Numerical Study of Self-Heating Maintenance Performance of an Integrated Regenerative Catalytic Reactor

Efficient utilization of low-calorific-value gases reduces emissions but remains challenging. Self-heat-maintained combustion uses fuel’s exothermic heat to sustain stability without external heat, yet the feed gas typically requires preheating (typically 573–673 K). This study innovatively proposes a compact regenerative catalytic reactor featuring an integrated helical heat-recovery structure and replaces empirical preheating with a user-defined function (UDF) programmed heat transfer efficiency model. This dual innovation enables self-sustained combustion at 0.16 vol.% methane, the lowest reported concentration for autonomous operation. Numerical results confirm stable operation under ultra-lean conditions, with significantly reduced preheating energy demand and accelerated thermal response. Transient analysis shows lower space velocities enable self-maintained combustion across a broader range of methane concentrations. However, higher methane concentrations require higher inlet temperatures for self-heat maintenance. This study provides significant insights for recovering energy from low-calorific-value gases and alleviating global energy pressures.