In this study, a dynamic model for a membrane dual-type methanol reactor was developed in the presence of long term catalyst deactivation. The proposed model is used to compare the performance of a membrane dual-type methanol reactor with a conventional dual-type methanol reactor. A conventional dual-type methanol reactor is a shell and tube heat exchanger reactor in which the first reactor is cooled with cooling water and the second one is cooled with synthesis gas. In a membrane dual-type reactor, the wall of the tubes in the gas-cooled conventional reactor is covered with a palladium-silver membrane, which is only permeable to hydrogen. Hydrogen can penetrate from the feed synthesis gas side into the reaction side due to the hydrogen partial pressure driving force. Hydrogen permeation through the membrane shifts the reaction towards the product side according to the thermodynamic equilibrium. The proposed dynamic model was validated against measured daily process data of a methanol plant recorded for a period of four years and a good agreement was achieved. The simulation results show that there is a favorable profile of temperature and activity of the membrane dual-type reactor relative to single and conventional dual-type reactor systems. Therefore, the performance of methanol reactor systems improves when a membrane is used in a conventional dual-type methanol reactor.