A study was
undertaken to determine the densification characteristics of three non-timber
forest tree residues, namely Bush Mango (Irvingia), Achi (Brachystegia
eurycoma) and Para Rubber (Hevea brasiliensis) shells for fuel. The shells were
reduced with a hammer mill to 1.00 mm, 2.00 mm and 4.75 mm particle size and
densified by mixing with starch with a densification apparatus at optimum
temperature and pressure of 100oC and 200 MPa, respectively. Mechanical
properties of the densified samples determined were shatter resistance and
durability index. Higher heating value (HHV) of Rubber, B. eurycoma and
Irvingia shells were 15.97, 13.0 and 13.10 MJ/kg, respectively. Bulk density of
the samples were arranged in the descending order of B. eurycoma (587 kg/m3),
Rubber (520 kg/m3) and Irvingia (517 kg/m3). The densified rubber shell had the
most favourable energy properties as fuel due to its high calorific values and
volatile matter content. It also had the least fixed carbon and ash contents.
There was no significant difference in the calorific value and volatile matter
contents of the Irvingia and B. eurycoma shells. The densified rubber shell had
the highest shatter resistance at various temperatures and pressures
investigated. The densified rubber shell is recommended for use as fuel due to
its high calorific and durability values.
