The process objective is to remove contaminants (nitrogen, sulphur, metals) and to convert low value gas oils into valuable products (naphtha, middle distillates, and ultra clean lubricant base stocks).
The hydrocracking unit receives feedstock from the vacuum distillation unit. First of all a hydrogenation phase is carried out to remove sulphur, nitrogen and metals. This is followed by the dealkylation of the aromatic rings, the opening of the naphthenic rings and the breaking of the paraffin bonds. Products obtained in this way are essentially light ends (sold as LPG), naphtha (sold as petrol or sent to the catalytic reforming unit) and diesel.
The dealkylation phase is carried out in one or more hydrocracking reactors with a fixed bed catalyst.
The hydrocracking unit consists of one or more down flow hydrocracking reactors.
The reactor configuration and the presence of internals (‘distributor and redistributor trays’, ‘mixing trays’, ‘catalyst support grids’ and ‘outlet collectors’) allow the fluids to flow downwards in the reactor, favouring the reactions for dealkylation of the aromatic rings, the opening of the naphthenic rings and the breaking of the paraffin bonds.
Distinctive characteristics of the Costacurta down flow reactor internals for the hydrocracking process are:
- Internal production of all the filtering elements used in making the internals (wire cloth weaving, punching and production of wedge wire screens)
- Internal production of all the internals, from the inlet to the outlet collector.
- Over 60 years of experience in mechanical design and construction of internals
- Availability of dedicated teams highly experienced in project management