Site Trials and Demonstration of a Novel Pilot Ventilation Air Methane Mitigator

Ventilation air methane (VAM) mitigation has been challenging to the coal mining industry because (1) VAM represents the largest proportion of coal mine methane emissions, (2) its air volume flow rate is large and the methane concentration is dilute and variable, and (3) it is almost 100% moisture saturated, and contains dust. This paper presents a novel pilot-scale VAM mitigator (VAMMIT) with a newly structured regenerative bed consisting of honeycomb monolith ceramic blocks for VAM destruction. The bed is designed to process 0.5–1 N·m3/s ventilation air. For the first time, a series of site trials of the VAMMIT prototype unit using actual ventilation air (VA) with 0.25–1.0 vol % methane was successfully carried out at an Australian coal mine site. The site trial results showed that the VAMMIT unit was able to operate as a thermal flow reversal reactor and was self-sustainable at VAM concentrations between 0.3 and 1.0 vol %. The pressure drop across the regenerative bed was 853–923 Pa, implying the potential to significantly reduce the energy consumption and VAM abatement cost. Regardless of the inlet VAM concentrations, less than 0.02% CH4 was measured in the flue gas. On average, over 96% of methane oxidation efficiency was achieved through the novel regenerative bed. The influence of dust on the mitigator’s performance was found negligible through a 2-week site trial with actual VA only. The VAMMIT unit is the first of its kind in the world, possessing significant advantages over other packed-bed mitigators in terms of no dust deposition, less footprint, and lower energy consumption.