In the current paper the dynamic behaviour of an industrial heterogeneous catalytic packed-bed reactor for the steam reforming of methane is examined. The model consists of a set of partial differential equations describing the physico-chemical processes that take place both in solid and gas phases accounting for diffusional limitations within the catalyst particles. The model was validated against literature data, while the heat provided to the reactor wall was optimised in terms of the optimal H2 yield using a quadratic wall temperature profile. The values of the physico-chemical properties were adjusted to the severe operating conditions (high pressures and temperatures) of the reactor accounting for multicomponent gas mixture properties. It is shown that the 2-phase reactor concept along with the optimised wall temperature profile capture very well the dynamic conversion, the temperature and the partial pressure profiles both at bed and at particle level.