The Master’s thesis by researcher Mahmoud Karim Ahmed—conducted at the Department of Chemical Engineering, College of Engineering, University of Basrah, under the supervision of Dr. Abdul-Wahid Abdul-Hassan Kadhim—was defended. The thesis is titled... SIMULATION AND OPTIMIZATION OF HEATEXCHANGER NETWORKS IN THE PETROLEUM REFINING INDUSTRY
Heat exchanger networks (HENs) are central to reducing energy consumption in crude oil distillation units by maximizing process-to-process heat recovery. However, many existing refinery networks perform sub-optimally because they retain configurations inherited from the original plant design, which makes retrofit an attractive route to better energy use with limited structural change.
This study investigates the thermal performance and retrofit of the crude oil preheat train of the Crude Distillation Unit (CDU-4) at Basrah Refinery, South Refineries Company. A model of the as-built network was developed in Aspen HYSYS V14 and validated against refinery operating data, then transferred to Aspen Energy Analyzer, where composite curves were used to assess it and pinch technology principles to develop retrofit options. Four strategies were examined, each with six scenarios (24 in total): relocation of one end of a heat exchanger, relocation of both ends, addition of a new heat exchanger, and enlargement of the heat transfer area of existing exchangers.
All scenarios raised the crude oil temperature at the furnace inlet by 4.1 to 26.9 °C relative to the as-built case and reduced fired heater duty by 3.3–27.1% relative to the simulated baseline. Cooling water duty fell by 9.5–47.0% and air cooler duty by up to 42.7%, while total network heat duty rose by up to 11.0%, indicating greater internal heat recovery. The best scenario of each strategy gave comparable results, with crude temperature gains of about 25–27 °C and fired heater reductions of about 26–27%. Relocation-based options achieved comparable savings without installing new exchangers.
The study shows that systematic retrofit using Aspen HYSYS and Aspen Energy Analyzer is a scientific and practical approach to improving refinery energy efficiency, and provides a basis for subsequent techno-economic evaluation of the proposed retrofits.