230 / 2018-05-05 08:03:24

Gases and thermal behavior during high-temperature oxidation of weathered coal

Spontaneous combustion process ‧ Characteristic temperature ‧ Initial exothermic temperature ‧ Thermal energy release

矿山职业健康与环境安全 > 防火

To investigate the spontaneous combustion characteristics of weathered coal, gas generation and thermal behavior of the contrast study on the weathered and fresh coal were adopted. A high temperature-programed experimental system was applied to simulate the spontaneous combustion process of the weathered and fresh coal. The characteristic parameters during oxidation between 30 and 650oC were obtained. The growth rate analysis method of the indicator gas was adopted to calculate the characteristic temperatures of high temperature coal spontaneous combustion. The C80 Calvet calorimeter was applied to capture the thermal behavior during the oxidation. Under the condition of the high temperature and low oxygen concentration, the weathered coal still kept oxidizing and releasing energy to maintain the oxidation. The concentration of gases produced by high temperature oxidation were smaller than that of fresh coal. The initial exothermic temperature of weathered coal was 43°C, which is lower than the fresh coal. There was a severe difference on thermal energy release of weathered coal and fresh coal in different oxidation stages. From critical temperature to crack temperature, the percentage of heat energy release of weathered coal was much smaller than that of fresh one.