LAUSR

Abstract The paper presents the results of chromatographic analyses of gas desorbed from freshly extracted different rank coal samples both, in the atmosphere of nitrogen and air. Samples in which coal remained in contact with nitrogen had higher concentrations of methane, ethane, propane, carbon dioxide, and hydrogen than in samples with air. On the other hand, samples in air found higher concentrations of carbon monoxide, ethylene, and propylene. When coal was in contact with nitrogen, the gaseous components present in the gas sample under investigation came mainly from natural desorption, whereas when coal was in contact with air, the oxidation of coal also occurred. In the process of natural desorption, mainly methane is emitted into the atmosphere of the mine along with the accompanying saturated hydrocarbons: ethane, propane and carbon dioxide. Diverse desorption of saturated hydrocarbons from the structure of coals results from the heterogeneity of hard coal and different content of hydrocarbons in the coal structure. No clear relationship was found between the content of desorbed hydrocarbons in the gas sample and the physicochemical properties of the tested coals. Carbon monoxide, ethylene and propylene are released as a result of contact of coal with oxygen from the air. The highest values of concentrations of carbon monoxide, ethylene and propylene were determined in gas samples desorbed from coals with the lowest, among the tested ones, degree of metamorphism and easily accessible internal pore structure.