The refining process

The refining process is sophisticated and complex, requiring a highly skilled workforce and a diverse range of engineering and business skills to manage the operations.

Heat, pressure and chemical reactions are used to transform crude oil into products including, petrol, diesel, jet fuel and LPG.

The refining of crude oil takes place in a number of units, linked by hundreds of kilometres of pipes and regulated by thousands of valves. The process is governed by instruments on every unit, linked to a highly sophisticated process control computer system. Through computer consoles, refinery technicians constantly monitor, regulate and optimise the process.

Refining begins by processing the crude oil through a "pipestill" or distillation tower. Intense heat is used to vapourise most of the oil and, as the vapours rise inside the tower, different compounds cool and separate. Heavier molecules rise a short distance, while lighter ones rise farther. As the various "fractions" condense to liquid form, they accumulate on collection trays at varying heights inside the tower. This process separates crude oil into its various components based upon the relative weights of their molecules.

Catalytic cracking is used to break apart or 'crack' heavier, lower value hydrocarbon molecules into lighter, and more useful molecules. The cracking process takes place at high temperatures using a sophisticated alumina-silicate catalyst to aid the process. This catalyst resembles a fine powder.

Other processes and technologies including catalytic reforming, alkylation, hydrotreating, alkali treating and benzene saturation are used to further refine and upgrade the different hydrocarbon compounds.

Some processes use a combination of heat and pressure to break larger, heavier molecules into smaller, lighter ones. Others, such as alkylation, convert light gases into heavier, more valuable liquid fuels.