Experiences with “Dithionite Based Additives (DBA) in (C)TMP” in lab, pilot and mill scale – synergies between high brightness, less specific energy consumption and development of pulp properties
Updated: 2016-10-27 | Print
a BASF SE, D-67056 Ludwigshafen, Germany
b Norske Skog Skogn, N-7620 Skogn, Norway
c Paper and Fibre Research Institute (PFI), NO-7491, Trondheim, Norway
The purpose of this paper is to report about our experiences with treating softwood mechanical pulp (MP) with DBA directly injected into the gap of high consistency (HC) refiners used as chemical reactors to improve the competitiveness and the ecological footprint of (C)TMP based products. After the description of the main factors and pros and cons of conventional oxidative and reductive bleaching of softwood MP the basic principles of the treatment of MP with DBA in the (C)TMP refiner are outlined. By means of exemplary results of trials in lab, pilot and mill scale as well as of productions the main advantages of “DBA in (C)TMP” are illustrated: efficient brightness gain, reduction of anionic trash, high wood yield, reduction of hard chelating agents, saving of refining energy and increase of strength properties. Using the example of Norske Skog Skogn it is demonstrated how the system works in practice in the production of high bright and standard newsprint made from normal and lower quality wood. Finally it is pointed out that to a certain extent DBAs can be tailored to the needs of the respective mill.