Application of multi-stream heat exchangers in heat recovery networks has a lot of advantages as low initial and operation costs, high thermal performance, low volume and weight. However, the main question arises encountering a real problem is: How many multi-stream plate fin heat exchangers are required for a specific process unit? Current work presents the financial drawbacks and thermal malfunction of the exchanger that may be appeared as a consequence of using a single heat exchanger in the process units consisted of several gaseous and liquid streams. Based on the design method, process limitations and physical properties, a new method of process decomposition will be introduced. In order to minimize the financial drawbacks due to increase of external utilities as a consequence of stream zoning, new stream zonal transfer will be presented. The applicability of the method is demonstrated on a case study. (c) 2007 Elsevier B.V. All rights reserved.