Energy & Fuels 2008, 22, 1449–1455
1449
Benzene Reduction in a Fuels Refinery: An Unconventional Approach Arno de Klerk* and Reinier J. J. Nel Fischer–Tropsch Refinery Catalysis, Sasol Technology Research and DeVelopment, P.O. Box 1, Sasolburg 1947, South Africa ReceiVed October 9, 2007. ReVised Manuscript ReceiVed February 25, 2008
The benzene content of motor-gasoline is regulated by fuel specifications that are becoming increasingly stringent. Acid catalyzed alkylation of benzene by olefins in commonly found refinery units was explored as a low cost benzene reduction strategy. Cofeeding benzene to aliphatic alkylation, etherification, and olefin oligomerization processes were evaluated. Benzene can be alkylated in a sulfuric acid-based aliphatic alkylation unit at 5 °C, but significant disruption of the aliphatic alkylation reaction occurs if the feed contains more than 3% benzene. No benzene alkylation was found during reaction at 90 °C in an acidic resin based etherification process, since the alcohol is the proton carrier. When the same process was operated as an olefin oligomerization process (no alcohol in feed), alkylation proceeded. Benzene was also successfully alkylated during H-ZSM-5 based oligomerization (180–280 °C, 4 MPa), but the pore constrained geometry of the zeolite resulted in
