Process retrofitting is one of the most common and complex activities in the chemical industry. Retrofit projects target overcoming process bottlenecks, yet many of them such as heat and mass transfer or reaction equilibrium limitations cannot be tackled within classical chemical engineering approaches. Hence, we need process intensification (PI) technologies to drastically improve chemical production processes and to overcome the most difficult process bottlenecks. However, the number of successful PI implementations in industry is limited. One of the reasons for this reluctance is the lack of suitable retrofitting methodologies enabling both identifying the most promising PI option for a given process bottleneck and evaluating possible improvements through the implementation of this technology. This paper presents an approach that builds on process analysis, bottleneck identification and selection of the most promising PI options from a broad database of PI technologies. These options are identified by considering the technological and process constraints and applying various shortcut methods to quickly quantify possible process improvements. Finally, the most suitable equipment for the improvement of a given bottleneck is integrated in the process flowsheet. This methodology is illustrated using ethylene oxide production as a case study. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.