Investigation of Intumescent Flame Retardant THEIC/APP on the Thermal Behaviors of Coal Based on Thermal Oxidative Kinetics

In this work, the influences of the intumescent flame retardant (IFR) composed of tri-(2-hydroxyethyl) isocyanurate (THEIC) and ammonium polyphosphate (APP) on the coal were studied in order to effectively prevent and control the coal spontaneous combustion. The effects of IFR on the thermal behaviors of the coal were investigated by Kissinger and Flynn-Wall-Ozawa methods. The results have shown that the mass ratio of THEIC/APP = 1:2 has the best effect on the coal. It has a better carbonization performance and thermal stability at high temperature. The activation energy of the treated coal with 30 wt% IFR was increased up to 283.1 kJ/mol, indicating it is more difficult to be oxidized than that of raw coal (168.4 kJ/mol). At 200 degrees C, the inhibition rate of coal treated by IFR reached approximately 56.5%. From fire extinguishing test, it can be found that an expanded carbonization layer was formed during the combustion for the treated coal with IFR which could effectively limit the transfer of heat, oxygen and combustible volatiles from the heat source to the coal, and prevent the coal from further burning. From this work, it is hoped to provide an efficient method to effectively prevent and extinguish the coal spontaneous combustion.