Pinch analysis of crude distillation unit using the HINT software and comparison with nonlinear programming technique

Abstract

The effectiveness of HINT is first verified by the application to a case study investigated for minimum area target, and then applied to a crude distillation unit (CDU) after obtaining a satisfactory solution which was within 1 percent when compared with existing solution for minimum area target. The HINT package accomplished the maximum heat recovery between the hot streams and the cold streams and later identified the utility required for the heat balance in the heat exchanger networks (HENs). Pinch analysis of the CDU plant showed that both hot and cold utilities are still needed after the maximum energy recovery between all the hot streams and all the cold streams present in the HENs synthesized. The total hot utility required was found to be 4.99 x 108 kJ/hr while that of cold utility was 5.08 x 108 kJ/hr. The ∆Tmin that gives the minimum total annual cost was found to be 2.95K and the corresponding total annualized cost was $4.88 million/yr. The findings also revealed that HINT is capable of returning solutions that are comparable with those of mathematical based techniques such as the nonlinear programming (NLP) technique used as a basis for comparison.