Hydrodynamics, mixing, gas-liquid mass transfer, and biological applications of a three-phase fluidized bed of low density particles

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:7036584

Tang, W T

Experiments were conducted to study the axial holdup distributions, liquid axial mixing and gas-liquid mass transfer behavior in a three-phase fluidized bed of low density particles. Axial phase holdups were determined using an electrical conductivity method coupled with pressure profile measurements. Gas holdup was found to be axially uniform. Axial solids holdup distributions changed only slightly with increasing gas velocity but varied significantly when a change in bubble flow regime was encountered due to changes in liquid velocity. A mechanistic model based on solids entrainment and deentrainment effects by bubbles was proposed and validated experimentally. The extent of liquid axial mixing in both a liquid-solid and a three-phase fluidized bed of low density particles is significantly smaller than that in a bed of heavy particles. Volumetric gas-liquid mass transfer coefficients in the present systems decreases with increasing solids concentration. For the low density particles studied, particles with a higher terminal velocity promoted greater extent of bubble coalescence which reduced gas holdup, and thus the rate of gas-liquid mass transfer. In addition, the dynamic responses of phenol biodegradation in a draft tube three-phase fluidized bed biofilm reactor subjected to a step increase in phenol inlet concentrations were investigated. A comprehensive mathematical model, which considered time delay phenomenon of microbial growth subjected to a nutrient shift up, phenol adsorption/desorption by carbon particles, and biofilm growth, was proposed and validated experimentally.

• Research Organization: Ohio State Univ., Columbus, OH (USA)
• OSTI ID: 7036584
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320305* -- Energy Conservation
Consumption
& Utilization-- Industrial & Agricultural Processes-- Industrial Waste Management
ADSORPTION
AROMATICS
BIODEGRADATION
BIOREACTORS
BUBBLES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DECOMPOSITION
DENSITY
DESORPTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
FILMS
FLOW RATE
FLUID FLOW
FLUID MECHANICS
FLUIDIZED BEDS
FLUIDS
GAS FLOW
GASES
HYDRODYNAMICS
HYDROXY COMPOUNDS
KINETICS
LIQUIDS
MASS TRANSFER
MATHEMATICAL MODELS
MECHANICS
MICROORGANISMS
MIXING
MULTIPHASE FLOW
ORGANIC COMPOUNDS
PARTICLES
PERFORMANCE TESTING
PHENOL
PHENOLS
PHYSICAL PROPERTIES
REACTION KINETICS
SORPTION
TESTING
TIME DEPENDENCE
USES