Investigation of Heat Exchanger Network Flexibility of Distillation Unit for Processing Different Types of Crude Oil

This paper summarizes the results of a study aimed to investigate the effect of the type of crude oil on the design of heat exchanger network of an atmospheric/vacuum distillation unit with maximum heat recovery, and to form a flexible heat exchanger network that is capable for processing all of the selected crude oils. Three different types (light - Crude A, medium - Crude B, heavy - Crude C) of crude oil were selected. Results showed that the heat recovery was the lowest (68.66 MW) and the external heat requirement was the highest (101.58 MW) in case of Crude A comparing to the other crude oils being investigated. It means that the processing of light crude oil is less energy efficient relative to medium and heavy ones. On the contrary the calculated heat exchanger area was the highest in Crude C (12,165 m(2)). This crude oil contained the high boiling fractions of low overall heat transfer coefficient in relatively large amount increasing the required heat transfer area. Heat exchanger network that is applicable for processing each selected crude oil with maximum heat recovery also formed. Results showed that only 4 additional heat exchanger units is required to form a network that can be used in a flexible way for processing all of the selected crude oils. The total heat exchanger area of the flexible heat exchanger network is 15,238 m(2), which is higher than the value obtained for each selected crude oil separately. Economic viability of the flexible heat exchanger network should be calculated considering the investment and operating costs as well as the amount of the different types of crude oil to be processed annually.