Mandarin Peels and Rice Husks as Substrates for Solid Biofuel

Abstract

Biomass, such as mandarin peels and rice husks, are among the most abundant and accessible sources for the conversion of crops into solid biofuel. It is important to highlight that sustainable bioenergy must have high efficiency; therefore, the heating values of biofuel samples produced from rice husks, mandarin peels, corn starch, glycerol, citric acid and acetic acid have been evaluated in the present study. The total moisture content, ash content and heating values of the sixteen biofuels produced were determined. The compressive strength was also determined and it was found that all the samples presented maximum resistance, appropriate for the storage and handling of the developed solid biofuel. Replacing rice husks with mandarin peels resulted in a reduction of the silica mass in the ash content. In addition, in four specimens, the amounts of nutrients (N, P, K, Ca and Mg) and heavy metals (Cu, Zn, Fe, Mn, Cd, Pb, Cr and Al) found in the ash were measured. It was found that the amount of nutrients increased proportionally with the quantity of mandarin peels in the solid biofuel. The solid biofuel with a higher quantity of mandarin peels showed greater high and low heating values, which were 19.18 MJ.kg -1 and 17.92 MJ.kg -1 , respectively. All the developed biofuels were shown to be capable of replacing traditional heat sources, such as firewood (7.12-10.47 MJ.kg -1 ).