EFFECT OF INCREASING WOOD CHIP DEFIBRATION ON THERMOMECHANICAL AND CHEMI-THERMOMECHANICAL REFINING EFFICIENCY

摘要

A method of increasing wood defibration prior to mainline refining was evaluated for reducing the total energy consumption of thermomechanical pulping. The method involves a gentle separation of fibers in wood chips using a combination of pressafining and refining actions in a pressurized environment. The importance of wood defibration under mild pressurized conditions, as opposed to atmospheric, was demonstrated on both spruce and pine wood furnishes. High-intensity thermomechanical pulps produced using the chip pretreatment method had 10% - 14% lower energy consumption compared to control high-intensity pulps. Increases in tear strength and refining intensity were also available when refining the defibrated wood chips. Further reductions in energy consumption were available when combining chip fiberization with chemical treatment. Separate chip defibration can have important implications for energy consumption, impregnation efficiency, and physical properties of chemi-thermomechanical and thermomechanical pulps.