An experimental and kinetic modeling study of propyne and allene oxidation

New experimental data for propyne and allene oxidation were obtained in a jet-stirred reactor (JSR) in the temperature range 800-1200 K at 1-10 atm for different fuel/oxygen equivalent ratios (0.2-2.0) Experimental data clearly indicate the different oxidation behavior of the two isomers and provide valuable information for extending the simulation capabilities of an already existing comprehensive kinetic scheme. Critical reactions are presented and discussed together with extended comparisons of model predictions with experimental data obtained in the JSR conditions, in the Princeton turbulent flow reactor (PTFR), and in a shock tube at higher temperatures. Finally. the effects on reaction paths of allene addition to a fuel-rich acetylene premixed flame are also discussed. Isomerization reactions proceeding cia direct and H addition routes are significant in the oxidation. As a result of H-abstraction reactions, both propyne and allene form the resonantly stabilized propargyl radical. These species are important intermediates ill all die combustion processes, and their successive reactions are relevant candidates in explaining the formation of aromatic and polyaromatic species, possible precursors of particulate and soot. The analysis of the mild combustion conditions of the JSR reactor also allows the reliability of the overall kinetic scheme to be extended to the so-called flameless conditions.