Thermal characteristics and kinetics of crude oils and SARA fractions

• Peak temperatures were increased with increase in heating rate.
• Heavy parts lost most of their mass in the HTO.
• Heavy fractions start and end their reactions at higher temperatures.
• Heavy parts have high reaction intervals compared to the light fractions.
• Heavy parts have the highest activation energy.

In this study, two Turkish crude oils from southeastern part of Turkey and their saturate, aromatic and resin fractions were analyzed by thermogravimetric analysis (TGA). The experiments were performed at three different heating rates (5, 10, 15 °C/min) under air atmosphere. Two different reaction regions were observed from thermogravimetry (TG), differential thermogravimetry (DTG) curves due to the oxidative degradation of crude oil components. From TGA curves, it was detected that the heavier fraction, resins, lost considerable amount of its initial mass in the second reaction region. While saturates, the lightest part of the crude oil fractions, lost very small amounts of its initial mass in the second reaction region. The kinetic analysis of the crude oils and their fractions were also performed using different kinetic methods. It was deduced that the resins gave the highest activation energy and Arrhenius constant for both reaction regions.