Thermoanalytical evaluation of the thermal stability of petroleum distillatesDistillates with a boiling range of 250–425 °C

The thermal stabilities of petroleum distillates with boiling point (b.p.) in the range 250–425 °C produced from a medium Iraqi crude oil were evaluated using different thermoanalytical techniques: differential scanning calorimetry; thermogravimetry; and differential thermogravimetry. Results obtained from these methods were correlated with some of the physico-chemical properties of the distillates studied. It was shown by differential scanning calorimetry that the stability of the distillates increased with increase in their total aromatic constituents, but was not related to the total content of sulphur compounds present. Thermogravimetry indicated that the thermal stabilities of the distillates increased with increase in their corresponding average molecular weights.