Coal tar pitch is a product with high carbon content and aromatic compounds. Modified coal tar pitch is a high quality raw material for the preparation of intermediate phase pitch, needle coke, carbon microspheres, et al. In this paper, modified coal tar pitch was used as raw material, nitrogen was used as protective gas, and thermal conversion was carried out at constant temperatures (370, 390, 410, 420 °C). Polarized light microscopy, SEM, elemental analysis, FTIR spectroscopy, Raman spectroscopy and XRD diffraction combined with split-peak fitting were used to characterize the microstructures of the thermal transformation products. The results showed that the Iar and CH3/ CH2 contents of the products increased with the gradual increase of the thermal conversion temperature, and the aromatic content increased. And the higher the temperature at the same heating rate, the more the ideal graphite microcrystal content, and the defective graphite microcrystals are converted into ideal graphite microcrystals during the thermal conversion process. When the reaction temperature exceeds 390 °C, the microstructure of the thermal transformation products is anisotropic spheres, and the small spheres fuse with each other and tend to be basin-like and mosaic structure as the temperature increases.

    Abstract
    1 Introduction
    2 Experiment
        2.1 Raw materials and reagents
        2.2 Preparation of MCTP-80
        2.3 Thermal conversion study of MCTP-80
        2.4 Characterization methods
    3 Results and discussion
        3.1 Property analysis and elemental analysis of MCTP-80 and thermal transformation products
        3.2 Microstructure of MCTP-80 and thermal transformation products
        3.3 Changes in Iar and CH3CH2 of MCTP-80 and thermal transformation products
        3.4 Raman analysis of MCTP-80 and thermal transformation products
        3.5 XRD analysis of MCTP-80 and thermal transformation products
        3.6 SEM analysis of thermal transformation products
    4 Conclusion
    Acknowledgements 
    References

• Qi Li(College of Petroleum and Chemical Engineering, Liaoning Petrochemical University)
• Dongyun Han(College of Petroleum and Chemical Engineering, Liaoning Petrochemical University)
• Haiyan Qiao(College of Petroleum and Chemical Engineering, Liaoning Petrochemical University)
• Weiwei Shi(College of Petroleum and Chemical Engineering, Liaoning Petrochemical University)
• Yuqi Zhang(College of Petroleum and Chemical Engineering, Liaoning Petrochemical University)
• Zubin Cao(College of Petroleum and Chemical Engineering, Liaoning Petrochemical University)