Performance of a Mobile Star Screen to Improve Woodchip Quality of Forest Residues
Institute of Forest Engineering, University of Natural Resources and Life Sciences, Vienna, Peter-Jordan-Str. 82/3, 1190 Vienna, Austria
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Academic Editors: Maarten Nieuwenhuis and Timothy A. Martin
Forests 2017, 8(5), 171; https://doi.org/10.3390/f8050171
Received: 4 April 2017 / Revised: 2 May 2017 / Accepted: 13 May 2017 / Published: 17 May 2017
Low harvesting costs and increasing demand for forest-derived biomass led to an increased use of full-tree (FT) harvesting in steep terrain areas in Austria. Logging residues, as a by-product of FT harvesting, present an easily accessible bioenergy resource, but high portions of fine particles and contaminants like earth particles and stones make them a complex and difficult fuel, as they affect storage capability, conversion efficiency, or emission rates adversely. The present research focuses on the productivity and performance of a star screen, which was used to remove fine and oversize particles from previously chipped, fresh Norway spruce (Picea abies (L.) Karst.) logging residue woodchips. Three screen settings, which differed in terms of different rotation speeds of the fine star elements (1861 rpm, 2239 rpm, 2624 rpm) were analyzed. Time studies of the star screen were carried out to estimate screening productivity and costs. Furthermore, 115 samples were collected from all material streams, which were assessed for particle size distribution, calorific value, ash content, and component and elemental composition. Average productivity was 20.6 tonnes (t) per productive system hour (PSH15), corresponding to screening costs of 9.02 €/t. The results indicated that the screening of chipped logging residues with a star screen influenced material characteristics of the medium fraction, as it decreased the ash content, the incidence of fine particles, and the nutrient content. The different screen settings had a noticeable influence on the quality characteristics of the screening products. An increase of the rotation speed of the fine stars reduced screening costs per unit of screened material in the medium fraction, but also lowered screening quality.
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Keywords:
screening; logging residue; woodchips; quality; cost; productivity
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MDPI and ACS Style
Huber, C.; Kroisleitner, H.; Stampfer, K. Performance of a Mobile Star Screen to Improve Woodchip Quality of Forest Residues. Forests 2017, 8, 171.
AMA Style
Huber C, Kroisleitner H, Stampfer K. Performance of a Mobile Star Screen to Improve Woodchip Quality of Forest Residues. Forests. 2017; 8(5):171.
Chicago/Turabian StyleHuber, Christoph; Kroisleitner, Huberta; Stampfer, Karl. 2017. "Performance of a Mobile Star Screen to Improve Woodchip Quality of Forest Residues" Forests 8, no. 5: 171.
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