Hydrodesulfurization and hydroconversion of heavy FCC gasoline on PtPd/H-USY zeolite

In the search for catalysts suitable for upgrading fractions of FCC gasoline, PtPd/USY zeolite was investigated. The objectives of the work were to reduce simultaneously the sulfur, nitrogen and aromatic contents of heavy FCC gasoline having various sulfur (30-203 ppmw) and 28 ppmw nitrogen contents. The process conditions were the following: temperature: 200-300 °C; pressure: 30 bar; liquid hourly space velocity: 1.0-3.0 h−1; H2/hydrocarbon ratio: 500 m3/m3. The results indicated that PtPd/H-USY zeolite catalyst can be applied for the desulfurization of heavy FCC gasoline up to 203 ppm sulfur content. When a base heavy FCC gasoline fraction of 30 ppmw sulfur content was used the catalyst was able to reduce the aromatic content by 14 abs.% as well as sulfur and nitrogen contents to <1 ppmw in one step. Blending calculations were made to evaluate the quality of a full range FCC gasoline obtained by mixing the desulfurized heavy FCC gasoline and the untreated light cut.