Optimal reaction concept and plant wide optimization of the ethylene oxide process Andreas Peschel a , Andreas Jörke b , Kai Sundmacher a,b , Hannsjörg Freund a,c,⇑ a Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstr. 1, 39106 Magdeburg, Germany b Process Systems Engineering, Otto-von-Guericke University Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany c Chemical Reaction Engineering, Friedrich-Alexander-University Erlangen-Nuremberg, Egerlandstr. 3, 91058 Erlangen, Germany highlights " Model-based method to determine best reaction concept within the overall process. " Includes process intensification aspects to yield innovative and superior reactors. " Detailed model of reaction system including rigorous model of the explosion limits. " Full process model including EO absorption, chemisorption of CO 2 , and utilities. " Reduction of production costs (2.2%), recycle stream (47%), and CO 2 emissions (8%). article info Article history: Available online 1 August 2012 Keywords: Chemical reactors Novel reactor technologies Process intensification Elementary process functions Optimization Design Ethylene oxide abstract In this paper, a new method for the identification of the best reaction concept from an overall process point of view is proposed. Using this method the optimal reaction route is determined independent of existing apparatuses and the recycle affecting the reactor is fully considered. The reaction concept and the design parameters of the process are simultaneously optimized. For this purpose, a detailed model of the reaction system including reaction kinetics, thermodynamic relationships, and intrinsic boundaries such as explosion limits as well as a complete model of the downstream process is set up. The potential of different reaction concepts including innovative process intensification alternatives can easily be deter- mined by comparison with an optimized reference case. The example considered in this paper is the oxygen based ethylene oxide process, which is one of the most important chemical bulk processes. Sophisticated cooling in combination with distributed oxygen dosing along the reactor length is identified as best technical reaction concept with a potential of reduc- ing the operating costs of an average sized plant by 1.35 Mio $/a compared to an optimized reference case. In addition, the utility consumption is reduced, especially the consumption of electricity is decreased by 46.3%, and the overall CO 2 emissions are cut by 8%. In conclusion, the proposed method enables the predictive determination of the best reaction concept from an overall process point of view taking the full interconnections between the reaction concept and the process into account and considering highly innovative process intensification options. Thereby, this method provides a key stone for the development of more economical and more sustainable chemical reactors and processes of the future. Ó 2012 Published by Elsevier B.V. 1. Introduction 1.1. Scope of the method and state-of-the-art in process design In this paper, a new method for the identification of the best reaction concept under consideration of the overall process requirements is proposed. This method includes innovative pro- cess intensification options for the reaction concept and allows to design highly innovative, tailor-made reactors which enhance the overall process performance. In the past, sequential and simultaneous process synthesis methods such as the process design hierarchy of Douglas [1], the onion model of a process of Smith and Linnhoff [2], and the super- structure modeling approach were developed. Beside the success- ful application of these methods to many examples, a method is missing which enables the derivation of optimal and innovative reaction concepts within the overall process. 1385-8947/$ - see front matter Ó 2012 Published by Elsevier B.V. http://dx.doi.org/10.1016/j.cej.2012.07.029 ⇑ Corresponding author at: Chemical Reaction Engineering, Friedrich-Alexander- University Erlangen-Nuremberg, Egerlandstr. 3, 91058 Erlangen, Germany. Tel.: +49 9131 8527424; fax: +49 9131 8527421. E-mail address: hannsjoerg.freund@crt.cbi.uni-erlangen.de (H. Freund). Chemical Engineering Journal 207–208 (2012) 656–674 Contents lists available at SciVerse ScienceDirect Chemical Engineering Journal journal homepage: www.elsevier.com/locate/cej