Regime transition in a gas–liquid–solid fluidized bed

Hydrodynamics of a liquid–solid circulating fluidized bed: Effect of dynamic leak

“…Vatanakul et al [30] while studying on gas-liquid-solid system noted the range of critical transitional liquid velocity around 0.125-0.135 m/s which is less than that of the present study (0.15 m/s) even though the particle characteristics and geometry of riser of the present study (d p = 1.36 mm, ρ s = 2468 kg/m 3 , H = 2.2 m, D = 0.08 m) are almost similar to them (d p = 1.3 mm, ρ s = 2500 kg/m 3 , H = 2.0 m, D = 0.076 m). These authors have taken liquid velocity corresponds to maximum peak at elevation H = 1.45 m which really indicates the pressure gradient measured when the solids occupied up to 1.45 m from the bottom of the bed and rest of the section above the 1.45 m is free board region with no solids.…”

“…Since there is a significant difference in hydrodynamic behavior from one regime to other, it is of primary importance to know the critical liquid velocities which demarcates one regime from the other. There are three different methods to identify the critical transitional liquid velocity that demarcates the conventional and circulating fluidized bed regimes [15,17,29,30]. Fig.…”

Characterization of gas–liquid–solid fluidized beds by S statistics

“…Consequently, the influence of bead size is negligible even at low gas velocities and the S value becomes lower than 3 at high liquid velocities. Such an insensitivity of the hydrodynamics of gas-liquid-solid fluidized beds to change in particle size at high liquid velocities has also been reported by Vatanakul et al (2005).…”

“…Thus, bubbles distribute more uniformly in the bed and flow upward faster, which reduces their chance of coalescing (Arjmandi-Tash & Zarghami, 2015;Kwon et al, 1994;Vatanakul et al, 2005;Zhang et al, 1997). Consequently, the influence of bead size is negligible even at low gas velocities and the S value becomes lower than 3 at high liquid velocities.…”

“…The locus of minimum liquid agitation velocity (U Lma ) had a minimum deviation from bed macrostructures (larger bubbles and bed surface oscillation) (Arjmandi-Tash & Zarghami, 2015). Particle size can have a significant effect on the size of bubbles produced within a dense bed (Kwon, Kang, Kim, Yashima, & Fan, 1994;Park & Kim, 2003;Vatanakul, Zheng, Jia, & Zhang, 2005). In addition, as discussed before, the bed weight is reduced at the onset of the agitated bed regime and particles move irregularly.…”