Studies on hydrodynamics of annular circulating fluidised bed drier with millet ragi particles mixture

Millet and ragi particles mixture with the millet particles having average diameter 2250 mum and density 1163.9 kg m(-3) and ragi particles of average diameter 1500 mum and density 1310.4 mg m(-3), with the mass fraction 0.5 each of millet and particles were used to study the hydrodynamics of an annular circulating fluidised bed drier. Gap openings were varied from 12 mm to 72 mm and it was found that mass flux of solids remained constant for all air rates for gap openings greater than 60 mm. Dilute phase flow and dense phase slugging flow regime models were verified. A correction factor, K has been incorporated for the dense slugging flow regime. The error in the use or the model for pressure drop calculation was 28%. As there was smooth flow of particle mixture and little variation in pressure drop in dilute phase regime, drying could be done in this regime.