Model and optimal operational windows for hydrodynamic fiber fractionation

Abstract

Based on fitted experimental data, an empirical fractionation model for mini-channel hydrodynamic fiber fractionation (miniFrac) is presented. This model, combined with an optimization procedure, is then used as a design tool to synergize competing fractionation performance characteristics, i. e., product quality, product yield and energy demand. Based on this model, miniFrac is compared to state-of-the-art fiber fractionation technology with respect to (i) long fiber-short fiber fractionation and (ii) fines-fiber fractionation. In terms of fines-fiber fractionation, miniFrac is outperformed by typical micro-hole pressure screening regarding the purity of fines fraction. However, a comparison with a slotted (slot width of 0.2 mm) and a smooth-holed pressure screen (hole diameter of 0.8 mm) shows, that miniFrac is capable of outperforming both systems regarding product quality and energy demand at a comparable product yield. If, in the case of fines-fiber fractionation, reject purity (i. e., fines exclusion) is more important than fines purity (i. e., long fiber remain in the reject), miniFrac is an interesting tool with some key advantages over pressure screens.