In a conventional well-mixed fluidized bed the solids are almost
completely mixed and the residence time for individual particles may vary
between zero and infinity. For materials especially sensitive to the processing
time, a wide distribution of residence time is extremely undesirable. A multi-compartment
fluidized bed was proposed to minimize this problem. The two-compartment
fluidized bed system was designed and experimentally
investigated with positive results. Residence time distributions were
measured with glass bead particles of 379 p.m mean diameter size. Tracer
particles were colored glass beads which had exactly the same properties as the
particles used for bed material. Two theoretical models were proposed to
predict the flow behavior of solids through the two-compartment fluidized
bed vessel. The results show the solids flow pattern can be described by the
axial dispersion plug flow model and the tanks-in-series model. The
parameters of both models can be determined by minimizing the sum of the
squared differences between experimental data and model predictions curves.
The influence of fluidization velocity, diameter of the orifice connecting the
two adjacent compartments, and the height of the overflow exit orifice were
investigated. The two-compartment fluidized bed can improve the residence
time distribution of solids from a single fluidized bed. The residence time
distribution of solids was also improved with decreasing fluidizing gas
velocity. Orifice diameter and height of the overflow exit orifice did not
influence significantly on particles flow in the two-compartment fluidized
bed system. However, a solids mass flow through the partition orifice is
predicted reasonably well, within moderate range of variance, by equation
developed by de Jong (1965) [12]. / Graduation date: 1994
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/37560 |
| Date | 14 January 1994 |
| Creators | Pongsivapai, Pajongwit |
| Contributors | Jovanovic, Goran |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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