Study on the enhancement of ventilation air methane thermal oxidation performance through pulverized coal heat supplement

To address the instability of regenerative thermal oxidizers (RTOs) in treating low-concentration ventilation air methane (VAM), this study develops a pulverized coal (PC) co-firing system. The effects of PC addition and key parameters (particle size, PC injection rate, and air supply velocity) on the RTO system performance are evaluated by three-dimensional numerical simulations. The results demonstrate that PC co-firing significantly elevates combustion temperature, preventing system destabilization while enhancing methane conversion from 20% to 80%. Parametric analyses further reveal that reducing particle size from 90 to 10 μm increases PC burnout rate by 11% and methane conversion by 1.8%. Increasing coal injection rate from 0.6 to 1.8 g/s enhances methane conversion but raises NO emissions to 78.2 mg/m3. Further, changing air supply velocity from 1 to 3 m/s improves PC burnout by 17.6% while reducing methane conversion by 11%. The optimal methane conversion rate of 80.0% with controlled NO emissions of 49.3 mg/m3 is achievable with PC particle size, injection rate, and air supply velocity of 30 μm, 1.2 g/s, and 2 m/s, respectively. Generally, this approach overcomes conventional RTO technology limitations, offering an environmentally sustainable and engineering-feasible solution for efficient and clean VAM utilization.