CO2 Biomass Fluidized Gasification. Thermodynamic and Reactivity Studies.

This study reports biomass gasification in a CREC Riser Simulator under thermal and catalytic conditions. Steam-CO2 and steam-inert were used as gasifier agents. Biomass feedstocks and a model compound were employed to evaluate gasification performance. It was proven that catalytic steam-CO2 gasification significantly reduces tar formation while improving carbon conversion to syngas. Experimental results were compared with thermodynamic equilibrium model predictions. This model accounts for biomass composition, bed temperature and gasifying agents. The model predictions are close to experimental results for steam-CO2 gasification, leading to a zero CO2 gain. 2-methoxy-4-methylphenol and 20%Ni-5%CeO2/γ-Al2O3 were selected as model compound and catalyst for the catalytic gasification. Results showed that catalytic activity reduces tars 22wt%. Furthermore, catalytic experiments under steam-CO2 displays an extra 15wt% of tar reduction. A process based on catalytic steam-CO2 gasification was proposed, leading to significant tar reduction with enhanced carbon conversion to syngas. Engineering of this process benefits of the reliability of the equilibrium thermodynamic model, to predict various synthesis gas components