Effect Of Ultrasonic Wave On The Stability Of Mixed Crude Oil

Due to the demand of crude oil and the lack of domestic crude oil resources, oil blending is an attractive solution to obtain a quality feedback. Asphaltene aggradation in a mixed crude oil has great impact on the process of transportation and refining. Therefor, it is important to study of the stability of mixed crude oil.In this thesis, the UV light transmittance was used to determined the flocculation points of mixed crude oil for evaluation the stability of mixed crude oil. Experimental results show that flocculation point of the mixed oil is negative (-9.036) when the content of northwest crude oil was 30～55%, which means the mixed oil was unstable and prone to asphaltenes deposition. Flocculation point of the mixed oil was 9.603 after ultrasonic radiation (800 W,40 KHz, radiation 10 min), which means the mixed oil was changed to stable. Ultrasonic radiation can also reduce the oil viscosity and carbon residue. The results of IR,1H-NMR, UV spectroscopy etc of the mixed crude oil and asphaltene showed that hydrogen bonds was weakened between asphaltene molecular and the association of Colloidal particles declined. C-C or C-H bond attached to aromatic rings was broken but the structure of aromatic hydrocarbon had not been changed. The aromaticity in asphaltene and molecular weight decreased too. The asphaltene deposition rate on the internal sureface of the pipe was impeded after ultrasonic radiation under 100～280℃in a dynamic thermal deposition experiment, which also proved that ultrasonic treatment could improve the stability of mixed crude oil.