The Crude Oil Distillation Unit (CDU) plays a central role in petroleum refining. Building a new
CDU is very expensive, so several retrofit projects must be considered on existing CDU facilities to
increase production capacity and reduce energy consumption. The application of a pre-flash drum
system to CDU in recent years has had a good effect on raising the performance of CDU, especially
when dealing with light crude oil. In this paper, the existing CDU has been retrofitted to raise the
performance of the unit, especially when dealing with light crude oil. The retrofit is based on the
implementation of a pre-flash drum and pump after the crude oil heat exchanger network and just
before the furnace. In addition, the present work determines the optimal pressure of the pre-flash
drum and the optimal input tray of pre-flash vapors into the CDU. The choice of optimal values
depends on the minimum power consumption of the CDU and the maximum obtained products.
HYSYS simulation software version 11 was used. The results showed a reduction in CDU operating
cost of 7.49% at the optimal pre-flash pressure and optimal input tray for pre-flashed vapors. The
presented study can be used as a guide in retrofitting existing heavy crude oil units and units under
design.
