This paper presents a non-stoichiometric equilibrium model for the simulation of the biomass gasification process in downdraft gasifiers to be used within simulation models of complex energy systems. The chemical equilibrium is determined by minimizing the Gibbs free energy. The feedstock is composed of five elements, while fifteen chemical species are considered for the syngas. The model calculates the relative quantities of gasification products and the lower heating value of the syngas. An advantage of the non-stoichiometric approach is that it can easily calculate not only the concentrations of the main gasification products, but also the concentrations of minor products, especially the pollutant chemical species containing nitrogen and sulfur.

To analyse the behaviour of the model, a sensitivity analysis of its process parameters is presented. The model is then validated by comparing its results with the results of the simulation carried out with equilibrium models and with experimental data found in literature. Finally, the model is applied to the study of the gasification of forest waste.

本文提出了一种非化学计量的平衡模型，用于模拟下式气化炉中的生物质气化过程，该模型将用于复杂能源系统的模拟模型中。通过最小化吉布斯自由能来确定化学平衡。原料由五种元素组成，而合成气考虑了十五种化学物质。该模型计算气化产物的相对量和合成气的较低热值。非化学计量方法的优点是，它不仅可以轻松计算出主要气化产物的浓度，而且可以轻松计算出次要产物的浓度，尤其是含有氮和硫的污染物化学物质。

为了分析模型的行为，提出了对其过程参数的敏感性分析。然后，通过将模型结果与平衡模型进行的仿真结果以及文献中的实验数据进行比较，对模型进行验证。最后，将该模型应用于森林废弃物气化研究。