Fast Pyrolysis of Biomass

Abstract

Pyrolysis Gas Chromatography (PGC) was used to study the devolatilization of wood under conditions of high heating rates, short residence times, high temperature and rapid-quenching. A new technique of placing the sample in the pyroprobe was used which minimized resistance of heat transfer to the sample and ensured immediate quenching of the primary products of pyrolysis. The aim of the study was to identify the parameters leading to maximum gas yields and minimisation of tar in the pyrolysis step of biomass as a precursor to gasification in a fluidized bed gasifier. The experimental variables examined were the final temperature, the heating rate, the geometry of the sample and the dimensions of the sample. In the final temperature range of 600 – 900°C the yield of gas increased while the yields of char and tar decreased with increasing temperatures. The heating rate had practically no effect on the product distribution of complete pyrolysis. The diameter of the sample had little effect on the char yield but the tar yield was increased at the expense of the gas yield.