Abstract The goal of this study is the simultaneous production of synthesis gas, hydrogen and propylene in a thermally double coupled steam reformer reactor. This reactor has three concentric tubes where the exothermic reaction of methane oxidation is supposed to occur in the middle tube and the inner and outer tubes are considered to be endothermic sides of steam reforming and propane dehydrogenation, respectively. The motivation is to combine the energy efficient concept of coupling one exothermic reaction with two endothermic reactions, enhancement of synthesis gas production, propylene and hydrogen production and also producing two different H2/CO ratio streams of syngas. A steady state homogeneous model of fixed bed for three sides predicts the performance of this new configuration. The simulation results are compared with corresponding predictions of the conventional steam reformer. The results prove that synthesis gas production is increased in a thermally double coupled reactor in comparison with conventional steam reforming. In addition, the thermally double coupled reactor reduces the capital and operating costs by reducing the reactor size and consumption of energy.