Simulation study on catalytic oxidation of low concentration mine gas in an oxidation device

Anthropogenic emissions of non-CO₂ greenhouse gases, such as low-concentration coal mine methane (cCH₄ < 30 vol%), have a significant impact on global warming. The main component of coal mine methane is methane (CH₄), which is both a greenhouse gas and a high-quality clean energy gas. To study the combustion and heat transfer reactions of low-concentration coal mine methane in a catalytic oxidation device, a numerical simulation approach was employed to establish a model of the catalytic oxidation device that includes periodic boundary conditions, methane combustion mechanisms, and turbulent-laminar flow characteristics. The core focus of this study is on the dynamic changes in the bed temperature of the oxidation device, the temperature of the extracted hot air, and the methane conversion rate. By varying parameters, the study explored the effects of factors such as methane concentration, switching time, and the amount of hot air extraction on the combustion efficiency and safety within the oxidation device. Furthermore, the optimal placement of the catalyst within the device was refined. The results indicate that the methane concentration in the oxidation device should not exceed 1.8 vol% to avoid equipment damage and potential safety risks due to excessively high methane concentrations. Under conditions where the methane concentration is between 1.6 and 1.8 vol%, the appropriate switching time is 30-60 s, and the amount of hot air extraction should be maintained within the range of 15-20% to achieve efficient combustion and heat transfer performance. Additionally, the placement of the catalyst needs to be finely adjusted according to the changes in the internal temperature field of the oxidation device to ensure the maximization of catalytic effects. This study not only provides theoretical basis and technical support for the efficient utilization of low-concentration coal mine methane (LC-CMM) but also offers references for its widespread promotion and application in the industrial field.