AGGRESSIVE LOW CONSISTENCY REFINING IN THERMOMECHANICAL PULPING: ENERGY CONSUMPTION AND FIBER DEVELOPMENT

Aggressive low consistency refining was investigated as a means of minimizing the energy consumption of thermomechanical pulping. Two spiral refiner plate designs of differing bar edge length were selected with the goal of preserving pulp strength while attaining a significant energy reduction. Low consistency refining using the more aggressive spiral plates achieved a 25% reduction in energy consumption and similar bonding strength compared to the high consistency refined pulp at newsprint freeness levels; some loss in fiber length and tear index was observed. Fractionation studies on the LCR and HCR pulps shed light on the similarities and differences between these pulps on bonding characteristics.