(53b) Optimize Gasoline Block Using Dividing Wall Column Technology

Gasoline Block in refinery processes full range naphtha (C5 to C12 carbon atoms) to useful fractions. These fractions are primarily used for gasoline blending or as feedstock to petrochemical complexes.

For gasoline blending, improvement in RON is of prime importance. A Naphtha splitter splits full range naphtha (FRN) into light naphtha (C5/C6) and heavy naphtha (C7+). Increase in RON for light Naphtha (C5/C6) is made possible by converting straight chain paraffins into their branched chain isomers through the process of isomerization. Heavy Naphtha (C7+) RON is improved through the process of catalytic reforming. Heavy Naphtha (C8+) can also be used as feedstock to paraxylene complex (PX).

Naphtha splitter pays a pivotal role in feed preparation to Isom, CCR and PX Complexes. Dividing wall column technology (DWC) is increasingly used to debottleneck conventional distillation columns. Besides energy and throughput increase, DWC revamp of naphtha splitters significantly improve the performance of downstream units. This presentation explores four case studies in revamp of gasoline block:

• Revamp of a sequence of naphtha splitters to DWC preparing feed for Isom and CCR Units.
• Revamp of a Side cut naphtha splitter to DWC preparing feed for Isom and CCR Units.
• Revamp of a Side cut naphtha splitter to DWC preparing feed for Isom and CCR & PX Units.
• Revamp of a reformate splitter to offload down stream aromatic extraction unit.

In all the above scenarios the revamp to DWC offered a payback of few months to less than a year.