A new insight to the assessment of asphaltene characterization by using fortier transformed infrared spectroscopy

This research aims to present asphaltene fraction of oil by FTIR spectrum technique. For this purpose, three different oil samples with various SARA contents and almost identical API degrees were utilized in this research. Two asphaltenic oil samples were referred to as ‘A’ and ‘B’, and the aliphatic oil sample was named as ‘C’. First of all, the asphaltene fraction was extracted through the IP-143 test. The possible chemical bonds and functional groups were identified through NMR tests. Then, the FTIR spectrums of the oil samples and the extracted corresponding asphaltene fractions were taken. The interpretations were used to find the functional groups in the FTIR of the oil samples that belong to the asphaltene fractions. Among the investigated oil samples, no asphaltene related peak with a unique assignment was observed for the FTIR for sample ‘A’. The FTIR of oil sample ‘C’ showed amine related peaks, which belonged to the asphaltene fraction. Also, the alcohol and amine related peaks, which correspond to the asphaltene fraction, were detected in the FTIR of the oil sample ‘B’. According to the oil samples' SARA contents, the ratio of the asphaltene content to the aromatic-based fraction seems to have a key role in this method. In other words, to detect the functional groups attached to the asphaltene fraction from the FTIR spectrum, the asphaltene fraction should have enough concentration compared to other aromatic-based components in the oil. The method's applicability is initially based on the specific functional groups existence in the asphaltene fraction. • A functional group in oil that is found in the asphaltene can be used to trace the asphaltene content changes. • Tracing asphaltene content of the oil by using the FTIR spectrum could not be performed in all of the oil samples. • The ratio of the asphaltene content to the aromatic-based fraction seems to have a key role in this method.