A HYDRODYNAMIC MODEL OF MASS TRANSFER IN A STIRRED VESSEL EXTRACTOR

Journal Article · Fri Feb 01 04:00:00 EST 1963 · Chemical Engineering Science (England)

DOI:https://doi.org/10.1016/0009-2509(63)80021-4· OSTI ID:4748449

Olander, D R

The flow patterns generated by the rotation of stirrer bars in the two immiscible liquids in a stirred vessel extractor were approximated by a simplified model. Each phase was divided into two regions: the core region, which is the cylindrical volume swept out by the stirrer bars, and the outer annular region, which comprises the remainder of the phase. The flow in the core region was assumed to be equivalent to that generated by an infinite body of fluid in solid body rotation over a surface rotating at a slower rate. The axial velocity in the outer annulus is then obtained by a simple material balance. Knowledge of the velocity profile in this latter region permitted a direct solution of the diffusion equation, which in turn resulted in a purely theoretical mass-transfer correlation for this extraction device. Comparison of the experimental data and the theoretical predictions showed the latter to be approximately 35 to 50 per cent too low; this agreement was considered sufficiently close to warrant tentative acceptance of the flow model upon which the theoretical predictions were based. Two important conclusions which follow from the model are: (1) a turbulent transport mechanism need not be postulated for extraction in a stirred vessel of the type considered here, since a purely laminar flow model comes quite close to reproducing the observed extraction rates; and (2) rippling of the interface does not result in pronounced increases in the mass-transfer coefficient, since the flow model was based upon a planar interface, and the experimental data represent various degrees of interfacial rippling. (auth)

• Research Organization: Univ. of California, Berkeley
• NSA Number: NSA-17-016241
• OSTI ID: 4748449
• Journal Information: Chemical Engineering Science (England), Journal Name: Chemical Engineering Science (England) Vol. Vol: 18; ISSN CESCA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ANALOG SYSTEMS
CONFIGURATION
DIFFUSION
DISTRIBUTION
ENGINEERING AND EQUIPMENT
EQUATIONS
ERRORS
FLOW MODELS
FLUID FLOW
HYDRODYNAMICS
LIQUID FLOW
LIQUIDS
MATHEMATICS
MIXING
RODS
ROTATION
SOLVENT EXTRACTION
STANDARDS
SURFACES
TURBULENCE
VELOCITY
VESSELS
ZONES