Evaluation of Syngas composition through a novel numerical model for downdraft gasifiers

In this study a numerical equilibrium model was developed to predict the composition, the heating value and the temperature of the producer gas from a downdraft gasifier fueled with biomass. The chemical equilibrium has been solved considering the methanation and the water-gas shift reactions for the modeling of gasification process. The model was calibrated and validated through the comparison with experimental data reported in other studies about a downdraft gasifier. The comparison of the model simulation results with the experimental data taken in account shown a good agreement. A sensitivity analysis was carried out to evaluate the ability of the model to predict the quality and the temperature of the producer gas, with biomass moisture content and equivalent ratio variation, and to investigate the effect of these parameters on the performance of gasification process. The influence of moisture content and equivalent ratio on the chemical composition, equilibrium temperature and heating value of producer gas was discussed. Keywords—biomass; downdraft gasifier; numerical modelling; moisture content; equivalent ratio