SOLVENT EXTRACTION AND DEWAXING

The figure provided here illustrates a block diagram for an aromatics extraction system.

Solvent treating is a widely used method of refining lubricating oils as well as a host of other refinery stocks.

Since distillation (fractionation) separates petroleum products into groups only by their boiling-point ranges, impurities may remain. These include organic compounds containing sulfur, nitrogen, and oxygen; inorganic salts and dissolved metals; and soluble salts that were present in the crude feedstock. In addition, kerosene and distillates may have trace amounts of aromatics and naphthenes. Lubricating oil base-stocks may contain wax as an undesirable impurity.

There are many types extraction processes. In some cases, solvent refining processes including solvent extraction and solvent dewaxing remove these undesirables just before sending the product to storage.