Retrofit of heat exchanger networks by graphical Pinch Analysis - A case study of a crude oil refinery in Kuwait

Energy integration of the existing chemical and petrochemical facilities is regarded as a keystone for sustainable energy systems. It is widely known that a considerable number of the petrochemical industries are not applying efficient heat exchanger network (HEN) systems to minimise the use of external utilities. In the present study, a Pinch Analysis-based graphical approach is used to retrofit an existing HEN for optimising a crude oil distillation operation. The existing HEN is represented using Thot-Tcold diagram, where the cold stream temperatures are plotted on the x-axis and the hot stream temperatures are plotted on the y-axis, for each exchanger unit. The graphical approach is applied to a real case study of a petroleum refinery plant located in Kuwait with the objective of performing energy analysis and retrofitting the existing HEN. Retrofit modifications are extracted from the graphical representation to enable scenarios for energy and emission reduction. The application of the proposed approach resulted in substantial energy savings of about 10.4 MW compared to the current operation, leading to annual operating cost savings of about MM$2 and less than one-year payback time. Overall, this study provides tools to address the energy traits in crude preheat trains of industrial feature, which can improve the overall economic-environmental sustainability of existing refineries.