The pyrolitic behaviour of non-conventional Diesel fuels in shock tube and single droplet experiments

The thermal behaviour of two "biofuels" has been investigated following different experimental approaches. A pure rapeseed oil has been tested at high temperature (1700-200K) and pressure (9-13 bar) in a shock tube environment. Its sooting tendency was assessed and compared with that of two pure hydrocarbon compounds, tetradecane and pentyl ether, and of a high grade diesel fuel. The soot yield of the rapeseed oil is lower than both the diesel fuel and tetradecane, and its average value is close to that of pentyl ether. A pyrolysis oil, obtained from mixed hardwood, was studied at ambient pressure in a drop tube furnace in the temperature range 20-850 °C. Light scattering measurement were used to follow the evolution of the oil droplets. Optical and electronic microscopy allowed to infer the size and the morphology of residual particles.