Effect of reference state on exergy efficiencies of one- and two-stage crude oil distillation plants

In this paper we deal with the effects of varying reference temperature on the exergy efficiencies of one- and two-stage crude oil distillation units. Such units essentially consist of the crude oil heating furnace, the distillation column and a network of heat exchangers. Since the exergy efficiency is a key parameter to see how well the system is performing, we undertake a study on the influence of the reference temperature on such efficiencies. In this regard, a commercial software package, SimSci/PRO II program is used for the calculations. The results show that increasing reference temperature decreases the exergy efficiency in both one- and two-stage crude oil distillation systems and also increases the difference between the exergy efficiencies of both systems. Therefore, the exergy losses increase in the crude oil distillation systems.