Study on the change of key groups and gasproduction mechanism of different degrees of coal under thermal effect

Abstract

The key active structure transformation process and gas generation mechanism of different degrees coal during low-temperature oxidation (LTO) under thermal effect were studied by quantum chemical methods, in situ FTIR and programmed temperature rise experiment. Results showed the C-O relative content gradually increased during LTO, and the temperature which the C-O content of low-rank coals increased sharply was earlier than that of high-rank coals, about 20 ℃-40 ℃ earlier. The C=O relative content gradually increased as the temperature increased. The overall content of COOH is lower in low rank coals during LTO, while the relative content of C=O gradually increases, the C-C/C-H content of coals with different degrees shows a similar decreasing trend during LTO, but the decreasing rate of high rank coals is smaller than that of low rank coals. The production of CO, CO2 and C2H4 shows a decreasing trend in stages as the rank of coals becomes larger.