Two-Step Thermal Cracking of an Extra-Heavy Fuel Oil: Experimental Evaluation, Characterization, and Kinetics

Abstract

This work deals with an efficient two-step thermal upgrading process for converting extra-heavy fuel oil to light olefins (ethylene, propylene, and butenes) and fuels (gasoline and diesel fuel). In the first step, mild thermal pretreatment was implemented at different temperatures (360–440 °C) in the liquid phase to obtain a more suitable feedstock for an olefin production unit. Thanks to this cost-effective pretreatment, the upgraded feedstock demonstrated considerable flowability and crackability compared to the initial fuel oil, making the subsequent vapor-phase operation easier to handle at temperatures as high as 800 °C with no severe operational impediments. The quantitative 1H and 13C NMR studies shed light on the enhanced features of the thermally treated feedstock toward lighter and more valuable products. As a result, remarkable olefin production (74.7 or 55.1 wt % light olefins based on the upgraded or the original feedstock) was accomplished in this two-step process. The process could be alter...