The work is devoted to experimental studies and construction of a mathematical model of n-hexadecane (as the simplest diesel surrogate) reforming over Rh/Ce0.75Zr0.25O2-δ-ƞ-Al2O3/FeCrAl wire mesh honeycomb catalytic module in auto-thermal reforming (ATR) and steam reforming (SR) modes. Experiments were performed using the scalable catalytic modules with recurrent meshy channeled internal geometrical structure. This provided the accurate reproduction of mass transfer limitations and accompanying homogeneous reactions, thus significantly simplifying the following scale-up procedures. Impossibility to apply simple isothermal reactor models was compensated by application of CFD modelling for reproduction of internal distribution of temperature, fluid velocities and composition inside the catalyst module. The earlier proposed reaction scheme was supported by additional reactions to account for the formation of light C2-C5 hydrocarbons. The proposed model provides good description of both ATR and SR process modes, at the same time demonstrating significant difference between them. The proposed model may be used for development, scale-up and optimization of catalytic reformers using SR and ATR modes and their combination for processing diesel and similar liquid hydrocarbon fuels.