Kinetic Coupling of Steady-State Dry Reforming of Methane and Self-Oscillating Partial Oxidation of Methane over Nickel

Abstract

The occurrence of dry reforming of methane (DRM) in a steady-state mode and partial oxidation of methane (POM) in a self-oscillating mode over a nickel foil sample and the simultaneous occurrence of these two reactions have been studied. It has been shown that during the cooccurrence of the DRM and POM reactions, a kinetic coupling of these reactions takes place; it is evident as a change in the self-oscillation period and a significant acceleration of the DRM reaction in certain phases of the self-oscillation cycle compared with the DRM rate over this Ni sample in a steady-state mode. The DRM acceleration effect is observed in a temperature range of 600–750°C. The maximum increase in the CO₂ conversion value averaged over the oscillation period is a factor of 2.6 at a temperature of 700°C for a feed gas mixture composition of CH₄ : CO₂ = 1 : 1 + 3.5% O₂. In addition, the effect of O₂ concentration in a range of 0.5–3.5% on the increase in the DRM rate has been studied. An interpretation of the observed effects has been proposed.