On the potential utilisation of sawdust and wood chip screenings

G5 Doktorsavhandling (artikel)


Interna författare/redaktörer


Publikationens författare: Risto Korpinen
Förläggare: Åbo Akademi University
Förlagsort: Turku
Publiceringsår: 2010
ISBN: 978-952-12-2417-1


Abstrakt

This work is based on the utilisation of sawdust and wood chip screenings for different purposes. A substantial amount of these byproducts are readily available in the Finnish forest industry.
A black liquor impregnation study showed that sawdust-like wood material behaves differently from normal chips. Furthermore, the fractionation and removal of the smallest size fractions did not have a significant effect on the impregnation of sawdust-like wood material.
Sawdust kraft cooking equipped with an impregnation stage increases the cooking yield and decreases the lignin content of the produced pulp. Impregnation also increases viscosity of the pulp and decreases chlorine dioxide consumption in bleaching. In addition, impregnation increases certain pulp properties after refining.
Hydrotropic extraction showed that more lignin can be extracted from hardwood than softwood. However, the particle size had a major influence on the lignin extraction. It was possible to extract more lignin from spruce sawdust than spruce chips.
Wood chip screenings are usually combusted to generate energy. They can also be used in the production of kraft pulp, ethanol and chemicals. It is not economical to produce ethanol from wood chip screenings because of the expensive wood material. Instead, they should be used for production of steam and energy, kraft pulp and higher value added chemicals.
Bleached sawdust kraft pulp can be used to replace softwood kraft pulp in mechanical pulp based papers because it can improve certain physical properties. It is economically more feasible to use bleached sawdust kraft pulp in stead of softwood kraft pulp, especially when the reinforcement power requirement is moderate.


Nyckelord

Black liquor impregnation, Chemicals, Energy, Ethanol, Hydrotropic extraction, Reinforcement fibre pulp, Sawdust, Sawdust cooking, Wood chip screenings

Senast uppdaterad 2019-17-09 vid 05:16