Sumitomo/Sunds Superbatch Cooking System

Abstract

Sumitomo Heavy Industries Ltd. has been exclusive licensee of Sunds Defibrator AB in the field of chemical pulping to Japanese market since 1988, at that time the development of a new cooking process was started in Sunds Defibrator.
In general, batch cooking has always had the advantage over continuous cooking by providing more flexibility in the operation of the digesters except lower energy efficiency.
This is especially when switching cooking would be done between different wood species and less homogenous and poor quality wood would be used as raw material.
Therefore, the Super Batch process was developed as a cooking system with energy consumption equal to or lower than that of continuous cooking.
The recent results obtained by means of the Super Batch cooking have shown that there are no major obstacles in taking both softwood cooking and hardwood down to the kappa number range of 10-15.
It is of primary importance that simultaneously the pulp quality is preserved and no excessive yield losses can be tolerated.
Mill scale trials show that this pulp is at least of equal quality compared to standard market pulp and it can be bleached to full brightness without molecular chlorine. Moreover this kappa level seems to be the key to reach full rightness in totally chlorine free bleaching. This fact is very important in view of environmental requirement.
This paper introduces the outline of the Sumitomo/Sunds Super Batch process and total fiber line technologies with the Super Batch.