Effect of Coal Spontaneous Combustion Gases on the Laminar Burning Velocity of the CH₄/Air Premixed Flame

Abstract

In order to investigate the effect of coal spontaneous combustion (CSC) gases such as CO, C 2 H 4 , C 2 H 6 , C 3 H 8 , C 2 H 2 , and H 2 on the laminar burning velocity (LBV) of the CH 4 /air premixed flame, a constant volume chamber and a highspeed camera were used to measure the LBV of a 90% (in vol) CH 4 and 10% CSC gas mixed fuel at an initial temperature of 300 K and over a wide equivalence ratio range from 0.7 to 1.3. Results show that the addition of all the CSC gases increases the LBV of CH 4 . Among all CSC gases, the CH 4 /C 2 H 2 mixed fuel has the highest LBV, and the CH 4 /CO mixed fuel has the lowest LBV. With the addition of three typical stages of CSC gases, the LBV of CH 4 was significantly enhanced. Based on the reaction path, mole fraction, and rate of production analysis, it is found that the addition of CSC gases in Stage 2 can increase the concentration of C 2 H 5 and the consumption rate in the CH 3 −C 2 H 6 −C 2 H 5 path, which is different from Stages 1 and 3. In addition, all the concentrations of H, O, and OH free radicals increase with the addition of three typical stages of CSC gases.