Record Details

An investigation of the effects of immersed heat exchanger tube spacing and arrangement on the quality of fluidization in a cold phase two-dimensional fluidized bed

ScholarsArchive at Oregon State University

Field Value
Title An investigation of the effects of immersed heat exchanger tube spacing and arrangement on the quality of fluidization in a cold phase two-dimensional fluidized bed
Names Lockwood, Dwight Norris (creator)
Junge, David C. (advisor)
Date Issued 1976-04-15 (iso8601)
Note Graduation date: 1976
Abstract The feasibility of fluidized bed combustion of coal for commercial
and industrial steam power generation has been established
and reported in the literature. Satisfactory removal of sulfur
oxides from the combustion product gases has also been reported.
In this experiment various heat exchanger tube patterns,
of commercial size tubes, were examined in a two-dimensional,
cold phase fluidized bed of limestone and dolomite. Several
variables such as tube pitch (triangular and rectangular), tube
spacing (horizontal and vertical), array location with respect to the
distributor plate, and superficial gas velocity were considered and
their effect on the quality of fluidization reported. Dolomite with a
mean surface/volume size of 569 microns (28 Tyler mesh) and
limestone with a mean surface/volume size of 1379 microns (12
Tyler mesh) were used as bed material.
The results indicate that the horizontal as well as vertical
spacing of tubes has a significant effect upon the start up phase of
fluidization and bed stability. Also, horizontal spacing which is too
close inhibits solids circulation. Triangular pitch arrangements
yielded good solids circulation and did not experience gas by-passing
to the extent seen with rectangular arrangements. Overall bed
stability was improved with the tube arrays closer to the distributor
plate. Rapid bubble growth and associated instabilities were
observedwhen.a relatively thick layer of solids were above the tube
arrays, indicating that the expanded bed surface should probably
not extend above the tubes. Further research in the area of
fluidized bed quality is recommended.
Genre Thesis/Dissertation
Topic Heat exchangers
Identifier http://hdl.handle.net/1957/46201

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