Chip Column Movement in a Continuous Digester

摘要

Most continuous digesters are between 30 - 50 years old and in many cases the production has been increased by 50 - 100 %. In some cases the kappa target and/or wood specie has been changed too. These digesters no longer operate under the conditions they originally were designed for. In order to produce pulp the chip column must be moving and this has become one of the most important tasks for the operator. The chip column movement in a two vessel hydraulic digester can be unproved by converting the digester to a two vessel steam/liquor phase digester. This paper describes the factors important for chip column movement and presents the results from a digester conversion at BillerudKorsnas, Gavle Mill, Sweden.