A new method is proposed for systematic generation of conceptual design of reactor networks. Here, non-isothermal conditions are considered. Optimal distribution of heat transfer area, in addition to optimal mixing and distribution of feeds are targeted. Given temperature and composition of feed streams, the objective is to find the sequence and size of ideal reactors, the distribution of extra feed streams, the heat transfer distribution along the reactor path and the total reaction time that maximizes the space-time yield of the key product component. The method can be applied to solve problems of any number of components and reactions. The method is applied to industrially important processes such as the methanol synthesis and the steam methane reforming process. Interesting results are obtained with respect to the required heat exchange area. (c) 2004 Elsevier Ltd. All rights reserved.