Effect of Methanol Additives on Soot Inhibition during n-Decane Pyrolysis

The soot emission during fuel pyrolysis is harmful to the human health, environment, and engine fuel efficiency. In this work, the effect of methanol addition on soot inhibition of n-decane pyrolysis was investigated both theoretically and experimentally. Thermal cracking and coking experiments of n-decane show that the coke mass decreases significantly with methanol addition. Molecular dynamics (MD) simulations indicate that the oxidative radicals (OH, HCO, and CH2OH) from the methanol additive will oxidize the key precursors (such as C2H2, C3H3, and C5H5) of polycyclic aromatic hydrocarbons (PAHs) to stable oxides. Six key reactions were determined and found to play a key role in inhibiting the soot formation. The corresponding kinetic parameters were calculated at the CCSD(T)/CBS level for kinetic simulations by adding to the CRECK model. The simulation results show that the mole fractions of C2H2, C3H3, C5H5, and BINs decrease significantly with methanol addition. It indicates that the methanol addition can inhibit the soot formation, which is in good agreement with the experimental findings. We hope that this comprehensive work can provide significant information for soot inhibition.