Most residential biomass combustion systems are highly suitable
for pellets and briquettes. The effect of size can be seen
significantly in four main areas: i) heat and mass transfer between
the combustion gases and the combustor surrounding medium, ii)
radiation absorption from the flames, iii) fluidity of the bed for easy
gas penetration and iv) combustion rate of the particles [12]. The
thicker particles have low aspect ratio (volume to surface area), and
that results in less area exposed to the radiation, whereas, smaller
size particles do not have high heat gradients within the particles,
which helps in fast combustion.