Thermal and mass spectrometer analysis (TG-DTG-MS) of different oAPI gravity crude oils from new oil fields in Turkey

In this research, thermal analysis and kinetics of four different crude oil samples (oAPI range of 21.1-34.1) from different new oil fields of Turkey were studied using thermogravimetry (TG-DTG) coupled with a quadruple mass spectrometer (MS). Mixtures of crude oils and limestone matrix are prepared to give a composition of 15 % wt. crude oil in the matrix and the ramped temperature experiments are performed at different heating rates (10, 20 and 30 degrees C/min) under air atmosphere. In TG-DTG analysis three different reaction regions were observed, known as low temperature oxidation (LTO), fuel deposition (FD), high temperature oxidation (HTO) and finally limestone decomposition, respectively. In MS analysis, combustion products of different crude oils on the basis of both relative intensities and relevancy was monitored simultaneously. Finally, two different model free kinetic methods known as Ozawa-Flynn-Wall (OFW) and Kissinger-Akahira-Sunose (KAS) were used to determine the activation energy of the crude oil samples. It was observed that the activation energy values are varied between 189.47 and 290.41 kJ/mol (OFW method) and 181.75-288.37 kJ/mol (KAS method) in HTO region, respectively.