Bagasse and trash gasification: modeling and exergetic cost analysis in a BIGCC cycle

Abstract

The ethanol production tends to grow up in next year's due of a very interest of many countries for the biofuels. In this context, Brazil is the biggest ethanol producer from sugar cane with approximately 27,7 billion liters in harvest 2010/2011 (MDIC, 2012). In Brazil almost sugar and ethanol mills are self-sufficient to attend thermal, mechanical and electrical demand to the production processes, however, the cogeneration system has a low efficiency with many plants based in Rankine Cycle with steam parameters in pressure of 22 bar and temperature of 300ºC. In last years, the electricity has been turn a new product to the mills, due a better commercialization conditions. Thus, the ethanol and sugar sector to see the electricity as a new and important product, leads to a search an improve the efficiency of the cogeneration systems. In this context, the gasification of bagasse and trash from sugar cane, yet not use in sector, integrated in a combined cycle to show a hopeful alternative to improve electricity generation in sugar and ethanol mills. The main objective of this propose is to performance the modeling of gasification process of bagasse and trash sugar cane and to propose a BIGCC (Biomass Integrated of Gasification Combined Cycle) cycle in a cogeneration plant to supply the thermal, mechanical and electric demand to an autonomous distillery. Two gasification models will be study based in the chemical equilibrium concept: chemical equilibrium stoichiometric and chemical equilibrium non-stoichiometric. Both models will be develop in EES® software and results compare with experimental data from literature and with Thermoflex® software. The efficiency of the BIGCC cycle will be assess through methodology of exergetic cost.