Coupling reaction and separation in a membrane reactor improves the reactor efficiency and reduces purification cost in the following stages. This paper focuses on modeling and optimization of methanol production in a dual-membrane reactor. In this configuration, conventional methanol reactor is supported by Pd/Ag membrane tubes for hydrogen permeation and alumina-silica composite membrane tubes for water vapor removal from the reaction zone. A steady state heterogeneous one-dimensional mathematical model is developed to predict the performance of this novel configuration. In order to verify the accuracy of the model, simulation results of the conventional reactor is compared with available industrial plant data. The main advantages of the optimized dual-membrane reactor are: higher CO(2) conversion, the possibility of overcoming the limitation imposed by thermodynamic equilibrium, improvement of the methanol production rate and its purity. Genetic algorithm as an exceptionally simple evolution strategy is employed to maximize the methanol production as the objective function. This configuration has enhanced methanol production rate by 13.2% compared to industrial methanol synthesis reactor. (C) 2011 Elsevier B.V. All rights reserved.