The structural transformation and reburning characteristics of gas coal in Ningwu coalfield fire

Abstract

With the expansion of the scale of coal mining, the safety problems caused by the reburning of coal are becoming more and more serious. In this paper, the pyrolysis characteristics of gas coal and the exothermic characteristics of reoxidation of residues were studied by using a synchronous thermal analyzer. The functional groups of pyrolysis residues were tested, and the group content and characteristic structural parameters were calculated based on quantum chemistry method. The results show that with the increase of pyrolysis temperature, Volatile maximum separation rate (Vmax) and the change in the residual weight of the coal sample (ΔWvp) increase. The increase of temperature will lead to the decrease of hydroxyl and aliphatic hydrocarbon content in coal, and the increase of aromatic hydrocarbon. With the deepening of pyrolysis, the ignition point temperature of coal samples decreases first and then rises, the combustion intensity and combustion concentration are strengthened. The pyrolysis results show that 462.8°C is the critical temperature for the transition during pyrolysis. The ignition point of the residue is less affected by the pyrolysis conditions, and the ignition temperature of the raw coal and the pyrolysis residue varies within 330.57°C–334.98°C.