Effect of low velocity liquid pulsations on some hydrodynamic characteristics of liquid and gas-liquid fluidized beds

Journal Article · Sat Mar 01 04:00:00 EST 1986 · A.I.Ch.E. J.; (United States)

DOI:https://doi.org/10.1002/aic.690320320· OSTI ID:5678913

El-Temtamy, S A; Epstein, N

Externally applied vibrations or pulsations have been extensively studied as a means for improving transfer characteristics in two-phase systems (Baird, 1966; Baird and Garstang, 1972; Kim and Baird, 1976; Battacharya and Harrison, 1976). Similar studies for three-phase systems, e.g., three-phase fluidized beds, have been limited to examining the effect on solid-liquid mass transfer of bubble cycling caused by vertical oscillation of a slurry column containing entrained gas bubles (Lemcoff and Jameson, 1975). In three-phase fluidization, bubble coalescence predominates over bubble breakup for small-particle beds (e.g., D/sub RHO/ < 3 mm for sand fluidized by water and air), so that the desirably high particle surface areas and low fluidizing velocities associated with such beds are accompanied by lower gas holdups and hence inferior gas-liquid volumetric mass transfer coefficients, compared to those for large-particle beds (Epstein, 1981; Deckwer and Schumpe, 1983). It is therefore of some interest to determine whether the undesirable features of small-particle beds are somewhat mitigated by the imposition of deliberately imposed liquid pulsations. In the present preliminary study at low pulse velocities (<5.8 mm/s), measurements were made, with and without pulsing, of phase holdups for liquid-solid, gas-liquid, and gas-liquid-solid systems; of liquid phase axial dispersion for the gas-liquid-solid systems; and of the hydrodynamic transition from a fixed to a fluidized bed for the liquid-solid system.

• Research Organization: Egyptian Petroleum Research Inst., Nasr-City
• OSTI ID: 5678913
• Journal Information: A.I.Ch.E. J.; (United States), Journal Name: A.I.Ch.E. J.; (United States) Vol. 32:3; ISSN AICEA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical &amp; Physicochemical Properties
42 ENGINEERING
420400* -- Engineering-- Heat Transfer &amp; Fluid Flow
BUBBLES
FLOW RATE
FLUID FLOW
FLUID MECHANICS
FLUIDIZATION
FLUIDIZED BEDS
FLUIDS
GAS FLOW
GASES
HYDRODYNAMICS
LIQUID FLOW
LIQUIDS
MASS TRANSFER
MEASURING METHODS
MECHANICAL VIBRATIONS
MECHANICS
MULTIPHASE FLOW
PULSATIONS
TWO-PHASE FLOW