The naphthalene plant processes the raw material, Refined Chemical Oil (“RCO”, refined coal-tar distillate also called coal tar oil) from an existing tar plant, through the following sections. 1. Feed Treatment - Acid Wash. The tar acid extraction process is used to remove phenols, cresols and xylenols from refined chemical oil (RCO). In addition, the process will remove chlorides from the feed, reducing corrosion in the distillation section. 2. Naphthalene Distillation 2.1 Dehydration. The acid free oil (“AFO”) is water saturated by its processing in the wash column. This water is removed in a dehydrator column. 2.2 Overhead Stream Removal. The Solvent Column removes the remaining components lighter than naphthalene as an overhead stream. The bottoms stream becomes the feed to the Naphthalene Column. 2.3 Naphthalene Separation. The Naphthalene Column separates out the naphthalene product, which is primarily naphthalene with a small amount of thionaphthene (benzothiophene), as the overhead stream. The heavier components leave as the bottoms stream Naphthalene Still Residue (NSR). A methylnaphthalene side stream consisting of primarily 1 and 2-methylnaphthalene with some residual naphthalene is also taken out on an as needed basis from a vapor side draw near the bottom of the column.