Parametric study of tapered fluidized bed reactor under varied taper angle using TFM

Abstract

Gas solid fluidized bed application has gained popularity as an excellent contacting device that is been widely used in thermo-chemical processes, drying application in food processing industries etc. due to its favorable heat transfer characteristics. Most of the outmoded fluidization activities reported is confined with columnar/cylindrical shaped bed reactors. Conventionally, tapered/conical reactors are used for energy conversion which has substantial dynamic characteristics over the columnar reactors in terms of smooth, steady operation with marginal pressure variation. This work focuses on the computational modelling and simulation on the effect of various parameters like par, Stagnant bed height, Superficial velocity, Minimum fluidization velocity and Heat transfer characteristics upon variation in the taper angle of Tapered Fluidized Bed Reactor (TFBR) using Computational Fluid Dynamics (CFD) solver FLUENT. Two Fluid Model (TFM) is adopted for the simulation studies where both the phases (Solid, Gas) are treated as fluids. The results obtained are compared with simulation conducted for columnar reactor having same axial length. 2D domain has the axial length of 1.2 m and bottom diameter of 0.15 m. Simulation results shows that the finer the particle size becomes, greater is the heat transfer by conduction from bed to wall compared to larger particles. The interphase heat transfer from Solid-Air is maximum in the reactor core section. Although the particle volume fraction is observed to be more in columnar reactor, better fluidization characteristics is observed in reactor with taper angle 4.52°.