Kinetics of Soot Formation Investigations into the Mechanism of Soot Formation in Hydrocarbon Diffusion Flames

Abstract

In most of the studies and theories about soot formation, the starting point of the discussion is the acetylene, disregarding the previous phase which covers the decomposition of the higher hydrocarbons to acetylene

In our opinion the primary reaction step of soot formation in diffusion flames is this decomposition by a thermal cracking process in the gaseous phase. The decomposition rate depends mainly on the molecular structure of fuels

We have shown that the dependence of soot formation on the fuel properties can be described by a simple linear relation between the concentration of soot (R_c) and a dimensionless characteristic fuel number BKZ. Instead of BKZ it is possible, to choose the free enthalpy of formation for characterising the decomposition properties of hydrocarbons also

It is suggested that the clear distinction of the effect to be ascribed to the influence of the fuel on the one hand and the conditions of combustion on the other will give a better insight into the mechanism of soot formation, to find out which of these influences are predominant for producing soot in the flame or to avoid it in the products of combustion.