Kinetics and Inhibition in the Selective Hydrogenation of FCC Gasoline

The USEPA Tier 3 Vehicle Emission and Fuel Standards Program will begin to take effect in 2017.  As a result, refiners and technology licensors have begun evaluating the options for satisfying the new fuel standards in the most economically appropriate way.  Selective hydrodesulfurization of FCC gasoline is the most widely practiced technology applied to reduce the sulfur in the FCC gasoline portion of the motor gasoline pool.  Selective hydrogenation is featured within most selective hydrodesulfurization technologies, since it is needed to selectively saturate di-alkenes to mono-alkenes, sweeten the light fraction, and isomerize α-mono-alkenes to ß-, etc.  This selective hydrogenation portion of the overall selective hydrodesulfurization technology was evaluated, with the intent of developing a kinetic model which rigorously describes the afore-mentioned reactions, and which appropriately incorporates the effect(s) of inhibiting species.  The effort and its results are the focus of this discussion.