Abstract
The hydrodynamic properties in the riser and standpipe. and the cyclone efficiency have been determined in a circulating fluidized bed (CFB) unit consisting of a riser (0.05 m-IDX3.8 m high), a standpipe (0.068 m-IDX2.5 m high) as a primary cyclone/bubbling fluidized bed, and a secondary cyclone. Silica gel powder (mean diameter = 46 μm) was used as the bed material. The effects of gas velocity in the riser and initial solid loading on the solid circulation rate, and the solid holdups in the riser and standpipe have been determined. The effects of gas velocity in the standpipe on the efficiencies of primary and secondary cyclones have been also determined as functions of solid circulation rate and solid entrainment rate. The solid circulation rate increases with increases in the gas velocity in the riser and in the initial solid loading. The efficiencies of primary and secondary cyclones increase with an increase in the gas velocity in the riser. However, the efficiency of primary cyclone decreases and that of secondary cyclone increases slightly, with an increase in the gas velocity in the standpipe.
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References
Arena, U., Cammarota, A. and Piston, L., “High Velocity Fluidization Behavior of Solids in a Laboratory Scale Circulating Bed”, Circulating Fluidized Bed Technology, Basu, P., ed., Pergamon Press, N.Y., 119 (1986).
Baran, V. and Rez, “Conversion of Uranium Hexaflucride to Uranium Dioxide with Minimum Fluorine Content”,Atomic Energy Review,174, 891 (1979).
Cho, Y. J, Namkung, W. and Kim, S. D., “Effect of Secondary Air Injection on Axial Solid Holdup Distribution in a Circulating Fluidized Bed”, Proc. 6th Symposium on Chemical Engineering (Chungnam-Kyushu), Sep. 6–7, Taejon, 9 (1993).
Hartge, E. U., Li, Y. and Werther, J., “Analysis of the Local Structure of the Two Phase Flow in a Fast Fluidized Bed”, Circulating Fluidized Bed Technology, Basu, P., ed., Pergamon. Toronto, 153 (1986); Fluidization V, Φstergaard, K. and SΦrensen. A., eds., Engineering Foundation, New York, 345 (1986).
Horio. M., “Hydrodynamics of Circulating Fluidization”. Circulating Fluidized Bed Technology III, Basu, P., Horio, M and Hasatani, M., eds., 3(1990).
Horio, M., Morishita, K., Murata, N. and Tachibana, O., “Solid Distribution and Movement in Circulating Fluidized Beds”, Circulating Fluidized Bed Technology II, Basu. P. and Large, J. F., eds., 147 (1988).
Knowlton. T., “Solids Transfer in Fluidized Systems”. Gas Fluidization Technolog)-, Geldart, D., ed., 341 (1986).
Kullendorff, A. and Andersson, S., “A General Review on Combustion in Circulating Fluidized Beds”, Circulating Fluidized Bed Technology, Basu, P., ed., Pergamon Press. N.Y., 83 (1986).
Kuramoto, M., Kunii, D. and Furusawa, T.,Powder Technol.,47, 141 (1986).
Kwauk, M., “Fast Fluidization”,Chemical Metallurgy,4, 1 (1980).
Li, X., Liu, D. and Kwauk, M., “Pneumatically Controlled Multistage Fluidized Beds-II”, Proc. Joint Meeting of Chem. Eng., SIESC and AIChE, Beijing, 382 (1982).
Li, Y. and Kwauk, M., “The Dynamics of Fast Fluidization”, Fluidization, Grace. J. R. and Matsen, J. M., eds., Plenum Press, 540 (1980).
Li, Y., Chen, B., Wang, F., Wang, Y. and Kwauk, M., “Hydrodynamic Correlations for Fast Fluidization”.Chemical Metallurgy,4, 20 (1980).
Merrow, E., “Linking R & D to Problems Experienced in Solids Processing”,Chem. Eng. Process, May, 14 (1985).
Nishiyama, N., Tashiro, H., Ijichi, K., Tanaka, Y., Uemura, Y. and Hatate, Y., Proc. 6th Symposium on Chemical Engineering (Chungnam-Kyushu), Sep. 6–7, Taejon, Korea. 15 (1993).
Takeuchi, H., Hirama, T., Chiba, T. and Leung, S., “On the Regime of Fast Fluidization”, Proc. World Congress III of Chemical Engineering, Tokyo, Japan,3, 477 (1986b).
Weinstein, H., Graff, R. A., Meller, M. and Shao, M.J., “The Influence of the Imposed Pressure Drop across a Fast Fluidized Bed”, Proc. IV Int. Conf. on Fluidization, 299 (1983).
Yerushalmi, J. and Cankurt, N. T., “Further Studies on the Regimes of Fluidization”,Powder Technol.,24, 187 (1979).
Youchou, L. and Kwauk, M., “The Dynamics of Fast Fluidization”, Fluidization, Grace, J. R. and Matsen, J. M., ed.. Plenum Press, New York, 537 (1980).
Zenz, F. A., “Maintaining Dense-Phase Standpipe Downflow”,Powder Technol.,47, 105 (1986).
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Choi, JH., Park, JH., Choung, WM. et al. Hydrodynamic characteristics of fine particles in the riser and standpipe of a circulating fluidized bed. Korean J. Chem. Eng. 12, 141–145 (1995). https://doi.org/10.1007/BF02705637
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DOI: https://doi.org/10.1007/BF02705637