A non-parametric bubble size correlation for a Two-Section Two-Zone Fluidized Bed Reactor (TS-TZFBR)

The Two-Zone Fluidized Bed Reactor (TZFBR) provides a high level of process integration, allowing heterogeneous catalytic reaction and simultaneous catalyst regeneration in two different zones of a single fluidized bed. This work considers a new reactor design that incorporates a different cross-sectional area in each zone to allow low flow rates in the regeneration zone. The reactor geometry, e.g. the transition angle α between the two zones in this Two-Section Two-Zone Fluidized Bed Reactor (TS-TZFBR), has a strong effect on the bubbling behavior. The present study focuses on obtaining a bubble size (db) correlation able to predict the experimental hydrodynamic behavior inside this novel TS-TZFBR. Experimental studies have been conducted on acrylic glass pseudo-2D TS-TZFBRs using several particle types and reactor geometries (α). Experimental results validate classical db correlations within the straight region of the reactor. A novel non-parametric bubble size correlation has been developed to predict the bubbling behavior within the tapered bed section, where an additional gas feed is also applied. This non-parametric model agrees with experimental results along the whole TS-TZFBR bed height for a wide range of operational conditions: ugas/umf = 1.5–3.5, ugas − umf = 5–25 cm/s, α = 0°–85°, umf = 1.2–20.5 cm/s.