Coal oxidation with air stream of varying oxygen content and flow rate - Fire gas emission profile

The knowledge of the behavior of coal undergoing oxidation under various conditions is important for the prevention and control of mine fires. The aim of the work was to investigate carbon oxides, ethane, propane, propylene and ethylene emissions from coal oxidation using an air stream of varying oxygen content. The experiment included the heating of coal in the temperature range of 30-210 degrees C at atmosphere that contains 10%, 15% and 21% oxygen. The results showed that oxygen enrichment in the atmosphere increases the chemical activity of coal and the amount of gases produced due to reaction. At the temperature of 90 degrees C, the reduction of the oxygen amount by half resulted in the decrease in outflow gases concentration by two times, while at the temperature of 130 degrees C by three times. The measurements confirmed the existence of a critical temperature (in the range of 80-90 degrees C) defined as the temperature above which the coal temperature and the amount of released gases increase rapidly. Coal sample heating was also tested at air flow rates of 0.05 L/min and 0.1 L/min, at the temperatures of 90 degrees C and 120 degrees C.