Effect of Surface Reactions in Catalytic Combustion

摘要

Experiments were conducted in order to better understand the role of catalytic surface reactions in determining the ignition characteristics of practical catalytic combustors. Measurements of hydrocarbon concentrations, carbon monoxide and carbon dioxide concentrations, hydroxyl radical concentrations and gas temperature were made at the exit of a platinum coated, stacked plated, catalytic combustor during the ignition of lean propane-air mixtures. The substrate temperature profile was also measured during the ignition transient. In these experiments, ignition was initiated by suddenly turning on the fuel and the time to reach steady state was of the order of ten minutes. The gas phase reactions, which were clearly observable from these measurements, showed no pronounced effect due to the catalytic surface reactions, except possibly the absence of an hydroxyl radical overshoot. The transient ignition measurements were found to be valuable in understanding the steady state performance characteristics.