Bojanowska, Milena
(Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie,
)
Rapeseed by-products of seeds de-oiling, particularly expellers and post-extracted meal, are currently considered an important biomass that can be used as an alternative energy source, either in raw form or after
conversion to biochar. Rapeseed biomass represents a difficult-to-handle cargo, mainly due to its sensitivity
to mechanical, climatic, and biological impacts, as well as its dusty nature. This study aims to determine the
physical properties of rapeseed meals and their fractions. Morphological and chemical features of six particle
sets are investigated in order to explain the variation in their physical properties having importance in handling
and transportation processes. The true density of fractions increases when the particle size decreases due to the
diminishing quantitative share of seed coats. No correlation is observed between true and bulk densities, as the
particle shape, surface sculpture, and adhesion affect the mutual particle arrangements. Along with a decrease
in the particle size from 0.4 mm, a rapid decrease in the flowability is observed. The tendency of the finest dust
(d < 0.075 mm) to form agglomerated complexes causes its lower bulk density, higher porosity, and higher
angles of repose in comparison to coarse dust (0.075–0.4 mm). It is concluded that a relatively low tendency to
free flowing of natural RSM is mainly caused by its wide-ranging particle size distribution and their geometry
differentiation, which facilitate mutual particle interlockings. The known cases of blockages of silos, bins,
hoppers, and transfer chutes may be mainly caused by the powder fractions (< 0.2 mm), with a much lower
flowability than other particles.