An Experimental Study of Liquid-Particle Flow in Circulating Fluidized Bed

摘要

A liquid-solid circulating fluidized bed (LSCFB) is operated at high liquid velocity,where particle entrainment is highly significant and between the conventional liquid fluidized bed and the dilute phase liquid transport regimes.LSCFB has potential applications in the fields of food processing,biochemical processing,and petrochemical and metallurgical processing.It is well known that the flow characteristics in a liquid-solid circulating fluidized bed are different from those of a conventional liquid-solid fluidized bed.The limited studies available in literature do not provide complete understanding of the flow structure in this typical regime.In the present work,experiments were carried out in a 0.0762 m ID and 3 m height laboratory-scale liquid-solid circulating fluidized bed apparatus by using various solid particles and tap water as fluidizing medium.In the experimental setup,two distributors (specially designed) were used to monitor solid circulation rate in the riser.The effects of operating parameters,i.e.,primary liquid flow rate in the riser (Up),solid circulation rate (G_s),and particle diameter (dp),were analyzed from the experimental data.Finally,a correlation was developed from the experimental data to estimate average solid holdup in the riser,and it was compared with present experimental and available data in the literature.They agree well with a maximum root-mean-square deviation of 7.83%.