Lessons learned from fires of the wood caused by the spontaneous combustion of coal dust in underground mines

摘要

Undesired fires from self-ignition of energy would bring serious economic losses and cause emission of carbon dioxide and toxic gases. Recently, a wood burning accident caused by self-heating of coal in underground mines was investigated. The combination of calorific value, TG, DTG, DTA and SEM experiments provided sufficient information to understand the spontaneous combustion or pyrolysis behavior of wood in coal dust. Numerical simulation and Frank-Kamenetskii theoretical method were employed to study the distribution of coal dust for the purpose of verifying the source of the heat from coal dust. Eventually, wood burning happened when the heat produced by the coal dust spontaneous combustion around wood was not readily dissipated. A large amount of heat and flammable gases were generated, while the charring of wood happened slowly and the pyrolysis reaction rate was high enough. Spontaneous ignition occurred when the smoldering developed into flame combustion. In order to prevent such accidents, coal dust near the belt conveyor in underground mines was needed to be regularly checked and cleaned up. And underground wood or other related materials were required to be fire-retardant-treated in order to eliminate fire hazards.