Preparation of medium and low temperature coal tar-based mesocarbon microbeads

The refining treatment of medium and low temperature coal tar was carried out by fraction cutting and mild hydrogenation. Mesocarbon microbeads were prepared from refined raw materials by staged thermal polymerization. The effects of refining treatment conditions on the properties of raw materials, macroscopic appearance and microcrystalline structure of mesocarbon microbeads were investigated. The raw materials were characterized by FTIR, GC-MS, group composition and elemental analysis, and the mesocarbon microbeads were characterized by SEM and XRD. The results showed that the distillate oil at 300-430℃ in medium and low temperature coal tar was better fraction for preparing mesocarbon microbeads. The content of n-heptane soluble (HS) and pyridine insoluble (PI) was 84.76% and 0.23%, respectively, while heteroatom was low and the ring number of aromatic compounds was 2-4. The refined raw materials were obtained by mild hydrogenation of 300-430℃ distillate oil under the conditions of TH=350℃, p=8MPa, t=1.5h, the mass ratio of catalyst to distillate oil is 1:40, and mesocarbon microbeads which were prepared from refined raw materials by thermal polymerization at 420℃ for 6h had better macroscopic appearance and microcrystalline structure. The particle size of mesocarbon microbeads ranges from 5μm to 15μm. The surface of the mesocarbon microbeads was smooth and the microstructure was globe-shaped. After calcination at 1450℃, the degree of graphitization reached 12. 33%. © 2020, Chemical Industry Press. All right reserved.