DIESEL COMBUSTION OF AN ALKYLATED POLYCYCLIC AROMATIC HYDROCARBON

The combustion of an alkylated PAH in a direct-injection diesel engine has been investigated using a low-aromatic diesel fuel spiked with 2- and 3-ethylphenanthrene. Exhaust samples were collected using a total exhaust solvent stripping apparatus (TESSA). The 2- and 3-ethylphenan threne were recovered in yields of 0.3 and 0.35 wt% respectively. The major product from the combustion of ethylphenanthrene was shown to be vinylphenanthrene, produced in a yield of 0.01 wt% of the total added ethylphenanthrene. Although there was no increase in the emission of phenanthrene or other PAH, a statistically significant increase in the emission of 3-methylphenanthrene was observed. These results suggest that for these isomers, under the engine conditions used, no significa nt dealkylation occurs. The results fit a model based on Dewar reactiv ity indices, which predicts the extent to which alkyl PAH isomers are dealkylated under pyrolysis conditions. Copyright (C) 1996 Elsevier Sc ience Ltd.