Известия Томского политехнического университета: Инжиниринг георесурсов (Jun 2019)
ON THE ISSUE OF STUDYING THE COMPOSITION OF HYDROCARBON GASES OF COALS AND DUST TO PREDICT THEIR POTENTIAL HAZARD
Abstract
The relevance of the research is caused by the need to ensure the safety of mining operations on high-gas-bearing outburst-hazardous coal seams, which are dangerous for dust. This direction is associated with the study of the entire composition of the gases of coal-bearing deposits and, in particular, of higher hydrocarbons, and assessment of their role in occurrence of explosive-fire situations and sudden releases of coal and gas in mines. Determining quantitative composition of hydrocarbon gases is a necessary component in identifying the level of outburst seams, as well as determining rational processing parameters of coal seams in order to decrease their gas content and dust-forming ability to reduce the risk of fire and explosion hazards in coal mines. The main aim of the work is to study the composition and quantity of hydrocarbon gases of high-gas-bearing outburst-hazardous coal seams, dangerous in dust; determine the temperature range during thermal degassing for complete recovery of sorbed hydrocarbons; compare the obtained data on hydrocarbons of coal and dust; assess the role of sorbed hydrocarbon coal dust in creating dust-explosion-hazardous situations in coal mines; calculate the amount of higher hydrocarbons in outburst coal seams. Methods: analysis of domestic and foreign experience; collection, systematization and analysis of information available in literary and stock sources on the number and composition of higher hydrocarbon gases of coal seams; gas chromatography using the «Crystal 5000.1» chromatograph, thermal degassing of coal and coal dust samples on the gas chromatograph «M-3700», screen analysis of the fractional composition of coal dust; methods of mathematical statistics for assessing the reliability of the results obtained by the number of higher hydrocarbon gases in coal and coal dust. Results. It was established that the main amount of sorbed hydrocarbons is released from coal during thermal degassing in the temperature range of 200–250 °C. The content of the ultimate hydrocarbons from methane to hexane in gases extracted from coals of the middle stage of metamorphism and coal dust amounted to 13,4–29,1 cm3/kg of coal and dust. The enrichment of desorbed hydrocarbons with heavy hydrocarbons was determined, with propane (C3H8) and butane (C4H10) being predominant, the release of which into the mine atmosphere can lead to decrease in the ignition temperature of the dust-air mixture, which represents a potential hazard of fire and explosion hazard in coal mines. The obtained data on higher hydrocarbons can be used to predict the degree of outburst hazard.
Keywords
