Avaliação da viabilidade técnica e econômica da produção de etanol em planta piloto a partir da batata-doce (Ipomoea batatas)

Abstract

Biofuels gradually expand their potential share in power generation, due to the progressive reduction of fossil carbon reserves, combined with growing energy demands of society. Brazil has favorable conditions for the cultivation of bioenergy sources due to its tropical climate and it s currently concentrated on a single source, sugar cane. However, due to the low temperatures in winter and incidences of frost, only the State of Rio Grande do Sul doesn´t have the potential climate for planting sugar cane and, consequently, its reduced share in the production of ethanol. An alternative to sugar cane are the starchy, among which we can highlight sweet potato and cassava. Apart from subsistence farming, sweet potatoes (Ipomoea batatas) may be marketed for the biofuels industry, benefiting small farmers. This project intends to determine the technical and economic feasibility of producing ethanol fuel in a small plant in the town of Santa Maria, the central region of Rio Grande do Sul, using as raw materials sweet potato (Ipomoea batatas) starch. Results show technical feasibility, obtaining 190 liters of hydrous ethanol from 1,000 kg of sweet potato. Processing cost amounts R$ 0.96 (US 0.46) per liter. From this value, 35.4% is the raw material contribution and 64.6% is due to processing cost. ABC cost was applied and the main expenditure element was manpower (37%) and the main activity cost was distillation (35%). Both technically and economically deploying a small industrial unit requires no large economic support, what means that it s an affordable investments for a small farmer. And finally, the process is flexible, because it can use several raw materials to produce ethanol, like manioc, sweet potato and sweet sorghums. That characteristic can allow a more continuous production around the year an can minimize the risks of dependence from one sole crop.