A model reduction method applied to the dynamic model of a single isothermal catalyst pellet with simultaneous chemical reaction, diffusion and adsorption is presented. The model of the pellet accounts for both internal and external resistances to mass transfer, and variable bulk gas concentration. The reduction of the model was performed by means of proper orthogonal decomposition (POD). Accuracy and computational efficiency of the reduced order model (ROM) were discussed for two kinetic models, i.e. a first order chemical kinetics and a Langmuir-Hinshelwood kinetics. To improve the computational efficiency of the model described by the Langmuir-Hinshelwood equation, the non-linear terms were approximated by a discrete empirical interpolation method (DEIM). High accuracy and efficiency of the proposed reduction approach was demonstrated. (C) 2016 Elsevier Ltd. All rights reserved.