Petroleum-based impregnating pitches were prepared from pyrolysis fuel oil (PFO) using a two-step heat treatment without a separation process. The pressurized heat treatment, the first step, was used to improve the properties of the pitches and enhance the product yield by promoting the cracking and polymerization of the components in the PFO. An atmospheric heat treatment as the second step was used only to synthesize the impregnating pitches from the liquid pitches prepared during the first step. The prepared impregnating pitches had the properties of a commercial petroleum-based impregnating pitch. The impregnation performance was evaluated by HT-XRD and an impregnation test. The HT-XRD results showed changes in the stacked structure of the pitches at the impregnation temperature. The bulk density of the carbon block was increased to 14.3% and the porosity was reduced by 10.3% after the impregnation/recarbonization process. The high reaction temperature during the first step induced the formation of quinoline insoluble (QI) components during the second step of the treatment, and the QI components adversely affected the impregnation process.

Preparation of petroleum impregnating pitches from pyrolysis fuel oil using two-step heat treatments
    Abstract
    1 Introduction
    2 Experimental
        2.1 Material and thermal treatment
        2.2 Impregnation and carbonization process
        2.3 Characterizations of PFO and the experimental pitches
    3 Results and discussion
        3.1 Characterization of PFO and liquid pitches after the first step of the treatment
        3.2 Characterization of impregnating pitches prepared by the two-step treatment
    4 Conclusion
    Acknowledgements 
    References

• Jong‑Eun Choi(Carbon Industry Frontier Research Center, Korea Research Institute of Chemical Technology (KRICT)/Advanced Materials and Chemical Engineering, University of Science and Technology (UST))
• Seunghyun Ko(Carbon Industry Frontier Research Center, Korea Research Institute of Chemical Technology (KRICT)/Advanced Materials and Chemical Engineering, University of Science and Technology (UST))
• Young‑Pyo Jeon(Carbon Industry Frontier Research Center, Korea Research Institute of Chemical Technology (KRICT)/Advanced Materials and Chemical Engineering, University of Science and Technology (UST))