Recycling methane from ventilation air is an effective
means of
reducing greenhouse gas emissions, improving gas utilization efficiency,
and developing green mines. Regenerative oxidation properties of ventilation
air methane (VAM) blending with dimethyl ether (DME) in a thermal
reverse flow reactor were investigated. By analyzing the operating
conditions, the influence of key process parameters on methane conversion
was determined. The results showed that the addition of DME could
greatly shorten the ignition delay time, lower the ignition temperature,
and significantly enhance methane conversion. The initial temperature
had the greatest influence on methane conversion, followed by methane
concentration, whereas the effect of VAM flow on methane oxidation
does not increase with an expanded flow rate, and there is an optimal
flow rate range adapted to the reactor size. Additionally, methane
conversion increases gradually as the equivalent ratio increases,
but the temperature field does not change noticeably. Furthermore,
understanding the reaction characteristics and mechanism of the CH4/DME mixture is critical for improving methane conversion
and thermal utilization efficiency. Temperature sensitivity and rate
of production during the oxidation process were analyzed, which revealed
that R145 and R1 show positive effects, while R189 and R146 have an
inhibitory effect at different DME mixing ratios and initial temperatures.
For OH, the most significant promotional reaction was R1, while R27
had the reverse effect. In general, regenerative oxidation of the
VAM/DME mixture contributes to an increase in methane conversion and
stability of the self-sustaining operation of the system. Therefore,
it is feasible to recover the thermal energy produced during the oxidation
process for comprehensive utilization. This technology is of great
practical importance for the improvement of methane utilization rates
and the promotion of the objective of zero gas emissions in coal mines.