Global reaction schemes for hydrocarbon combustion

Abstract

Global reaction schemes for the combustion of alkane hydrocarbons up to butane in mixtures with air in premixed and diffusion flames have been derived using analysis of flame structures. The schemes include two competing fuel breakdown reactions, and equilibrium assumptions have been used to derive initial estimates of the forms of the rate expressions. The deduced four-step reaction mechanism is C n H 2n+2+ n 2 O 2⤳n CO+(n+1) H 2 C n H 2n+n H 2O⤳n CO+(2n+1) H 2 H 2+ 1 2 ⇌ H 2O CO+ H 2 O⇌ CO 2+ H 2 The final kinetic parameters for the resulting rate equations have been determined by comparisons with experimental data for premixed methane and propane flames, along with diffusion flame data for a methane-air flame. The resulting schemes have been found to combine mathematic tractability with good agreement for a range of flame parameters such as flame speed, flame thickness, and species profiles.