Ciclo de cogeração com bagaço de cana - análise exergoeconômica e exergoambiental

Abstract

The global demand for energy increases in line with countries' technological and economic development. In Brazil, the electric energy matrix is predominantly renewable, due to hydraulic plants, however it makes it hostage to climatic conditions. As a way of diversifying the energy matrix, biomass has been used as a renewable source for the generation of electrical energy, especially sugarcane, whose main products are sugar, biofuel (ethanol) and bioelectricity. In this work, exergetic, exergoeconomic and exergoenvironmental analyzes of a cogeneration system with sugarcane bagasse were carried out, using real data from the plant in operation during the harvest period, which has as products: steam for the plant process and energy both for self-sufficiency and for sale to an electric utility. The results show that the furnace has the largest contribution of the destroyed exergy rate of the system with 60.22% and the total exergetic efficiency of the plant was 20.55%. The products of the system had a cost rate per unit of electricity from the cogeneration system of 5.967 US$/GJ or 21.83 US$/MWh and the cost rate per unit of steam exergy was 3.96 US$/GJ. Environmentally, a specific environmental impact rate of 6.06 mPt/MJ or 21.82 mPt/kWh for electricity and 4.06 mPt/MJ for the specific environmental impact rate of steam. Based on the exergoeconomic parameters of the components, it is concluded that the evaporator and the superheater are the economically viable components for future investments. And, environmentally, the furnace has the highest environmental impact rate of the plant, mainly due to the emission of pollutants.