The purpose of the project is to maximize gasoil yields, a feed stock for FCC, by “deep-cut” fractionation of the Vacuum Distillation Unit, following specific modifications.
The Vacuum Unit processes bottoms (long residues) from the atmospheric crude distillation unit under vacuum conditions to produce increased yield of gasoils (cracking feedstock) and a heavy vacuum residue (asphalt / bitumen base stock). It essentially consists of a long residue desalter, a pre-heat exchangers train, two fired heaters, a main vacuum tower and a stripper (both with conventional trays), two vacuum systems & other equipment, instrumentation and control systems.
Extensive modifications were required to upgrade the unit operation, though the basic design feature of this revamp project was to substitute the distillation trays with packed beds to boost Light and Heavy Vacuum Gasoil yields which provide the feed to FCC.
