The Crude Distillation Unit (CDU) is among the major CO2 emitters in any petroleum refinery. In view of
the simultaneous increase in the energy cost and environmental concerns, there is strong motivation to
analyse alternative methods to improve the energy efficiency and consequently, to minimize CO2
emissions from conventional crude distillation. Crude pre-flashing is among promising techniques for
minimizing the heating energy requirements of the CDU. However, this might be at the cost of product
yield and/or throughput. This paper investigates the effects of using different pre-flash designs on the
energy efficiency and associated CO2 emissions of the CDU. The resulting optimal solutions are presented
and their significant features are discussed.