Abstract
Biomass has been studied as an alternative for production of fuels. However, biomass presents some difficulties to overcome, such as its high moisture content, hygroscopic nature, low energy density, which causes high costs during transportation, handling, and storage. These difficulties could be overcome if the biomass is thermally treated. The solution is a torrefaction process, a thermal treatment to upgrade biomass to a higher quality and more attractive biofuel. The present work aimed to study the benefits of torrefaction process for the energetic properties of wood Eucalyptus chips. The raw and torrefied samples were characterized to compare the results. All analysis was performed according to the Standard Test Method (ASTM). The characteristics of the wood chips were determined by physic-chemical analysis as elemental analysis; determination of immediate analysis and Higher Heating Value (HHV). Temperatures degradation of lignin, cellulose and hemicellulose were determined by TGA/DTG (Thermogravimetric Analysis). According to the results, it was found that the roasting process has improved significantly the energy properties of biomass studied. The HHV has increased (around 30%) and the moisture (70%) and volatiles (around 60%) contents decreased. This demonstrates that torrefaction process is a viable procedure for energy conditioning of Eucalyptus biomass. Thermogravimetric analysis was conducted to show the dynamic weight of the eucalyptus biomass to understand the effects of temperature on torrefaction process. The trends of the TGA curves for the raw sample and torrefied sample at 250 °C are similar, were the samples that decreased a major biomass weight percent. This is due to the high amount of hemicelluloses was lost in these samples. In the stage from 260 to 300 °C, cellulose and lignin are the main energy components. TGA experiments have indicated that the torrefied samples presented different volatile release and burning profiles. This treatment causes significant changes in their properties and benefits for its transportation. Viable logistics and favorable changes of the torrefied biomass properties have different purposes for its application in the generation of thermal or electric energy.
