Microwave heating as a novel route for obtaining carbon precursors from anthracene oil

Abstract

This work describes a novel route for the preparation of pitches by oxidative polymerization of an industrial anthracene oil (AO) in a microwave semi-pilot equipment consisting in a multi-mode applicator having a 2.45 GHz magnetron with variable microwave power. The experimental five variables of microwave heating of AO air-blowing range between 320 and 380 °C (temperature), 0.2–3.9 °C min−1 (heating rate), 1.5–5 h (soaking time), 16–20.5% (air/AO ratio) and 200–1500 g (initial weight). Their effect on the overall microwave air-blowing process is evaluated by means of a statistical analysis. A detailed characterization of the pitches has been carried out in terms of ultimate analysis, softening point, solubility parameters (toluene insolubles (TI) and quinoline insolubles (QI)) and thermogravimetric analysis. The experiments were also carried out by using conventional heating for comparative purposes. The detailed study of the electric energy consumption of the overall microwave treatment allows estimating a significant electric energy saving of about 20% when compared to conventional heating thus representing an excellent result in the production of carbon precursors.