Kinetic analysis and comparison of the coking behavior of coal Tar oil

This article focused on the coking characteristics of aromatic oils derived from coal tar. The study examines fresh and degraded lighter oils with a density up to 1045 kg/m³ and a naphthalene content below 7%, as well as heavier oils with a density above 1055 kg/m³ and a naphthalene content exceeding 10%. The coke residue yield was assessed and the component composition was determined via gas chromatography-mass spectrometry (GC-MS). Results showed that light oil exhibited a higher tendency to form coke compared to heavy oil. Oxidation products formed during oil operation within a concentration range of 0.1-0.3%, with a higher concentration of these products observed in light oil. Thermogravimetric analysis confirms that light oil residue degrades in a more controlled manner, resulting in higher coking ability due to rapid decomposition and favorable coke precursor kinetics. In contrast, heavy oil undergoes slower, more complex decomposition, forming denser, more graphitic coke. FTIR confirms that light oil has higher coking ability due to its aliphatic content and reactive groups (C = O, OH), with a 9.0% C = O peak at 1771-1772 cm⁻¹ absent in heavy oil. In contrast, heavy oil forms denser coke with lower yield due to its stable aromatic nature.