The steam cracker is the starting point for many of the chemical products produced at Fawley. It takes a feedstock of heavy naphtha or gas oil from the refinery to produce basic chemical building blocks: ethylene, propene and butene.
Ethylene is shipped directly to customers; the propene and butene streams are used as feedstocks, mainly for the higher olefins plant and the isobutylene plant.
The higher olefins plant is the largest chemical plant at Fawley. The 14 higher olefins manufactured at Fawley are shipped to ExxonMobil Chemical plants in Europe for further processing. They are used in the manufacture of plasticizers - the component in plastics which makes them flexible - and also in the manufacture of performance fluids.
The isobutylene plant, as its name suggests, produces an isobutylene feedstock for the polymers plant. Residue from the isobutylene plant is used in the manufacture of MEK (methyl ethyl ketone) - a solvent used in paints and adhesives.
The one polymer product made at Fawley is halobutyl rubber. Halobutyl rubber's most important property is its impermeability to air and water and it is therefore in great demand worldwide for use in products such as tyre linings and air-tight stoppers for the pharmaceutical industry. The solid halobutyl rubber is formed into bales and packed into crates in which it is shipped to customers around the world.
The company produced the world's first butyl rubber in 1937 – technology which we later developed to pioneer the commercial production of halobutyl rubber in 1960.
For more information about butyl polymers, visit the ExxonMobil Chemical website.