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A new fluid distribution system for scale‐flexible expanded bed adsorption
Author(s) -
Hubbuch Jürgen J.,
Heebøll–Nielsen Anders,
Hobley Timothy J.,
Thomas Owen R. T.
Publication year - 2002
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.10170
Subject(s) - distributor , fluidized bed , volumetric flow rate , rotation (mathematics) , adsorption , mechanics , materials science , tracer , flow (mathematics) , analytical chemistry (journal) , packed bed , flow velocity , superficial velocity , rotational speed , chemistry , chromatography , thermodynamics , geometry , physics , mathematics , classical mechanics , organic chemistry , nuclear physics
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