Bulk density measurement of the biomass powder or large particles can be performed
according to the method of ASTM D1895B [17] or ASABE S269.5
OCT2012 [18]. For the biomass ground particles (i.e., less than 2 mm in diameter),
a container with a volume of 0.615 L was used, above which a funnel with the opening
diameter of 1.5 cm was suspended. The funnel was then filled with the biomass
grinds and they were allowed to flow freely into the circular container from a height
of 20 cm. The biomass grinds were stirred continuously by a thin metal wire
throughout the pouring operation to prevent clogging inside the funnel opening. The
excess material on top of the container was scraped off with a straight edge. The
container with sample was weighed and weight/volume (loose bulk density) was
determined. For tapped density, the loosely filled container was tapped on the laboratory
bench five times in a vertical direction. The weight of the filled container was
recorded after five tappings