Comparison among Proposals for Energy Integration of Processes for 1G/2G Ethanol and Bioelectricity Production

Abstract

Brazil has an important role in the world market of ethanol production and the implementation of technologies of second generation ethanol will intensify its production. In this work Pinch Analysis was used in order to perform energy integration of processes for first and second generation (1G/2G) ethanol and bioelectricity production, using hydrothermal and diluted acid pretreatments of sugarcane bagasse, both including and not including pentoses fermentation step. Processes that include pentoses fermentation step, for both considered pretreatments, have higher ethanol production when compared to the ones that do not make use of hemicellulose fraction of bagasse to produce ethanol, but steam consumption increases in the same order of magnitude of ethanol production. For the four evaluated scenarios the application of energy integration demonstrated a reduction in energy consumption of more than 50% when compared to the corresponding cases without any energy integration and of more than 30% when compared to partially integrated processes, as commonly found in Brazilian industrial plants. Besides the economical advantage, due to the decrease in costs of hot and cold utilities, energy integrated processes increase bagasse availability for production of second generation ethanol.