Abstract
The upgrading of an aromatic-rich feedstock (pyrolysis gasoline) has been investigated over bifunctional Pt catalysts in order to evaluate the effect of the support on conversion, selectivity and deactivation. The experiments were conducted in a fixed-bed reactor at a pressure of 5 MPa and 350-450 degrees C. Pt was incorporated into five acidic supports: MFI, BEA and FAU zeolites, and an amorphous silica-alumina (ASA). Their surface properties and acidity were then assessed by means of several characterization techniques and related with their intrinsic activity-selectivity-deactivation. Using high hydrogen pressure (to minimize catalyst deactivation), we report the suitability of several catalysts for different purposes: Pt/MFI19 catalyst for a steam cracker feedstock production, Pt/BEA catalyst for isoalkane-rich gasoline pool manufacture and Pt/ASA catalyst for severe aromatic reduction while controlling the extent of ring scission. The results of accelerated deactivation experiments under low hydrogen pressure lead to the conclusion that MFI-supported catalysts (Pt/MFI19 and Pt/MFI95) yield less coke, but Pt/BEA deactivates to a lesser extent during hydrogenation. (C) 2007 Elsevier B.V. All rights reserved.