The influence of nitrogen-containing polycyclic aromatic hydrocarbons(NC-PAH)on the formation of carbonaceous mesophase remains enigmatic,despite extensive research on the production of carbonaceous materials from aro...The influence of nitrogen-containing polycyclic aromatic hydrocarbons(NC-PAH)on the formation of carbonaceous mesophase remains enigmatic,despite extensive research on the production of carbonaceous materials from aromatic-rich oils.Molecular dynamics simulation was used to investigate the variations in pyrolysis behavior between PAH and NC-PAH based on the composition analysis.Through adjusting the content of NC-PAH,the influence of NC-PAH on the thermal stability of slurry oils(SOs)was evaluated by thermogravimetry,viscosity,coke value,and quinoline insoluble(QI).The morphology and structure of mesocarbon microbeads(MCMBs)prepared with SOs were measured by a polarized-light microscope,SEM,XRD,and Raman.Simulation results indicate that NC-PAH possesses much higher reactivity and tends to produce highly condensed solid and coke products.It corresponds to the QI and high viscosity in thermal stability experiments.Therefore,high concentrations of NC-PAH result in nonuniform morphology and disordered structures.In a system with low viscosity and few QIs,SO,which has a low nitrogen content(475 ppm),reacts gently to produce MCMBs with a uniform particle size(10-40μm)and an excellent spherical shape.As NC-PAH content decreases,the crystalline size of graphitization elevates,as evidenced by parallel layers(10.472-11.764)and stack height(3.269-3.701 nm).The graphitization degree becomes worse and nonuniform with the increase of the content of NC-PAH,and the best is 20.58%evaluated by Raman spectra area ratio(AG/Aall).Overall,this work suggests a nitrogen content reference and a controlling technology of nitrogen for the preparation of superior MCMB.展开更多
基金support of National Natural Science Foundation of P.R.China(22308104).
文摘The influence of nitrogen-containing polycyclic aromatic hydrocarbons(NC-PAH)on the formation of carbonaceous mesophase remains enigmatic,despite extensive research on the production of carbonaceous materials from aromatic-rich oils.Molecular dynamics simulation was used to investigate the variations in pyrolysis behavior between PAH and NC-PAH based on the composition analysis.Through adjusting the content of NC-PAH,the influence of NC-PAH on the thermal stability of slurry oils(SOs)was evaluated by thermogravimetry,viscosity,coke value,and quinoline insoluble(QI).The morphology and structure of mesocarbon microbeads(MCMBs)prepared with SOs were measured by a polarized-light microscope,SEM,XRD,and Raman.Simulation results indicate that NC-PAH possesses much higher reactivity and tends to produce highly condensed solid and coke products.It corresponds to the QI and high viscosity in thermal stability experiments.Therefore,high concentrations of NC-PAH result in nonuniform morphology and disordered structures.In a system with low viscosity and few QIs,SO,which has a low nitrogen content(475 ppm),reacts gently to produce MCMBs with a uniform particle size(10-40μm)and an excellent spherical shape.As NC-PAH content decreases,the crystalline size of graphitization elevates,as evidenced by parallel layers(10.472-11.764)and stack height(3.269-3.701 nm).The graphitization degree becomes worse and nonuniform with the increase of the content of NC-PAH,and the best is 20.58%evaluated by Raman spectra area ratio(AG/Aall).Overall,this work suggests a nitrogen content reference and a controlling technology of nitrogen for the preparation of superior MCMB.
