Experimental uncertainty reconciliation in drop tube characterization of reacting streams of particles

One promising technology for carbon capture and sequestration (CCS) is oxy-fuel combustion, in which solid fuel (coal/biomass) combustion takes place in a mixture of oxygen and recycled flue gases, instead of air. The development of this technology requires further advancements, mainly aimed at providing high-fidelity simulation tools, as those based on Computational Fluid Dynamics, to be used for the design of practical burners and furnaces in power generation plants. So far reliable solid fuel combustion models are available only for conventional combustion, mainly because the lack of knowledge on the combustion process (e.g. devolatilization, char oxidation) in an atmosphere that is different from air. Indeed, even if some experimental data are available on oxy-fuel conditions, most of them have been generally taken in lab-scale reactors, and are hardly applicable to real furnaces. The present work wants to derive heterogeneous kinetics in oxy-fuel combustion from experiments performed in a pilot-scale drop tube reactor, which ensures heating rates and temperatures similar to the industrial ones. A new procedure, based on both experimental data analysis and reactor modeling, is proposed to derive heterogeneous kinetics and to estimate the different sources of uncertainties. A proper treatment of the cloud of reacting solid particles was found to be fundamental for the determination of kinetics.