Advancements in distillation plays a key role in enhancing & debottlenecking existing units in a refinery. DWC’scan boost the octane of isomerization units by 2-4 points. An isomerization process converts low octane straight chain hydrocarbons to high octane branched chain isomers. Since the isomerization reactions are in equilibrium, the product octane is defined by the number of separation units in the process. A typical light naphtha isomerization unit with a deisohexanizer (DIH) column can produce an isomerate product of RON 87-88. For further increase in RON additional deisopentanizer (DIP) and depentanizer (DP) columns are required. Dividing wall column retrofits in existing DIH column and provides it with an additional functionality of a DIP or a DP column.