Agro-Residues for Clean Electricity: In-Lab Trial of Power Generation from Blended Cocoa-Kolanut Wastes

Abstract

As a way of waste-to-voltage conversion, a laboratory-based test trial of electricity generation from a blend of cocoa and kola nut harvest by-products is presented in this study. Bioethanol obtained from the blend through a process of fermentation is mixed with gasoline at specific proportions and employed to fire a spark-ignition engine that serves as a prime-mover in driving a four-pole three-phase salient-pole synchronous machine. Performance of the driving machine as the fuel-mix proportion and its speed of rotation varies is studied. Likewise, the electric power output characteristic of the driven machine operated at its rated synchronous speed is examined. It is found that the driving machine performs better on mixed fuel than on pure gasoline as the machine develops a gradual increase in mechanical torque and power as the proportion of ethanol in the fuel-mix and the rotational speed increases. While the highest values of torque and power developed on using pure gasoline are 12.4Nm and 2574W respectively at 1900rpm, 13.1Nm torque and 2953W power are obtained from the machine when powered with 10%-bioethanol fuel-mix at the same speed. Also, with 90V excitation voltage and rotation at 1500rpm synchronous speed, the driven machine continuously generates electricity at 207.6Vrms (line-to-line), 1.169A, 0.698pf, 48.17Hz, 0.294kW output. Therefore, this investigation shows that the availability of cocoa and kola nut harvest wastes could be explored as a steady source of biofuel for off-grid microgrid electrification at locations with such agricultural wastes advantages.