Low consistency refining system design for high yield pulping processes

Project leader
Christer Sandberg, MIUN/Holmen

Project group
Jan-Erik Berg, MIUN
Rita Ferritsius, MIUN/Stora Enso

Low consistency (LC) refining is more efficient than high consistency (HC) refining (to certain tensile index) but today it is not widely utilized in production of mechanical pulps. The purpose of the project is to increase the maximum specific energy in LC refining of TMP and increase the efficiency of the refining i.e. attain higher degree of fibre development at a certain specific energy in the LC refiner. The goal is to make it possible to apply 300 kWh/adt in LC refining and at this energy input increase tensile index by 20 Nm/g. This will roughly correspond to a reduced refining energy of 300 kWh/adt compared to a BAT TMP line today.

Most of the work will be made with full scale mill refiners through process modifications and optimization. One important part of the project is to evaluate different combinations of HC and LC refining. Earlier work has shown that pulp properties are developed differently in HC and LC refining. Different types of HC refiners also give different pulp quality profiles and it is thus important to combine HC and LC refiners in an optimal way.