Date of Award


Degree Name

Master of Science


Chemical and Paper Engineering

First Advisor

Dr. Richard B. Valley

Second Advisor

Dr. David K. Peterson

Third Advisor

Dr. Raymond L. Janes

Access Setting

Masters Thesis-Open Access


Two commercial feedforward centrifugal cleaners were used in the study of vessel segment removal from bleached eucalyptus pulp. The reduction of vessel elements yielded a reduction of vessel pick tendency and other problems caused by vessel elements which limit the use of eucalyptus pulp in paper stock furnishes. The operating conditions of the centrifugal cleaners were evaluated for their effect on separation efficiency. Pulp loss with rejects was reduced by multiple stage separation. The Vandercook Proof Press was used to compare the picking of cleaned, original pulp and two higher-vessel-content pulps. Regression analysis and ANOVA showed significant effects of feed consistency and pressure drop on separation efficiency. The picking of eucalyptus pulp was reduced greatly after removal of more than 52% of large vessel segments. Tear strength of the cleaned pulp was also improved. Other strength properties were not affected by removal of vessel segments.