An Experimental Investigation on the Devolatilization Behaviour of Raw and Torrefied Lignocellulosic Biofuels

Energy from biomass is recognised as the renewable energy source with the highest potential towards sustainable development in the near future. Devolatilization is a basic mechanism for all thermochemical processes (pyrolysis, combustion, gasification). A detailed characterization (including reaction kinetics and products distribution) of biomass devolatilization is required to provide fundamental parameters for the feasibility, design, modelling, optimisation and scaling of biomass conversion systems. In the present study the devolatilization behaviour of several biomass fuels of different origins was investigated: biomass from energy crops (miscanthus), agricultural residues (corn cobs, rice husks, vine prunings), and torrefied biomass (from palm kernel shells, with different degrees of torrefaction). Thermogravimetric (TG) analysis was used for the study of devolatilization parameters. An isoconversional model was used for the estimation of the kinetics. Furthermore, thermogravimetric analysis coupled with Fourier Transformed InfraRed spectroscopy of evolved gases (TG-FTIR) was applied to study the compounds evolving in the pyrolysis of the selected biomass fuels. Important information on the devolatilization behaviour, that is the identification and the quantitative determination of major volatile species and the temperature range of release, were obtained.