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

Wood gasification in a fluidized bed reactor is regards as a promising technique to efficiently exploit the energy from biomass, which has attracted great attention. To further understand complex fluid mechanics and thermal behaviors of wood during the gasification process, a multiphase reactive model is presented, and a computational fluid dynamics (CFD) simulation of wood gasification in a bubbling fluidized bed gasifier is implemented. To account for the impact of bubble-structure on the gassolid interaction, a revised bubble-based energy minimization multiscale (EMMS) drag model is developed and incorporated into a two-fluid model. Flow behaviors and reactive characteristics in a bubbling fluidized bed gasifier are analyzed. Profiles of temperature and concentration of gas and solid phase are also obtained. By comparisons of the outlet gas species concentrations, the prediction by a revised bubble-based EMMS drag model agrees better with experimental results than that by the conventional drag model.