Experimental Investigation of Minimum Fluidization Velocity and Pressure Drop in Fluidized Bed of Teff Grain

Demissie Boset, Lemi; Abdi Debele, Zewdu; Wako Koroso, Amana

doi:10.22075/jhmtr.2025.35810.1632

Experimental Investigation of Minimum Fluidization Velocity and Pressure Drop in Fluidized Bed of Teff Grain

Document Type : Full Length Research Article

Authors

Lemi Demissie Boset ¹

Zewdu Abdi Debele ²

Amana Wako Koroso ¹

¹ School of Mechanical, Chemical, and Material Engineering, Adama Science and Technology University, Adama, Oromia, 0000, Ethiopia

² Faculty of Agriculture, University of Eswatini, Luyengo, Eswatini, M205, Eswatini

10.22075/jhmtr.2025.35810.1632

Abstract

Gas-fluidization characteristics of teff grain are crucial for understanding its behavior under gas flow, enabling it to act like a fluid, which is vital for pneumatic conveying systems. Key parameters include the minimum fluidization velocity and the pressure drop across the fluidized bed, which reflect the interaction between gas and grains. These characteristics are essential for selecting the appropriate phase of the pneumatic conveying system, ultimately improving the processing and handling of teff grain. Air retention capabilities are significant indicators of a material's suitability for dense-phase conveying. Gas fluidized bed tests were performed to evaluate the bulk flow behavior of teff grain for both dilute and dense-phase pneumatic conveyors. Results indicated that teff grain has poor air retention, evidenced by bubble formation at low airflow rates, suggesting it is more suitable for dilute-phase conveying. Experiments measured the minimum fluidization air velocity and pressure drop per bed height using a CEL-MKII apparatus at various airflow rates. Experimental studies revealed that bubbles form in the fluidized bed at the minimum superficial gas velocity, with a pressure drop ranging between 100 mbar/m and 107 mbar/m and a minimum fluidization velocity of 0.56 m/s and 0.575 m/s. These findings guide the design of effective drying and pneumatic conveying systems for teff grain.

Keywords

Minimum fluidization velocity

Pressure drop

Pneumatic conveyor

Drying

Teff grain

Subjects

Gas-Solid reactions

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