The present work is an experimental study on the solid circulation rate in a recirculating fluidized bed and mathematical modeling of the same based on the experimental results and existing literature. The effects of particle size, spacing between the draft tube bottom and distribution plate, inventory of solids, and superficial gas velocity on the solid circulation rate are studied experimentally on a semicircular cold model recirculating fluidized bed. A mathematical model is developed for the solid circulation rate incorporating the effect of the various operating and design parameters. The model is based on the present experimental work and data available in the literature for the same kind of reactors. Dimensional analysis and nonlinear regression models are used to develop the model. The final model equation is a non linear relationship between the different operating and design variables. The model equation gives good results for the same kind of systems and can be used with reasonable accuracy for a wide range of operating parameters.