The aim of this study was to further evaluate the viability of the integrated pulp mill biorefinery concept.
On one side the properties of hot-water pre-extractions were studied, in order to determine the effect
of extraction on soda pulping and bleachability. On the other side, the performance of two dry-strength
agents on the paper properties obtained from extracted and un-extracted (control) samples were investigated.
It was found that hemicelluloses removal of the depithed bagasse chips was 24.6% at 140 ◦C for
10 min with a solid to liquor ratio (S:L) of 1:8 (w/w), and that mass removal increased with extraction time
and temperature. The hemicelluloses removal reached 65.5% at 170 ◦C for 30 min. The residual extracted
bagasse were subjected to soda pulping at 160 ◦C for 1 h with 11, 14 and 17% active alkali charge and
a S:L of 1:5 (w/w). Conventional elemental chlorine free bleaching (D0ED1) sequence was also used to
compare the results with the un-extracted ones. Compared with the control sample, the overall pulp
yield for extracted bagasse increased considerably while Kappa number and rejects decreased moderately.
In addition, yield and Kappa number of the pulps improved with increasing alkali charge from 11%
to 17%. After pre-extraction, better brightness compared with the control pulp was also shown. However,
hot-water extraction was found to negatively impact some pulp properties including decreases in burst
and tensile indices while addition of chitosan and cationic starch could improve the strength properties.
Overall, papers treated with chitosan gave superior mechanical properties compared to the papers
treated with cationic starch.