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Petroleum Processing

Summary and Final Tasks



Distillation, a key separation process in petroleum refining, is considered as a gateway to all refinery processes. Fractionation of crude oil by distillation into a number of streams generates feedstocks for all the subsequent separation, conversion, and finishing processes that lead to the refinery

products. Prior to distillation, crude oil is subjected to desalting to remove in particular the Cl¯ion to prevent corrosion in downstream processes. Both atmospheric and vacuum distillation processes are used to separate the desired fractions from crude oil which has a boiling range of over a 1000° F. Three different distillation methods used in laboratory include True Boiling Point distillation, used for characterization of crude oils, ASTM distillation for product characterization, and Equilibrium Flash Vaporization for conducting efficient flash operations in the refinery. The performance of an atmospheric distillation column can be monitored through using the ASTM distillation data obtained for the distillate products. The three parameters that control the performance of a distillation column in terms of the quality of separation achieved in the process are number of plates, reflux ratio, and the amount of steam used in the operations. Empirical correlation relates these three factors to control the quality of separation in an operating distillation column or help design a new distillation column.

Learning Outcomes

You should now be able to:

  • compare and evaluate different distillation methods;
  • define boiling point ranges (TBP) of distillation fractions of crude oil;
  • identify and exemplify distillation terminology, including cut points and product yields in distillation ranges;
  • illustrate the crude fractionation in Atmospheric Distillation and calculate the extent of separation between the distillation fractions;
  • analyze the vapor-liquid equilibrium and evaluate the application of Fenske Equation to distillation in Light Ends Unit;
  • illustrate Vacuum Distillation and assess the application of Watson Characterization Factor to select the temperature in Vacuum Distillation Tower.

Reminder - Complete all of the Lesson 4 tasks!

You have reached the end of Lesson 4! Double-check the to-do list below to make sure you have completed all of the activities listed there before you begin Lesson 5. Please refer to the Course Syllabus for specific time frames and due dates. Specific directions for the assignments below can be found within this lesson.

Lesson 4 tasks
Reading J. H. Gary and G. E. Handwerk, Chapter 4 (Crude Distillation)
Assignments Exercise 3: Submit your answers to the Exercise 3 assignment in the Lesson 4 Module.
Quiz 2: Will cover the material in Lessons 3 and 4.


If you have any questions, please post them to our Help Discussion (not email), located in Canvas. I will check that discussion forum daily to respond. While you are there, feel free to post your own responses if you, too, are able to help out a classmate.