Fire incidents in underground coal storage

Autoignition of coal in underground storage facilities is reviewed in the light of recent incidents of smouldering fires. The opportunities to prevent and extinguish closed-space fires are also considered considering the efficiency of the available alternatives. The challenges of such fires are highlighted by an example case, describing the observations and outcome of a smouldering coal storage fire. The principles of self-heating and most critical factors in spontaneous combustion such as the condition and quality of coal are fairly well known, but usually only provide partial help in fire prevention. The experience suggests that nitrogen injection can be useful for extinguishing controllable fires, while more extensive measures may be needed against uncontrolled fires. In general, efficient fire extinction during plant operation can be challenging, as any air ingress tends to feed the fire. Methods and indicators for predicting and detecting the ignition are discussed, and improvements are suggested to enhance the storage and plant availability. Also, new experience on dealing with frozen coal is discussed in brief.