Refining

The largest refinery in the Mediterranean

heart of the Group is the Sarroch refinery, the largest in the Mediterranean in terms of production capacity – with over 15 million tonnes per year, equal to 300,000 barrels per day, about 21% of Italy’s total output – and one of the most advanced in terms of plant complexity (Nelson Index of 11.7).

The industrial site, managed by Sarlux, is located on the south-western coast of Sardinia, in a strategic in the Mediterranean ensuring proximity to several crude oil producing countries and to the main consumer markets for refined products.

The refinery is equipped with advanced technology plants performing both separation (e.g. distillation) and conversion processes (catalytic and thermal) and able to adapt the steps of the production cycle to the characteristics of the crude oil to be processed, so as to obtain high-grade and more environmentally-friendly oil products.

Currently, more than 80 percent of the facility’s output consists of low environmental impact products.

In terms of technology, a key strength of Sarlux production is the integration of the oil refining cycle with electricity generation: this allows the facility to maximise the conversion of raw materials into valuable products and energy.

PRODUCTION PROCESSES

The integrated production process, described in the ‘Explore’ section, is developed through a series of units which, over the years, have undergone several technology upgrades to optimise production efficiency and minimise environmental impacts.

Steps of the refining process

Topping (atmospheric distillation) and Vacuum (vacuum distillation) are the distillation plants of crude oil for the production of primary fractions:

  • heavy fuel oil
  • kerosene
  • naphtha
  • butane
  • propane

The Mild Hydro Cracking (MHC), the Fluid Catalytic Cracking (FCC) and the Visbreaker are the conversion plants in which hydrocarbons and heavy distillates are transformed into medium-light fractions:

  • diesel fuel
  • naphtha
  • propylene

Catalytic Reforming (CCR) is the plant in which the transformation of light distillates (naphtha) into high octane components takes place, with simultaneous production of hydrogen, used in desulphurisation treatments.

The PSA plants purify the hydrogen that will be used by the desulfurization plants.

Desulphurisation plants subject middle distillates (kerosene and gas oils) to catalytic hydrogenation processes to remove sulphur and improve product quality, in particular the U800 Unit of the catalytic cracking plant allows the production of low content gasolines of sulphur.

Ter-Amil-Metil Eteri (TAME) is the plant for improving the qualitative characteristics (alkylation) and performance of gasoline.

RECYCLING

The Visbreaker sends the heavy hydrocarbon residues (TAR) to the IGCC plant for the production of electricity.

The DEA plants treat the non-condensable fuel gas by removing sulphur compounds (H2S) from the gas, which can then be reused in the refining processes.

The Tail Gas Treatment Unit (TGTU) treats tail gases increasing the recovery of sulphur, which is used in chemistry (sulphuric acid for batteries), agriculture (fertilisers and insecticides) and in the pharmaceutical industry.
This recovery process reduces air emissions of sulphur dioxide (SO2).

Water treatment plants produce recycled water that covers about 26% of the total needs of the plants.

END PRODUCTS

The Sarlux plants in Sarroch supply the whole of Sardinia with fuels and electricity (covering 47.7% of the island’s demand).

Oil production has a high output of middle distillates (diesel and kerosene) and light oil products, such as LPG, gasoline and virgin naphtha, which in 2017 accounted for around 90% of total production.

The refinery’s products are mainly delivered to the central and western Mediterranean region.

a
Finished products
(in 2017)
51.0%

Diesel and Kerosene
27.9%

Gasoline and Virgin Naphtha
5.1%

Fuel oil and other
2.0%

LPG
7.7%

Petrochemical products

STORAGE

The raw materials and finished products are stored in the Tank Farm, while excise-duty paid products are held in the National Storage Facility,
located outside the ‘bonded area’. Liquefied gases (LPG) are stored in pressure tanks, called ‘spheres’, ‘bullets’ and ‘horton spheres’.

In total, the refinery has 161 tanks with a capacity of approximately 4.3 million m3. All tanks are fitted with permanent fire-prevention systems and containment basins in reinforced concrete and concrete floors, or with earth banks, to isolate the products and protect the soil from leaks.

The fire prevention system in the LPG storage areas is controlled by a device that, in response to a set of parameters (including wind direction), can activate fire-prevention and leak containment measures. To prevent accidents, the LPG tanks are also equipped with pressure monitoring and unexpected pressure surge relief systems.