Multiphase CFD modeling: Fluid dynamics aspects in scale-up of a fluidized-bed crystallizer

Fluidized-bed crystallizers are widely utilized across numerous branches of industry. However, they have proven difficult to scale up. The present work reports the scale-up of an Oslo fluidized-bed crystallizer with a classification leg using computational fluid dynamic (CFD) methods. The apparatus was modeled in six volumes: 0.039, 0.33, 2.64, 29, 97, and 230 m3. Calculations cover polydispersive suspension of NaCl crystals with the initial concentration equal to 10 vol.%. Ten size classes of the crystal diameter were assumed, varying from 0.4 to 3 mm. Simulations were run using the commercial package Fluent. To model two-phase flow, an Eulerian multiphase model was used with the standard k–ɛ method. The chosen scale-up factor was the outlet liquor velocity. Results are compared with industrial data.