Techno-Economic Evaluation for Ethanol Production from Residual Cashew Apple Using a Flocculant Yeast

Biofuels, especially ethanol, have gained immense popularity in the global energy sector, driven by a significant increase in demand. Ethanol production using agroindustrial residues reduces costs and can provide a destination for these residues that are generally wasted. In this context, the cashew apple emerges as an attractive and unconventional feedstock for bioethanol production. Although the technology to obtain ethanol from cashew apple juice is present in several studies, the key elements that determine its economic feasibility have never been defined. Then, this study aimed to present the first techno-economic assessment of ethanol production from cashew apple juice. Two industrial full-detailed scenarios were proposed based on the application of the obtained ethanol, where in scenario I, 2.1 x 10(6) liters of ethanol are produced for combustion purposes (94% w/w), while in scenario II, 2.8 x 10(6) liters of ethanol are produced for antiseptic purposes (70% w/w). The yields calculated in the proposed scenarios I and II were 66.5 L/ton and 88.9 L/ton, respectively, values comparable with those found in the literature using sugar cane and sweet sorghum as feedstocks. Then, the production of ethanol from cashew apple juice proved technically feasible. Economic sensibility analysis showed that both proposed scenarios are economically viable, as long as the cashew apple acquisition cost is at most 17.2 US$/ton for the scenario I and 28.1 US$/ton for scenario II. The raw material cost was the most crucial parameter to impact the economic analysis. In conclusion, the proposed biorefinery returned promising results, and it can consolidate a new raw material for ethanol production, provided that idle capacity is reduced and heat generation from cashew apple bagasse is optimized.