Measuring and modeling solids movement in a large, cold fluidized bed test facility. Second quarterly report, January 1, 1980-March 31, 1980
The plume model is developed to represent a tube-filled AFBC with large particles, in which air-entrained coal enters in a number of feed ports from below. It assumes that the volatiles are rapidly released from the coal at the feed entry ports to rise as plumes of combustible vapors. Graphs have been prepared to display the predictions of this model for narrow size cuts of a typical coal feed. For a feed of wide size distribution, use these single size charts and properly sum. The lowest carbon efficiency always comes with an intermediate size of feed coal, not with very large or very small feed sizes. Thus the coal feed to the AFBC should try to avoid this critical size. The plume behavior, whether it breaks the surface of the bed, the temperature jump above the bed, concentration variations across the bed, etc., are all governed by one dimensionless group HD/u/sub 0/L/sub 2//sup 2/, which depends primarily on the spacing of feed ports in the bed. For a given coal feed, the carbon efficiency depends only on superficial gas velocity in the bed, the excess air, and elutriation rate constant. A special case and simplification of this model views the coal as being uniformly distributed all over the bed before the volatiles are released. Here analysis is very much simpler, not involving plumes and no volatiles leaving the bed. This plumeless model should reasonably represent AFBC using large feed particles, introduced across the top of the bed and then rapidly mixed by large scale convective flow of solids. The analysis shows that, even in beds with plumes, the simpler plumeless model can be used with negligible error to calculate carbon efficiency; for volatile efficiency, temperature jumps and composition variations across the bed, the complete plume model must be used.
- Research Organization:
- Oregon State Univ., Corvallis (USA). Dept. of Chemical Engineering
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC01-79ET13152
- OSTI ID:
- 5309849
- Report Number(s):
- DOE/ET/13152-2
- Country of Publication:
- United States
- Language:
- English
Similar Records
Atmospheric fluidized-bed combustion testing of western Kentucky limestones
Attrition and elutriation phenomena in industrial atmospheric fluidized bed combustors
Related Subjects
42 ENGINEERING
FLUIDIZED-BED COMBUSTION
MATHEMATICAL MODELS
TEST FACILITIES
BENCH-SCALE EXPERIMENTS
COAL
FUNCTIONAL MODELS
CARBONACEOUS MATERIALS
CHEMICAL REACTIONS
COMBUSTION
ENERGY SOURCES
FOSSIL FUELS
FUELS
OXIDATION
THERMOCHEMICAL PROCESSES
014000* - Coal
Lignite
& Peat- Combustion
421000 - Engineering- Combustion Systems