Pyrolysis kinetics of atmospheric residue and its SARA fractions

Thermal analysis of atmospheric residue from heavy crude oil and its SARA fractions was carried out and the tendency of each fraction toward coke formation was determined. The coke yield was 16.3 wt.% for atmospheric residue, 43.1 wt.% for asphaltenes, 4.6 wt.% for resins, 3.8 wt.% for aromatics, and 0.3 wt.% for saturates. Pyrolysis kinetics of residue and its fractions, i.e., asphaltenes, resins and aromatics was also investigated. The TG experiments were conducted at three different heating rates of 8, 12, and 16 °C/min from room temperature up to 800 °C under nitrogen atmosphere to verify the weight variation with reaction temperature. Isoconversional analysis to fit data assuming first order kinetics was employed. Asphaltenes was the fraction that produces coke in higher amount having a range of activation energy of 41.0–58.6 kcal mol−1 whereas activation energy for atmospheric residue ranged from 11.5 to 30.0 kcal mol−1.