Authors: Cesar Medina-Pedraza a; Hugo de Lasa a
a Chemical Reactor Engineering Centre, Department of Chemical and Biochemical Engineering, The University of Western Ontario, Canada
Source: Industrial & Engineering Chemistry Research 2020 59 (46), 20325-20336
Description: This study reports a numerical hybrid cluster simulation of a downer reactor unit using CPFD Barracuda VR software. This model includes an experimentally determined particle cluster size distribution to describe the particle cluster morphological changes as well as the cluster acceleration. Gas–solid flows are considered for a fluid catalytic cracking catalyst with an apparent particle density of 1722 kg/m3, flowing in a 5.08 cm-ID column with air at 300 K and with a pressure close to atmospheric. Conditions for the simulations consist of 1.0–1.6 m/s superficial gas velocity and 30–50 kg/m2 s solid mass flux ranges. Calculations developed involve the Hölzer–Sommerfeld and Ganser drag correlations. The proposed numerical model is validated by comparing experimental and simulated radial cluster particle velocities and particle volume fractions. Simulations developed show that the Hölzer–Sommerfeld drag function in conjunction with a proper selection of cluster geometry provides good cluster velocities and particle volume fraction values both in the cluster acceleration and cluster-stabilized flow unit sections.