Shu-San Hsiau
National Central University, Taiwan
Title: CFD Modeling of Paper Reject Gasification in a Lab-Scale Dual Fluidized Bed Gasifier
Biography
Biography: Shu-San Hsiau
Abstract
The technology of dual fluidized bed (DFB) steam gasification has been well-known to generate product syngas of high quality with high heating value and free nitrogen. The present study investigates either combustion or gasification of biomass fuel in a lab-scale DFB gasifier. The fluid dynamics with heat and mass transfers taking place in a two-dimentional DFB system were performed by applying computational fluid dynamics (CFD) technique. A combination of fluid flow model, heat transfer model and species transport model was used to study the unsteady behaviors of the phases including process agents (air, steam), biomass fuel (paper reject) and bed material (silica sand) during the whole process. Our model was first validated with published studies, and then was developed to optimize the critical parameters and conditions affecting the system operation. Accordingly, a parametric study was conducted for the major factors, such as inlet air/steam velocities, operating temperatures, to determine their effects on the hydrodynamics, heat transfer characteristics and product yields. Some typical results were obtained for the fluid flow patterns, distributions of velocities, pressure, temperature and species’ concentration in different zones and along the height of the DFB system. It was found that the input parameters and the system geometry were important influences affecting modeling results, and thus system performance. All predicted results are expected to improve the design and efficiency of the practical systems. Further validation with corresponding experiments and modification are intended to make the model more convinced.