Ignition characteristics and CO emission of packed bed combustion of methane/air mixture

In order to gain further understanding of fluidized bed combustion, characteristics of ignition and CO emission of the gas phase combustion of methane/air mixture in a packed bed have been investigated. Temperature and CO₂ concentration measurements showed that the ignition of the mixture strongly depends on bed temperature but equivalence ratios of supplied mixtures. A large amount of CO is generated just prior to the ignition in the packed bed. Numerical simulation proved that such CO emission is due to the early stages of combustion, in which large heat release is not accompanied but some species started reacting. This CO emission is dominated by reaction delay time and residence time of the mixture in the bed.