The concept of an effective installation for burning methane from mine ventilation air

Abstract

This publication presents a concept for a system for utilizing methane contained in the ventilation air of hard coal mines. The developed system enables the conversion of methane’s chemical energy into electricity and usable cooling using well-known unit processes: adsorption. desorption. and combustion in a gas turbine. or in a turbine with an additional catalytic converter. A key element of the concept is the use of the chemical energy of ventilation air to regenerate the adsorption dryer and methane concentrator. which allows for high energy efficiency of the entire cycle. Calculations were performed for flow rates ranging from 82.900 m3 n/h of air with a methane content of 0.7% by volume to 248.000 m3 n/h of air with a CH4 content of 0.2% by volume. The installation. with a net capacity of 1.3 MW of electricity and 3.5 MW of cooling. allows for the utilization of an average of 691 kg/h of CH4 from ventilation air methane (VAM) and 314 kg/h of CH4 from methane drainage (CMM). These values   correspond to a reduction in CH4 emissions of 5.2 Gg CH4/year from VAM and 2.4 Gg CH4/year from methane drainage gas, assuming 86% availability. Economic analysis showed that the payback period depends significantly on the method of calculating emission costs. In variants that take into account the cost of CO2 emissions and the effect of avoided methane emissions. the payback period can be shortened to less than 9 years. The obtained results confirm that the proposed technology is an effective solution to the problem of methane emissions in the mining industry. enabling the simultaneous production of electricity and cooling with a positive economic balance.