Three-dimensional full-loop simulation of a high-density CFB with standpipe aeration experiments

Three-dimensional full-loop simulation of a high-density circulating fluidized bed (HDCFB) is conducted using the multiphase particle-in-cell (MP-PIC) method. The computational results are in good agreement with the experimental data of pressure distribution and solids circulation rate under different aeration conditions of the standpipe. The main feature of gas-solid flow in the riser is qualitatively predicted, with coexistence of the developed flow in the upper region and the acceleration flow in the lower region. The flow regime in the standpipe is mainly concurrent downward gas-solid flow in the close packing region. Due to the influence of the aeration gas, the pressure gradient presents a wave variation along the height of standpipe. The predicted solids residence time distribution in the standpipe exhibits a feature of early peak with an extended tail, indicating that the solids flow is not uniform in the standpipe. (C) 2017 Elsevier B.V. All rights reserved.