Process for gas phase delignifying lignocellulosic material.

摘要

An improved apparatus and processor for delignifying lignocellulosic material (16) are disclosed in which the material has a consistency of 15 percent or greater and is contacted with the chlorine dioxide gas (14) to delignify the material, is then treated by direct alkaline extraction in the absence of an intermediate washing step to produce a delignified material with substantially reduced level or adsorbable organic halides (AOX). The effluent discharge from the bleaching process of the present invention has less than about 2.0 kg adsorbed organic halides (AOX) per ton of wood pulp. The improved apparatus employs a movable supporting web (11) for the lignocellulosic material that is gas-porous.