Biorefinery in a pulp mill: simultaneous production of cellulosic fibers from Eucalyptus globulus by soda-anthraquinone cooking and surface-active agents

Abstract

Abstract Industrial Eucalyptus globulus wood chips were submitted to different autohydrolysis conditions followed by kraft cooking and soda-anthraquinone cooking. The autohydrolyzed wood chips were much easier to delignify than the control wood chips. Soda-anthraquinone cooking could be performed at a cooking temperature that was 20°C lower than that for the kraft cooking on control wood chips. Furthermore, the active alkali could be reduced. The resulting unbleached pulps reacted as well to oxygen delignification as the control pulps and could be further bleached to 90% ISO brightness with a D(EP)D sequence. The autohydrolysis liquors were investigated for their suitability as a source for the synthesis of alkylpolyxylosides (APX). These surface-active agents are synthesized through the reaction between the saccharides of the autohydrolysates and a fatty alcohol, with the former being the hydrophilic and the latter being the hydrophobic part of the molecule. The impact of the substances detected in autohydrolysates on the APX synthesis was studied. It was demonstrated that lignin dissolved during autohydrolysis should at least partially be removed before the production of APX.