HYDRODYNAMIC CHARACTERISTICS OF FINE PARTICLES IN THE RISER AND STANDPIPE OF A CIRCULATING FLUIDIZED BED

Choi JH; Park JH; Choung WM; Kang Y; Kim SD

Korean Journal of Chemical Engineering, Vol.12, No.2, 141-145, April, 1995

Choi JH, Park JH, Choung WM, Kang Y, Kim SD

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-ID×3.8 m high), a standpipe(0.068 m-ID×2.5 m high)as a primary cyclone/bubbling fluidized bed, and a secondary cyclone. Silica gel powder(mean diameter=46㎛) 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 initial solid loading. The efficiencies of primary cyclone decreases and that of secondary cyclone increases slightly, with an increase in the gas velocity in the standpipe.

Keywords:Circulating Fluidized Bed;Solid Circulation Rate;Gas Velocity;Solid Holdup

[References]

Arena U, Cammarota A, Piston L, "High Velocity Fluidization Behavior of Solids in a Laboratory Scale Circulating Bed," Circulating Fluidized Bed Technology," Basu, P., Eds., Pergamon Press,N.Y., 119 (1986)
Baran V, Atomic Energy Rev., 174, 891 (1979)
Cho YJ, Namkung W, Kim SD, "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 EU, Li Y, Werther J, "Analysis of the Local Structure of the Two Phase Flow in a Fast Fluidized Bed," Circulating Fluidized Bed Technology, Basu, P., eds., Pergamon, Toronto, 153 (1986)
Fluidization V. Ostergaard K, Sorensen A, 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, 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 Technology, Geldart, D., ed., 341 (1986)
Kullendorff A, Andersson S, "A General Review on Combustionin Circulating Fluidized Beds," Circulating Fluidized Bed Technology, Basu, P., ed., Pergamon Press, N.Y., 83 (1986)
Kuramoto M, Kunii D, Furusawa T, Powder Technol., 47, 141 (1986)
Kwauk M, Chem. Metallurgy, 4, 1 (1980)
Li X, Liu D, Kwauk M, "Pneumatically Controlled Multistage Fluidized Beds-II," Proc. Joint Meeting of Chem. Eng., SIESC and AIChE, Beijing, 382 (1982)
Li Y, 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, Kwauk M, Chem. Metallurgy, 4, 20 (1980)
Merrow E, Chem. Eng. Process., May., 14 (1985)
Nishiyama N, Tashiro H, Ijichi K, Tanaka Y, Uemura Y, Hatate Y, Proc. 6th Symposiumon Chemical Engineering (Chungnam-Kyushu), Sep. 6-7, Taejon, Korea, 15 (1993)
Takeuchi H, Hirama T, Chiba T, Leung S, "On the Regime of Fast Fluidization," Proc. World Congress III of Chemical Engineering, Tokyo, Japan, 3, 477 (1986)
Weinstein H, Graff RA, Meller M, Shao MJ, "The Influence of the Imposed Pressure Drop Across a Fast Fluidized Bed," Proc. IV Int. Conf. on Fluidization, 299 (1983)
Yerushalmi J, Cankurt NT, Powder Technol., 24, 187 (1979)
Youchou L, Kwauk M, "The Dynamics of Fast Fluidization," Fluidization, Grace, J.R. and Matsen, J.M., eds. Plenum Press, New York, 537 (1980)
Zenz FA, Powder Technol., 47, 105 (1986)

[Referenced By]

[1] Arena U, Cammarota A, Piston L, "High Velocity Fluidization Behavior of Solids in a Laboratory Scale Circulating Bed," Circulating Fluidized Bed Technology," Basu, P., Eds., Pergamon Press,N.Y., 119 (1986)

[2] Baran V, Atomic Energy Rev., 174, 891 (1979)

[3] Cho YJ, Namkung W, Kim SD, "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)

[4] Hartge EU, Li Y, Werther J, "Analysis of the Local Structure of the Two Phase Flow in a Fast Fluidized Bed," Circulating Fluidized Bed Technology, Basu, P., eds., Pergamon, Toronto, 153 (1986)

[5] Fluidization V. Ostergaard K, Sorensen A, Engineering Foundation, New York, 345 (1986)

[6] Horio M, "Hydrodynamics of Circulating Fluidization," Circulating Fluidized Bed Technology III, Basu, P., Horio, M. and Hasatani, M., eds., 3 (1990)

[7] Horio M, Morishita K, Murata N, Tachibana O, "Solid Distribution and Movement in Circulating Fluidized Beds," Circulating Fluidized Bed Technology II, Basu, P., and Large, J.F., eds., 147 (1988)

[8] Knowlton T, "Solids Transfer in Fluidized Systems," Gas Fluidization Technology, Geldart, D., ed., 341 (1986)

[9] Kullendorff A, Andersson S, "A General Review on Combustionin Circulating Fluidized Beds," Circulating Fluidized Bed Technology, Basu, P., ed., Pergamon Press, N.Y., 83 (1986)

[10] Kuramoto M, Kunii D, Furusawa T, Powder Technol., 47, 141 (1986)

[11] Kwauk M, Chem. Metallurgy, 4, 1 (1980)

[12] Li X, Liu D, Kwauk M, "Pneumatically Controlled Multistage Fluidized Beds-II," Proc. Joint Meeting of Chem. Eng., SIESC and AIChE, Beijing, 382 (1982)

[13] Li Y, Kwauk M, "The Dynamics of Fast Fluidization," Fluidization, Grace, J.R. and Matsen, J.M., eds., Plenum Press, 540 (1980)

[14] Li Y, Chen B, Wang F, Wang Y, Kwauk M, Chem. Metallurgy, 4, 20 (1980)

[15] Merrow E, Chem. Eng. Process., May., 14 (1985)

[16] Nishiyama N, Tashiro H, Ijichi K, Tanaka Y, Uemura Y, Hatate Y, Proc. 6th Symposiumon Chemical Engineering (Chungnam-Kyushu), Sep. 6-7, Taejon, Korea, 15 (1993)

[17] Takeuchi H, Hirama T, Chiba T, Leung S, "On the Regime of Fast Fluidization," Proc. World Congress III of Chemical Engineering, Tokyo, Japan, 3, 477 (1986)

[18] Weinstein H, Graff RA, Meller M, Shao MJ, "The Influence of the Imposed Pressure Drop Across a Fast Fluidized Bed," Proc. IV Int. Conf. on Fluidization, 299 (1983)

[19] Yerushalmi J, Cankurt NT, Powder Technol., 24, 187 (1979)

[20] Youchou L, Kwauk M, "The Dynamics of Fast Fluidization," Fluidization, Grace, J.R. and Matsen, J.M., eds. Plenum Press, New York, 537 (1980)

[21] Zenz FA, Powder Technol., 47, 105 (1986)