One of the main shortcomings of existing multifunctional reactor concepts for the autothermal coupling of endothermic and exothermic reactions is inefficient heat integration leading to excessive maximum temperatures or poor reactor performance. For the asymmetric operation of a reverse-flow steam reforming reactor, conditions under which these shortcomings can be overcome are proposed. The asymmetric process is based on the formation of travelling reaction zones. The features of these transient phenomena are analysed by means of a simplified model. During the endothermic semicycle, the heat consumption forms a temperature wave with ark expansive low-temperature and a compressive high-temperature part. During the exothermic semicycle a proper axial distribution of the beat supply is necessary in order to maintain a favourable temperature profile in the cyclic operation mode. The results obtained with the simplified model are verified by direct dynamic simulation. (C) 2003 Elsevier Science Ltd. All rights reserved.