Abstract
A new fluid distribution system designed for expanded bed adsorption was introduced and studied in a 150‐cm diameter column. Based on fluid application through a rotating distributor, it eradicates the need for perforated plates, meshes, or local mixers. The effect of rotation rate on column performance was examined by fluidizing a 30‐cm high bed of supports with tap water and introducing pulses of dye or acetone tracer. Linear bed expansion was seen as the superficial fluid velocity was raised from 170 cm · h^−1^ to 450 cm · h^−1^ (3000 L · h^−1^ to 8000 L · h^−1^), and there was little change in expansion characteristics as distributor rotation rate was increased from 2.5 to 10 rpm. The distributor was observed to generate a flow pattern suitable for expanded bed adsorption when the supports were fluidized at a superficial fluid velocity of 283 cm · h^−1^ and dye pulses introduced. At a rotation rate of 2.5 rpm, no significant dead zones were observed, and a discrete band was formed that moved up through the bed. Furthermore, the pattern of dye movement could be used to calculate interstitial linear fluid velocities of 460 cm · h^−1^ and 572 cm · h^−1^ at the column wall and center, respectively, indicating a parabolic flow profile. The distributor rotation rate giving the best operating conditions was found to be 2.5 rpm when the bed was fluidized at a flow velocity of 283 cm · h^−1^ and the residence time distribution of acetone tracer examined. Under these conditions, the coefficient of axial dispersion was 6.1 × 10^−6^ m^2^ · s^−1^ and 29 theoretical plates were measured. When the rotation rate was raised to 10 rpm, the coefficient of axial dispersion increased to 8.08 × 10^−6^ m^2^ · s^−1^ and the number of theoretical plates decreased to 22. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 35–43, 2002; DOI 10.1002/bit.10170