Hydrothermal and pulp processing of Eucalyptus

Hydrothermal processing of Eucalyptus wood was performed at operation temperature of 181degreesC, processing time or 37.5 min and solid water ratio of 1/6 to ensure a maximum loss of xylan recuperation with minimum cellulose fibre degradation. Under those conditions, the loss of xylan was 22% less than that achieved with the conditions 196degreesC, 50.6 min and 1/8 (solid/water). In addition, an experimental design was used to study the influence of process variables: temperature (145-175degreesC), pulping time (40-120 min) and ethanol concentration (40-70% weight concentration), on the properties of pulps (yield, kappa number, viscosity, cellulose, xylan, lignin acetyl groups contents and brightness) and paper sheets (stretch index, burst index and tear index) obtained from the solid fraction after hydrothermal treatment of Eucalyptus globulus. Pulps with acceptably high physical and chemical properties can be obtained operating at 175degreesC for 90 min with 55% ethanol concentration. (C) 2002 Elsevier Science Ltd. All rights reserved.