Modeling and simulation of biomass air-steam gasification in a fluidized bed

Abstract

By considering the features of fluidized-bed reactors and the kinetic mechanism of biomass gasification, a steady-state, isothermal, one-dimensional and two-phase mathematical model of biomass gasification kinetics in bubbling fluidized beds was developed. The model assumes the existence of two phases – a bubble and an emulsion phase – with chemical reactions occurring in both phases. The axial gas dispersion in the two phases is accounted for and the pyrolysis of biomass is taken to be instantaneous. The char and gas species CO, CO₂, H₂, H₂O, CH₄ and 8 chemical reactions are included in the model. The mathematical model belongs to a typical boundary value problem of ordinary differential equations and its solution is obtained by a Matlab program. Utilizing wood powder as the feedstock, the calculated data show satisfactory agreement with experimental results and proves the effectiveness and reliability of the model.

Keywords

biomass / fluidized bed / air-steam / gasification / mathematical model