TY - JOUR
T1 - Solids behaviour in a gas-solid two-phase mixture flowing through a packed particle bed
AU - Ding, YL
AU - Wang, ZL
AU - Wen, DS
AU - Ghadiri, M
AU - Fan, Xianfeng
AU - Parker, D
PY - 2005/9/1
Y1 - 2005/9/1
N2 - This paper reports the solids behaviour in a dilute gas-solid two-phase mixture flowing through a packed bed. The positron emission particle tracking (PEPT) technique was used in the work, which allowed investigation of three-dimensional solids motion at the single suspended particle level. Processing of the data gave solids velocity, the residence time of suspended particles, bed tortuosity in terms of solids motion, as well as solids occupancy in the cross-section of the packed bed. The results suggest that the wall effect on the motion of suspended particles is limited to approximately one packed particle diameter under the conditions of this work. Both the average axial and radial velocities of suspended particles, normalised by the superficial gas velocity, change periodically with radial position, but the periodicity does not correspond exactly to the packed particle diameter. The peak and trough values of the average axial velocity of the suspended particles in the bulk region are, respectively, similar to 25% and similar to 15% of the superficial gas velocity under the conditions of this work and the superficial gas velocity shows little effect. The peak and trough values of the average radial velocity of the suspended particles in the bulk region are, respectively, +5% (positive) and -5% (negative) of the superficial gas velocity. The results of the residence time and tortuosity of the suspended particles show an approximately Gaussian distribution with the peak residence time and tortuosity increasing with decreasing superficial gas velocity. The occupancy data suggest that particles spend more time in an annular region close to the wall, indicating a non-uniform particle distribution across the packed bed cross-section. (c) 2005 Elsevier Ltd. All rights reserved.
AB - This paper reports the solids behaviour in a dilute gas-solid two-phase mixture flowing through a packed bed. The positron emission particle tracking (PEPT) technique was used in the work, which allowed investigation of three-dimensional solids motion at the single suspended particle level. Processing of the data gave solids velocity, the residence time of suspended particles, bed tortuosity in terms of solids motion, as well as solids occupancy in the cross-section of the packed bed. The results suggest that the wall effect on the motion of suspended particles is limited to approximately one packed particle diameter under the conditions of this work. Both the average axial and radial velocities of suspended particles, normalised by the superficial gas velocity, change periodically with radial position, but the periodicity does not correspond exactly to the packed particle diameter. The peak and trough values of the average axial velocity of the suspended particles in the bulk region are, respectively, similar to 25% and similar to 15% of the superficial gas velocity under the conditions of this work and the superficial gas velocity shows little effect. The peak and trough values of the average radial velocity of the suspended particles in the bulk region are, respectively, +5% (positive) and -5% (negative) of the superficial gas velocity. The results of the residence time and tortuosity of the suspended particles show an approximately Gaussian distribution with the peak residence time and tortuosity increasing with decreasing superficial gas velocity. The occupancy data suggest that particles spend more time in an annular region close to the wall, indicating a non-uniform particle distribution across the packed bed cross-section. (c) 2005 Elsevier Ltd. All rights reserved.
KW - solids motion
KW - PEPT
KW - two-phase flows
KW - residence time
KW - tortuosity
KW - gas-solid mixtures
KW - occupancy
KW - packed bed
UR - http://www.scopus.com/inward/record.url?scp=22144478984&partnerID=8YFLogxK
U2 - 10.1016/j.ces.2005.04.052
DO - 10.1016/j.ces.2005.04.052
M3 - Article
SN - 1873-4405
VL - 60
SP - 5231
EP - 5239
JO - Chemical Engineering Science
JF - Chemical Engineering Science
IS - 19
ER -