The chemistry and structure of torrefied biomass

Abstract

Torrefaction has been identified as a potential means of enhancing energy production from biomass by improving feedstock handling logistics. Using thermogravimetric analysis, torrefaction of pine wood (Pinus radiata) was shown to follow a two step kinetic model. Based on the HPLC analysis of torrefaction products, it was proposed that this two-step model represents rapid hemicellulose loss followed by slower degradation of cellulose. Thermogravimetric analysis showed that torrefaction raised the activation energy of wood with respect to gasification by up to 100%, but longer treatment was shown to lower the activation energy to within 20% of the original. Based on NMR analysis, it is proposed that the apparent reactivity changes were due to disruption of cellulose crystallinity.