This paper presents a novel thermodynamic analysis tool, the energy-flow framework diagram (EFD), and proposes a new method called the EFD graphic analysis method. It is a visual method of energy analysis and integration and is fairly convenient to analyze variety of complicated information, with the aim at bring forward a creative energy-saving system. It is proved that the new method is effective and useful through an application study on a 560 kt/a methanol synthesis process by means of the EFD and the revelatory criteria. (C) 2004 Elsevier Ltd. All rights reserved.