Simulação numérica da termofluidodinâmica de um reator (riser) de craqueamento catalítico em leito fluidizado.

Abstract

In the petrochemical and oil processing industry riser is the main equipment of the fluid catalytic cracking (FCC) unit, used for the refining of heavy petroleum fractions. For design and optimization of riser, it is essential to understand the thermo fluid dynamics of the gas-solid mixture inside. In this respect, computational fluid dynamics (CFD) has been shown to be a good alternative for the study of complex systems. Therefore, this work aims to study the thermo fluid dynamics of a FCC riser with high flux, via CFD using commercial software Ansys Fluent version 15. The mathematical model is based on the Eulerian - Eulerian approach, considering a Kinetic Theory of Granular Flow (KTGF) and the k - ϵ two equations turbulence model. Numerical results of fields of velocity, volumetric fraction and pressure of the gas and particulate phases, at constant temperature, are presented, analyzed and compared with data of an experimental plant with 76 mm ID and 10 m height, presenting good agreement, except in regions with high particle density. Thus, the proposed model showed better representation of the flow in regions and operating conditions that result in lower particle concentrations (lower solids flow and / or higher gas flow).