An extruder was developed and tested for forming biomass from agroprocessing wastes. The experimental treatments included four screw speeds (0.789, 1.05, 1.41and 1.57m/s.), four die hole diameters of extruder (6, 8, 10 and 12mm) and three moisture levels (7.5, 10.5 and 13.6%) of two agro-processing wastes at different particle size (sawmill dust (≤ 3mm) and coarser corncob grinds (≤6.5mm). The results of the experiments showed that the particle size had a significant effect on machine

more »

... ty, pellets density, durability and specific energy requirement. The finer sawdust resulted in higher productivity, pellets density, durability and lower specific energy than the coarser corncob grinds. The machine productivity of sawdust was higher value by about 7% than the productivity of corncobs. The pellets density ranged from 0.81 to 1.24g/cm 3 for sawdust and form 0.76 to 0.94g/cm 3 for corncobs. The durability of sawdust pellets was higher by about 15.6% for corncobs pellets. While, the energy requirement of sawdust pellets was lower value by about 41.7% than for corncobs pellets. The pellets produced on the smallest die and lower moisture content had the best quality values. The combustion test indicated that the combustion of the pellets is more regular than the combustion of loose materials and provided the highest flue gas temperature and low carbon monoxide contents emitted. INTRODUCTION he interest in producing energy from biomass has increased in recent years, owing to depleting fossil energy supplies and climate change caused by carbon emissions. Low densities of 40-60 kg/m 3 for lignocellulosic and 200-400 kg/m 3 for woody biomass limit their application for energy purposes. *Agric. Eng. Res. Ins. (AEnRI), Dokki, Giza, Egypt. E-Mail: Shoughy_AERI@Yahoo.com T Misr J. Ag. Eng., 30 (2): 537 -558