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Licensed Unlicensed Requires Authentication Published by De Gruyter September 9, 2011

Properties of wood chips for thermomechanical pulp (TMP) production as a function of spout angle

Lisbeth M. Hellström, Per A. Gradin, Per Engstrand and Øyvind Gregersen
From the journal


Spruce wood chips were produced under well-controlled conditions in a laboratory wood chipper at spout angles of 30°, 40°, and 50° at a cutting rate of 20 m s-1 and with a nominal chip length of 25 mm. The chips were then refined under thermomechanical pulp (TMP) conditions in a pilot refiner plant. The pulp properties such as freeness, average fiber length, and shives content were determined and evaluated as a function of specific energy consumption. For a first stage refining and for a freeness value of 350 ml, a decrease in specific electrical energy consumption could be achieved by performing the wood chipping at a spout angle of 50° as compared to 30° which is the spout angle commonly used. A patent application regarding this method has been filed and is pending. It is realized that a freeness value is not directly indicative of any quality measure, such as, for example tensile index and light scattering coefficient but the obtained results can be interpreted to be promising. Further studies are needed regarding the impact of the modified chipping process.

Corresponding author. Mid Sweden University, FSCN, Department of Natural Science Engineering and Mathematics SE-851 70 Sundsvall, Sweden

Received: 2010-8-10
Accepted: 2011-4-4
Published Online: 2011-09-09
Published Online: 2011-09-9
Published in Print: 2011-10-01

©2011 by Walter de Gruyter Berlin Boston

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