Development of a low-temperature water heating system based on the combustion of CH4 in porous-media

Abstract This paper develops a novel two-dimensional mathematical model for the combustion of CH4 within a porous medium for the heating of industrial process water. This model involves a global combustion mechanism, coupled with a population balance model for the sintering phenomenon. The time evolution of the pore size distribution of the porous medium and its effect on the combustion process were predicted and compared with experimental data in order to validate the model proposed herein, finding that the model properly describes the behavior for both stagnant and flowing water regimes. Although sintering occurred during CH4 combustion, it did not significantly affect the water heating process, indicating that this technology is suitable for industrial combustion processes. However, the CH4 did not combust completely under the experimental conditions of this work, motivating future burner modification for an improved fuel consumption rate. Finally, the gas and solid temperatures were similar, indicating that silicon carbide acts as a heat store.