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Friction between co‐current upward gas–solid flow and column wall
Author(s) -
Qi Xiaobo,
Huang Weixing,
Zhu Jesse
Publication year - 2008
Publication title -
asia‐pacific journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.348
H-Index - 35
eISSN - 1932-2143
pISSN - 1932-2135
DOI - 10.1002/apj.150
Subject(s) - mechanics , flow (mathematics) , pressure drop , current (fluid) , fluidized bed combustion , column (typography) , materials science , volumetric flow rate , fluidization , particle (ecology) , gas pressure , fluidized bed , chemistry , thermodynamics , petroleum engineering , geology , engineering , mechanical engineering , physics , oceanography , connection (principal bundle)
Friction between co‐current upflow gas–solid flow and column wall was investigated by measuring apparent solids concentrations and actual ones in two circulating fluidized bed (CFB) risers with fluid catalytic cracking (FCC) and sand particles, respectively. A new model to predict frictional‐pressure drops between the gas–solid flow in the fully developed zone and the column wall was developed. The results show that the friction between the gas–solid flow and the riser wall causes a significant deviation of the apparent solids concentration from the actual ones, especially under those operating conditions with higher superficial gas velocities and solids‐circulation rates. When superficial gas velocities are greater than 8 m/s, the apparent solids concentrations in the fully developed zone of the risers can be greater than 60% of the actual ones. Particle diameters have different influences on the frictional‐pressure loss under different superficial gas velocities. After the frictional‐pressure drops predicted by the proposed model are deducted from the measured total pressure drops, the predicted actual solids concentrations agree well with the measured actual ones. Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd.