Impacts of biodiesel and Fischer-Tropsch fuels on the reactivity and nanostructure of diesel soot

This work focuses on the impacts of biodiesel (B100), Fischer-Tropsch fuel (FT), and ultra low sulfur diesel fuel (BP15) on soot reactivity and nanostructure. A 2.5L, 4-cylinder, turbocharged diesel engine operated at 2400rpm and 64Nm was used in generating soot samples. The fuel injection parameters have been adjusted such that all the test fuels have similar combustion phasing. The soot samples were investigated by thermogravimetric analysis (TGA), X-ray diffraction (XRD), and Transmission Electron Microscopy (TEM). B100 soot exhibits the fastest oxidation on a mass basis with BP15 and FT soot in order of oxidation rate. XRD analysis shows that B100 soot has the smallest average number of stacking layers, while FT soot has the longest basal plane diameter. TEM image analysis confirms a relation between soot reactivity and nanostructure: the shorter fringe length and larger fringe tortuosity are related to the faster oxidation rate of soot even for B100.