One of the most complex refineries in the world and the second-largest of Europe's six integrated refining-petrochemical "supersites," the Sarroch Refinery on the Italian island of Sardinia boasts a capacity of 300,000 b/d.

The Saras S.p.A.-owned refinery, which has been in operation since 1965, uses a highly flexible multi-train configuration that allows it to process a diverse slate of crude oils including: light extra sweet, light sweet, medium sweet, light sour, medium sour, and heavy sour. Centrally located in the Mediterranean region, the refinery sources more than 50% of its crude oil from Libya. Other significant sources of crude for the facility include the North Sea, the Former Soviet Union, and the Middle East.

Major process units at the Sarroch Refinery include the following: atmospheric distillation (3 units); vacuum distillation (2); visbreaking; distillate cracking (FCC); cat reforming (CCR); distillate hydrocracking (2); hydrotreating (5); alkylation; oxygenates (TAME); hydrogen/PSA (2); gasification (3); BTX plant; and semi-rigernerative reformer.

Light and medium products--particularly liquefied petroleum gas (LPG), gasoline, and diesel--constitute more than 80% of the refinery's product yield. Of this figure, approximately one-half comprises medium distillates (primarily diesel).

Upgrade strategy

The Sarroch Refinery is noted for its ability to process heavier, more acidic unconventional crude oils, which are less expensive but more difficult to refine. Saras is enhancing the refinery's unconventional crude processing capability even further. In fact, roughly 57% of the company's approximately EUR1.1 billion refining capital spending plan for 2008 through 2011 is earmarked to support a strategy of continuous upgrading. Also, Saras plans to increase its conversion capacity at the facility--increasing diesel production/middle distillate yield by 2.5% (or 365,000 t/y) at the expense of fuel oil.

Saras plans to achieve its goal of increasing the refinery's conversion capacity in party by revamping the refinery's second mild hydrocracking unit (MHC 2) and installing a new steam reforming unit. In March 2008, Foster Wheeler announced that Saras awarded it an engineering, procurement, and construction management project to revamp MHC 2. The revamp will upgrade the facility's mild hydrocracking capacity, performance, and conversion while achieving a longer catalyst life duration. It includes major modification to the reaction section, including installation of a new pretreat reactor. In addition, the revamp calls for upgrading the gas compression circuit and installing a new high-pressure amine wash section. The revamped MHC 2 and new steam reforming unit, which will boost the refinery's diesel production by 5,500 b/d, should be online in Second Half 2010.

The visbreaking unit at the refinery also will be revamped. The project, which will enable the facility to produce an extra 2,000 b/d of diesel, is slated for completion in the second half of 2011.