Faculty Publications
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Item An Experimental Investigation of Slugging Phenomenon in 2D Binary Gas–Solid Tapered Fluidized Beds(John Wiley and Sons Inc, 2025) Sahoo, L.K.; Sarkar, S.Gas–solid fluidized beds are widely employed in metallurgical industries to produce direct reduced iron. For such practical applications, tapered fluidized beds are most suitable for handling particles with wide size distribution due to the axial velocity gradient. Herein, the slug behavior in binary tapered fluidized beds has been studied using a high-speed camera and digital image analysis method. The influence of taper angle, air velocity, and fine fraction on local parameters such as slug size, rise velocity, and aspect ratio, and bulk parameters such as slug number and its area fraction, and bed expansion ratio has been investigated. The local parameters increase with taper angle, air velocity, and fine fraction. The slug area fraction and the bed expansion ratio increase with air velocity and fine fraction. The bed expansion ratio increases while the slug area fraction decreases with taper angle. The slug number fraction, slug area fraction, and bed expansion ratio range from 0.027–0.241, 0.20–0.63, and 1.11–1.42, as taper angle, air velocity, and binary composition vary from 0°–15°, 0.20–0.35 m s?1, and 0.25–0.75, respectively. An empirical correlation is proposed for bed expansion ratio prediction. Based on the present investigation, the optimum taper angle is 5°–10°. © 2024 Wiley-VCH GmbH.Item Mathematical Modeling of Fluidized Bed Magnetizing Roasting of Iron Ore Fines(John Wiley and Sons Inc, 2025) Sahoo, L.K.; Mantripragada, V.T.; Sarkar, S.The fluidized bed magnetizing roasting of low-grade iron ore fines is employed as a beneficiation technique in iron-making and steel-making industries. In the present work, the unreacted shrinking core reaction kinetic model is coupled with the two-fluid and kinetic theory of granular flow gas–solid flow model to simulate magnetizing roasting of hematite to magnetite in iron ore fines using a fluidized bed reactor. The model is validated with published experimental findings. Thereafter, the influence of different process parameters such as gas temperature, composition, velocity, and particle size on the reduction fraction and rate along with (Formula presented.) mass fraction and emission is studied. The reduction rate increases with gas temperature and (Formula presented.) mass fraction while it decreases with particle size. The (Formula presented.) emission increases with gas temperature, particle size, and (Formula presented.) mass fraction. However, the influence of gas velocity on these parameters is not significant. The reduction rate and time vary from 0.0010 to 0.0067 s?1 and 65 to 553 s, respectively, at a reduction fraction of 0.5. The (Formula presented.) mass fraction and emission range from 0.80 to 0.92 and from 0.63 to 4.14 g kg?1 ore, respectively. © 2024 Wiley-VCH GmbH.