Conference Dates

March 8-13, 2009


The pyrolysis of various agricultural wastes (grape residues, dried distillers grains, forestry residue and sugarcane residues) was carried out in a pilot-scale bubbling fluidized bed pyrolyzer operating at temperatures ranging from 300oC to 600oC , for vapor residence times ranging from 2 to 20 seconds. Products yields and properties, as well as process heat requirements were determined. The main objective was the optimization of the production of liquid bio-oil without any use of fossil fuel.

The composition of the product gases was measured, from which their heating value was calculated. The liquid bio-oil was recovered with cyclonic condensers and separated into an aqueous phase and an organic phase. The environmental parameters for the disposal of the distilled fraction (85oC to 115oC) of a typical aqueous phase were determined, while the heating value of the organic phase was measured. Furthermore, the thermal sustainability of the pyrolysis process for each biomass was estimated by considering the energy contribution of the product gases and of the liquid bio-oil in relation to the pyrolysis heat requirements. The optimum pyrolysis temperatures were identified in terms of maximizing the liquid yield, maximizing the energy from the product bio-oil, and maximizing the net energy from the product bio-oil after ensuring a self-sustainable process by utilizing all the product gases and some of the bio-oil as heat sources.

Different drying agents have been applied to the organic phase bio-oil to increase its heating value and therefore improve the fuel properties. The heating value can, thus, be increased by 21.5%.

The results show that some biomasses are more suitable for the production of char, whereas others tend to produce more bio-oil or gas.