Hydrodynamics of gas–solid fluidization of a homogeneous ternary mixture in a conical bed: Prediction of bed expansion and bed fluctuation ratios--颗粒学报PARTICUOLOGY

Dora, D. T. K., Panda, S. R., Mohanty, Y. K., & Roy, G. K. (2013). Hydrodynamics of gas–solid fluidization of a homogeneous ternary mixture in a conical bed: Prediction of bed expansion and bed fluctuation ratios. Particuology, 11(6), 681–688. https://doi.org/10.1016/j.partic.2013.02.009

Hydrodynamics of gas–solid fluidization of a homogeneous ternary mixture in a conical bed: Prediction of bed expansion and bed fluctuation ratios

D.T.K. Dora ^a, S.R. Panda ^b, Y.K. Mohanty ^a, G.K. Roy ^b *

a Department of Chemical Engineering, Gandhi Institute of Engineering and Technology (GIET), Gunupur, Rayagada 765 022, Odisha, India
b Department of Chemical Engineering, National Institute of Technology (NIT), Rourkela 769008, Odisha, India

10.1016/j.partic.2013.02.009

Volume 11, Issue 6, December 2013, Pages 681-688

Received 3 January 2012, Revised 20 February 2013, Accepted 24 February 2013, Available online 17 June 2013.

E-mail: gkroy1234@gmail.com

Highlights

• Hydrodynamic characteristics of ternary mixture in conical fluidized bed were studied.

• Dimensional analysis and factorial design were used to investigate influence of process parameters.

• Correlations for determining fluctuation and expansion ratios were derived.

• Predicted values using the correlations were in good agreement with experimental data.

Abstract

Hydrodynamic characteristics of fluidization in a conical or tapered bed differ from those in a columnar bed because the superficial velocity in the bed varies in the axial direction. Fixed and fluidized regions could coexist and sharp variations in pressure drop could occur, thereby giving rise to a noticeable pressure drop-flow rate hysteresis loop under incipient fluidization conditions. To explore these unique properties, several experiments were carried out using homogeneous, well-mixed, ternary mixtures with three different particle sizes at varying composition in gas–solid conical fluidized beds with varying cone angles. The hydrodynamic characteristics determined include the minimum fluidization velocity, bed fluctuation, and bed expansion ratios. The dependence of these quantities on average particle diameter, mass fraction of the fines in the mixture, initial static bed height, and cone angle is discussed. Based on dimensional analysis and factorial design, correlations are developed using the system parameters, i.e. geometry of the bed (cone angle), particle diameter, initial static bed height, density of the solid, and superficial velocity of the fluidizing medium. Experimental values of minimum fluidization velocity, bed fluctuation, and bed expansion ratios were found to agree well with the developed correlations.

Graphical abstract

Keywords

Gas–solid fluidization; Conical bed; Homogeneous ternary mixtures; Bed fluctuation ratio; Bed expansion ratio

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