Currently, many countries set limits on gasoline aromatics in general, benzene in particular, and olefin (alkene) content. Such regulations have led to an increasing preference for alkane isomers, such as isomerate or alkylate, as their octane rating is higher than n-alkanes. In the European Union, the benzene limit is set at 1% by volume for all grades of automotive gasoline. This is usually achieved by avoiding feeding C6, in particular cyclo-hexane, to the reformer unit, where it would be converted to benzene. Therefore, only (desulphurized) heavy virgin naphtha (HVN) is feed to the reformer unit