Partic. vol. 21 pp. 179-186 (August 2015)
doi: 10.1016/j.partic.2014.08.009

Constraint strength and axial/radial particle velocity profiles for an integrated riser outlet

Dewu Wang^{a, b}, Chaoyu Yan^b, Chunxi Lu^{b, *}, Rui Li^a, Bin Zhao^a Shaofeng Zhang^{a, c}

lcx725@sina.com

Abstract

To study axial/radial profiles of particle velocity in the affected region of an integrated riser outlet, a cold model was developed for the integrated riser reactor combining the gas–solid distributor with the fluidized bed. Constraints, related to the gas–solid distributor and the upper fluidized bed, imposed on the particle flow in the riser outlet region, were investigated experimentally. The experimental results showed that with increasing superficial gas velocity, these constraints have strong influences on particle flow behavior, the particle circulation flux in the riser, and the height of the static bed material of the upper fluidized bed. When the constraints have greater prominence, the axial profile of the cross-sectionally averaged particle velocity in the outlet region initially increases and then decreases, the rate of decrease being proportional to the constraint strength. Along the radial direction of the outlet section, the region where the local particle velocity profile tends to decrease appears near the dimensionless radius r/R = 0.30 initially and then, with increasing constraint strength, gradually extends to the whole section from the inner wall. Based on the experimental data, an empirical model describing the constraint strength was established. The average relative error of the model is within 7.69%.

Graphical abstract

Keywords

Combined fluidized bed; Riser; Outlet structure; Particle velocity; Constraint strength