Hydrodynamics and interfacial gas-liquid mass transfer of gas-liquid-solid fluidized beds
Hydrodynamic characteristics of a cocurrent, gas-liquid-solid fluidized bed is studied to simulate the resid hydrotreating reaction conditions using an aqueous surfactant solution. Reaction conditions for hydrotreating of residual oils and coal liquefaction, which uses cylindrical hydrotreating catalysts under conditions of high gas holdup, are simulated using an aqueous t-pentanol (0.5 wt%) solution as the liquid phase. A mathematical model is developed to described the minimum fluidization velocity behavior. Bed voidage, gas holdup and terminal velocity of the particles are analyzed and correlated empirically to investigate the effect of particle shape and liquid surface tension. Systematic effects of particle properties on bubble wake structure as well as bubble rise characteristics for a single rising bubble in a liquid-solid fluidized bed are studied visually. In order to determine the solids holdup in near wake behind a single bubble, an image processing technique is employed. The bubble rise velocity, the volume ratio of primary wake to bubble, the volume ratio of liquid wake to bubble, and the wake solid holdup are strongly dependent on the particle terminal velocity and the bed expansion. A spectrophotometric technique is developed for the measurement of the instantaneous mass transfer coefficient and the interfacial areas of a bubble as well as the local concentration distribution around the bubble-wake. An ozone and starch-potassium iodide reaction is employed to visualize the gas-liquid mass transfer to a single bubble in liquids and liquid-solid fluidized beds. Axial variations of the concentration, bubble volume and the mass transfer rate are studied. The mass transfer coefficient is found to be dependent on bubble size and bed expansion.
- Research Organization:
- Ohio State Univ., Columbus, OH (USA)
- OSTI ID:
- 6859458
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
010405* -- Coal
Lignite
& Peat-- Hydrogenation & Liquefaction
02 PETROLEUM
020400 -- Petroleum-- Processing
BUBBLES
CATALYSTS
CHEMICAL REACTIONS
COAL LIQUEFACTION
COAL LIQUIDS
ENERGY SOURCES
FLUID MECHANICS
FLUIDIZATION
FLUIDIZED BEDS
FLUIDS
FOSSIL FUELS
FUELS
GASES
HYDRODYNAMICS
HYDROGENATION
LIQUEFACTION
LIQUIDS
MASS TRANSFER
MATHEMATICAL MODELS
MECHANICS
PARTICLE SIZE
PETROLEUM
PETROLEUM FRACTIONS
PETROLEUM RESIDUES
PROCESSING
REFINING
SHAPE
SIMULATION
SIZE
SOLIDS
SPECTROPHOTOMETRY
SURFACE PROPERTIES
SURFACE TENSION
THERMOCHEMICAL PROCESSES