Sustainable Thermochemical Valorization of Cashew Nut Waste in West Africa: Experimental Study and Evaluation of the Energy Potential in Côte d'Ivoire

Abstract

The local shelling of cashew nuts in West Africa generates very abundant and troublesome waste for high-capacity processing units. In order to contribute to the local production of sustainable energy and to overcome the difficulty of managing these agro-industrial residues, our study focused on the valorization of shells into energy vectors, using pyrolysis furnaces. Thus, the thermochemical study and elementary analyses made it possible to evaluate the net calorific values of the shell coal and fuel gas generated by pyrolysis, respectively at 6,801 kcal/kg and 4,300 kcal/kg. For Côte d'Ivoire, the world's leading producer and first processor in the sub-region, local processing of cashew nuts can generate the availability of 44,398 to 104,717 tonnes of shells per year. The study of the energy potential showed that from the year 2018, the annual energy potential of this biomass in Côte d'Ivoire will evolve from 20,597 to 48,580 toe with a production capacity of 62.93 to 148.43 GWh of electricity and 7,547.66 to 17,802 tons of shell coal. For a national energy consumption close to that of 2018, the rate of renewable energies in the electricity mix could therefore be increased from 0.63% to 1.5% and wood charcoal consumption reduced from 12.88% to nearly 30.4%.  The development of cashew nut shell pyrolysis in West Africa could therefore reduce the use of fossil fuels for power generation and deforestation, two of the main causes of local climate change.