This paper deals with an experimental study on hydrodynamics of 400 um silica sand in a circulating fluidized bed (CFB) set-up having its riser diameter and height of 0.108 meter and 7 meters, respectively. By increasing the primary air flow rate from 170 to 220 m3/h and with three values of total solid inventory (i.e 20 kg, 25 kg and 30kg) , solid circulation rate of solid particles was experimentally estimated to be in the order of from 3.53 to 6.67 kg/m2/s. A mathematical correlation was then developed that help predict solid circulation rate as a function of primary air flow rate, aeration air flow rate and total solid inventory of the CFB.