Impact of sustainable valorization of agro-industrial residues on local climate change in West Africa: a case study of cashew nut waste in Côte D'Ivoire

The cashew nut sector has contributed to the mitigation of local climate change by achieving in 2018 a carbon footprint of - 349,711 tCO2eq. However, shell burning in landfills has degraded the carbon footprint of that sector, reaching an additional + 34,844 tCO2eq of greenhouse gas emissions. This therefore justifies the study of sustainable thermochemical recovery of these agro-industrial wastes and the evaluation of the environmental potentialities. Thus, the study shows that the pyrolysis of cashew nut shells generates on average 17% shell charcoal, 81% fuel gas and 2% inorganic matter. Carbon accounting reveals that with a potential of 49,331 to 116,352 tons of shells generated annually by cashew nut shelling in Côte d'Ivoire, the local production of electricity from pyrolysis gas and the partial substitution of wood charcoal by cashew nut shell charcoal will avoid the annual release of 106,866 to about 252,055 tCO2eq of greenhouse gases into the atmosphere, from the year 2018. That is, a potentiality of 2.166 tCO2eq of greenhouse gases to be saved per ton of shells recovered (2.166 tCO2eq/t). Thus, in general in West Africa, the integration of pyrolysis recovery of cashew nut shells would therefore contribute to the mitigation of local climate change.