spontaneous heating of coal; coal pre-treatment; gas evolution

Two samples of bituminous coal were studied to describe changes in evolution of the gases indicating early stage of spontaneous combustion process. Three types of coal pre-teatment procedures were used to simulate in situ conditions of the coal lying near the ?spon-com? site in the sealed off area: i) pre-oxidation of coal (200, 250°C), ii) pre-heating of the coal under inert gas (200, 250°C), and iii) extinguishing of pre-heated coal (200, 250°C) by liquid water. After the pretreatments, amount and composition of gases evolved from the coal during aerial oxidation at temperatures 40 - 200°C were measured at continuous flow reactor. Irrespective of type of the pre-treatment, oxidation of the pre-treated coal was found to be accompanied by increased CO evolution in comparison with not-treated coal (up to temperature 100°C).