Dynamic Compression: A Novel Technique to Reduce Energy Consumption during Wood Fiber Production

Thermo-mechanical refining is a common fiber production process known for its high energy demands. Throughout this process, wood chips are subjected to repetitive shearing and compression such that the fibers separate and subsequently fibrillate. There is a growing body of research in the development of mechanical pre-treatments that reduce energy demands during chemo- and thermo-mechanical pulping, with shear/compression combinations currently standing as the most efficient method of initiating defibration. Given the common grounds between the fiberboard and paper refining processes, it could be possible to use paper pre-treatments during fiberboard pulp refining. Furthermore, as pulping fibers for fiberboard are less worked and refined, mechanical pre-treatments are assumed to be more efficient. In this study, the effectiveness of dynamic compression was assessed as a pre-treatment step before the chips enter the refiner. Shaped wet chips with an annual ring orientation of 45° were struck by a free-falling weight with a fixed potential energy using a special prototype. After refining both the reference and pre-treated chips using a pressurized disc refiner, the energy consumption of those fibers was 48% lower than that for non pre-treated chips for a comparable fiber quality.