1. Some key aspects on screening of chemical pulp to achieve a fine fraction – a literature review
- Author
-
Björk, Elisabeth
- Subjects
chemical pulp ,screening ,Naturvetenskap ,fractionation ,fines ,Natural Sciences - Abstract
This literature review focus on fibre length-based fractionation with screens to achieve a fine fraction, how fractionation results can be evaluated and on the influence of different screening parameters when using pressure screens. The design of the screen basket, and in particular the aperture size and shape, have a predominant effect on fractionation. Smaller aperture size leads to improved fractionation efficiency. Furthermore, it seems clear that screen plates with holes fractionate better than slotted, even when the slots are narrower than the hole diameter. Moreover, smooth screen plates are more efficient for fractionation, as contoured screen plates increase the fibre passage. For slotted screens the fibre passage ratio is affected by the fluid velocity through the aperture, while the fibre passage ratio for screen plates with small holes is independent of the fluid velocity. Microperforated screens, i.e. screens with holes with a diameter of less than 300 micrometre, are very efficient for fines fractionation in order to enrich the fines in the accept fraction.
- Published
- 2020