Estudo comparativo do gás energético obtido pela gaseificação de biomassa em reator de leito fluidizado circulante alotérmico e autotérmico utilizando modelo de equilíbrio não-estequiométrico

Abstract

The pursuit of renewable and less polluting energy sources makes biomass gasification an interesting route to obtain a gaseous fuel. In this process, where predominantly endothermic reactions occur, temperature and energy supply play a fundamental role. Considering the existence of autothermal and allothermal processes of gasification, with their respective advantages and disadvantages, the present work intends to compare these two operating modes. A non-stoichiometric equilibrium model was developed for simulations. This model allowed predicting the composition of the energetic gas, its higher heating value and the efficiency of each process. It was possible to assess the modes of operation according to these criteria. Results indicated the production of a gas with greater higher heating value through alothermic mode, due to the higher concentration of combustible compounds. However, the need for external heat supply makes efficiency of this process low in comparison with that of autotermic operating mode. Results also suggest the need for developing models that are more realistic to obtain estimated values closer to that of experimental ones.