Use better fractionation to manage gasoline sulfur concentration
SUMMARY
Knowing the temperature at which various sulfur species distill, refiners can tighten FCC distillation cuts to meet blending pool targets.
TEXT
FCC gasoline fractionation will be increasingly more important as refinery pool sulfur levels are reduced. Refiners’ sulfur treating strategy and gasoline pool sulfur levels will determine the role fractionation plays. Fig. 1 shows one potential treating strategy. Light, medium and heavy gasolines can be processed in one of the caustic extraction technologies – a licensed process – and a conventional hydrotreater, respectively. To better manage sulfur levels for the gasoline blending pool, refiners should reconsider FCC fractionation operations as they affect gasoline sulfur distribution, hydrocarbon boiling range where the sulfur species distill, and practical considerations. How to fractionate the heavy gasoline and how much heavy gasoline can be yielded from the FCC main fractionator is equally important…