Torrefaction and Pelletization of Moringa oleifera Pods, for Sustainable Energy Development

Abstract

Moringa oleifera pods were torrefied and then pelletized, using cassava starch gel as a binder. The results for the ultimate analysis, showed an increase in the carbon content from 43.63% for the raw Moringa oleifera pods to 58.73% for the torrefied Moringa oleifera pods and a decrease in oxygen content from 48.42% to 35.59%, resulting in decrease in both O/C and H/C ratios from 1.11 to 0.61 and 0.14 to 0.07 respectively. The results of the proximate analysis showed increases in both the fixed carbon content from 13.87% to 45.20% and ash content from 4.05% to 17.75%, while the moisture and volatile matter contents decreased from 9.78% to 7.75% and from 72.20% to 29.39% respectively. The FT-IR analysis indicated the major absorption bands of 3350 cm-1, 2950 cm-1, 1540 cm-1, 1400 cm-1, 1260 cm-1, 1120 cm-1, 1070 cm-1, 840 cm-1, 780 cm-1, 750 cm-1, 690 cm-1, 650 cm-1, 620 cm-1. The spectra of both the raw and torrefied Moringa oleifera pods were similar. However, the intensities of the torrefied Moringa oleifera pods became weak due to the breaking of some bonds; such as O-H, C=O and C-O, leading to the formation of small molecular gases such as CO and CO2, leaving more C-C bonds with higher energy. The Higher Heating Value (HHV) increased from 14.80 MJ/kg to 19.09 MJ/kg; while the Lower Heating Value (LHV) increased from 13.34 MJ/kg to 18.22MJ/kg.