Grit Segments in TMP Refining - Part 2: Potential for Energy Reduction

The use of grit segments in thermomechanical pulp (TMP) refining and their effects on energy consumption, and pulp and paper properties have been studied. The refining was performed with a two stage process using a Sunds Defibrator RGP 44 single-disc refiner. The grit segments were installed in the first stage refiner, while the second stage refiner was equipped with reference segments. The results showed that when grit segments were used in combination with optimised refining conditions, the first stage pulp was found to have greater breakdown of the cell walls resulting in fast development of freeness in the second stage refining. Potential for reducing the energy consumption was at least 10% with minimal negative impacts on pulp and paper properties.