Simulação computacional e análise exergética da gaseificação de bagaço de cana-de-açúcar em leitos fluidizados borbulhantes

Abstract

This work presents the development of a detailed mathematical modeling to describe the sugarcane bagasse gasification process in bubbling fluidized beds using an Euler-Euler approach. The use of the developed methodology may help the future design of new gasifiers as the understanding of the flow behavior inside some already existent gasifiers. Here, the effects of the use of thermofluid dynamics closure models and chemical mechanisms on the model predictive capabilities of the quantities of interest in the sugarcane bagasse gasification process are studied. A two dimensional domain is used to describe the investigated situations. The chemical reaction mechanisms are developed from schemes available in the literature. The numerical implementation of the mathematical model is realized through the open code MFIX (Multiphase Flow with Interphase eXchange). The modeling implementation is first validated by comparing simulation results with experimental data available in the literature. The influence of the chemical models is quantified by calculating the percentage contribution of each reaction to the production of the gases yielded in the sugarcane bagasse gasification. In addition to the modeling of the sugarcane gasification process, the entropy and exergy transport equations are also developed here. The obtained equations allow a detailed investigation of the sources of irreversibility in gas-particle reactive flows.