Title: Systematic investigation of the conversion of asphaltenes during hydrothermal upgrading process of heavy crude oil in the presence of supercritical water

Authors: Djimasbe Richard; Ameen Ahmed Al-Muntaser; Michael Kwofie; Rustam R. Davletshin; Mikhail A. Varfolomeev; Boudkhil Affane; Dmitry Aleksandrovich Feoktistov

Addresses: Department of Petroleum Engineering, Kazan Federal University, Kremlevskaya 18, Kazan 420008, Russia ' Department of Petroleum Engineering, Kazan Federal University, Kremlevskaya 18, Kazan 420008, Russia ' Department of Petroleum Engineering, Kazan Federal University, Kremlevskaya 18, Kazan 420008, Russia ' Alexander Butlerov Chemistry Institute, Kazan Federal University, Kremlevskaya 18, Kazan 420008, Russia ' Department of Petroleum Engineering, Kazan Federal University, Kremlevskaya 18, Kazan 420008, Russia ' Department of Petroleum Engineering, Kazan Federal University, Kremlevskaya 18, Kazan 420008, Russia ' Department of Petroleum Engineering, Kazan Federal University, Kremlevskaya 18, Kazan 420008, Russia

Abstract: This study is devoted to investigating the transformation of asphaltenes of heavy oil in the supercritical water (SCW) with (water/oil of 1:2, 1:1 and 2:1) at 400°C. The results indicated that increasing the ratio of water/oil, the amount of maltenes increases from (78.39%-85.27%) to (82%-94.2%) and the asphaltenes decreases from 6.33% to 2.58% and 6.33% to 1.14%, respectively. FTIR spectroscopy and GC/MS showed that the maltenes yields increase because of a mechanism reactions of dealkylation of aromatic structures which took place, resulting an increase of aromaticity asphaltenes and alkyls structure (-CH₃ and -CH₂-) in maltenes fractions. Therefore, the optimal condition of upgrading are of (water/oil of 2:1), the time between 30-60 min with a significant decrease of asphaltenes. This average size of asphaltenes ranging from 79.48 nm to 72.97 nm can decreases the early deposition velocity on the equipment during the production and transporting process. [Received: July 21, 2021; Accepted: August 26, 2021]

Keywords: heavy oil; hydrocarbon; supercritical water; SCW; conversion; upgrading; asphaltenes; cracking; dehydrogenation; GC-chromatography; FTIR spectroscopy.

DOI: 10.1504/IJOGCT.2022.125055

International Journal of Oil, Gas and Coal Technology, 2022 Vol.31 No.1, pp.18 - 37

Received: 20 Jul 2021
Accepted: 26 Aug 2021
Published online: 24 Aug 2022 *

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