Análisis numérico de la variación de velocidad superficial del gas y del flujo másico de sólidos en un riser de craqueo catalítico fluido

The gas-solid flow has been considered in many industrial processes due its high capacity for transferring mass, momentum and energy. At the petroleum refining industry, the Fluid Catalytic Cracking process (FCC) is one of the most relevant because vacuum gas-oil is converted into lighter compounds, like gasoline, by means of cracking reactions in the riser, where the atomized and vaporized gas-solid flow is combined with a fluidized solid catalyst. The gas-solid flow formulation is no easy due to the phase to phase, and phase to riser walls interactions presented in the flow. Since 30 years ago several Computational Fluid Dynamics (CFD) efforts have been developed oriented to understand and reproduce the biphasic flow behavior. In this paper the mass and momentum balance equations, a drag model, and constitutive equations are joined in a CFD model in order to compute the solid phase's properties, and phase's interaction in an air solid catalyst system. By means of a parametric study the hydrodynamics of the flow varying the air superficial velocity and the solid catalyst flow at the riser inputs are performed to confirm the CFD model capability to predict the annular flow pattern and then, in the future to be able to apply this model to gas oil-steam-catalyst system's analysis. It is confirmed that the proposed model properly predicts the annular flow pattern for every operation condition case analyzed.