A novel approach for computing washcoat diffusional effects in reduced order models of monolith reactors

•A novel domain-decomposition based method is presented for monolith reactors.•The method can speed-up the simulation of monolith reactors by orders of magnitude.•The method is accurate for nonlinear kinetics and multi-component systems.•Examples are provided to illustrate the utility of the proposed method.•The method is well suited for real-time simulation, control and optimization.