oa GASEOUS POLLUTANTS GENERATED DURING DRY AND HYDROUS PYROLYSIS OF COAL WASTE: SIMULATION OF THE SELF-HEATING PROCESSES

Pyrolysis experiments were conducted without and with water in temperatures 250, 360 and 400oC during 72 h to simulate pollutants generation from self-heating coal wastes under oxygen-depleted conditions. The molecular composition of gases generated during these experiments and their relationship with the amount of organic matter in the rock (TOC), its maturity, the temperature of the process and the influence of the water was determined. Alkanes up to C8 and alkenes to C4 were identified. The sulphur-containing compounds comprise inorganic (H2S, COS/SO2) and organic (methyl- and ethyl mercaptans, and methyl-, ethyl-, propyl- and butyl sulphides) components. The H2, CO, CO2 and N2 were recorded among the inorganic gases. The molecular composition of generated gases strongly relates to the temperature of the process. The concentration of usually increase with the increasing temperature of pyrolysis. Presence of water and elevated TOC amounts boost generation S-compounds (dominated by H2S). Presented results helped to understand and evaluate the emission of gaseous pollutants during pyrolysis of the stored coal wastes induced by self-heating. The most dangerous to the environment is the 300–400°C regime connected with the emission of elevated concentrations of hydrocarbons and S-containing compounds, especially from TOC-rich rocks.