Combustion Characteristics of Ventilation Air Methane Blending with Ether in a Thermal Reverse Flow Reactor

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.

Automated summary

Recycling methane from ventilation air can effectively reduce greenhouse gas emissions, improve gas utilization efficiency, and develop green mines. The regenerative oxidation properties of ventilation air methane (VAM) blending with dimethyl ether (DME) in a thermal reverse flow reactor were investigated. The addition of DME greatly enhanced methane conversion by shortening the ignition delay time and lowering the ignition temperature.