Performance of Auto-Cyclic Reactor in Catalytic Combustion of Lean Fuel Mixtures

Abstract

This work examines the experimental assessment of the conditions required for sustainable autothermal catalytic combustion of mixtures of lean fuels (methyl ethyl ketone (MEK), acetone, propane, and methane) in a small nonadiabatic laboratory auto-cyclic reactor (ACR) loaded with a combination of laboratory-prepared monoliths and commercial palladium catalyst pellets. Despite the non-optimized physical parameters of this reactor, the experiments demonstrated that, for a given fuel, the domain of autothermal operation is dependent primarily on fuel/catalyst reactivity that, in turn, dictates the minimum heat output (power) requirement of the air/fuel mixture and, to a lesser degree, flow rate. In correlation with the reactivity of individual fuels, the power requirement for a flow rate of 64 L/min (ambient) increased, from 375 W for MEK and acetone to ∼480 W for propane and 613 W for methane. For propane and methane combusted under the limiting conditions, oscillatory behavior was observed with the periods that correlated with the power of the fuel/air mixture. When the methane/air feed mixture was heated to 400 °C before entering the ACR, sustained combustion was assured for 0.6% methane flowing at a rate of 97.2 L/min.