A scale-up strategy for a mini-channel hydrodynamic fiber fractionator

An increasing demand on wood fiber based products requires an increasing efficiency of wood fiber resources. This can be achieved by a selective treatment and usage of two different fiber length classes, which are separated by a novel high performance fractionator. Hydrodynamic fractionation in a mini-channel (miniFrac) exploits network formation of fibers when flowing through a narrow channel: while longer fibers are linked to the network, shorter fibers can be extracted by a suction slot. Since an increase of slot suction rate would decrease fractionation performance, total suction rate is increased by connecting several suction slots in series. We present a scale-up strategy to a pilot scale plant by parallel connection of 16 fractionation channels (i.e., equaling-up). Therefore, a novel bifurcation distributor for fiber suspensions is developed. A comparison of the miniFrac pilot plant to a state of the art fractionation device, i.e., a pressure screen, shows that miniFrac can be operated with higher fractionation performance. Moreover, miniFrac is shown to be significantly more energy efficient than typical pressure screens.