Hydrodynamics of a Gas-Solid Fluidized Bed at Elevated Temperatures Using the Radioactive Particle Tracking Technique

Document Type: Research Note

Authors

1 School of Chemical Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563 Tehran, I.R. IRAN

2 Department of Chemical Engineering, Ecole Polytechnique de Montreal, P.O. Box 6075 Station Centre-Ville, Montreal, Quebec, CANADA

Abstract

Effect of temperature on hydrodynamics of bubbling gas-solid fluidized beds was investigated.  Experiments were carried out in the range of 25-600 ºC and different superficial gas velocities in the range of 0.17-0.78 m/s with sand particles. Time-position trajectory of particles was obtained by radioactive particle tracking technique. These data were used for determination of mean velocities of upward-moving (including bubble wake and ascending clusters) and downward-moving (descending clusters) particles. It was found that the upward velocity increases by increasing temperature up to 300 ºC, however, it decreases by further increase in temperature. Due to the wall effect, there is no significant change in the mean velocity of downward-moving clusters. The change in hydrodynamic parameters with temperature can be a consequence of changing physical properties of the bed which have been represented by Reynolds number in this study.   

Keywords

Main Subjects


[1] Xu Ch., Zhu J.X., Effects of Gas Type and Temperature on the Particle Fluidization, Particuology, 4, p. 114 (2006).
[2] Formisian B., Girimonte R., Mancuso L., Analysis of the Fluidization Process of Particle Beds at High Temperature, Chem. Eng. Sci., 53, p. 951 (1997).
[3] Formisiani B., Girimonte R., Pataro G., The Influene of Operating Temperature on the Dense Phase Properties of Bubbling Fluidized Beds of Solids, Powder Technology, 125, p. 28 (2002).
[4] Guo O., Yue G., Suda T., Sato J., Flow Characteristics in a Bubbling Fluidized Bed at Elevated Temperature, Chemical Engineering and Processing, 42, p. 439 (2003).
[5] J.Subramani H., Balaiyya M.B.M., Miranda L.R., Minimum Fluidization Velocity at Elevated Temperature for Geldart's Group-B Powders, Experimental Thermal Fluid Science, 32, p. 166 (2007).
[6] Geldart D., Kapoor D.S., Bubble Sizes in a Fluidized Bed at Elevated Temperatures, Chem. Eng. Sci., 31, p. 842 (1976).
[7] Kai, T., Furusaki, S., Behavior of Fluidized Beds of Small Particles at Elevated Temperatures, J. Chem. Eng. Japan, 18, p. 113 (1985).
[8] Hatate Y., Ohmagari K., Ikari A., Kondo K., King D.F., Behavior of Bubbles in Cylindrical Fluidized Bed at an Elevated Temperature, J. Chem. Eng. Japan., 21, p. 424 (1988).
[9] Kunii D., Levenspiel O., “Fluidization Engineering”, Butterworth-Heinemann, New York, Second Edition, (1991).
[10] Lettieri P., Newton D., Yates J.G., The Influence of Interparticle Forces on Fluidization Behavior of Some Industrial Materials at High Temperature, Powder Technology, 110, p. 117 (2000).
[11] Lettieri P., Newton D., Yates J.G., High Temperature Effects on the Dense Phase Properties of Gas Fluidized Beds, Powder Technology, 120, p. 34 (2001).
[12] Cui H., Sauriol P., Chaouki J., High Temperature Fluidized Bed Reactor: Measurements, Hydrodynamics and Simulation, Chem. Eng. Sci., 58, p. 3413 (2003).
[13] Cui H., Chaouki J., Effects of Temperature on Local Two-Phase Flow Structure in Bubbling and Turbulent Fluidized Beds of FCC Particles, Chem. Eng. Sci., 59, p. 3413 (2004).
[14] Radmanesh R., Mabrouk R., Chaouki J., Guy C., The Effect of Temperature on Solids Mixing in a Bubbling Fluidized Bed Reactor, Inter. J. Chem. Reactor Eng., 3, A16, (2004).
[15] Larachi F., Chaouki J., Kennedy G., 3-D mapping of Solids Flow Fields in Multiphase Reactor with RPT, AIChE J., 41, p. 439 (1995).
[16] Mostoufi N., Chaouki J., Local Solid Mixing in Gas-Solid Fluidized Beds, Powder Technology., 14, p. 23 (2001).
[17] Mostoufi N., Chaouki J., On the Axial Movement of Solids in Gas-Solid Fluidized Beds Source: Chem. Eng. Res. & Des. Part A Transactions of the Institute of Chemical Engineers., 78, p. 911 (2000).
[18] Stein M., Ding Y.L., Seville J.P.K., Parker D.J., Solids Motion in Bubbling Gas Fluidized Beds, Chem. Eng. Sci., 55, p. 5291 (2000).
[19] Mostoufi N., Chaouki J., Flow Structure of the solids in Gas-Fluidized Beds, Chem. Eng. Sci., 59, p. 4217 (2004).
[20] Mabrouk R., Chaouki J., Guy C., Effective Drag Coefficient Investigation in the Acceleration Zone of an Upward Gas-Solid Flow, Chem. Eng. Sci., 62, p. 318 (2007).
[21] Bai D., Jin Y., Z.Q., Acceleration of Particles and Momentum Exchange Between Gas and Solids in Fast Fluidized Beds, in: M. Kwauk, M. Hasatani (Eds.) "Fluidization VI, Science and Technology", Science Press, Beijing, 46-55, (1991).
[22] Gidaspow, D., "Multiphase Flow and Fluidization, Continuum and Kinetic Theory Description", Academic Press, San Diego, CA, (1994).
[23] Cui H., Mostoufi N., Chaouki J., Characterization of Dynamic Gas-Solid Distribution in Fluidized Beds, Chem. Eng. J., 79, p. 133 (2000).