In this work, a comparative analysis of attainable performance is presented for three different reactor structures including a fixed-bed reactor, and two different feeding structures of packed bed membrane reactors. For this purpose, three types of kinetic models, namely La2O3/CaO, Mn/Na2WO4/SiO2, and PbO/Al2O3 have been used under a wide range of operating conditions. Thus, the effect of several variables such as operating temperature, membrane thickness, methane-to-oxygen ratio, feed flow rate, gas streams composition, and reactor length are investigated. Moreover, kinetic-analysis based on a proposed graphical approach enables determination of the suitable operational condition range and allows analysis of the feasible and optimal performance that corresponds to the effect of several dependent operating variables. The results show that tracking the optimum area of operation has a monotonic direction under some range of operating conditions, while it reflects qualitative trade-offs under some other ranges of operating conditions. For all investigated reactor concepts and catalysts, optimal operating conditions and the best corresponding performance are presented. (C) 2010 Elsevier Ltd. All rights reserved.