Water reuse and recycling according to stream qualities in sugar-ethanol plants

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Sugarcane is one of Brazil's most important industries, mainly because of ethanol, one of its products. Ethanol has a low production cost and low GHG emissions per unit of energy produced, as compared to other fossil fuels. However, several authors have expressed concern about the high water consumption expected in the coming years for biofuel production. This work presents a proposal to reduce water consumption in the industrial stage, taking into account demand and supply quality restrictions. A water supply mix is suggested, with direct reuse of 648 L/t of cane, and another 176 L/t of cane covered indirectly by recycled streams. This reduces the required external withdrawal to 405 L/t of cane - a value within the limit mandated for the sugarcane industry in the State of Sao Paulo. (C) 2013 International Energy Initiative. Published by Elsevier Inc. All rights reserved.175546554Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FINEP [01/06/004700]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)CNPq [135595/2008-8, 556212/2010-0, 304820/2009-1, 470481/2012-9]FAPESP [2011/05718-1, 2011/51902-9]FINEP [01/06/004700

Production of bioethanol and other bio-based materials from sugarcane bagasse: Integration to conventional bioethanol production process

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Ethanol may be produced using sugarcane bagasse as raw material through the Organosolv process with dilute acid hydrolysis, thus increasing ethanol production with the same cultivated sugarcane area. In this work simulations of bioethanol production from sugarcane juice and bagasse are carried out using software UniSim Design. A typical large scale production plant is considered: 1000 m(3)/day of ethanol is produced using sugarcane juice as raw material. A three-step hydrolysis process (pre-hydrolysis of hemicellulose, Organosolv delignification and cellulose hydrolysis) of surplus sugarcane bagasse is considered. Pinch analysis is used to determine the minimum hot utility obtained with thermal integration of the plant, in order to find out the maximum availability of bagasse that can be used in the hydrolysis process, taking into consideration the use of 50% of generated sugarcane trash as fuel for electricity and steam production. Two different cases were analyzed for the product purification step: conventional and double-effect distillation systems. It was found that the double-effect distillation system allows 90% of generated bagasse to be used as raw material in the hydrolysis plant, which accounts for an increase of 26% in bioethanol production, considering exclusively the fermentation of hexoses obtained from the cellulosic fraction. (C) 2009 The Institution of Chemical Engineers. Published by Elsevier B.V All rights reserved.879A12061216Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FINEPFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP