Design and Simulation of an Igniter for Surrounding-Type Underground In-Situ Coal Gasification

To optimize the gas passage of underground coal igniters and enhance the performance and efficiency of ignition heaters, meeting the demands of actual underground operations, this paper designs a set of annular ignition heaters. By simulating the internal gas flow within the igniter, the pressure distribution and velocity characteristics inside the igniter are analyzed. Utilizing combustion flow field simulation technology, a comparison is made between the heating and ignition effects of annular igniters and central igniters in coal heating. The performance of the deflecting tube under different eccentric angles is simulated to determine the optimal eccentric angle for achieving the best heating effect. The results indicate that annular igniters for underground in-situ coal gasification have significant advantages over traditional igniters in terms of wellbore heating and flame penetration, with the optimal eccentric angle of the igniter being 10°.