Abstract: Mesophase pitches with different crystal structures were prepared from FCC slurry by thermal polycondensation and nitrogen blowing process. The light component removal rate was regulated by changing the reaction temperature, reaction time, and nitrogen flow rate. The influence of removing light components on the formation and development of mesophase structure was investigated. The results showed that pressurized treatment at the early stage gives an opportunity for small molecules to react into precursor pitch, and nitrogen blowingat the subsequent stage drives the rapid concentration of the precursor pitch into mesophase spheres of the appropriate size and coalescence into mesophase pitch with excellent optical texture by efficiently removing the residual light components and low-boiling point isotropic components. The removal rate of light components can be increased by increasing the reaction temperature, reaction time and nitrogen flow rate.The increase in the removal rate of light components increased the mesophase content and promoted the formation of a ‘broad domain’ mesophase structure, which increased the size of the thickened cyclic aromatic hydrocarbon molecules of mesophase pitch and improved the orderly arrangement of the microcrystalline structure.

Key words: mesophase pitch, aromatic-rich heavy oil, microcrystalline size, mesophase structure