Effect of Shapes, Binders and Densities of Faecal Matter - Sawdust Briquettes on Ignition and Burning Times

Abstract

Wood fuels are a major source of energy in the developing world whose sustainability is diminishing in forest cover and production increases in demand due to rising population. Alternative environmentally friendly accessible sources of energy for households are therefore a necessity. These include faecal matter, forest and agricultural residues that are convertible into briquettes. There source will depend on availability, impact on environment, renewability and energy content. The benefit of briquettes arises from near equal mass balance of carbon dioxide demand by photosynthesis in the atmosphere to the amount released during combustion. Briquetting thus need designed agglomeration machines and understanding of the engineering properties. The parameters density and shape have effect on combustion and performance characteristics hence should be determined. The research thus focused on spherical, triangular and cylindrical shapes and densities of 600 kg/m3, 700 kg/m3 and 800 kg/m3 on ignition and burning time. Carbonization of faecal matter and sawdust with binders was the activities. There was significant difference on ignition time on shapes and densities and none on burning times with shapes and binders. The average ignition time ranged from 2.7 to 3.7minutes irrespective of shapes and binders. The average burning time ranged from 18 to 26 minutes for molasses and starch bonded cylindrical briquettes. The spherical briquettes had the least ignition time of 2.7 minutes. Packing ratio, evenly distributed air spaces, higher volatile matter in binder, porosity due density advantaged the spherical briquettes.