Experimental investigation and modeling of mass transport properties of O2 in biomass chars

•Extension of the pore-structure dependent kinetic adsorption (PSK) model for O2.•Adsorption kinetics of O2 on two biomass chars from 298 to 373 K and 0.26 to 300 kPa.•Modeling O2 adsorption kinetics on biomass chars based on experimental results.•Extrapolation of mass transfer properties discussed for temperatures up to 1100 K. This study presents two sets of kinetic adsorption data for O2 on two different biomass chars at temperatures from (298 to 373) K and pressures from (26 to 300) kPa. Thereon, incorporating data of 21 adsorption kinetic curves on a hydrochar and 24 adsorption kinetic curves on a torrefied beechwood char, a parameterization of the pore-structure dependent kinetic adsorption (PSK) model is obtained for the two investigated chars. Extensive possibilities to predict time- and pore-structure-resolved mass transport properties using the PSK model are discussed. The mass transfer coefficient and the adsorption flow rate are direct outcomes and derivatives of the PSK model and hold for a physically sound description of the time-resolved mass transport of gaseous species in the porous structure of particles. The physical and extrapolative behavior of the modeled mass transfer coefficients and adsorption flow rates are discussed for temperatures up to 1100 K, allowing for new insights into the mass transfer.