TY - JOUR
T1 - Measurement of the residence time distribution of a cohesive powder in a flighted rotary kiln
AU - Paredes, Ingrid J.
AU - Yohannes, Bereket
AU - Emady, Heather
AU - Muzzio, Fernando J.
AU - Maglio, Al
AU - Borghard, William G.
AU - Glasser, Benjamin J.
AU - Cuitiño, Alberto M.
N1 - Funding Information:
This work was supported by the Rutgers Catalyst Manufacturing Consortium . The authors would also like to acknowledge help from the following people: Maham Javed and Sahil Navodia for assistance in analyzing samples, and Artem Vityuk, Bill Dolan, Richard McCaffrey, Dennis Reinerstein, Linda Hratko, Lucas Dorazio, William Harris, Gustavo Abasolo, Michael Conklin, and Keenan Deustch for providing material for this study as well as training and assistance in kiln operation.
Publisher Copyright:
© 2018
PY - 2018/12/14
Y1 - 2018/12/14
N2 - The rotary kiln is an essential device in chemical and metallurgical industries, with applications in a wide range of solids manufacturing processes. In particular, in the preparation of industrial chemical catalysts, the kiln has become a popular reactor for continuous calcination of catalysts ranging from millimeter-sized extrudates to micron-sized powders. As granular and powder flow behaviors are difficult to characterize, the design and scale-up of rotary calcination processes are often performed empirically. The goal of this research is to improve the fundamental understanding of powder flow in rotary kilns to aid in optimization of the continuous calcination process. For successful calcination to occur, the residence time of the particles must exceed the time required for heating and subsequent treatment. For uniform treatment of the feed, the particles must also exhibit low axial dispersion. In this work, the mean residence time and axial dispersion coefficient for a cohesive fluid catalytic cracking powder were determined in a pilot plant kiln by measuring the residence time distribution. This study utilized a pulse test developed by Danckwerts. Results were fit to the Taylor solution of the axial dispersion model and compared to the Sullivan prediction for mean residence time. It was found that the mean residence time decreases as the feed rate, kiln incline, and rotation rate increase. It was also found that the axial dispersion coefficient increases with speed of rotation and angle of incline. However, the axial dispersion coefficient decreases as the feed rate is increased.
AB - The rotary kiln is an essential device in chemical and metallurgical industries, with applications in a wide range of solids manufacturing processes. In particular, in the preparation of industrial chemical catalysts, the kiln has become a popular reactor for continuous calcination of catalysts ranging from millimeter-sized extrudates to micron-sized powders. As granular and powder flow behaviors are difficult to characterize, the design and scale-up of rotary calcination processes are often performed empirically. The goal of this research is to improve the fundamental understanding of powder flow in rotary kilns to aid in optimization of the continuous calcination process. For successful calcination to occur, the residence time of the particles must exceed the time required for heating and subsequent treatment. For uniform treatment of the feed, the particles must also exhibit low axial dispersion. In this work, the mean residence time and axial dispersion coefficient for a cohesive fluid catalytic cracking powder were determined in a pilot plant kiln by measuring the residence time distribution. This study utilized a pulse test developed by Danckwerts. Results were fit to the Taylor solution of the axial dispersion model and compared to the Sullivan prediction for mean residence time. It was found that the mean residence time decreases as the feed rate, kiln incline, and rotation rate increase. It was also found that the axial dispersion coefficient increases with speed of rotation and angle of incline. However, the axial dispersion coefficient decreases as the feed rate is increased.
KW - Axial dispersion coefficient
KW - Calcination
KW - Particle technology
KW - Powder flow
KW - Rotary kilns
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U2 - 10.1016/j.ces.2018.06.044
DO - 10.1016/j.ces.2018.06.044
M3 - Article
AN - SCOPUS:85048986650
SN - 0009-2509
VL - 191
SP - 56
EP - 66
JO - Chemical Engineering Science
JF - Chemical Engineering Science
ER -