Based on a cold CFB model

the effect of horizontal orifice areas of Loop Seal on performance was studied in detail. The resistance properties across orifice were obtained under its different operational conditions. An empirical relation between the pressure drop across horizontal orifice and solids circulating flow rate was proposed and a new orifice discharging coefficient was also defined according to the experimental results and theoretical analysis. These will provide a sound basis for the optimum design and operation of Loop Seal.