Abstract
Biomass is the world's largest source of renewable energy and can replace part of the fossil sources. Main components of biomass are cellulose, hemicelluloses and lignin, which are compounds of C, H and O and represent high energy content. Fast pyrolysis (flash pyrolysis) at temperatures up to 500 °C for a time of few seconds gives a high yield of bio-oil to around 80 %, containing hundreds of components, such as alkanes, alkenes, cyclic hydrocarbons, aromatics, phenols, also ketones, esters, ethers, sugars, alcohols and others. Bio-oil can be directly used as fuel in boilers or after upgrading as motor fuel and a source of chemicals. By upgrading, the catalytic cracking in the presence of zeolites and hydrogenation are mainly used. The paper describes the results of fractionation of bio-oil by aqueous extraction. The yield and composition of the obtained fractions are given.
