Experimental Investigation of the Effect of Ultrasonic Wave on the Saturated Hydrocarbons in Castilla Crude Oil

Abstract

AbstractSaturated hydrocarbons in heavy crude oil are rarely investigated under ultrasonic treatment since the transformation of asphaltenes is a key part in heavy oil upgrading. To gain a more complete understanding of the cracking of compounds in heavy oil under ultrasonic wave, the effects of ultrasonic power and irradiation time on the saturated hydrocarbons in Castilla crude oil (Colombia) have been investigated. Functional groups and compound identification of saturated hydrocarbons in the crude oil before and after the ultrasonic treatment have also been analyzed by Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS) respectively. Experimental results show that at least 13 kinds of long-chain or multi-branched chain saturated compounds are cracked and disappeared in crude oil by ultrasonic wave. The irradiation time has more effect on the kind of saturated compounds than does the ultrasonic power. The content of saturated hydrocarbons declines by 32.5% at 40 min, but increasing 38.4% dramatically at 50 min. It seems that the cracking of heavy aromatic hydrocarbons contributes more to the increase of the content than that of asphaltenes or resins. The ratio value of infrared absorbance of methylene (=CH2) to methyl (–CH3) increases by 40.0% when the irradiation time is 40 min, but declining 22.6% at 50 min. The optimum value of the irradiation time or ultrasonic power in forming methyl compounds should be more than 50 min or 80 W respectively.KeywordsHeavy oilUltrasoundCavitationSaturated hydrocarbons