Simulation of an Autothermal Steam Oxygen-Bubbling Fluidized Bed Gasification of Biomass Waste for Hydrogen and Biofuel Production

Developing a predictive model of a bubbling fluidized bed reactor is challenging due to the complexity of gas-solid mixing patterns and the existence of a broad range of volume- and temperature-sensitive reactions. This study presents a predictive model of an autothermal bubbling fluidized bed gasifier operated with steam and oxygen that utilizes waste biomass to produce clean syngas, suitable for synthesis of biofuels and hydrogen by using process simulation software, such as Aspen Plus. The two-phase theory of fluidization's underlying principles were taken into account when designing the model. The reactor is divided into three main reacting zones connected in series and parallel: the dense/bed phase (emulsion plus bubbles), the splashing zone where the feed entry is located, and the freeboard. Using experimental, pilot-scale data, the model was validated with high accuracy. This model can be employed to assist industries with process design and scale up, and further improve the process efficiency and/or product quality for bubbling fluidized bed gasification of various biomass feedstock types