What is unstabilized naphtha?

Unstabalized naphtha (also known as light naphtha) consists of the light components of a crude oil distillation which have not yet had the C4 components removed from it. Unstabalized naphtha is fed to a tall distillation column (approximately 20-30 trays) known as a debutanizer where all C4 components (and any lighter boiling point components) are removed. The bottom product of a debutanizer is stabilized naphtha.