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CFD simulation of gas and solids mixing in FCC strippers
Author(s) -
Liu Yingjie,
Lan Xingying,
Xu Chunming,
Wang Gang,
Gao Jinsen
Publication year - 2012
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.12646
Subject(s) - baffle , residence time distribution , mixing (physics) , bubble , mechanics , computational fluid dynamics , péclet number , drag , dimensionless quantity , mass transfer , thermodynamics , chemistry , flow (mathematics) , dispersion (optics) , multiphase flow , physics , quantum mechanics , optics
Abstract The gas and solid mixing in fluid catalytic cracking strippers with and without internals were investigated using computational fluid dynamics simulations. The Eulerian–Eulerian two‐fluid model coupled with the modified Gidaspow drag model was used to simulate the gas‐solid flow behavior. The grid independency study and the comparison of 2D and 3D simulations were carried out first. The residence time distribution model and axial dispersion model were utilized to obtain the parameters indicating the back‐mixing degree, such as mean residence time, dimensionless variance and Peclet number of gas and solids. Moreover, the influence of bubble size and gas/solid flow distribution on the mass transfer between the bubble and emulsion phase were also analyzed. The results show that the baffles in the V‐baffle stripper can efficiently enhance the gas and solids mixing, reduce the back‐mixing degree of gas and solids, strengthen the mass transfer between the bubble and emulsion phase, and hence improve the stripping efficiency. © 2011 American Institute of Chemical Engineers AIChE J, 2012