Structural targeting for heat integration retrofit

Abstract A new targeting method for the retrofit of heat exchangers networks is presented. It combines existing targeting and design methods for retrofit with the concept of zoning used in grassroots design. The structural targeting retrofit method gives targets not only for the utility saving and exchanger area investment, but also for the extent and locations of the required modifications. This targeting requires a special way of zoning based on the existing network. This zoning is extensively discussed. Practical aspects like functionality, lay-out and operability can be taken into account. Two case studies are presented: a simplified aromatics and a real C3/C4 separation case. Both cases illustrate that structural targeting is an effective method to identify parts of the original network with a high saving to investment potential. The method favours simple adaptations and is especially effective for large networks. The C3/C4-case also shows how structural targeting provides a number of alternatives, many of which are independent of each other, to adapt the existing network. The retrofit design effort is significantly reduced compared to existing methods.