Methane reforming is the most important and economical process for hydrogen and syngas generation. In this work, the dynamic simulation of methane steam reforming in an industrial membrane reformer for synthesis gas production is developed. A novel deactivation model for commercial Ni-based catalysts is proposed and the monthly collected data from an existing reformer in a domestic methanol plant is used to optimize the model parameters. The plant data is also employed to check the model accuracy. It was observed that the membrane reformer could compensate for the catalyst deactivating effect. In order to assure the long membrane lifetime and decrease the unit price, the membrane reformer with 5 mu m thick Pd on stainless steel supports is modeled at the temperature below the maximum operating temperature of Pd based membranes (around 600 degrees C). The dynamic modeling showed that the methane conversion of 76% could be achieved at a moderate temperature of 600 degrees C for an industrial membrane reformer. The cost-effective generation of syngas with an appropriate H-2/CO ratio of 2.6 could be obtained by membrane reformer. This is while the conventional reformer exhibits a maximum conversation of 64 at 1200 degrees C challenging due to its high syngas ratio (3.7). On the other hand, the pure hydrogen from membrane reformer can supply part of the ammonia reactor feed in an adjacent ammonia plant. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.