Modeling on the Hydrodynamics of Pressurized High-Flux Circulating Fluidized Beds (PHFCFBs) by Eulerian–Lagrangian Approach

Authors: Shangyi Yin ^a, Wenqi Zhong ^a, Baosheng Jina ^a, and Jianren Fan ^b
a Ministry of Education of Key Laboratory of Energy Thermal Conversion and Control, School of Energy & Environment, Southeast University, Nanjing 210096, PR China
^b State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, PR China

Source: Yin, S.; Zhong, W.; Jin, B.; Fan, J. Modeling on the Hydrodynamics of Pressurized High-Flux Circulating Fluidized Beds (PHFCFBs) by Eulerian–Lagrangian Approach. Powder Technology 2014, 259, 52–64.

Abstract: A novel Eulerian–Lagrangian approach based on the multi-phase particle-in-cell (MP-PIC) methodology was applied in the simulation of the hydrodynamic behavior of pressurized high-flux circulating fluidized beds (DHFCFBs) in this work. The sensitivities of key model (i.e. the drag model) and modeling parameters (particle–particle restitution coefficient, normal particle–wall restitution coefficient, and tangential particle–wall restitution coefficient) on the predictions have been tested systematically. Experimental results of Richtberg et al. [Powder Technol. 2005, 155(2), 145–152] and Yin et al. [Chem. Eng. Technol. 2012, 35(5), 904–910] were used as a numerical benchmark to assess the simulations quantitatively. The results show that the Gidaspow drag model displays better agreement with both the axial profiles of pressure drop and the radial distributions of particle volume fraction. Compared with the perfectly elastic particle collision (e_p = 1.0), the non-ideal particle–particle interaction could get more reasonable prediction results. The particle–wall restitution coefficient has somewhat of an effect on the simulated gas–solid flow behaviors in the risers. However, no critical changes of simulated flow characteristic in the trends of pressure drop and solid volume fraction distribution have been found. Based on the comparison of simulation results with experiments, a suitable model (i.e., Gidaspow drag model) and a group of modeling parameters, namely a particle–particle restitution coefficient (e_p = 0.9), a normal particle–wall restitution coefficient (e_wn = 0.1) and a free-slip boundary condition (i.e. the tangential particle–wall restitution coefficient, e_wτ = 1.0) for modeling the hydrodynamic behavior in the DHFCDB riser were determined and verified.