Thermodynamic equilibrium model based on stoichiometric method for biomass gasification: A review of model modifications

Highlights: • The stoichiometric thermodynamic equilibrium model developments were reviewed. • Modifications of model based on experimental data improve prediction accuracy. • Reviewed modified models may include tar and/or char yields. • Reviewed modified models may use artifices to affect equilibrium of reactions. -- Abstract: Gasification is a thermochemical process to convert the biomass chemical energy into a gaseous fuel, which is a suitable renewable energy source as a substitute for fossil fuel. Research on this technology has been developed to improve its efficiency and syngas quality. Computational modeling of the gasification process is an advantageous tool for predicting a complex process reducing actual experiments. This paper aims to present an updated review of application of stoichiometric thermodynamic equilibrium model that was widely investigated on the scientific literature. Due to its limitations in being based on ideal theoretical conditions, some authors modified the model based on experimental data to obtain more accurate results. The review presented in this work comprehends explaining the method of model implementation highlighting main modifications proposed by authors. The importance of this study is that the extensive literature review of model modifications provides a better understanding of gasification modeling that may serve as a basis for future research. In this way, further works will be able to develop new approaches for this model, contributing to the scientific knowledge of the area. As result of this research it was possible to point out as main modifications the following topics: to include tar and/or char; and to force the change in the equilibrium of reactions through the application of multiplication factors to equilibrium constants. It was proved that modified models predict the gas composition much closer to the experimental value than the basic model.