(202e) A Kinetic Model for Updraft Biomass Gasification By Aspen Plus

Biomass gasification is now widely accepted as a potential and environment-friendly energy resource. In this work, a kinetic model for updraft biomass gasifiers is presented. The model is developed in Aspen Plus V8.6 by solving the detailed gasification kinetics and it approximates the composition of syngas by two steps. The biomass pyrolysis step is accomplished by stoichiometric reactions and the biomass combustion/gasification step is simulated by plugging in heterogeneous and homogeneous reaction kinetic information. Two lab-scale updraft gasifiers experiments available in literature are used to test the kinetic model (K-model) and a widely used minimizing Gibbs Energy model (MGE-model). The syngas composition predicted by K-model agrees well with experimental measurements. K-model is also more accurate than MGE-model especially for the prediction of tar. Moreover, the gasification of new biomass samples at different equivalence ratio (ER), gasification temperature and air/steam ratio are also investigated. Simulation results show that gasification process can be improved if extra heat is available to the gasifier or when it is operated under the desired ER range.