Mesophase pitch production from FCC slurry oil: Optimizing compositions and properties of the carbonization feedstock by slurry-bed hydrotreating coupled with distillation

Slurry-bed hydrotreating coupled with distillation may optimize the compositions and properties of heavy oils, including improving their hydrogen-donating ability of heavy oils. The effects of slurry-bed hydrotreating coupled with distillation on the compositions and properties of FCC slurry oil were determined by various analytical methods. H-1 NMR was used to characterize and determine the hydrogen-donating ability of FCC slurry oil, and the structure of mesophase pitches formed by carbonization of FCC slurry oil were characterized by polarizing microscope, softening point and X-ray diffraction method. The results showed that slurry-bed hydrotreating obviously prevents FCC slurry oil from coking behavior during the distillation process, and overall compositions and properties of FCC slurry oil after optimization meet the requirements for producing mesophase pitch. Most importantly, the hydrogen-donating ability of FCC slurry was drastically increased from 0.392 (mg-H/g-Oil) to 1.917 (mg-H/g-Oil). In turn, in contrast with the raw FCC slurry oil, the slurry oil after the slurry-bed hydrotreating coupled with distillation easily formed mesophase pitch with a large flow domain structure, low softening point, and ordered microcrystal structure through carbonization. Thus, the purpose of preparing high-quality mesophase pitch was achieved.