Steam Gasification of Pine Wood in a Fluidized Bed Reactor: Model Development and Validation at Different Operative Conditions

One of the most important issues in biomass gasification is the correct prediction of gasification products, with particular attention to the Topping Atmosphere Residues (TARs). In this work, performed within the European 7FP UNIfHY project, develops and validates experimentally a model able of predicting the outputs, including TARs, of a steam-fluidized bed biomass gasifier. Pine wood was chosen as biomass feedstock: the products obtained in pyrolysis tests are the relevant model input. Hydrodynamics and chemical properties of the reacting system are considered: the hydrodynamic approach is based on the two phase theory of fluidization, meanwhile the chemical model is based on the kinetic equations for the heterogeneous and homogenous reactions. The derived differentials equations for the gasifier at steady state were implemented and solved via MATLAB. Simulations were carried out varying steam/biomass ratio (0.5-1) and operating temperature (750-850°C).The comparison between model and experimental results showed that the model is able of predicting gas mole fractions and production rate including most of the representative TARs compounds.