Oil

We are building our biggest refinery in Saudi Arabia, on the shores of the Persian Gulf. Boasting the latest technological innovations, the refinery will be able to process heavy oil from the world's biggest fields.

Located in Jubail's industrial district, barely 10 kilometers from the Persian Gulf coast, the refinery will be supplied by pipeline from two giant offshore fields, Manifa and Safaniya. It will have a capacity of 400,000 barrels of crude oil per day, or roughly 20 million metric tons a year. The new facility will help to meet constantly growing demand for refined products in the Middle East and Asia when it comes on stream in late 2012.

An abundance of sour, heavy oil

Both the Manifa and Safaniya fields were discovered in the 1950s. Manifa will be developed for the first time during the refinery's construction. Its estimated 11 billion barrels of reserves make it one of the world's largest still undeveloped deposits. Safaniya, by far the biggest offshore oil field, with reserves estimated at 19 billion barrels in 2004, currently supplies mostly bitumen and heavy fuel oil for industry and bunker fuel for the shipping sector.

With its high sulfur content and unusually high proportion of heavy residues, the crude oil from these fields cannot be used directly. It must first undergo a complex process, called deep conversion, which requires sophisticated, capital-intensive installations.

A full-conversion refinery

To support full conversion, Total plans to equip the Jubail refinery with a comprehensive palette of units to process heavy crude oil. They will include a distillate hydrocracker (DHC), a fluid catalytic cracker (FCC) and a delayed coker. This configuration will optimize the production of diesel fuel and jet fuel. Plans also call for annual production of 700,000 metric tons of paraxylene, 140,000 metric tons of benzene and 200,000 metric tons of high-purity propylene for the petrochemical industry.

Another asset of the site is its nearness to the city of Jubail's infrastructure, most notably an industrial port, power and water supply systems and a residential district.

A DHC for lighter products with the help of hydrogen

A distillate hydrocracker (DHC) is a furnace, reactor and distillation column all rolled into one. Heavy distillates from the initial refining operation are heated in the furnace in the presence of hydrogen. They are then fed into the reactor, where the large oil molecules are cracked into smaller ones. The resulting lighter mixture must be further refined to separate its different constituents. This is where the distillation column comes in, separating the components into LPG, naphtha for petrochemical production, jet fuel, "clean" diesel fuel for diesel engines, high-grade bases for lubricants and specialty fluids and, finally, residues known as bottom fractions.

Fluid catalytic conversion

With fluid catalytic conversion (FCC), the cracking process is carried out in the presence of a catalyst that makes it possible to induce the reaction at a lower temperature. The catalyst is made up of particles so fine they behave like a liquid. It circulates in the reactor, from which it is extracted continuously for regeneration and subsequent reinjection into the process. The vacuum distillates and coker effluent are processed using this method to produce gasoline and diesel fuel. The catalytic cracker converts certain heavier fractions into lighter products.

Coking: removing carbon to lighten heavy bottom fractions

Basically, coking consists of breaking large oil molecules and extracting some of their carbon atoms. In practical terms, heavy bottom fractions are fed into a furnace and heated to between 485 and 505°C, then sent on to a coke drum. The heat in the drum cracks the heavy molecules, yielding lighter compounds and coke. The lighter compounds are sent to a fractionating column, where they separate naturally in order of density by condensing at different heights. Moving from top down you find LPG, followed by naphtha and middle distillates, with petroleum coke at the bottom.

Drums usually operate in pairs, alternately: the cracking reaction produces coke, which accumulates at the bottom. When the first drum is full, cracking shifts to the other drum, while the first is cooled, depressurized and emptied with the aid of a very high-pressure water jet. This process is repeated ad infinitum. The coke is recovered in a pit, then moved by conveyor belt to an open-air storage area. It is subsequently sold, usually as an industrial fuel.