Upgrading of Light Cycle Oil to High-Octane Gasoline through Selective Hydrocracking over Non-Noble Metal Bifunctional Catalysts

Three non-noble metal bifunctional catalysts (Ni-W/H beta-Al2O3, Ni-W/HY-Al2O3, and Ni-Mo/HY-Al2O3) were prepared and applied to the selective hydrocracking of light cycle oil (LCO) into high-octane gasoline. The structures of catalysts were characterized by various techniques, and the catalytic performances were tested at 400 degrees C, 8.0 MPa, and a liquid hourly space velocity of 0.8 h(-1) using a once-through mode at a pilot-scale reactor. Among the three catalysts, Ni-Mo/HY-Al2O3 showed the highest yield of gasoline (43.4 wt % in which aromatics accounted for 31.6%) and highest research octane number (RON, around 85), which were mainly due to high total acidity, high surface area, and homogeneous distribution of the active phase on the catalyst. In a long-term test (3200 h), with a partial recycle mode at the pilot reactor, Ni-Mo/HY-Al2O3 exhibited a high and stable gasoline yield (about 53 wt %) with a RON of 92-95, indicating its high performance for the selective hydrocracking of LCO. This catalyst was eventually commercialized in a refinery, which gave rise to a stable gasoline yield of about 40 wt % with a RON of 91 during 250 days on stream. Moreover, the chemical and structural properties of the used catalyst were preserved.