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Chip geometry

methods to impact the geometry of market chips

Bjurulf, Anders (2006). Chip geometry. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2006:61
ISBN 91-576-7110-9
[Doctoral thesis]

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In general there is an understanding that geometrical consistency of chips is desirable in the pulping processes (both for mechanical and chemical pulping). Scandinavian pulp mills normally communicate requirements for chip geometry to the producers through quality regulations and bonus penalty systems. To optimize their deliveries sawmills try to produce chips of optimal size and screen out undesired fractions, and as a standard procedure they re-chip oversized chips into acceptable sizes. This thesis evaluates the level of consistency of market chips and the possibilities to increase consistency. Studies were conducted in the value chain from the point of chip production in sawmills to the point of delivery at the pulp mill gate. The geometry of chips from a single sawmill is almost as uniform as that of chips made by a pulp mill and the geometry is relatively consistent over time. However the geometry differs among sawmills and the resulting mix can be expected to have low consistency. There are possibilities to increase total consistency by steering chips from different sawmills toward common geometrical targets. In 2001 an additional (fifth) screen was introduced in the SCAN-standard for measuring chip fractions, with the aim to increase possibilities to promote consistency. When constructing bonus penalty systems for the new standard it is important to take into consideration the effects the additional screen has on the classification result. Oversized chips that are re-chipped were found to differ from ordinary market chips in geometry, in addition to having high content of bark and defects.

Authors/Creators:Bjurulf, Anders
Title:Chip geometry
Subtitle:methods to impact the geometry of market chips
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :October 2006
Number of Pages:43
ALLI. Bjurulf A. (2005a): Dimensional consistency of wood chips over time, Nordic Pulp and Paper Research Journal vol 20 no. 1/2005, 43-47. II. Bjurulf A. (2005b): Effects on chip size distribution when an extra screen is added in SCAN:CM 40:01, Tappi Journal, March 2005, vol 4:no 3, 28-31. III. Bjurulf A., Ekström J., Fuglem G., Sørli A. & Tooley C. (2006): Possibilities to control chip dimensions, examples from two sawmills, submitted. IV. Bjurulf A. & Rosenquist B. (2006): Re-chipping of oversized chips in sawmills, manuscript.
Place of Publication:Uppsala
ISBN for printed version:91-576-7110-9
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:wood chips, dimensions, consistency, production, quality, methods
Keywords:Chip geometry, chip dimensions, chip market, chip quality, re-chipping, wood chips
Permanent URL:
ID Code:1251
Department:(S) > Institutionen för skogens produkter och marknader (t.o.m. 061231)
Deposited By: Anders Bjurulf
Deposited On:26 Oct 2006 00:00
Metadata Last Modified:02 Dec 2014 10:10

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