Deep Adsorption Desulfurization of Fluid Catalytic Cracking Light Gasoline on NiO/ZnO-TiO2 Adsorbents with a High Breakthrough Sulfur Capacity

Two kinds of NiO/ZnO-TiO₂ adsorbents were prepared by equal volume impregnation (NiO/ZnO-TiO₂-1) and kneading (NiO/ZnO-TiO₂-2) methods. The adsorbents were characterized by X-ray diffraction, mercury intrusion porosimetry, scanning electron microscopy, energy dispersive X-ray spectroscopy, H₂ temperature-programmed reduction, and H₂ temperature-programmed desorption. It was found that NiO/ZnO-TiO₂-2 had a smaller average pore diameter and a larger specific surface area as well as a more uniform distribution of the nickel element. Additionally, more Ni⁰ active sites together with a stronger interaction between the active component and the support were detected on the surface of NiO/ZnO-TiO₂-2, which was beneficial to the inhibition of olefin saturation during desulfurization. The desulfurization performance of the adsorbents was investigated in a fixed bed reactor with fluid catalytic cracking light gasoline as a feed oil. The evaluation results confirmed NiO/ZnO-TiO₂-2 with a better desulfurization performance with less olefin saturation. It could reduce the total sulfur content from 300 ppmw to less than 5 ppmw, and the breakthrough time and breakthrough sulfur capacity were 91 h and 6.71% (67.1 mg S/g adsorbent), respectively.