Comparison of synergistic effect of ethylene-propane and ethylene-DME on soot formation of ethylene-air flame

Abstract

Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.In this study, the synergistic effects of ethylene-propane and ethylene-dimethyl ester (DME) mixtures on soot formation were investigated experimentally using a co-flow diffusion flame burner. The soot volume fraction, soot particle diameter, and number density were measured and compared to the homogenous mixture. Addition of DME and propane to the ethylene fuel increased soot volume fraction in the ethylene flames. The ethylene-propane has more pronounced synergistic effect in comparison to the ethylene–DME flames. This is due to the fact that during the decomposition of propane some methyl radicals are generated. The reactions related to these methyl radicals promote the formation of propargyl radicals consequently the formation of benzene through propargyl selfreaction and finally to the soot formation. Although DME decomposition produces methyl, C-O bond in the DME removes some carbon from the reaction path to form soot. Hence the soot formation in ethylene-DME mixture is much lower than that of ethylene-propane mixture.