The entrainment of solid particles in a 240cm High x 14.5cm i.d. fluidized bed was studied using low grade coal as the bed material.
The effect of gas velocity (30.5-137.2 cm/sec) on the entrainment rate was smaller at low gas velocity than that at high gas velocity in the given particle size.
The effect of particle size on TDH was more pronounced than that of gas velocity and the TDH of coal particles was also found much higher than that of FCC catalyst or glass bead.
The entrainment rate decreased somewhat with the bed height above the TDH.
The empirical equations were derived for calculating the entrainment rate and the TDH as follows :
$$\frac{B}{\rho_gu_g} = 1.0 \times 10^{-7} \Bigg(\frac{Ug^2}{gdp}\Bigg)^{1.66}$$ $$TDH = 9.55 \times 10^2\, Ar^{-0.56} Re^{0.75}$$
