Numerical simulation for the loop seal in the circulating fluidized bed and experimental validation

The controllable and flexible loop seal of CFBs is essential for steady and high-efficient circular running. Based on the energy-minimization multi-scale (EMMS) model, a revised drag force coefficient expression was coupled with the two-fluid model (TFM) and the kinetic theory of granular method (KTGF) to investigate the hydrodynamic characteristics of the loop seal and standpipe in a CFB. 2D simulations for the standpipe and loop seal were implemented to test the validity of the physical and mathematical models, and excellent numerical performances and encouraging results were observed. The flow character and solids' streamline in the standpipe and loop seal, solids inventory, aeration position and the fluctuation of riser's total pressure drop were analyzed in detail. Some suggestions on the design of the experimental apparatus were proposed to ensure the experimental system's stability and controllability. Under the working conditions in this paper, the simulation results are in agreement with the laboratory ones, which reveals these models in this work is competent for the simulation of the standpipe and loop seal of CFBs.

The comparison of the experiment and simulation results is shown. It can be seen that the simulation result based on the revised drag force coefficient model give a good agreement with the experiment results under the working condition considered in this article.Figure optionsDownload as PowerPoint slideHighlights
► The two-fluid mode, kinetic theory of granular and EMMS method are coupled.
► A 2D numerical simulation for a loop seal in the circulating fluidized bed is implemented.
► Excellent numerical performances and encouraging consistence is obtained.