PAPER PLANT - METHOD AND APPARATUS FOR PRODUCING PULP FROM AND CELLULOSE FIBROUS RAW MATERIALS AND RECOVERING CHEMICALS AND ENERGY FROM PULP LIQUORS

摘要

The invention includes a treatment apparatus (10) for beating fibrous cellulosic raw material suitable for use in a paper making plant comprising extracting means for extracting contrary material from the raw material, crushing means for crushing the raw material to remove nodes therefrom and splitting means for splitting the crashed raw material lengthways. A co-rotating twin screw conveyor (12) is used to pulp the crushed material, the conveyor being divided op into a plurality of zones, means for inserting treatment materials into at least one zone and means for controlling the temperature and/or pressure of all of the zones. The black liquor effluent produced in the pulping process is treated in an apparatus (14) comprising an evaporator for concentrating the liquor to 30-70 % solids, a processing vessel for treating the concentrated liquor at a temperature of between 300-650 °C, and a closed conveyor for transporting the concentrated liquor from the evaporator tn the processing vessel in excess of 90 °C. The invention also includes the method involved in using the above apparatus.