Radial gas mixing in a circulating fluidized bed

The effects of gas velocity, solid circulation rate, the secondary air inje ction ratio, and secondary injection type on the radial gas-mixing coeffici ent (D-r) in a circulating fluidized bed (CFB) (0.1 m i.d., 5.3 m high) hav e been determined. It increases with increasing solid circulating rate and the secondary air ratio (SAR), but decreases with increasing gas velocity. Based on the present and previous studies, D-r increases with increasing co lumn diameter. The effect of secondary air injection type on the radial gas -mixing coefficient is more pronounced with the tangential than with the ra dial air injection. The radial gas-mixing coefficient in terms of Peclet nu mber has been correlated based on the isotropic turbulence theory. (C) 2000 Elsevier Science S.A. All rights reserved.