Chemical Sciences

The MSAT – II regulations which became active on January 1, 2011 (“EPA Regulatory Announcement” – EPA420-F-07-017, February 2007), restricts the average benzene level in Gasoline sold in U.S (except California), to 0.62 % vol. Another driving force behind this technology is the conversion of conventional Naphtha Crackers to Gas Crackers due to availability of low cost feedstocks like shale gas. A light naphtha cracker produces nearly 10 times the amount of Pyrolysis Gasoline – which can be converted into aromatics – than an ethane cracker. This ongoing shift to lighter feedstocks can have a significant negative impact on heavier co-products such as aromatics, with yields cut by as much as 55%. Currently FCC gasoline comprises nearly 10-20 % of the gasoline pool in a typical refinery. Full range FCC gasoline contains around 15-30 vol. % aromatics with up to 2 vol. % benzene and 1000 – 2000 ppm sulfur. A narrow C6 heart cut fraction of the full range gasoline will contain anywhere between 11 – 19 wt. % benzene and up to 500 ppm sulfur.