Energy Recovery from Agri-Food Processing Waste Using a Thermal Process: Formulation and Characterization of Biofuels from Citrus sinensis and Manihot esculenta Peelings

Abstract

This work proposes an energy recovery from agri-food waste through its transformation into biofuel. The agri-food wastes concerned in this work are Manihot esculenta and Citrus sinensis peels and cassava wastewater, which served as a binder. The carbonization phase made it possible to obtain 34.68% dust for the Citrus sinensis peels and 29.06% for the cassava residues. These dusts made it possible to propose two biofuel formulas : L8M92, composed of 8% dry matter powder of the binder and 92% cassava peeling powder ; and L8O92, composed of 8% dry matter powder of the binder and 92% orange peel powder. The characterization of the formulated biofuels made it possible to note that biofuels based on orange peel contain 8.88% ash, a fixed carbon rate of 36.07%, and a Lower heating value (LHV) of 21.54 MJ/kg. Biofuels based on cassava peels contain 19.65% ash and 36.59% fixed carbon, with an LHV of 21.13 MJ/kg. The controlled combustion test (CCT) tests using the formulated biofuels showed that the CO and PM2.5 emission factors are, respectively, 22.38 g/kg and 1.38 g/kg for the biofuel from peelings. Orange, 22.05 g/kg, and 1.45 g/kg for biofuel from cassava peelings. From these results, it is concluded that biofuels formulated from cassava and orange are recoverable, and they have CO and PM2.5 emission factors close to those of charcoal. These biofuels have an interesting energy content with fairly modest CO and PM2.5 emission factors, close to those obtained from charcoal. Also, the characteristics of the formulated biofuels are in the same order of magnitude as those in the literature. These results indicate that cassava and orange waste can be used to contribute to the diversification of the energy supply through biofuel production. However, further work is needed to improve these results.