Ozone Activated Low Temperature Combustion of Propane in a C.S.T.R.

Abstract

The gas phase ozone activated oxidation of propane is investigated in the temperature range 350-530 K by means of thermal analysis and identification of reacting species through the different steady states attained by the system in a continuous stirred tank reactor, System reac-tivities are evaluated in terms of the overall heat release rates measured under steady state conditions. Products are analyzed by means of gas-chromatographic and chemical methods. A negative temperature coefficient of the reaction rate occurs above 485 K. Results indicate that in the investigated temperature range the propane oxidation process is not adequately sustained by propagation steps leading to branching intermediates. Radical-radical reactions of s-propyl peroxy radicals and partly their decomposition products appear to be favoured. The negative temperature coefficient of the reaction rate is caused by the increased rate of ozone thermal decomposition as compared to initiation and propagation reactions with increasing reaction temperatures. The minor differences recorded between propane and n-butane behaviours are also explained on the basis of reaction patterns responsible for the observed product distributions.