Hydrodynamics of Annular Circulating Fluidised Bed Drier with Millet and Ragi Particle Mixture

Abstract

Millet and ragi particle mixture with the millet particles having average 2250 μm diam and density 1163.9 kg/m3and ragi particles average 1500 μm diam and density 1310.4 kg/m³, with the mass fraction 0.25 of millet particles and 0.75 of ragi particles were used to study the hydrodynamics of an annular circulating fluidised bed drier. Gap openings were varied from 12mm to 72mm and it was found that mass flux of solids remained constant for all air velocities greater than 4.05m/s and for gap openings greater than 56 mm. Dilute phase flow and dense slugging flow regime models were verified. A correction factor, K was incorporated for the dense slugging flow regime. The error in the use of the model for pressure drop calculation was 20 per cent.