Pressure Drop and Bed Expansion in a Mobile Bed

Abstract

The pressure drop, ΔP and the expanded bed height, H in mobile beds have been related to states of fluidized packings. The bed is operated best under the conditions such that the pressure drop across the bed is constant and independent of gas velocities.
Correlations of ΔP and H with operating conditions are presented.
1. The pressure drop, ΔP is calculated by the following equation.
ΔP=ρ_P/ρ_LH_P+ε_SLH_S
where ρ_P, ρ_L, are densities of packing and liquid, and H_s is the static bed height.
2. The expanded bed height, H could be calculated by the following equation.
H/H_S= (1+ε_SL-ε_SP) / (1-ε_G)
where ε_SL, ε_SP are the holdup of liquid based on the static bed height and the void fraction in the dry packed bed, respectively, and ε_G is the gas holdup based on the expanded bed height.