Effects of Inductive Condensation on Mesophase Development during Aromatic-Rich Oil Carbonization

Abstract

A novel method was discussed for the preparation of petroleum-based mesophase pitch with a large domain structure and an ordered microcrystal structure. A condensation pitch with a certain amount of anisotropic structures was generated from an aromatic-rich oil from FCC slurry oil by heat treatment. The aromatic-rich oil was used to prepare mesophase pitch by inductive thermal condensation with n-heptane insolubles of the above condensation pitch as seed. Inductive effects of seed on mesophase formation and development were investigated by analyzing the properties of thbe carbonized products. Results showed that mesophase pitch obtained by inductive thermal condensation possessed more anisotropic structures, better optical texture, and microcrystal structure when compared to mesophase pitches produced through direct thermal condensation at low or high reaction temperatures. The introduction of seed was conducive to the improvement of mesophase pitch properties by reducing the reaction activation energy and inducing the formation of anisotropic structures at a low temperature.

Correlation of Mesophase Properties with Molecular Structures of Pitches from Different Sources

“…Also, the signal peak intensities of CLP and CTP decrease exponentially with the increase in molecular mass, reflecting the typical molecular mass distribution characteristics of coal pitch. It is inferred to be a result of the kinetic properties of polycyclic aromatic compounds during their formation . The average molecular mass M W and M N of CLP are 613 and 476, respectively, which are greater than those of CTP.…”

“…The special molecular structure of CLP, which is highly condensed but has many alkyl groups, determines the higher mesophase content and more ordered optical composition of MP-CLP compared to MP-VR and CTP. The rich naphthenic structure ensures that thermal polycondensation takes place at low viscosities, providing good mobility and facilitating the ordered arrangement of the large aromatic molecules. , In the range of 360–480 °C, the highest mesophase content is 54.4% of MP-CLP-400 °C, in which the content of fiber and flaky texture is 47.7%. Fiber and flaky textures are not prone to form defects during subsequent carbonization compared to mosaic texture and are therefore ideal structures for preparing high-quality carbon materials …”

“…It is inferred to be a result of the kinetic properties of polycyclic aromatic compounds during their formation. 25 The average molecular mass M W and M N of 5, and atoms with contents less than 1 in the calculations were neglected in the average molecular structure.…”

“…It has further been shown that the alkyl side chains seriously affect the laminar orientation of mesophase molecules. , The disordered cross-linking between large radicals forms poorly planar macromolecules, reducing the lamellar orientation and graphitization ability of the carbonaceous mesophase, and eventually destroying the ordered microstructure of carbon materials. ,− Due to the influence of the process parameters, the properties of industrial pitches as a raw material for mesophase pitch are unstable, and the technology in China for the stable and continuous production of high-quality mesophase pitch from different industrial pitches has not yet been realized. The key point is that the influence of molecular structure characteristics on liquid-phase carbonization behavior is not clear since industrial pitch is a complex mixture of molecules with different structures and reactivities. − Therefore, exploring the correlation between mesophase properties and raw materials at the molecular level is essential to providing directions for the modification and preparation of mesophase from industrial pitch. , …”

Research progress in the preparation of mesophase pitch from fluid catalytic cracking slurry

“…[37][38][39] Nevertheless, FCC oil slurry contains a large amount of aromatic hydrocarbons and heavy components that can be used to prepare mesophase pitch and other high value-added chemical materials. [40][41][42] 2. Research status and advantages of mesophase pitch…”