Distillation in Process Application

Distillation is a process of separation components in a mixture using boiling and condensation. Distillation is applicable to many industries; it is the most effective way to separate molecules in different boiling ranges. In the industrial application the distillation is commonly known as fractionation.

A simple distillation has a minimum of a reboiler in which the source material is heated, a condenser in which the heated vapor is cooled back to the liquid state, and a receiver in which the concentrated or purified liquid, called the distillate, is collected.

Some of a key variable in operating a distillation column are:

• Feed rate
• Feed condition
• Inlet location
• Operation condition
• Temperature
  • T_r
  • T_c
• Pressure
  • P_r
  • P_c
• Reflux ratio Rr
• Boil up ratio
• Feed/ OVGD

A Case study:

A customer who is fractioning to make jet fuel using a vacuum distillation is having issues to keep their product on spec. The specs are specific to jet fuel product. Specs such as: BP, SG and Flash point.

The customer is consistently getting high flash point on the product. Too much light material appear in their final product.

After a thorough investigation, field data was matched with the simulation.

In conclusion, a set of operating parameters were provided to the client to optimize the column’s operation. The solution also included discarding small amount of light material (less than 1%) to either recycle it back to the feed, or dispose of it into the flare.

Distillation operation can be changed by changing any of the key variables. Distillation can be modeled in a process simulation for troubleshooting and optimization.

References:

Refining crude oil - the refining process - U.S. Energy Information Administration (EIA)

Distillation - Wikipedia