Pressurized hot water flow-through extraction of birch sawdust - Effects of sawdust density and sawdust size

A1 Journal article (refereed)

Internal Authors/Editors

Publication Details

List of Authors: Petri Kilpeläinen, Veikko Kitunen, Jarl Hemming, Andrey Pranovich, Hannu Ilvesniemi, Stefan Willför
Publisher: Mid Sweden University
Publication year: 2014
Journal: Nordic Pulp and Paper Research Journal
Journal acronym: NORD PULP PAP RES J
Volume number: 29
Issue number: 4
Start page: 547
End page: 556
Number of pages: 10
ISSN: 0283-2631
eISSN: 2000-0669


Birch sawdust was extracted using a pressurized hot water (PHW) flow-through system, with the aim of recovering polymeric, water- soluble xylans. The extraction temperature was 180 degrees C for 60 min with a constant water flow through the extraction vessel. The sawdust was packed in the extraction vessel with densities in the range of 0.2 - 0.7 kg/l. Higher packing densities of birch sawdust gave higher concentration of extract. Higher sawdust densities had also lower liquid to wood ratios during extractions. The highest extract concentration peak was achieved with 0.5 kg/l density of birch sawdust. At the beginning of the higher density extractions, more xylans and lignin were extracted than lower densities. Birch sawdust with three different particle sizes was also extracted under the same conditions. The amounts of extracted xylans were higher for the smallest particle size. Higher sawdust densities decreased the difference in the extraction yield between different particle sizes of sawdust.


Birch, Flow-through, Packing, Pressurized hot water extraction

Last updated on 2020-28-03 at 08:00