Abstract
In this study, the theoretical relationship between
pressure and density was investigated on cylindrical hollow fuel
briquettes produced of a mixture of fibrous biomass material using a
screw press without any chemical binder. The fuel briquettes were
made of biomass and other waste material such as spent coffee beans,
mielie husks, saw dust and coal fines under pressures of 0.878-2.2
Mega Pascals (MPa). The material was densified into briquettes of
outer diameter of 100mm, inner diameter of 35mm and 50mm long.
It was observed that manual screw compression action produces
briquettes of relatively low density as compared to the ones made
using hydraulic compression action. The pressure and density
relationship was obtained in the form of power law and compare well
with other cylindrical solid briquettes made using hydraulic
compression action. The produced briquettes have a dry density of
989 kg/m3 and contain 26.30% fixed carbon, 39.34% volatile matter,
10.9% moisture and 10.46% ash as per dry proximate analysis. The
bomb calorimeter tests have shown the briquettes yielding a gross
calorific value of 18.9MJ/kg.