Numerical Simulation of Hydrogen Production via Chemical Looping Reforming in Interconnected Fluidized Bed Reactor

Abstract

A multiphase reactive fluid dynamic model has been applied to simulate a complete chemical looping reforming (CLR) system, including an air reactor (AR), a fuel reactor (FR), a cyclone, and a loop seal. A two-fluid model with consideration of frictional stress between particles at high solid concentrations is used. A bubble-structure-dependent drag coefficient model is proposed and incorporated into the computational fluid dynamics (CFD) code to account for the effect of multiscale structures in the bubbling fluidized reactor. The predictions by the model are in good agreement with the experimental results. Flow pattern, profiles of bubbles, and distributions of gas compositions and temperatures are obtained. In addition, the influence of reaction temperature, operating velocity, and H2O/CH4 molar ratio on the gas concentration is also investigated.

Computational fluid dynamics simulation for chemical looping combustion of coal in a dual circulation fluidized bed

“…The spherical shrinking core model and the linear shrinking core model for the reaction kinetics were evaluated and compared; the effects of different kinetic models, oxygen carrier mass flows and reactor bed heights on the methane conversion and bed temperature were investigated. Recently, Wang et al [37] conducted a multiphase CFD simulation for chemical looping reforming (CLR) in dual circulation fluidized beds; the effects of bed temperature, superficial gas velocity and H 2 O/CH 4 ratio on the gas conversion efficiency were investigated.…”

CFD Simulation of a Bubbling Fluidized Bed Gasifier Using a Bubble-Based Drag Model

“…These structural parameters are obtained by solving a set of nonlinear equations in Table 2. Detailed parameters can be found in Wang et al 21 Here, it is emphasized that the global operating parameters (U g , G s ) in the original bubble-based EMMS model are replaced by the local variables (u g , u s , ε g ) in the computational cell. In the simulation of unsteady flow, local dynamic parameters are more reasonable to determine the drag coefficient in the grid.…”

“…This model was further verified by comparison with empirical relations and experimental data. Wang et al , and Zhao et al applied the bubble-based EMMS model to carry out simulations of chemical looping reforming system and methanol to an olefin fluidized bed reactor, respectively. However, these models used the global hydrodynamic parameters to derive the correlation between drag coefficient and voidage, and neglected the effect of local velocity on the heterogeneity.…”

“…These structural parameters are obtained by solving a set of nonlinear equations in Table . Detailed parameters can be found in Wang et al…”

A Bubble-Based Drag Model at the Local-Grid Level for Eulerian Simulation of Bubbling Fluidized Beds

“…It is to be noted that, in the above models, the global operating conditions are used to deduce the correlation between drag coefficient and voidage (or bed height), which neglect the effect of local information on the drag coefficient. Subsequently, the bubble-based EMMS model has been revised and extended to the local-grid level [48][49][50]. In this development, the local energy dissipation was introduced and assumed to be minimal.…”