Development of a thermo-chemical equilibritation model for biomass gasifiers with tar and char formation

Modelling biomass conversion to syngas in gasifiers is addressed through a thermo-chemical equilibrium model that also accounts for tar and char formation. The developed model is applied to biomasses of different nature, for which experimental data concerning the released syngas composition are available in the literature. The restrictive hypotheses underlying the model are here in some way relaxed by modifying the actual equilibrium constants. To increase the accuracy of model results, the calibration is needed: the modified equilibrium constants can be defined as the actual equilibrium constants multiplied by the degree of approach to equilibrium. Based on this consideration, the thermo-chemical equilibrium model is coupled with a genetic algorithm (MOGA II) in order to find the correction factors minimizing the error between the computed and the experimentally measured syngas yields and temperatures. The approach is repeated to simulate the thermo-chemical treatment of different biomasses with increasing carbon content such as peach, straw paper, wood sawdust pellet, olive pits, grass plants, rubber wood, untreated wood, treated wood and sawdust paper