Investigation of Sonochemical Treatment of Ultrasound-assisted Cavitation of Heavy Hydrocarbon
Date
2020-09-24
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Abstract
Heavy oil from the oil sands production poses several limitations on transportation through pipelines and during processing into refined products due to its high viscosity. Partial upgrading of heavy oil targets meeting the pipeline specification with reduced viscosity with minimum diluent addition and provides higher valued hydrocarbon products. This study aims to investigate the viability of cavitation-assisted upgrading of heavy hydrocarbon with a proprietary additive at low temperature and ambient pressure. This study uses 20 kHz ultrasound through an ultrasonic horn to induce cavitation, also known as sonication. Cavitation is a phenomenon comprising of formation, growth and collapse of bubbles in a liquid medium. Collapse of bubbles lead to extreme conditions, creating regional hotspots capable of breaking chemical bonds and generation of free radicals. This study uses n-hexadecane (C16) as a model molecule. The effect of sonication showed a significant change in the conversion of n-hexadecane. For the samples treated with the additives at 230℃ under sonication, the conversion of n-hexadecane was 5.0±3.0%. The additives with decalin at 230℃ under sonication resulted in 9.3±0.7% conversion of n-hexadecane. The conversion of n-hexadecane corresponding to the modeling of cavitation-induced cracking at 25℃ and 250℃ were 0% and 3.7%, respectively. The pressure waves induced by sonoprobe excitations were measured experimentally with the acoustic emission sensor and high sampling rate data acquisition system. Using the obtained calibration constant of 1582.7 Pa/mV, the experimental acoustic pressure was 6.33 MPa which varied 6.79% from the theoretical acoustic pressure of 6.79 MPa. Cavitation has been extensively studied in the field of research in heavy oil. Cavitation is viewed as an effective and inexpensive alternative to initiate and enhance chemical reactions. Chemical and physical transformations induced by cavitation showed its possibility for enhancing cracking of petroleum feedstock. Cracking of petroleum feedstock includes yield in light and middle distillates, breakage of asphaltene contents and reduction in asphaltene agglomeration, reduction in sulfur, nitrogen and metals. The applications of cavitation for cracking have shown to improve the quality of heavy oil and reduce viscosity and density of heavy oil. This makes cavitation promising for partial upgrading of heavy oil.
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Keywords
Partial upgrading, Cracking, Cavitation, Heavy hydrocarbon, Sonication
Citation
Kim, B. (2020). Investigation of Sonochemical Treatment of Ultrasound-assisted Cavitation of Heavy Hydrocarbon (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.