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

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 degrees 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]