Design retrofit targets of pump-around refluxes for better energy integration of a crude distillation column

Crude oil distillation is a highly energy-intensive process and represents one of the most important areas for energy integration in a refinery. Curre nt practice recovers "useful energy" by pump-around refluxes in type A colu mns for the preheating of crude oil in heat exchanger trains; however, ener gy-recovery "targets" are not well-defined or known a priori. This work pre sents a simple methodology for developing invariant" column grand composite curves (CGCCs) for type U and type A columns using the well-established pr inciples of "pinch analysis" and the refining-industry accepted Packie's me thod for designing/rating crude columns. The CGCCs for type U and type A co lumns set the "thermodynamic" and "practical" heat-recovery targets, respec tively. Since the CGCCs developed in this work are invariant with respect t o pump-around reflux and depend only on the feed and product rates and spec ifications at given conditions of temperature and pressure, they set "reflu x-energy-recovery" targets for either designing a "new" crude column or ret rofitting an existing column. The application of this methodology is illust rated by means of a "case study".