The impact of energy resource utilisation on the environment can be quantitatively addressed by methods using the concept of exergy. In this paper, is performed an exergetic analysis on a autonomous distillery for the production of ethanol from sugarcane, in which an UASB reactor is supposed to be added to the system in order to treat all the stillage produced in the distillery. The exergetic costs are calculated for two different uses of the biogas: direct burning in the steam generator substituting part of the bagasse and used in the sugarcane transport vehicles after being cleaned as pure methane. The results show that while the pollutant is kept away from the environment, the performance of the system is improved with higher exergy savings.315171527Macedo, I., Greenhouse gas emissions and energy balance in bio-ethanol production and utilization in Brazil (1996) (1998) Biomass and Bioenergy, 14 (1), pp. 77-81Rosillo-Calle, F., Cortez, L.A.B., Towards PROALCOOL II - A review of the Brazilian bioethanol programme (1998) Biomass and Bioenergy, 14 (2), pp. 115-124Souza, M.E., Fuzaro, G., Polegato, A.R., Thermophilic anaerobic digestion of vinasse in pilot plant UASB reactor (1992) Water Science and Technology, 25 (7), pp. 213-222Driessen, W., Tielbaard, M., Vereijken, T., Experience on anaerobic treatment of distillery effluent with the UASB process (1994) Water Science Technology, 30 (12), pp. 193-201Conservation of energy in the sugar and ethanol industry (1990), IPT - Technological Research InstituteSao Paolo Technological Research Institute, São Paulo(in Portuguese)Pinto, Cláudio plaza technology for anaerobic digestion of stillage and sustainable development (1999), Master of Science Thesis, FEM/Unicamp(in Portuguese)Gloeden, E., Cunha, R.C.A., Fraccaroli, M.J.B., Cleary, R.W., The behaviour of vinasse constituents in the unsaturated and saturated zones in the Botucatu aquifer recharge area (1991) Water Science Technology, 24 (11), pp. 147-157Cruz, R.L., Righetto, A.M., Nogueira, M.A., Experimental investigation of soil and groundwater impacts caused by vinasse disposal (1991) Water Science Technology, 24 (11), pp. 77-85Rosen, M.A., Dincer, I., On exergy and environmental impact (1997) International Journal of Energy Research, 21, pp. 643-654Lozano, M.A., Valero, A., Theory of the exergetic cost (1993) Energy, 18 (9), pp. 939-960Castier, M., Rajagopal, K., Thermodynamics analysis of alcohol distillery (1988) Energy, 13 (5), pp. 455-45
