(165b) Heat Integration in a Crude Distillation Unit Using Pinch Analysis Concepts

It is widely known that crude distillation unit is an energy-intensive process. A new design or a retrofit of a crude distillation unit has to deal simultaneously with heat recovery and fractionation requirements. In recent years, researchers have been studying the heat integration concerning the location and duty of the pumparound sections. There is a trade-off on how much heat that can be recovered from a given section and the internal liquid reflux flow at the sections above, in order to meet the required fractionation, and also the influence on the overall cost, including the heat exchanger network (HEN).

The column and the HEN interaction must be calculated and evaluated at the same time to achieve the most cost-effective design for a given crude and products quality based on pinch analysis. Pinch analysis presents the minimum cost, considering cold and hot utilities duties and capital costs.

The purpose of this work is to present a design procedure to achieve the maximum heat recoverable in a section and at the same time meeting the required fractionation, based on the evaluation of the influence of the hot streams distribution below and above the pinch location. Moreover, it is possible to increase refinery margins by changing the pinch temperature through process modifications.

Some case studies will be presented highlighting the advantages of the proposed methodology providing savings in overall costs.