Naphtha, which is a lighter fraction of the crude oil, is the raw material for gasoline production. The octane number of the naphtha is too low, and has to be increased before it may be used as motor fuel.
First, sulfur is removed in a desulfurization plant, and next the octane number is increased from around 50 to 100 in a catalytic reformer. It is this product, the reformate, which is the main component in the gasoline marketed at the petrol stations.
The naphtha is mixed with suitable components to make the end product gasoline. By conversion of naphtha to reformate, hydrogen is split from the naphtha molecules, and this hydrogen gas is used in all desulfurization plants.
In 1998, a separate benzene extraction plant was installed to comply with new petrol specifications.