1.2.2. Bulk density
Most agricultural residues have low bulk densities. For
example, the bulk density of chopped straw and rice husks
are 50–120 [15] and 122 kg/m3 [4], respectively. They are
very low compared with the bulk densities of coals, which
are in the range of 560–600 kg/m3 for brown coals and
between 800 and 900 kg/m3 for bituminous coals. The low
densities of the residues complicate their processing, transportation,
storage and firing.