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Exit effects in circulating fluidized bed risers
Author(s) -
Pugsley Todd,
Lapointe Diane,
Hirschberg Bernd,
Werther Joachim
Publication year - 1997
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450750602
Subject(s) - pressure drop , fluidized bed combustion , mechanics , flow (mathematics) , materials science , drop (telecommunication) , metre , geology , engineering , fluidized bed , physics , mechanical engineering , waste management , astronomy
Abstract The relative influence of smooth and abrupt exit configurations on the axial pressure drop profile in Circulating Fluidized Bed (CFB) risers has been investigated. Experiments were performed with sand and FCC catalyst in two cold model CFBs of 0.1 metre and 0.2 metre riser diameter. The influence of the abrupt exit on the profile was observed to extend all the way to the base of the larger diameter riser for sand. However, the abrupt exit influenced only the final 1.5 to 2 metres of the riser length for the case of sand in the narrow diameter riser. When FCC catalyst was circulated, the effect of the abrupt configuration was seen only in the upper portion of the riser, irrespective of the riser diameter. A simple empirical modification to the model of Pugsley and Bermti (1996) provides a good description of the axial pressure drop profiles for the abrupt exit configurations, with the exception of the case of sand in the 0.2 metre diameter riser. This discrepancy is attributed to the lack of fully developed flow in the larger riser.