Kinetic Analysis of Asphaltene Conversion under Supercritical Water Conditions

Abstract

Kinetic studies of chemical compounds in crude oil are essential to provide a better understanding of the reaction mechanisms occurring under heavy crude oil upgrading conditions. This study analyzes the reaction kinetics of asphaltenes, the most complex fraction of crude oil, under supercritical water (SCW) conditions for the upgrading of heavy crude oil. Experimental data reported in the literature and a proper reaction scheme were analyzed to develop kinetic models capable of predicting the reactive behavior of asphaltenes and their reaction products. The results showed that asphaltenes are mainly converted to coke, while the selectivity toward maltene and gas compounds varies considerably concerning the reaction temperature. Additionally, produced maltenes undergo cracking reactions to produce gases or condensation/polyaddition, generating asphaltenes. Furthermore, the effect of NaOH on the diverse reaction rates during asphaltene conversion was analyzed. The predictions of the developed models show adequate agreement with the experimental data, corroborating that the proposed reaction scheme correctly represents the asphaltene transformation and its reaction products under SCW conditions.