Estudo da dinâmica do escoamento em leitos de lama para aplicação em reatores de Fischer–Tropsch

Abstract

The search for more sustainable and efficient solutions, such as the production of sustainable aviation fuels, has driven the study of multiphase reactors, among which slurry bubble column reactors stand out. In this context, computational fluid dynamics has emerged as a valuable tool for investigating the hydrodynamic behavior of gas–liquid–solid systems and supporting the development of optimization strategies for these processes. Initially, a numerical analysis of the flow dynamics in a bubble column operating in a gas–liquid regime was performed at superficial gas velocities of 0.05, 0.10, and 0.30 m/s, assessing the impact of different interfacial forces and bubble breakup parameters on gas distribution. In the two-phase regime, it was observed that the choice of drag and lift coefficients significantly influenced the global and local gas holdup. The calibration of the breakup parameters (Wecr = 3, Cg = 0.673) allowed reproducing the increase in Sauter mean diameter with column height. Subsequently, the impact of adding glass particles with a diameter of 250 µm was evaluated using an Eulerian modeling approach, at two different concentrations (10% and 20% vol.). The presence of the solid phase reduced the global gas holdup, an effect associated with the formation of a core–annular flow pattern. However, unlike the reference experimental data, the simulations showed a decrease in the mean bubble diameter with increasing solid concentration, due to intensified breakup phenomena. The results highlight the role of interfacial force modeling and breakup parameters in predicting the hydrodynamics of bubble columns and reveal that the addition of particles modifies the flow dynamics and reduces gas retention.