Effectiveness factor correlations for spherical nickel catalyst pellets used in small-scale steam methane reformers

•Effectiveness factors of catalyst pellets for steam methane reforming are calculated.•Operating conditions relevant to small-scale steam methane reformers are considered.•A simple method is proposed to accurately retrieve the calculated effectiveness data.•The method is validated for various reforming conditions and geometrical parameters.

A simple method is devised for determining the effectiveness factors of spherical nickel catalyst pellets used for steam methane reforming (SMR) processes; specifically, the factors are determined for reforming conditions relevant to small-scale hydrogen production systems (1–3 bar pressure, 600–800 °C temperature, 2–4 steam/carbon ratio). The effectiveness factors are plotted with respect to a newly proposed effective Thiele modulus that considers the mass transfer limitation near the equilibrium methane conversion. Then, a modified Thiele modulus is introduced to make the effectiveness factors for various reforming conditions and structural parameters fall on a single correlation curve. The results indicate that the proposed method can properly describe the effectiveness factors of nickel catalyst pellets for the SMR conditions considered in this study.