IMPROVING THE ETHANOL PRODUCTION FROM SUGAR CANE BIOMASS

摘要

The sugar and ethanol production is one of the most important economical activities in Brazil, mainly due to its efficiency and competitively. The alcohol production is made through the following steps: juice extraction, purification, fermentation and distillation. The process begins with the sugar cane juice extraction, usually made in mills, where the juice is extracted by compression of the sugar cane between great pronged cylinders. The extracted juice goes to purification and fermentation operations where it is converted in an ethanol/water mixture called wine, after, it is heated in a heat exchanger and through a distillation operation, as a sub product in the process, hydrated ethanol is finally obtained. Each step of this process consumes electric and thermal energy that coming from a cogeneration system whose fuel is the own sugar cane bagasse, obtained as a sub product, in the extraction operation., Energy and exergy balances along the process were performed, the exergy of water/sucrose and water/ethanol solutions were carefully calculated considering that them are non ideal solutions. The exergetic cost methodology was applied as a tool to suggest modifications to improving the use of energy in ethanol, electrical energy and bagasse production.