(28f) Aromatics Extraction in a Single Column to Meet the Demands for Aromatics Production and Benzene Reduction in the Gasoline Pool

UOP licenses process technology to the refining, gas processing, and petrochemical industries. For over 40 years liquid-liquid extraction, followed by extractive distillation and solvent recovery, has been the preferred method for extraction of aromatics from reformate and pygas streams. In recent years, the refining and petrochemicals industries have embraced extractive distillation alone, followed by solvent recovery, as a way to reduce investment cost. UOP has developed several flowschemes that make use a single column, the ED Stripper, to accomplish the functions formerly performed in the Raindeck Extractor, Raffinate Water Wash and Stripper Columns:

o Separation of aromatics from non-aromatics (Extraction Zone)

o Removal of solvent from the non-aromatics product stream (Rectification Zone)

o Stripping of non-aromatics from aromatics (Stripping Zone)

For some feedstocks, this flow-scheme offers significant savings in capital costs, energy costs, or both. Where applicable, there is also a reduction in plot space requirements and reduced solvent inventory. Two examples of this technology came on-stream in 2006 and two more are expected on-stream by the end of 1Q2007. Examples will be shown to indicate how process considerations influence the design of this column.