Estimation of the potential for bioethanol production from the residues of cacao husks in Ecuador

In this study, the theoretically obtainable bioethanol production potential is estimated from the use of cacao residues in Ecuador, through the formulation of a mathematical model of the acid hydrolysis in cellulose of cacao husks and its conversion to ethanol by fermentation. Methodologically, the study was based on official documentation on the national and provincial amount of residual biomass of this crop, and on a kinetic model adapted to the case under study. An amount of 8.28 Mml of bioethanol was obtained, whose mixture with extra gasoline, at a ratio of 5:95 v/v, results in the Ecopaís E5C gasoline. Production of 166 Mml of E5C was estimated, corresponding to 10 % of the national production for the year 2017 and 56 % of the production for the year 2014, year in which the residual biomass of cacao was estimated. The coastal region contributes with 71 % of the national bioethanol and E5C production, led by the province of Guayas, in which E5 gasoline represents 25 % of its consumption in 2017. It is concluded that this production route of bioethanol is an attractive diversification option of the current production route based on the cultivation of sugarcane, adding value to residual biomass that is currently discarded. The theoretical results constitute the basis for more detailed studies in those provinces that combine a high potential for cacao residues and increasing consumption of E5 but must be complemented with experimental research to corroborate their validity and provide elements that determine the viability of the bioethanol production route studied.