BED-TO-WALL HEAT TRANSFER CHA- RACTERISTICS IN A CIRCULATING FLUIDIZED BED

Cho YJ; Kim SD; Han GY

Korean Journal of Chemical Engineering, Vol.13, No.6, 627-632, November, 1996

The bed-to-wall heat transfer coefficients were measured in a circulating fluidized bed of FCC particles(d_p=65㎛). The effects of gas velocity (1.0-4.0 ㎧), solid circulation rate(10-50 ㎏/m²s)and particle suspension density(15_-100㎏/m³) on the bed-to-wall heat transfer coefficient have been determined in a circulating fluidized bed(0.1m-ID X 5.3m-high). The heat transfer coefficient strongly depends on particle suspension density, solid circulation rate, and gas velocity. The axial variation of heat transfer coefficients is a strong function of the axial solid holdup profile in the riser. The obtained heat transfer coefficient in terms of Nusselt number has been correlated with the pertinent dimensionless groups.

Keywords:Heat Transfer Coefficient;Circulating Fluidized Bed;Particle Convective Heat Transfer;Heat Transfer Length;Suspension Density

[References]

Arena U, Cammarato A, Piston L, "High Velocity Fluidization Behavior of Solids in a Laboratory Scale Circulating Fluidized Bed," CFB Technology, Basu, P. eds., Pergamon Press, New York, 119 (1986)
Bai DR, Jin Y, Yu ZQ, Zhu JX, Powder Technol., 71, 51 (1992)
Baskakov AP, Maskaev VK, Ivanov IV, Usoltsev AG, J. Eng. Phys., 59, 1570 (1991)
Basu P, Fraser SA, "Circulating Fluidized Bed Boiler: Design and Operation," Butterworth-Heinemann, Boston (1991)
Basu P, Nag PK, Int. J. Heat Mass Transf., 30, 2399 (1987)
Chen CC, Chen CL, Chem. Eng. Sci., 47, 1017 (1992)
Dou S, "Heat Transfer Characteristics in Circulating Fluidized Beds," Ph.D. Dissertation, Lehigh University, Bethlehem, U.S.A. (1991)
Glicksman LR, "Circulating Fluidized Bed Heat Transfer," CFB Technology II, Basu, P. and Large, J.F., eds, Pergamon Press, New York, 13 (1988)
Grace JR, "Heat Transfer in Circulating Fluidized Beds," CFB Technology, Basu, P. eds., Pergamon Press, New York, 63 (1986)
Han GY, "Experimental Study of Radiative and Particle Convective Heat Transfer in Fast Fluidized Beds," Ph.D. Dissertation, Lehigh University, Bethlehem, U.S.A. (1992)
Hartge EV, Li Y, Werther J, "Analysis of the Local Structure of Two-Phase Flow in a Fast Fluidized Bed," CFB Technology, Basu, P. eds., Pergamon Press, Canada, 153 (1986)
Holman JP, "Heat Transfer," McGraw-Hill, New York (1986)
Kobro H, Brereton CMH, "Control and Fuel Flexibility of Circulating Fuidized Bed," CFB Technology, Basu, P. Eds., Pergamon Press, New York, 263 (1986)
Li Y, Kwauk M, "The Dynamics of Fast Fluidization," Fluidization, Grace and Masten eds., Plenum Press, New York, 537 (1980)
Nag PK, Moral MNA, Int. J. Energy Res., 14, 965 (1990)
Namkung W, Cho YJ, Kim SD, HWAHAK KONGHAK, 32(2), 241 (1994)
Rhodes MJ, Geldart D, "The Hydrodynamics of Re-Circulating Fluidized Beds," CFB Technology, Basu, P. eds., Pergamon Press, New York, 194 (1986)
Wu RL, Lim CJ, Chaouki J, Grace JR, AIChE J., 33, 1888 (1987)
Wu RL, Grace JR, Lim CJ, Brereton CMH, AIChE J., 35, 1685 (1989)
Wu RL, Lim CJ, Grace JR, Can. J. Chem. Eng., 67, 301 (1989)

[Referenced By]

[1] Arena U, Cammarato A, Piston L, "High Velocity Fluidization Behavior of Solids in a Laboratory Scale Circulating Fluidized Bed," CFB Technology, Basu, P. eds., Pergamon Press, New York, 119 (1986)

[2] Bai DR, Jin Y, Yu ZQ, Zhu JX, Powder Technol., 71, 51 (1992)

[3] Baskakov AP, Maskaev VK, Ivanov IV, Usoltsev AG, J. Eng. Phys., 59, 1570 (1991)

[4] Basu P, Fraser SA, "Circulating Fluidized Bed Boiler: Design and Operation," Butterworth-Heinemann, Boston (1991)

[5] Basu P, Nag PK, Int. J. Heat Mass Transf., 30, 2399 (1987)

[6] Chen CC, Chen CL, Chem. Eng. Sci., 47, 1017 (1992)

[7] Dou S, "Heat Transfer Characteristics in Circulating Fluidized Beds," Ph.D. Dissertation, Lehigh University, Bethlehem, U.S.A. (1991)

[8] Glicksman LR, "Circulating Fluidized Bed Heat Transfer," CFB Technology II, Basu, P. and Large, J.F., eds, Pergamon Press, New York, 13 (1988)

[9] Grace JR, "Heat Transfer in Circulating Fluidized Beds," CFB Technology, Basu, P. eds., Pergamon Press, New York, 63 (1986)

[10] Han GY, "Experimental Study of Radiative and Particle Convective Heat Transfer in Fast Fluidized Beds," Ph.D. Dissertation, Lehigh University, Bethlehem, U.S.A. (1992)

[11] Hartge EV, Li Y, Werther J, "Analysis of the Local Structure of Two-Phase Flow in a Fast Fluidized Bed," CFB Technology, Basu, P. eds., Pergamon Press, Canada, 153 (1986)

[12] Holman JP, "Heat Transfer," McGraw-Hill, New York (1986)

[13] Kobro H, Brereton CMH, "Control and Fuel Flexibility of Circulating Fuidized Bed," CFB Technology, Basu, P. Eds., Pergamon Press, New York, 263 (1986)

[14] Li Y, Kwauk M, "The Dynamics of Fast Fluidization," Fluidization, Grace and Masten eds., Plenum Press, New York, 537 (1980)

[15] Nag PK, Moral MNA, Int. J. Energy Res., 14, 965 (1990)

[16] Namkung W, Cho YJ, Kim SD, HWAHAK KONGHAK, 32(2), 241 (1994)

[17] Rhodes MJ, Geldart D, "The Hydrodynamics of Re-Circulating Fluidized Beds," CFB Technology, Basu, P. eds., Pergamon Press, New York, 194 (1986)

[18] Wu RL, Lim CJ, Chaouki J, Grace JR, AIChE J., 33, 1888 (1987)

[19] Wu RL, Grace JR, Lim CJ, Brereton CMH, AIChE J., 35, 1685 (1989)

[20] Wu RL, Lim CJ, Grace JR, Can. J. Chem. Eng., 67, 301 (1989)