A study on the effects of using different ignition sources on explosion severity characteristics of coals in oxy-fuel atmospheres

•We searched the explosion severity characteristics and the burning velocity of two types of coals in Oxy-fuel atmospheres.•We studied the impact of the alternative ignition source on explosion characteristics.•The maximum pressure, maximum rate of pressure rise and burning velocity depend on oxygen concentration in oxy-fuel.•Applied ignition source has a significant influence on the maximum rate of pressure rise.•Ignition source impact on the maximum pressure is negligible.

In this study, the explosion characteristics of coal powder in O2CO2 atmospheres are studied. All experiments are performed in a 20 L spherical vessel. The maximum explosion pressure and the maximum rate of pressure rise are derived from the pressure time evolutions. A three-zone theoretical model has been applied to calculate the flame speed. To overcome the drawbacks of the non-spherical flames generated by pyrotechnical igniters, a continuous ignition spark is used as an alternative ignition source. The experimental results show that maximum explosion pressures are similar when different ignition sources are used. The maximum rate of pressure rise and the flame velocity are very sensitive to the ignition source.