Fundamentals of agglomeration in a fluidized bed

Thesis/Dissertation · Tue Jan 01 00:00:00 EST 1985

OSTI ID:5603197

Huang, C S

A visually observable fluidized bed, which can be operated under conditions in which agglomeration of the bed materials occurs, was designed and constructed. Polyethylene particles and silica sand coated with a thin layer of Elvax were chosen as bed materials. The coated particles used were in three different size ranges +180-250, +250-425, +425-600 ..mu..m and had three different coating thicknesses, 1, 3, and 5 ..mu..m. Two types of fluidized gas distributors were used: a porous plate with an independently fed jet at the center. The fluidized bed could be operated in either continuous-feed mode or in batch mode. In the case of polyethylene particles as bed material in the batch system, the amount of agglomerates increased linearly with residence time and increased exponentially with either auxiliary air or jet air temperature. The amount of agglomerates increased with jet nozzle size at the constant jet air flow rate. For a given jet nozzle size the agglomeration rate increased initially with jet air velocity, reached a maximum value and then decreased. In the case of coated particle as bed material, in the batch fluidized bed, the amount of agglomerates increased with residence time and then leveled off. It increased sharply with jet air temperature, coating thickness, concentration of coated particles and decreasing particle sizes. The agglomeration rate constants calculated from the model agree reasonably well with those obtained from experimental data. The model provides the better understanding of the complicated phenomena of agglomeration and could be an initial guide in choosing the operating conditions of an agglomerating fluidized bed.

• Research Organization: Illinois Inst. of Tech., Chicago (USA)
• OSTI ID: 5603197
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
FLUIDIZED BEDS
AGGLOMERATION
MATHEMATICAL MODELS
AIR FLOW
FLOW RATE
FLOW VISUALIZATION
NOZZLES
PARTICLE SIZE
POLYETHYLENES
SILICA
SIZE
SPRAYED COATINGS
THICKNESS
TIME DEPENDENCE
CHALCOGENIDES
COATINGS
DIMENSIONS
FLUID FLOW
GAS FLOW
MINERALS
ORGANIC COMPOUNDS
ORGANIC POLYMERS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
POLYMERS
POLYOLEFINS
SILICON COMPOUNDS
SILICON OXIDES
014000* - Coal
Lignite
& Peat- Combustion