Computational Fluid Dynamics study of the CREC Riser Simulator: Mixing patterns

Abstract

The CREC Riser Simulator Reactor is a novel mini-Riser unit. This study considers a laminar-turbulent CFD (Computational Fluid Dynamics) simulation using the COMSOL Multiphysics® module to establish gas-solid mixing patterns. The proposed CFD calculations are verified using both experimental data (<10–15% difference) and mass balance errors (<0.1%). Results show the significant detrimental effect of basket vertical baffles implemented in earlier designs of the CREC Riser Simulator Reactor. On the basis of this, it is demonstrated that a double vortex flow leading to high gas mixing is favored in a new reactor configuration “without” basket vertical baffles. For instance, at 4200rpm, in a basket unit loaded with 0.8g of catalyst, close to ~69cm/s gas axial velocities were observed. This shows turbulent or fast fluidization conditions with smaller than 0.51s mixing times. In addition, this new suggested design with enhanced mixing places the CREC Riser Simulator in a new class of laboratory scale fluidized catalytic units.