Dry reforming of methane (DRM) over nickel in a fixed-bed reactor of spheres was studied experimentally and with CFD simulations. Temperature and mole fraction profiles were measured in a dedicated profile reactor as function of axial coordinate. Particle-resolved CFD simulations took into account conjugate heat transfer, surface-to-surface radiation, and surface reactions described by microkinetics. Energy transport of CFD simulations were verified by studying heat transfer without chemical reactions. DRM experiments could not be reproduced with the original microkinetics formulation, even with the axial temperature profile applied. A detailed analysis of the microkinetics showed that thermodynamic inconsistencies are present, which are amplified by high surface coverage of CO*. After modifying the mechanism the experiments could be reproduced. This study shows how complex interactions between local transport phenomena and local kinetics can be quantified without relying on transport correlations. (c) 2016 American Institute of Chemical Engineers AIChE J, 62: 4436-4452, 2016