FCC Gasoline Upgrading over Modified Nanoscale HZSM-5 Catalyst

Abstract

Nanoscale HZSM-5 zeolite was hydrothermally treated with ammonia water at 773K and then loaded with La2O3, NiO and MoO3. The parent and modified nanoscale HZSM-5 zeolite catalysts were characterized by XRD, NH3-TPD, Py-FTIR and N2 adsorption. The characterization results indicated that the acid strength of the parent nanoscale HZSM-5 was weakened, the L/B acidity increased notably and the metal species were well dispersed on the surface of the supports after the combined-modification measurement. In the presence of hydrogen, the performance of the modified HZSM-5 catalyst for FCC gasoline upgrading was evaluated in a fixed bed reactor. Under the given reaction conditions, the average olefin content in FCC gasoline was decreased from 33.2 vol% to 11.3 vol% within 300 h time on stream; the aromatic and isoparaffin contents in the product were increased from 29.8 vol% and 25.9 vol% to 39.0 vol% and 35.4 vol%, respectively. The modified nanoscale HZSM-5 catalyst reduced sulfur concentration in FCC gasoline by about 90% without gasoline octane number loss.