The surface and gas-phase reactions in microscale catalytic partial oxidation of n-butane/air mixture

The surface and gas-phase reactions in microscale catalytic combustion can directly influence the fuel combustion characteristics. In this study, the catalytic partial oxidation of a rich n-butane/air mixture in a microscale honeycomb ceramic reactor with and without catalyst is investigated by conducting experiments. Experimental results show that, depending on the reaction temperature, the oxidation process of the rich n-butane/air mixture can be generalized into three regions, namely, controlled by surface reaction at low temperature (T < 600 K), controlled by gas-phase reaction at high temperature (T > 770 K), and controlled by combined surface/gas-phase reaction at medium temperature (600 K < T < 770 K). Meanwhile, kinetic analysis with detailed surface or/and gas-phase reaction mechanisms are conducted for the three regions and the major reaction paths are obtained to better understand the key reaction steps in the regions and the interaction between the surface and gas-phase reactions in the medium-temperature region. Kinetic analysis indicates that surface reaction occurs at low temperature and can inhibit the gas-phase incomplete oxidation and pyrolysis to a certain extent.