Refining is a complex operation that depends upon the skills of operators, engineers and planners in combination with cutting edge technology to produce products that meet the demands of an intensely competitive market.
Some of the greatest challenges for the refinery in recent years have been changes to the specification of transportation fuels. The switch from leaded to unleaded petrol, the reduction of sulphur levels in diesel and petrol, and, more recently, the increased use of biofuels in diesel and petrol, necessary under European legislation, have all required major investment in new units and upgrades to existing refinery units.
At its simplest, oil refining is the separation of crude oil by distillation into different fractions. But many other complex processes are necessary to produce a full range of products, that includes propane and butane (LPG), petrol, jet fuel, diesel, marine fuels, heating oil, lubricant basestocks and fuel oil.
The refinery at Fawley also supplies feedstock to the adjacent ExxonMobil Chemical plant.
The catalytic cracking unit, known as the cat cracker, is one of the most important plants on the refinery. The cat cracker takes the heavier, less valuable molecules from the distillation process and breaks them down into smaller ones. These smaller, more useful and therefore more valuable molecules are used for manufacturing petrol and provide feedstocks for the chemical plant.
Refining processes use substantial amounts of energy and there has been considerable investment in recent years to make the refinery more energy efficient. A £60 million combined heat and power (CHP) generating plant was installed in 1999, reducing energy costs by more than £2 million per year. Using less energy brings the additional environmental benefit of reducing emissions of gases such as sulphur dioxide, carbon dioxide and nitrogen oxides.