The production of hydrogen from partial oxidation concepts (POX) is a topic of active research due to the imminent fuel cell revolution. We have used the advantages offered by porous media combustion, namely the fact that the reaction zone can be made to run at high temperatures (“superadiabatic” combustion), to stabilise ultra-rich premixed flames.
Porous foams and beds of packed beads of alumina have been used (Fig. 1) and we have burned methane, methanol, octane and commercial-grade petrol. Figure 2 shows that very rich flames can burn stably at equivalence ratios higher than the conventional rich flammability limit and that the present POX burner can be made to produce products close to equilibrium. A patent application has been filed.
Figure 1. The porous media burner used for stabilising very rich flames. Top view through a mirror located immediately downstream the porous foam.
Figure 2. Measured species mole fractions compared to calculated equilibrium composition for methanol.