(6d) Guidelines for BTX Distillation Revamps

There are many reasons to revamp a process unit. These include increased purities, increased recoveries, decreased environmental impacts and increased capacity. The best revamps will include each of the listed items.

With the current environmental mandates to reduce the benzene in the gasoline pool, the production of benzene for use in other products is increasing. In the United States the benzene in the gasoline pool is regulated to very low levels, whereas in other parts of the world the standard is 1.0 weight percent. As this world standard is lowered this benzene will need to be purified for downstream reprocessing.

Currently many of the benzene separation units are utilizing liquid / liquid extraction which can be revamped to extractive distillation for increased purities, increased recoveries, decreased environmental impacts and increased capacity. The authors will examine the choices for revamping benzene distillation, review a case study of an April 2006 revamped liquid / liquid extraction to extractive distillation, and guidelines for future revamps.