Effect of Modified Cooking on Bleachability of Eucalyptus globulus and Eucalyptus nitens

Abstract

This work evaluates the effect of SuperBatch™ (SB), CompactCooking™ (CC), and Lo-Solids™ (LS) modified cooking concepts on pulp bleachability of Eucalyptus globulus and Eucalyptus nitens. E. globulus wood samples presented higher amounts of cellulose and E. nitens higher amounts of hemicellulose and acetone extractives. The same trend was observed in brownstock and in fully-bleached pulps. E. globulus wood sample presented lower amounts of lignin and higher S/G ratio than E. nitens. In the brownstock pulps, the amount of Hexenuronic Acids (HexA) and total lignin for E. globulus and E. nitens did not present significant difference variation in the contribution to kappa number 17±0.5. No significant differences were found in intrinsic viscosity among modified cooking methods in unbleached and in fully-bleached pulps. For both species, the CC produced pulps with the highest hemicelluloses content after cooking to the fully-bleached pulp. In this work, one cannot observe differences in bleachability of E. globulus and E. nitens caused by different modified cooking concepts.

Keywords

• Pulping
• Bleaching
• Bleachability
• Modified cooking
• Hardwood
• Eucalyptus globulus
• Eucalyptus nitens
• Kraft cooking
• SuperBatch
• Lo-Solids
• CompactCooking