Efficiently reducing olefin content of FCC gasoline over ZSM-5 zeolite based catalyst via hydro-upgrading

The reduction of olefin content in FCC gasoline is challenging for clean gasoline production, owing to the tightened regulations at 15% (vol%) olefin content of clean vehicle fuels with China VI standard. The best route for olefin reduction has been proposed by selective converting olefins to aromatics or iso-alkanes with a high-octane number. Here, ZSM-5 zeolite supported metal catalysts have been developed for hydro-upgrading FCC gasoline. ZSM-5 zeolite blended with alumina was firstly treated by hydrothermal treatment at 450 °C, 500 °C and 550 °C, respectively, and the effect of Zn, Ni-Zn and La-Ni-Zn deposition on hydro-upgrading was also investigated. The hydrothermal modification effectively reduced acidity of ZSM-5 zeolite with the increase of B/L ratio and the decrease of L acid sites. The introduction of Zn, Ni and La to the zeolite supports increases the proportion of medium-strong acid from 42% to 48%, and the resulting catalyst shows excellent olefin reduction performance in FCC gasoline hydro-upgrading. The content of aromatics increases 5% (1.2 vol%); iso-alkane content increases 16% (5.5 vol%) and the research octane number (RON) increases 4.6. These findings show the ZSM-5 supported Zn-Ni-La catalyst can be served as a potential industrial catalyst for FCC gasoline hydro-upgrading.