Effects of ultrasonic irradation on the upgradation of lube base oil investigated using terahertz time-domain spectroscopy

The use of physical fields to treat and degrade petroleum products has sparked considerable controversy. To our knowledge, no work studying the effects of the ultrasonic treatment of lube base oil (LBO) has been conducted to date. Terahertz time-domain spectroscopy (THz-TDS) was employed to characterize the optical parameters of LBO subjected to annealing and ultrasonic treatments. Specifically, for an LBO with a higher alkane content, annealing and ultrasonic methods can effectively increase its kinematic viscosity (KV), whereas the KV of LBO with a higher aromatic content is reduced under an ultrasonic field during 4, 6 and 12 h sonication treatments. The degradation mechanism was determined for each method based on the characteristic absorption peaks in the THz region. The results indicated THz-TDS has great potential for the identification of degradation mechanisms in the petroleum industry.