Bottom and exit region solids hold-ups in circulating fluidized bed risers

Data obtained under high density/high solids flux conditions in this work and from the literature are used to develop two new correlations for solids hold-up in the bottom and exit regions of CFB risers. The data cover a wide range of particle sizes and densities and were obtained from risers up to 400 mm in diameter and 15.8 m in height for gas velocities and solids circulation fluxes up to 11 m/s and up to 425 kg/m(2)s, respectively. The correlations are incorporated in a one-dimensional model and used to calculate cross-sectional mean solids hold-up profiles along the height of a 76 mm diameter riser used in the study, resulting in good agreement between predicted values and experimental data.