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Gas velocity distribution in conical spouted beds with high-density particles

2021    Dogan, Neslin; Koksal, Murat; Kulah, Gorkem

Local gas velocity measurements were conducted utilizing a Pitot tube in two small-scale (D-c = 150 mm, gamma = 30 degrees, 60 degrees) and one large-scale (D-c = 250 mm, gamma = 66 degrees) conical spouted beds. Three different types of particles, zirconia (rho(p) = 6050 kg/m(3)), zirconia-toughened alumina (rho(p) = 3700 kg/m(3)), and glass beads (rho(p) = 2460 kg/m(3)), were used in the experiments. Careful calibration of the Pitot tube for determination of gas velocities in the annulus section was carried out in a separate, loosely packed-bed set-up, which represents the flow conditions in the annulus section of the spouted bed. Solids hold-up profiles were used to calculate the superficial gas velocities and determine the amount of air flowing through the spout, interface, and annulus. Effects of axial position, conical angle, bed size, and particle density on gas velocity profiles were investigated. It is shown that the amount of air flow through the annulus increases as the axial distance and particle density increases; however, it decreases with increasing cone angle. Dispersion of the gas into the annulus is found to be significantly higher in the large-scale unit than the small-scale unit.