Torrefaction of Short Rotation Coppice Willow. Characterization, hydrophobicity assessment and kinetics of the process

Abstract

Short Rotation Coppice Willow (SRCW) is one of the newest sources of renewable energy. Torrefaction enhances the initial poorest characteristics of SRCW, such as hygroscopicity or low heating value compared to traditional fuels, to use it as a fuel. Non-oxidative and oxidative torrefaction of SRCW were compared. Torrefaction were conducted within the range 200–240 °C and torrefied SRCW and released gases were characterized (proximate, ultimate, compositional and heating value analysis as well as hydrophobicity assessment, Py-GC/MS and chemical-kinetics parameters). At optimal torrefaction temperature, mass and energy yields were around 88% and 93%, respectively, moisture was reduced up to 1.22–1.28% and H/C and O/C atomic ratios up to 1.4 and 0.6, respectively. Biomass turns hydrophobic since contact angle increase and the amount of water absorb decrease in contact angle and liquid penetration studies, respectively. The global reaction order was 2 and kinetic constant values were in the range 4.6 10−5 s−1–3.6 10−5 s−1.