ツインロール型プレスによるパルプ洗滌の概念

抄録

The new twin-roll press with the displacement concept was introduced to market in 1975 by Sunds Defibrator, Sweden. Since then more than 160 machines has been delivered to various applications such as brown stock, post oxygen washing and bleaching of chemical pulps.
The dewatering press is used for interstage washing, high consistency refining and hydrogen dioxide bleaching of CTMP as well as in the prior stage of flash drying of all grades of pulps. More than 200 dewatering presses have been sold worldwide since the beginning of 1960. The dewatering presses are also used in the viscose industry and Sunds Defibrator has delivered about 180 units to that area.
The worldwide demand for industrial activities to answer the recent highly restricted environmental pollution abatement continually increases. Pulp and paper industry is of course no exception and is required to put more emphasis on design of processes and machinery associated to cut down pollutant substances. The well proven rigid constructed displacement press is a key machine with good combination of dewatering and displacement principle can minimize carry-over of not only solved inorganic material but also dissolved organic material to the subsequent bleaching process in beneficial for economic and environmental reasons. The incoming trend demanding wholly chroline free product needs more selection condition in the newly developed bleaching sequence with chemical of ozon and/or hydrogen peroxide and Sunds Defibrator's twin-roll displacement press overall performs other types of washers such as filters and diffusers.
Mill data and simulations show a new main criterion by which real washing efficiency is judged-low wash loss of dissolved organic material is of great importance to minimize bleaching chemical consumption and decrease discharge of pollutant. Building volume is another point to be considered-the twin roll press offers comparatibly low civil engineering cost.