Wedin H.,Institute of Chemical Technology |
Antonsson S.,Metso Paper Sweden AB |
Ragnar M.,Svenskt Gastekniskt Center |
Lindstom M.E.,Institute of Chemical Technology
BioResources | Year: 2012
Common metrics for evaluating the efficiency of oxygen delignification include the kappa number and Klason lignin content. As a change in xylan content often leads to a change in HexA content, the kappa number must be corrected for the HexA contribution before evaluating the degree of oxygen delignification when trying to understand the process in detail. Questions could also be raised about the accuracy of the Klason lignin method for oxygen-delignified hardwood kraft pulps, since the amount of residual lignin is small in such pulp. This study investigates the influence of xylan content on oxygen delignification efficiency in Eucalyptus urograndis kraft pulps. Xylan content was varied using two methods: treatment with xylanase and with acid prehydrolysis for various times before kraft cooking. The degree of oxygen delignification, expressed as the HexA-corrected kappa number, indicated no significant trend with xylan removal, and no significant trend was evident when expressed as Klason lignin content. Source
Metso Paper Sweden Ab | Date: 2011-09-01
Metso Paper Sweden Ab | Date: 2014-02-13
The feed system is for a continuous digester where at least two pumps are arranged in parallel at the bottom of a pre-treatment vessel and a stirrer is provided in direct connection to inlets to pumps. The system makes it possible to provide a feed system with an improved accessibility and operational reliability, and to operate the main part of the pumps at optimal efficiency even if the production capacity is reduced.
Metso Paper Sweden Ab | Date: 2012-02-16
Metso Paper Sweden Ab | Date: 2011-12-15
A method and apparatus for processing pulp is disclosed including opposed endless wires conveyed in the same direction and defining a web-forming space therebetween for dewatering the web, a pair of perforated dewatering tables supporting the endless wires for pressing the wires towards the web, the first perforated dewatering table ending upstream of the second perforated dewatering table, and a press roll downstream of the back end of the first perforated dewatering table and opposed to the back end of the second perforated dewatering table to form a nip between the press roll and the back end of the second perforated dewatering table, which has a profiled surface that interacts with the press roll to prolong the nip between the press roll and the back end of the second perforated dewatering table.