Impact of fuel aromatic content on soot particle physicochemical properties of marine auxiliary diesel engine

Fuel aromatic content (AC) is one of the main reasons for PM (particulate matter) emissions from ocean-going ships. The present study investigates the influence of AC on physicochemical characteristics of soot particles from marine auxiliary diesel engine. The TEM (transmission electron microscopy), Raman spectroscopy, FTIR (Fourier transform infrared spectroscopy), and TGA (thermalgravimetric analyzer) are employed to jointly characterize samples. The results reveal that soot particles from high-AC fuel have bigger dp (primary particle size), longer fringe length (La), and higher graphitization degree, all of which have significant impacts on chemical properties such as more VOF (volatile organic fraction), higher concentrations of aromatic C-H and C=C groups. These are mainly due to several aromatic rings decomposed from aromatic components could promote the growth of carbon layer, and incomplete pyrolysis productions are also present in soot particles. The relative amounts of aromatic C-H and C=C are well correlated with dp and La, respectively