Three dimensional kinetic modeling of fluidized bed biomass gasification

Biomass gasification in fluidized bed system by using air-steam mixture as the gasifying agent is a promising way of utilizing biomass because it produces a gaseous fuel having relatively higher calorific value as well as higher hydrogen content with minimum or no heat addition to the gasifier. In the present work, a three dimensional numerical simulation of a bubbling fluidized bed biomass gasifier has been carried out. The numerical simulation is based on the Eulerian-Lagrangian approach where the fluid phase is solved by using a continuum approach and the solid is modeled by using Lagrangian computational particle model. The chemical reactions are coupled with the complex hydrodynamic calculation of gas-solid fluidized bed. The simulations are performed by varying the gasification temperature, equivalence ratio and steam-to-biomass ratio. Detail analyses of flow pattern, pressure distribution, and gas composition distribution have been presented. The complex three dimensional flow structures are revealed by plotting the results in different planes. The results provide a detail insight into the gasifier's behavior including fluidization, thermal and chemical characteristics. Simulated outlet gas compositions are compared with our own experimental data and a very good resemblance is observed. (c) 2014 Elsevier Ltd. All rights reserved.