coal gasification ignition; the chemical coagulant ignition method has problems such as difficulty in putting in

Among the many new technologies currently proposed, there are also certain technical problems: the Chinese patent "An Underground Gasification Ignition Method" with the publication number CN103726818A proposes a method for building a furnace and igniting it, but this method requires a large initial investment. There is a lot of preparation work, and more vertical drilling is required to better implement, and there is no remedial measure after one ignition failure; the Chinese patent "ultra-deep coal underground gasification technology" with publication number CN101864941A proposes a furnace construction process and The high-temperature-resistant telescopic igniter uses electric power to ignite butane for ignition. This method has complex processes, large capital investment, and high requirements for safety and stability; the Chinese patent with publication number CN108729916A "A kind of underground gasification Furnace coal seam ignition device and retreat type repeated ignition gasification method", this device has a large defect in applicability, when used in a gasifier with channel protection tubes, the ignition device cannot pass through the gap between the protection tubes smoothly The connection buckle and possible coal bumps in the gasification channel, etc., the ignition device is likely to be stuck in the gasifier and cannot be used; the Chinese patent "Underground Coal Gasification Ignition Device and Ignition Method" of Publication No. CN107461188A The ignition system proposed by "has potential safety hazards, and can not realize secondary ignition; the ignition device of the Chinese patent "water-bearing coal seam water control igniter" with the publication number CN101382066B needs to consume a large amount of energy when igniting the ignition point with a larger water content Electric energy, and the circuit is prone to short-circuit faults; the Chinese patent "Mobile Ignition Device for Underground Coal Gasification" with publication number CN102635346A is easy to get stuck at the buckle of the casing when it is applied to the gasifier with gas injection casing technology, and the ignition supply Wind requires additional drilling, increasing construction costs

[0013] It is necessary to design specific parameters such as the wheelbase and height of the mobile ignition device according to the specific actual data of the intake passage and the passage protection pipe, and it is impossible to design a general-purpose mobile ignition device;

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