ABSTRACT

 A prototype briquetting machine was designed, fabricated and evaluated. Available local and standard materials were used which enabled low cost of production. Briquettes were made from elephant grass, bahia grass and elephant grass mixed with bahia grass. The method involved reducing the grasses to 40 mm and weights of 0.200 kg, 0.3 00 kg, and 0.400 kg of each sample were collected. Each weight per grass was individually mixed with cassava starch and cow dung as binders and briquetted. The maximum machine efficiency, machine capacity, briquetting time and length of briquette for starch and cow dung analysis were 90%, 84.5 kg/hr, 1.96 mins, 96.2 mm and 94.33%, 234.8 kg/hr. 1.66 mins, 96.8 mm, respectively. The maximum ash content, calorific value, resistance to water penetration, compressive strength and density for starch and cow dung analysis were 12.33%, 16.66 KJ/kg, 67.03%, 2.46 N/mm2, 2.983 kg/rn3and 5.5%, 32.82 KJ/kg, 82.17%, 3.87 N/mm2, 3.763 kg/rn3, respectively. Bahia grass has maximum calorific values and compressive strength at 8% moisture content dry basis. Mixture of elephant and bahia grasses has maximum length of briquette. There were highly significant differences in machine capacity and briquetting time between the two speeds at 5% and 1% confidence levels. There was significant difference in efficiency, length of briquette between the two speeds at 5% confidence, but no significant difference at 1%. There was highly significant difference in calorific value between the speeds for elephant grass mixed with bahia grass with starch at 1% confidence. There was no significant difference in resistance to water penetration, compressive strength and density between the two speeds. Since the aim of briquetting is to produce briquette that will serve as good source of fuel and support combustion, the best briquette was produced when grasses were mixed with cow dung. The binders do not contain harmful agents and also environmentally friendly.