Energy recovery from ventilation air methane via reverse-flow reactors

• Huge amount of methane is emitted to the atmosphere with coal mine ventilation air.
• Methane emission increasing the greenhouse effect causes great loss of valuable fuel.
• Thermal CH4 combustion in a reverse-flow is a promising solution to the problem.
• Kinetic and simulation studies performed provide a solid basis for development.

Nearly 70% of the methane released from hard coal seams, as the so-called Ventilation Air Methane, is emitted to the atmosphere with the air discharged by the mine ventilation system. Therefore, utilization of this emission, especially with a rational heat recovery becomes an important challenge for hard coal mines. The paper proposes combustion in Thermal Flow Reversal Reactors, currently as the most promising and technically advanced method of solving this problem. The operating principle of such reactors is briefly described with a short review of the current literature on the subject, particularly focussing on aspects of heat recovery. A progress report of research and development activities, carried out in the recent years in the Institute of Chemical Engineering, Polish Academy of Sciences in Gliwice, Poland, has been given. This part provides a brief overview of kinetic studies on thermal combustion, results of experiments carried out on a research and demonstration plant, discussion of computer simulations as well as preliminary analysis of the possibilities of the process intensification. The article draws attention to the possibility of thermal asymmetry formation in the flow reversal reactors. The ways of the process control to prevent asymmetry are also discussed.

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