THE RATE OF TEMPERATURE RISE OF A SUBBITUMINOUS COAL DURING SPONTANEOUS COMBUSTION IN AN ADIABATIC DEVICE - THE EFFECT OF MOISTURE-CONTENT AND DRYING METHODS

This work investigates the effect of the moisture content of coal on i ts spontaneous ignition in oxygen (40 degrees C-140 degrees C). It has been found that the highest heating rate is achieved at a medium mois ture content of similar to 7 wt% for an initial inherent moisture cont ent of the coal before drying (in dry nitrogen at 65 degrees C) of sim ilar to 20 wt%. This is particularly noticeable at temperatures below 80 degrees C and tends to support previous studies showing that a maxi mum oxidation rate occurs at such a moisture content in the same tempe rature range. Two drying methods have been adopted in the current work and the effects of their operating conditions on the heating rates ar e described.