Characterisation of the non-oil Jatropha biomass material for use as a source of solid fuel

Jatropha curcas L. plant (Jatropha) is cultivated in many countries for biodiesel production. This is to provide for high energy demand and mitigate global warming from the combustion processes of fossil fuels. The production of Jatropha oil for biodiesel production in Botswana following the recent government decision to promote biofuels is likely to generate large volumes of non-oil biomass. The residual non-oil biomass material can be used in place of firewood in low-income communities. This is perceived to be one of the effective ways of utilising non-oil biomass from the plant. However, for the non-oil biomass material to be used effectively in place of firewood, its properties related to fuel value need to be investigated. The objective of this study was therefore to characterise the Jatropha non-oil biomass from Botswana material for effective use as solid fuel source. The characterisation results showed that Jatropha seed cake has relatively high calorific value of 19.28 MJ/kg, high bulk density of 0.75 MJ/kg, high fixed carbon content of 24.28 MJ/kg and low ash content of 5.04 MJ/kg, which are good properties for solid fuel source. The Jatropha seed cake also has more carbon content to the value of 46.15% when compared with the stem’s carbon content of 43.68% and the fruit husk carbon content of 36.05%. The thermal gravimetric analysis showed that the thermal degradation of the Jatropha seed cake is slow when compared to the other Jatropha biomass materials under investigation. It can, therefore, be concluded that, the Jatropha seed cake can be a good source of solid fuel when compared with the Jatropha stem and the Jatropha fruit husk.