A hydrodynamic model of loop-seal for a circulating fluidized bed

Loop-seal is one of the most common valves used in circulating fluidized bed (CFB) system. In the present work, a hydrodynamic model is developed for the operation that the particles in the recycle chamber are fluidized by the air, while the particles in the standpipe are in moving bed condition. Through hydrodynamic analysis, a hydrodynamic model including three equations has been established, whose solution results in the actual gas velocity, particle velocity and bed voidage in the recycle chamber. The model also predicts the solids flow rate, gas flow rate and pressure drop in both standpipe and recycle chamber. Experiments were conducted in a circulating fluidized bed with silica gel particles (Geldart group A). The model predictions showed good agreement with experimental data.