LAUSR

Jurassic coal samples from Liuhuanggou (LHG) and Wudong (WD) coal mines, Xinjiang Province, China, were selected for oxidative thermal energy experiments. A temperature-programmed experimental system measured the variation of gaseous products and the changes in thermal energy release with temperature. Thermokinetic parameters, namely the apparent activation energy (Ea) and pre-exponential factor (A), of the coal samples for four heating rates were determined using a thermogravimetric analyser. During the low-temperature oxidation stage, two samples had temperature curves characterised by their production levels of the index gas (CO); the temperature changes were approximately equal, but the critical temperatures differed. The WD sample produced less CO gas. However, the maximum and minimum exothermic strengths of the two samples had some similarities to the temperature change curves. The characteristic temperatures for the coal samples were discovered using different heating rates. For the WD sample, the characteristic temperature varied according to the heating rate, and the thermogravimetry (TG) and derivative TG curves of the samples lagged with an increase in the heating rate. The characteristic temperatures of the sample increased with the increase in the heating rate. Isokinetic analysis (the Flynn–Wall–Ozawa and the Kissinger–Akahira–Sunose models) was used to calculate the thermokinetic parameters of the sample. The range of the heating rates was 2 to 15 °C min−1 for oxygen concentration of 21 vol%, and the Ea of the samples decreased with the increase in the heating rate.