Abstract
A zero-dimensional mathematical model for downdraft gasification of biomass in fixed or slowly moving bed gasifiers was developed and implemented in Engineering Equation Solver (EES). The proposed model does not consider the gasification process as a black box, it takes into account the main gasification sub-processes (drying, pyrolysis, gasification) and their products. The model successfully predicts conversion behaviours of different types of biomass during a gasification process in terms of yield and composition of products. The model has been validated with published experimental data from the literature, showing good agreement. In addition, a sensitivity analysis was carried out using the model, varying different operating parameters (gasification temperature, equivalence ratio, air preheating temperature, steam injection amount, oxygen enrichment degree etc.). The simulation results are presented and discussed. The developed model can be considered a useful tool to simulate the influence of a wide variety of biomass feedstocks and operating parameters on gas characteristics.