Thermal Treatment of Fluid Catalytic Cracking Slurry Oil: Determination of the Thermal Stability and its Correlation with the Quality of Derived Cokes

Pretreatment of slurry oil (SO) from fluid catalytic cracking process is critical to its high value-added utilization in producing carbonaceous materials. In this study, the SO fractions before and after thermal treatment were characterized in terms of bulk property, composition, and thermal stability. A method using thermal excitation followed by spot test was proposed to evaluate the thermal stability of the fractions. The average structural information shows that the fractions after thermal treatment have shorter alkyl side chain length and are increased in aromaticity. The composition analysis reveals that the middle fraction is mainly composed of three to five-ring aromatics with short side chains, and that the content of four-ring aromatics decreases while the contents of three-ring as well as five-ring aromatics increase after thermal treatment. An increase in thermal stability of the middle fraction as well as the corresponding five narrow fractions is observed and is attributed to the conversion of reactive components in the middle fraction into residues. The carbonization experiments reveal that feedstocks with higher thermal stability tend to have better mesophase development performance.