Characterization of Liquid Products from Slow Pyrolysis of Woody Biomass

In the present work, birch and spruce woodchips were pyrolyzed in a fixed bed reactor under different pyrolysis conditions. The effects of pyrolysis temperature and atmosphere (i.e., with and without gas purging) on yield and chemical composition of liquid products were investigated. The liquid products from the pyrolysis experiments were condensed, collected and analysed by using a gas chromatograph equipped with a mass spectrometer (GC/MS). The results showed that the yields of liquid products from pyrolysis of birch and spruce wood were different upon changes of pyrolysis temperature, purge gas flow rate and the different initial fuel chemical compositions. Higher yield of liquid products was obtained from pyrolysis of the birch wood at higher temperature or with purging of N2. The organic composition of liquid products from pyrolysis of spruce and birch wood is dominated by acetic acid, levoglucosan, and oxygenated aromatic compounds consisting mainly of phenol and phenol derivatives. Change of pyrolysis conditions caused changes in the chemical composition of liquid products from pyrolysis of birch wood. The chemical composition of liquid products from pyrolysis of birch and spruce wood are different, which is mainly related to different chemical composition of these two kinds of wood, being respectively hardwood and softwood.