Impact of Torre faction on the Fuel Properties of Lignite, Coconut Shells, Cassava Peels and Their Blends

ABSTRACT The effect of torrefaction temperature and residence time on the fuel properties of lignite, biomass (coconut shells and cassava peels) and their blends was investigated. The samples were subjected to three torrecfaction temperatures (200, 260 and 300o C) and at two residence times (10 and 20 minutes) using programmable muffle furnace. Blends of torrefied lignite and biomass were prepared in two different ratios (80:20 and 70:30). The energy content, proximate and ultimate analyses of the samples were determined using ASTM methods. Scanning electron microscope (SEM) was used to evaluate the pore size, fiber content, topography and the morphology of the samples. The potential emissions of SO2, CO2 and NOx from the torrefied samples were evaluated using emission estimation model for fossil fuel electric power generation. The proximate analysis showed that the ash (8.0 %) and moisture (30.0 %) contents of lignite were higher than that of the biomass. The coconut shells and cassava peels had higher volatile matter of 72.9 % and 68.1 % respectively and much lower fixed carbon. The data showed that release of volatile matter decreased at severe torrefaction condition. The content of fixed carbon and energy increased with the severity of the torrefaction condition except for cassava peels which decreased at 300 o C. One–way analysis of variance on the results of the proximate analysis showed that there was significant difference (P