Torrefaction of Wood Pellets in Uruguay: Effect in the Energy Properties

Abstract

The objective of this work was to study the process of torrefaction of pellets produced from pine residues generated in the sawmill process in Uruguay. The pellets were torrefied in a tubular furnace at a heating rate of 5 °C/min under an inert atmosphere. The experimental torrefaction tests were carried out at temperatures of 250 and 300 °C and holding times of 30 and 60 min. The performance of the process was evaluated in terms of mass yield, energy yield, and torrefaction factor. The raw and torrefied pellets were evaluated for thermal, physical, and chemical characterization. The effect of the torrefaction process on the pellet quality was studied. In addition, the combustion behavior of the raw and torrefied pellets was analyzed using thermogravimetric analysis (TG-DTG) and differential scanning calorimetry (DSC). The increase in temperature reduces the mass yield of the torrefied pellets while increasing the HHV, carbon content, and ash content. Incorporating torrefaction and pelletizing processes improves the energy properties of pellets, other research is required to evaluate the costs associated with handling, transportation, and storage for power generation applications.