Effect of Temperature and Time Torrefaction on the Energetic Properties of Bracatinga Wood

Abstract

Torrefaction of Bracatinga wood was realized to determine the effect of temperature (200°C, 220°C and 240°C) and time (30 min, 60 min and 90 min) on its energetic properties. We found that the gravimetric yield of torrefied wood decreased from 99.27% to 85.60%. The heat treatment at 240°C for 60 min produced the less hygroscopic sample as evidenced by an equilibrium moisture content of 37% lower than fresh wood (control sample). In addition, torrefaction produced samples of higher fixed carbon and lower levels of volatile content, reaching a maximum increase of 21% and decrease of 9%, respectively. As the most important, the gross calorific value of terrified wood is about 5% higher than control. The increase of fixed carbon together with the reduction of both moisture and volatiles content show that this thermal treatment improve the energy content of torrefied wood that becomes a promising option for biofuels.