Effect of feed atomization and vessel configuration of fines formation and entrainment from fluidized-bed calciners

Technical Report · Wed Nov 01 04:00:00 EST 1978

DOI:https://doi.org/10.2172/6768085· OSTI ID:6768085

Bonder, S. S.

Fines and granules are produced during fluidized-bed calcination of liquid radioactive wastes. Fines are generated by attrition of larger bed particles and spray drying of atomized feed droplets. Some of the fines have sufficient residence time in the bed to provide seed particles for the particle growth; the remainder are elutriated from the bed or withdrawn with the product. Methods which were tested to reduce the generation and entrainment of fines during the calcination process are discussed. A pneumatic, flat-faced, feed atomizing nozzle has proven adequate for feed introduction, bed particle size control, and seed particle generation. Other pneumatic nozzle types (the extended divergent, long extended convergent, and short extended convergent) did not control bed particle size. Testing of a single-fluid pressure nozzle and the combination nozzle and cyclone fines return jet was discontinued before completion. However, no further testing to improve nozzle operating characteristics is presently justifiable, as the flat-faced nozzle has proven adequate. Limited tests confirmed that a cylindrical fluid bed with an expanded vapor space results in lower entrainment rates than a conventional cylindrical fluid bed. A reduction of the superficial gas velocity in the expanded vapor space by a factor of 3.2 reduced entrainment by a factor of 8. Double ''venetian blind'' baffles in the calciner vapor space were 20% more effective in suppressing fines entrainment than single ''venetian blind'' and fan baffles. Submerged baffles increased bed particle attrition and subsequent fines entrainment. The New Waste Calcining Facility will have a cylindrical calciner vessel with an expanded vapor space containing a double ''venetian blind'' baffle.

• Research Organization: Allied Chemical Corp., Idaho Falls, ID (USA). Idaho Chemical Programs - Operations Office
• DOE Contract Number: EY-76-C-07-1540
• OSTI ID: 6768085
• Report Number(s): ICP-1175
• Country of Publication: United States
• Language: English

Related Subjects

052001* -- Nuclear Fuels-- Waste Processing
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
CALCINATION
CHEMICAL REACTIONS
DECOMPOSITION
ENTRAINMENT
FLUIDIZED BED
MANAGEMENT
NOZZLES
PROCESSING
PYROLYSIS
RADIOACTIVE WASTE PROCESSING
THERMOCHEMICAL PROCESSES
WASTE MANAGEMENT
WASTE PROCESSING