An evaluation of the energy potential of shea nut waste briquettes as an alternative fuel to shea wood charcoal for domestic and industrial applications

Abstract

In most developing countries including Uganda, there has been a rapid growth in demand for energy with current demand superseding supply in most cases and energy scarcity hindering sustainable economic transformation. The specific objectives were to; determine the ideal ratio of shea nutwaste with cassava starch and clay as binders to achieve the highest energy density in the briquettes, determine the thermal and chemical characteristics of shea nut waste briquettes and shea wood charcoal, compare the fuel properties and characteristics of the briquettes and wood charcoal obtained. A forced air convection oven (BOFC-104) and a Gallenkamp bomb calorimeter were used to determine the physical properties and calorific value for feedstock and briquettes respectively. Parikh model and Shen model were used to determine the elemental composition of feedstocks. Combustion efficiency tests that were conducted include; water boiling test, ignition test, burning rate and specific fuel consumption. Calorific values and bulk density of the briquettes with different binders were obtained. For briquettes with starch binder, the calorific values and bulk densityvalues were ranging between 21.70 MJ/kg – 25.84 MJ/kg and 723.31 kg/m3 -842.45kg/m3 respectively. Briquettes with clay binder, the calorific values and bulk density values were ranging between 17.58 MJ/kg – 21.51 MJ/kg and 833.94 kg/m3 – 910.52 kg/m3 respectively. The shea wood charcoal had a calorific value 29.4758616 MJ/kg. Comparison of the shea wood charcoal and starcg binder 16% briquette, charcoal had a heating value of 29.48 MJ/kg and the briquette had 24.31 MJ/kg. Comparing their respective physio-chemical and thermal properties, it can be concluded that there is not much a difference. In this study, it was concluded that briquettes with starch binder of 12% were most ideal to be used as an alternative to charcoal as it possessed the best fuel properties amongst the other ratios. This research has provided an insight for the utilization of shea nut waste with cassava and clay as binders in development of briquettes as alternative fuel to shea wood charcoal for domestic and industrial applications. However, there is need for further studies to be done on the TechnoEconomical and Environment analysis production of these briquettes and the mechanical strength.