Contract n° BOS-085-UK

Summary

A literature survey indicated that Anthraquinone could be used for the N.S.S.C. pulping of hardwoods. The main benefits would be from increased pulp yield, reduced chemical usage and savings on energy. This research was aimed at identifying these benefits, the best areas of application and values. It was carried out in three stages; firstly a number of small scale laboratory digestions to study a wide range of pulping process variables. Using results from this work, a limited number of pulping process variables which showed the best potential benefits from using Anthraquinone, were selected for further investigation. Stage two was to study these variables using larger scale laboratory digestions which enabled pulp quality, etc. to be evaluated. From the results of this work, a production plant trial was run to establish if the laboratory results could be reproduced on a production unit. At the end of the three stages, it was concluded that Anthraquinone could be used to pulp hardwoods by the N.S.S.C. process with the following benefits: Reduced usage of pulping chemical, reduced energy consumption and to some degree, improved pulp quality. To enable Anthraquinone to be used effectively, the pH of the pulping liquor needed to be raised to 12.5 before adding the Anthraquinone.