Bio-oil, produced from biomass feedstock like rice hull, straw, wood flour and other biomass wastes by fast pyrolysis where the biomass feedstock is heated and pyrolized with a rapid rate and the pyrolysis gases produced are condensed rapidly, is an interesting potential alternative fuel oil.
Cooling rate of the biomass pyrolysis gas is an important factor effecting the production of bio-oil. In order to speed up the cooling rate, the high temperature biomass pyrolysis gas is cooled and condensed by spray droplets of produced bio-oil with low temperature in this paper. It was assumed that the chemical reactions among the components of pyrolysis gas can be ignored, a theoretical model based on the classic film model and the Maxwell-Stefan equation was presented to simulate the heat and mass transfer characteristics of the spray condensation of biomass pyrolysis gas. The effects of the initial pyrolysis gas temperatures, the initial bio-oil droplets temperatures and diameters, and the flow ration of the gas and the liquid droplets on the heat and mass transfer between the gas and the liquid droplets were analyzed by the model.