Production system and method for distributed injection and exhaust passage narrow strip coal underground gasification furnace

Abstract

The invention belongs to the technical field of underground coal gasification, and discloses a production system and a method for a distributed injection and exhaust passage narrow strip coal underground gasification furnace; and the method comprises the steps of: sequentially performing coal seam ignition in the gasification furnace, injecting a gasifying agent and forming a gasification passage,moving back a flame working face and retracting a gas injection point, exhausting and transporting gas; temperature monitoring and stop operation of the gasification furnace, and gasification furnacefilling, meanwhile, the invention discloses a production system for distributed injection and exhaust passage narrow strip coal underground gasification furnace. The invention does not need to manually dig a coal seam roadway in the gasification furnace as a gasifying agent injection lane, a gasifying passage and a gas transportation lane, and does not need to construct a large isolation and sealing of the gasification furnace and the external roadway after the personnel exit; the purpose of not tunneling or destroying the integrity and tightness of the coal seam is realized, and the purposeof less disclosure and interference of the coal seam is achieved; the complete structure of the surrounding rock is kept, so the gasification furnace has good sealing and pressure bearing capacity during the operation process.

Description

technical field [0001] The invention belongs to the technical field of underground coal gasification, and in particular relates to a production system and method of an underground coal gasification furnace with narrow strips of distributed injection and exhaust channels. Background technique [0002] Currently, the closest prior art: [0003] Compared with traditional mechanized mining, underground coal gasification is one of the new mining methods for coal resources. A flame working surface (gasification reaction interface) is formed in the coal seam direction, and complex oxidation-reduction reactions and coal pyrolysis reactions occur. The coal underground stope needs to keep the internal space isolated from the external free space, so that there is gas pressure in the reaction space, preventing gas leakage and facilitating the reaction. [0004] The gas injection channel-reaction interface-exhaust channel should form a smooth air flow state, so that a stable air flow s...

AI Technical Summary

Problems solved by technology

[0015] (1) The existing furnace construction method needs to manually excavate the coal seam roadway in the gasifier as the gasification agent injection road, gasification channel and gas transportation roadway. It is difficult to construct an effective seal to completely isolate the high-temperature gas under the high-temperature pyrolysis and dry cracking environment in the coal roadway, and the larger the cross-section of the channel, the more difficult it is to completely isolate it. Once the isolation fails, it will cause serious safety accidents

[0016] (2) The existing gasifier gas injection roadway lacks effective gas injection pipelines and mobile gas injection devices

If there is no gas injection pipeline in the gas injection channel, the gasification agent will be transported from the open hole (or roadway) in the coal seam, causing the combustion interface of the flame working surface to flow upwards against the gas injection, expanding the combustion range to the gas injection channel, not only Enlarging the combustion range and boundary in the gasifier will also cause turbulence in the gasification furnace, and the mixed combustion of gasification agent and gas will reduce the quality of the gas; if there is no mobile gas injection device in the gas injection channel or the distance between the reserved gas injection ports When the value is too large, the injection point of the gasification agent cannot move with the directional movement of the flame working surface, and the distance from the gasification agent to the flame working surface from the burn-out area increases, resulting in turbulent air flow in the gasifier, which will also cause lead to lower gas quality

[0017] (3) The existing technology does not propose a suitable layout plan for the gasifier and the injection and exhaust channels in the furnace for thick coal seams and extra thick coal seams. Due to the occurrence characteristics of thick coal seams and extra thick coal seams, a single plane The layout of the type injection and exhaust channels cannot take into account the coal body in the height direction of the thick coal seam, resulting in the ineffective gasification of the top coal seam, a large amount of residual coal in the gasifier, and a decrease in the recovery rate in the gasifier

[0018] (4) The existing technology has poor control over the stability of the surrounding rock of the gasifier, and insufficient research and unclear understanding of the overlying rock stress distribution and movement and deformation laws of the thermal coupling between the underground coal gasification surrounding rock and the flame working face. The dimensional design of the gasifier fails to meet the requirements for the stability control of the surrounding rock, resulting in large-scale collapse of the overlying rock, excessive development of fracture zones, and communication with the aquifer, resulting in gas leakage in the furnace, a drop in gas pressure, excessive influx of groundwater, and even Flooded gasifier, causing major operational accidents

[0020] (1) The underground coal gasifiers and production systems constructed in the past have deficiencies in gas injection and surrounding rock control, as well as the controllability of the entire gasification process

[0021] (2) The scale of underground coal gasification is small and the gas production is unstable

[0022] (3) The existing technology is prone to cause operation accidents, safety accidents, low gas quality and low recovery rate

[0024] There is insufficient theoretical understanding of the rock mass damage characteristics of the thermal-mechanical coupling effect of the surrounding rock during the underground coal gasification process, and there is a lack of design methods and basis for the reasonable mining width of the underground coal gasification zone; another difficulty lies in the understanding of the underground coal gasification process. In terms of gas injection guidance and control, there is a lack of effective mobile gas injection devices, resulting in a mismatch between the position of the gas injection point and the movement of the gasification reaction interface, resulting in an unstable gas production process

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