ENERGY, EXERGETIC AND ENVIRONMENTAL ANALYSIS OF TECHNOLOGIES AIMING TO REDUCE VINASSE PRODUCTION IN SUGAR-ALCOHOLIC PLANTS, INCLUDING DIFFERENT ENERGY DISPOSAL AND USE PROCESSES
The sugar and ethanol sector in Brazil is one of the most important in the national economy, representing a relevant part of agribusiness. Thus, in the process of producing sugar and ethanol, one of the main residues is vinasse, which is the bottom product of the distillation columns and the main effluent of the distilleries. It has been used in natura in fertiirrigation due to its mineral and nutrient content. However, it also has other characteristics that make it a polluting agent, such as an acidic and corrosive nature, a high BOD in the range of 14.4 to 29.7 g/l; which causes an unpleasant smell due to the putrefaction of the organic components. Furthermore, it is a residue that is produced in large quantities (10-15 l vinasse/l ethanol produced), which is the main problem for its disposal. Thus, this work aims to evaluate technologies to reduce the volume of vinasse produced and for its disposal and energy use. The technology considered to reduce the volume of vinasse was fermentation with a high concentration of sugar, while the technologies for disposal and energy use considered were the concentration, incineration, and biodigestion of vinasse. As preliminary results, fermentation with high sugar concentration allowed a reduction of 38.8% in vinasse production when compared to conventional fermentation.