PREDICTING CTMP BLEACHABILITY USING WOOD SHAVINGS
To predict the brightness reduction in a chemithermomechanical process as well as the bleachability of pulps produced from different species of wood raw materials there are, at present, no shortcuts available. Pulps have to be manufactured in pilot or mill scale and bleached; evaluating and predicting the bleachability has consequently been very resource consuming and thus expensive - until now! Due to this, we have used a laboratory method based on 60 x 60 mm wood shavings making it possible to predict the bleachability of primarily chemithermomechanical pulps but also other mechanical pulps. Our experiments showed that retention time and impregnation temperature appears to have no impact on the final brightness of birch shavings. When being subjected to a simulated chemithermomechanical pulp process, eucalyptus exhibited an increase in chromophore content before the bleaching stage. In addition, eucalyptus suffered from severe alkaline darkening. After the bleaching stage, the alkaline darkening diminished. A higher retention temperature resulted in lower brightness of the eucalyptus shavings compared to when using a lower retention temperature. Birch reached the highest final brightness levels and had a higher overall yield too.
wood shavings bleachability CTMP birch eucalyptus
Helena,Fjellstrom Per,Engstrand ThomasGranfeldt Louise Logenius
FSCN (Fibre Science and Communication Network),Mid Sweden University, 851 70Sundsvall, SWEDEN Metso Paper Sundsvall AB, SE-851 94, Sundsvall,SWEDEN
国际会议
16th International Symposium on Wood,Fiber and Pulping Chemistry(第十六届木材、纤维及制浆化学国际会议)
天津
英文
613-616
2011-06-08（万方平台首次上网日期，不代表论文的发表时间）