The code was validated on several steady-state, coflow diffusion flames (fed with H2, CH4 and C2H4), widely studied in the literature, both experimentally and computationally. The numerical simulations showed a satisfactory agreement with the experimental data, demonstrating the feasibility and the accuracy of the suggested methodology. Then, the C2H4/CH4 laminar coflow flames experimentally studied by Roesler et al. [J.F. Roesler et al., Combust. Flame 134 (2003) 249-260] were numerically simulated using a detailed kinetic mechanism (with ¡«220 species and ¡«6800 reactions), in order to investigate the effect of methane content on the formation of aromatic hydrocarbons. Model predictions were able to follow the synergistic effect of the addition of methane in ethylene combustion on the formation of benzene (and consequently PAH and soot).