Equipment Design, Production and Characterisation of Clean Briquette fuel from composite agro-plastic wastes

Abstract

Large quantities of agricultural and plastic wastes are generated annually in the Ghana.  Plastics possess high calorific value and when combined with agricultural wastes will not only serve as alternative fuel but also address the plastics waste disposal problems. This article dealt with the production of clean composite briquette from plastic wastes and agro residues for household and industrial applications. Coconut shells was carbonized, mixed with shredded plastic waste in the ratio of 10:3 and densified in a cylindrical mould into briquetting fuel. ASTM analytical methods was used to determine the proximate compositions of the briquettes whiles that of the physical properties were determined by direct measurements and calculations. The briquettes have average compressed density of 1711.82kg/m3, relaxation ratio of 2.7 and burning time of 143mins. It has a relatively low porosity index (0.03%) and high relaxed density (662.43kg/m3) indicating that the briquette has a low tendency to attract less moisture and can also withstand long exposure to the weather with little deterioration. The high shattering index (98.76%)) suggests that the briquettes have the ability to produce low amount of fine particles during handling. Typically, as an organic based fuel, it possessed a low ash content (2.62%) and high organic content (97.38%), responsible for the high heating value of 32839.38kJ/kg. The physical properties of the composite briquettes are desirable and hence, incorporating plastics waste into biomass as an energy source has undoubtedly improved the heating value of briquettes for its use domestically and industrially. A screw briquetting machine was also designed with throughput of 68 tons/day which requires a motor power of 2.23kW (3hp).