Determinação da composição dos gases combustíveis resultantes do processo de gaseificação de biomassa em reator de leito fluidizado circulante utilizando a teoria de minimização da energia livre de Gibbs

Abstract

This work develops a computational routine able to predict the composition of the gas obtained from a biomass gasification process in a circulating fluidized bed gasifier through the implementation of equations that describe the physical and chemical phenomena by using the Gibbs free energy minimization approach. Mathematical tools are implemented to generate the profiles of the variation in the volumetric percentage for methane, hydrogen and carbon monoxide compounds. This model determines the effect of the variables of the process, such as equivalence ratio, system temperature, addition of steam as a gasifying agent, fuel moisture and higher heating value in the composition of the resultant gas when the composition of the fuel used is obtained by chemical analyzes. The simulation parameters ranging between 0,2 and 0,54 for equivalence ratio, 1073 to 1273 K for the temperature and from 0 to 0,2 for the content of steam added as a gasifying agent. The behavior of this components in the resultant gas was as expected when compared to data from previous studies, showing that the modified equilibrium model employed can be useful for obtaining optimal operating points in the design of gasifiers.