Similarity of gas-solid two-phase flow behavior in CFB riser

Hydrodynamic similarity of particle flow behavior in the fully developed region of upward gas-solid CFB riser was experimentally investigated. The experiments were carried out in a 15.1 m high and 100 mm i.d. CFB riser with FCC catalyst particle, and the axial pressure gradients, local solids holdups and particle velocities were measured over a wide range of operating conditions. Through extensive analysis and comparison of particle flow behavior, it was found that the cross-sectional average solids holdups in the fully developed region changed linearly with the number group of (G_s/ρ_p)^1.2/ U_g^2.0, although G_s and U_g showed different effects on particle flow. It was also showed that with different operating conditions, if the value of (G_s/ρ_p)^1.2/ U_g^2.0 was the same, the local solids holdups, particle descending velocities, solids concentrations inside cluster and cluster frequencies displayed the same spatial distributions, respectively. The research indicated that the number group (G_s/ρ_p)^1.2/ U_g^2.0 makes the effects of G_s and U_g combined, and with the same (G_s/ρ_p)^1.2/ U_g^2.0, the particle flow behavior in the fully developed zone of upward gas-solid two-phase flow exhibited very similar micro and macro hydrodynamic characteristics.