An approach to calculate oxygen consumption rate of underground coal fires with lean oxygen concentration and incomplete combustion at high temperature.

air-fuel equivalence ratio and timescales of kinetic reaction and oxygen transport were used to analyze the combustion of underground coal fires at different temperature stages. At high temperature stage, due to the fast rate of kinetic reaction, oxygen concentration transported from galleries or cracks was lower than that required by theoretical kinetic reaction. Thus the oxygen consumption rate of coal combustion was controlled by oxygen transport rate and the coal fires were incomplete combustion because of lean oxygen concentration. According to the Single-Particle Reaction- Diffusion model proposed by Krishnaswamy, a formula to estimate oxygen consumption rate of underground coal fires with lean oxygen concentration and incomplete combustion at high temperature was developed. A numerical case study was conducted to analyze and examine the proposed formula. The investigated results show that the proposed formula can effectively estimate oxygen consumption rale controlled by oxygen transport at high temperature. [ABSTRACT FROM AUTHOR]