Application: Process to produce vacuum distillates that are suitable for lubricating oil production by downstream units, and as feedstocks to FCC and hydrocracker units.
Feed: Atmospheric bottoms from crude oils (atmospheric residue) or hydrocracker bottoms.
Product: Vacuum distillates of precisely defined viscosities and flash points (for lube production) and low metals content (for FCC and hydrocracker units) as well as vacuum residue with specified softening point, penetration and flash point.
Description: Feed is preheated in a heat-exchanger train and fed to the fired heater. The heater outlet temperature is controlled to produce the required quality of vacuum distillates and residue. Structured packings are typically used as tower internals to achieve low flashzone pressure and, hence, to maximize distillate yields. Circulating reflux streams enable maximum heat recovery and reduced column diameter.
A wash section immediately above the flash zone ensures that the metals content in the lowest side draw is minimized. Heavy distillate from the wash trays is recycled to the heater inlet or withdrawn as metals cut.
When processing naphthenic residues, a neutralization section may be added to the fractionator.