CHEMICAL ENGINEERING TRANSACTIONS VOL. 43, 2015 A publication of The Italian Association of Chemical Engineering Online at www.aidic.it/cet Chief Editors: Sauro Pierucci, Jiří J. Klemeš Copyright © 2015, AIDIC Servizi S.r.l., I SBN 978-88-95608-34-1; I SSN 2283-9216 Comparison between Single and Multi-Effect Evaporators for Sugar Concentration in Ethanol Production Cristina A. Prado a , Ozair Souza a , Noeli Sellin a , Cintia Marangoni b * a University of Joinville Region, Chemical Engineering Department, Rua Paulo Malschitzki 10, Joinville/ SC – Brazil Zip Code 89219-710 b Federal University of Santa Catarina, Blumenau Campus, Rua Pomerode 710, Blumenau/SC – Brazil Zip Code 89065-300 cintia.marangoni@ufsc.br Among lignocellulosic materials, the waste generated in banana cultivation, such as the discarded fruit, peels, leaves and pseudostem demonstrates great potential for ethanol production. After hydrolysis, a concentration step of the hydrolyzate material is carried out to increase the amount of sugar available for the subsequent fermentation process, which is directly related to ethanol production. Despite being widely employed, the concentration continues to demonstrate certain limitations with respect to its use for cellulosic materials in second generation ethanol production due to the high energy consumption. Besides, the use of banana waste is not completely established, so studies concerning this process are important to evaluate all productive routes. Based on this, simulations of concentration of sugar from hydrolyzed lignocellulosic banana waste were carried out using the software Aspen HYSYS ®, aiming to obtain a concentrated broth containing 65 g/L of sugars with a simple evaporation system operating an atmospheric pressure. Same conditions were used to compare these results with a multi-effect evaporation system. Glucose concentration, the total amount of available sugars and inhibitors concentration were evaluated. Results have demonstrated that the energy consumption with multi-effect evaporator system is low with all residues: discarded fruit (636 kJ/h), banana peels (720 kJ/h) and pseudostem (734 kJ/h). Similar behavior was found for steam requirement: respectively 0, 2397 kg/h 0.3317 kg/h 0.3385 kg/h. As it is known, this is due to the fact that the steam generated in the first effect is used as heating fluid of the next effect. Even the multi-effect system proposed did not reach the 65 g/L of glucose with all residues, it is considered better than a single evaporator because the hydrolyzate streams contain additional sugars that can also be metabolized to ethanol during fermentation. 1. Introduction As cited by Lora et al. (2002), renewable energy sources, such as biomass, minimize the environmental impact and are an attractive alternative for energy production. One example is ethanol, which is produced from sugar cane in Brazil, from corn or starch in the USA, and from beetroot in Europe. As an alternative to the conventional substrates, the production of biomass from agricultural or agroindustrial waste is extremely environmentally friendly. Indeed, the overall environmental impact is minimized because the emission of CO2 into the atmosphere is balanced by its absorption during the growth of new biomass (Balat et al., 2008). Waste, resulting either from agriculture or from any other source, is generated across the world. Thus, it appears reasonable to use it as a source for energy production. Among lignocellulosic materials, the waste generated in banana cultivation, such as the fruit peels, the pseudostem, the leaves, and the banana plant stalk, demonstrates great potential for ethanol production. Soffner (2001) relates that a conventional banana plantation generates a large amount of waste with an excellent fibrous potential, which is suitable for biomass production. The model for ethanol production from lignocellulosic materials includes the hydrolysis of biomass polysaccharides into fermentable sugars, the subsequent fermentation of these sugars for ethanol production, and a final purification step. After the delignification step (i.e., pre-treatment), various methods of polymer DOI: 10.3303/CET1543091 Please cite this article as: Prado C., Souza O., Sellin N., Marangoni C., 2015, Comparison between single and multi-effect evaporators for sugar concentration in ethanol production, Chemical Engineering Transactions, 43, 541-546 DOI: 10.3303/CET1543091 541