Changes in Commercial Dendromass Properties Depending on Type and Acquisition Time

Abstract

Forest dendromass is still the major raw material in the production of solid biofuels, which are still the most important feedstock in the structure of primary energy production from renewable energy sources. Because of the high species and type diversity of production residues generated at wood processing sites, as well as at logging sites, the quality of commercial solid biomass produced there has to be evaluated. The aim of this study was to assess the thermophysical characteristics and the elemental composition of ten types of commercial solid biofuels (pinewood sawdust; energy chips I, II, and III; veneer sheets; shavings; birch bark; pine bark; pulp chips; and veneer chips), depending on their acquisition time (August, October, December, February, April, and June). Pulp chips had the significantly lowest moisture content (mean 26.92%), ash content (mean 0.39% DM—dry matter), nitrogen (N) content (mean 0.11% DM), and sulfur (S) content (mean 0.011% DM) and the highest carbon (C) content (mean 56.09% DM), hydrogen (H) content (6.40% DM), and lower heating value (LHV) (mean 13.61 GJ Mg−1). The three types of energy chips (I, II, and III) had good energy parameters, especially regarding their satisfactory LHV and ash, S, and N content. On the other hand, pine and birch bark had the worst ash, S, and N contents, although they had beneficial higher heating values (HHVs) and C contents. Solid biofuels acquired in summer (June) had the lowest levels of moisture and ash and the highest LHV. The highest moisture content and the lowest LHV were found in winter (December).

Energy Efficiency of Conifer Cones and Seed Extraction Residue Biomass

“…Similar values of HHV and LHV in the cones of the examined tree species were reported by other researchers [7,35,41]. The HHV and LHV of conifer cones were higher than the values noted in pinewood chips, other types of sawmill waste (sawdust, woodchips) from coniferous trees, and the biomass of forest residues [10,47,52]. These parameters can be increased through torrefaction [53].…”

“…The examined cones were somewhat more abundant in carbon and hydrogen than cones harvested in other regions and seasons [46,51]. The sulfur and nitrogen content of the analyzed cones was somewhat higher than that reported in forest waste biomass [10,11,47]. The concentration of sulfur was highest in empty seeds, and similar observations were made in other studies of forest waste biomass [54].…”

“…The examined cones contained less ash than other types of forest biomass, including timber and sawdust of the same tree species, and their ash content was similar to that noted in certain types of woodchips [46][47][48]. The concentration of ash in seed wings, waste from cleaning dewinged seeds, and empty seeds was similar to that reported in pine and larch bark [47]. The high ash content of waste from precleaning winged seeds could be associated with the cone harvesting method.…”

“…Ash content was relatively low (0.93-1.35% DM) in cones (pine and spruce) and cone fragments (larch), which is a desirable trait in solid biofuels [7]. The examined cones contained less ash than other types of forest biomass, including timber and sawdust of the same tree species, and their ash content was similar to that noted in certain types of woodchips [46][47][48]. The concentration of ash in seed wings, waste from cleaning dewinged seeds, and empty seeds was similar to that reported in pine and larch bark [47].…”

Properties of Forest Tree Branches as an Energy Feedstock in North-Eastern Poland

“…When woodchips are harvested, they are most commonly used directly for energy purposes, such as fresh woodchips with a high moisture content (40-50%). In contrast, bales are stored in heaps to naturally reduce the moisture content of biomass and then are shredded into chips, which, depending on the weather conditions and the bale storage duration, can have a significantly lower moisture content (20-30%) [14].…”