Write a blog post that reviews the utility of different distillation methods and their applications in petroleum refining.

There are three common different distillation methods. These methods are very important because they allow us the opportunity to obtain a better perspective of crude oil. Using these methods crude oil can be distilled into different oils which have varying characteristics. Each method is a different level of separation. These three methods are:

True Boiling Point Distillation (TBP): In this batch distillation method only one distillation occurs based upon boiling point. This method allows for the most efficient separation. It uses a large number of stages for liquid to vapor contact in the distillation column with a very high reflux ratio while raising the temperature. When a certain boiling point is hit that only applies to a specific portion of the crude, that specific portion will begin to evaporate. Once the portion of the crude with this boiling point changes phases through vaporization it can then be extracted, thus in total now having two different oils. This form of distillation has no standard test methods.

ASTM Distillation: This method is also a batch operation but it does not use contact plates and has a reflux ratio of zero. This method uses a heater and cooling water and instead of distilling after hitting one certain temperature it gradually distills over time. It has much more of an exponential distillation curve for a binary mixture where for TBP distillation it was completely linear with one jump in the graph. This is the standard test method used for refinery products to determine property calculations and correlations.

Equilibrium Flash Vaporization (EFV): This distillation method uses a heater to heat up the liquid and then a flash drum to separate the liquid and vapor phases. This provides data that is useful for determining proper flashing operations in a refinery. By looking at the distillation curve for this method it can be noted that this gives the lowest degree of separation.

The boiling point reached for separation to occur decreases from TBP to ASTM to EFV. The degree of separation also decreases for the same order. Each distillation method is very important and has its own application in petroleum refining.