A multi-index-classified early warning method for spontaneous combustion of coal under air leakage blocking

Judging development trends in coal spontaneous combustion (CSC) accurately has long been a global problem. Once a CSC phenomenon is found, the coal temperature tends to reach or exceed the critical temperature. To address this problem, the CSC characteristic parameter testing device is used to simulate the air reduction environment after the coal low temperature oxidation reaches the critical temperature, and long-flame coal was tested. The results show that the gas index can be used to judge the development trend and the characteristic temperature point for the initial stage of CSC. The development of oxidation at low temperature can be effectively predicted by using the composite indexes-Graham (G), CO/CO2 and 100x (C2H4/CO). Based on this information, a multi-index early warning method for comprehensive classification was proposed. The results have guiding significance for determining the development trend of CSC fires and fire prevention and extinguishing work. [Received: August 10, 2019; Accepted: May 26, 2020]