Monitoring moisture and inorganic content of forest harvesting residues for energy production purposes: A case study

Abstract

Forest harvesting residues are potentially a vast source of feedstock for bio-based energy facilities. However, the high moisture content of the residues lowers the energy density and adversely impacts the efficiency of transportation. Inorganic and ash contents of forest harvesting residues could also reduce the efficiency of combustion processes and cause fouling, slagging, and corrosion in forest residue-burning apparatuses. The main objective of this research was to conduct measurements to monitor moisture, ash, and inorganic (Ca, K, Mg) contents of forest harvesting residues throughout the year. This would help to decide the optimum size of the residue, height and orientation of the residue pile, as well as the optimum season (that is, when those contents are at their lowest) to remove the residues from the forest to biomass-based facilities. Samples of aspen and pine residues, together with temperature, humidity, and precipitation measurements, were taken bi-weekly in two sites at Cynthia and Drayton Valley, Alberta, Canada, from early spring to early fall, and analyzed for two successive years. The results suggest mainly small-size residues should be stored in toll piles until late September and the piles of such residues should be oriented southward before removing them from the forest.