Ordinary torrefaction process has objectives on the increase of higher heating
value and energy density. Because of these expectations, the torrefaction of
biomass pellet is facing many limitations. The other interest way to upgrade
biomass pellet is short torrefaction which focuses on improvement of hydrophobic
property and maintain energy density at the similar level to untreated biomass
pellet. This work studied variations of equilibrium moisture content (EMC),
durability index, and energy density of cassava rhizome pellet when it was
torrefied at short residence times of 0-15 min. The normal residence times of 30
and 60 min were also conducted to identify the suitable residence time for short
torrefaction process. The mathematical model was also developed to predict
properties of cassava rhizome pellet after torrefaction. It was found that EMC and
durability index drastically decreased for short residence times (0-15 min). There
was insignificant difference in EMC and durability index for residence times of 30
and 60 minutes. Slight difference in energy density was found for residence time
and torrefied temperature range of 0-60 min and 230-270C, respectively.
Therefore, the suitable residence time was dependent on EMC and durability
index. ETC...
Keywords
Biomass, Durability, Energy density, Pellet upgrading, Torrefaction