Investigation of the Kinetics of Catalyzed Combustion of Fuel

A program of fundamental studies in catalytic combustion is described. Argon-diluted mixtures of fuel and oxygen were spontaneously reacted on platinum family surfaces. The specific surface reaction rate of fuel was obtained using an analytical program treating both mass transport and chemical reaction. Observed activation energies range from 5 Kcal/mole for propylene to 20 Kcal/mole for methane. Conditions of test varied from 250 to 500 C inlet at fuel-air equivalence ratios of 0.4 to 3.0. Two-fuel mixtures were studied to determine the extent to which a more-reactive component influences the system. For mixtures of 10% propylene in methane, the reaction is essentially the same as for propylene alone, although methane under similar conditions is nearly unreactive. The condition of the surface was varied by pretreatment with fuel or oxygen. An extension in the transient time to steady operation was found, but neither suppression nor change in steady-state efficiency was seen, and the effect is entirely reversible. Interaction of NO with hydrogen reactions was observed by addition of NO to inlet mixtures. A threshold temperature of 700 C appeared to be required for reduction in excess of 50%. (Author)