Numerical Studies on Average Solids Holdup in a Liquid–Solid Circulating Fluidized Bed Riser

Abstract

Computational fluid dynamic simulations were carried out to predict the radial profiles of solids volume fraction, liquid velocity and solids velocity. The effect of primary and auxiliary liquid velocities on average solids holdup in the riser was computed and the results were found to compare favourably with the experimental data. The effect of method of operation on average solids holdup in the riser was studied for three different methods of operations and the simulations were able to predict the average holdup values in close agreement with the experimental data. The effect of viscosity of the liquid on radial and axial profiles of solids holdup and average solids holdup in the column were studied and found to match well with experimental data. The effect of locations of the inlet of solids into the riser was also studied by comparing the radial profiles of solids volume fraction at different heights along the riser for various locations of solids inlet.