Dynamics of Asphaltene Aggregates under High-Pressure CO2 Revealed by Pulsed-Field Gradient NMR | Sciact - CRIS-system of Boreskov Institute of Catalysis

Dynamics of Asphaltene Aggregates under High-Pressure CO2 Revealed by Pulsed-Field Gradient NMR Full article

Journal

Energy and Fuels
ISSN: 0887-0624 , E-ISSN: 1520-5029

Output data

Year: 2023, Volume: 37, Number: 22, Pages: 17215–17226 Pages count : 12 DOI: 10.1021/acs.energyfuels.3c02862

Tags

Aromatic compounds,Diffusion,Hydrocarbons,Precipitation,Transport properties

Authors

Morozov Evgeny V. ^1,2,3 , Trukhan Sergey N. ^3,4 , Kozhevnikov Ivan V. ^3,4 , Peterson Ivan V. ^1,3 , Martyanov Oleg N. ⁴

Affiliations

1	Institute of Chemistry and Chemical Technology, Federal Research Center “Krasnoyarsk Science Center of Siberian Branch of the Russian Academy of Sciences”, Krasnoyarsk 660036, Russia
2	Kirensky Institute of Physics, Federal Research Center “Krasnoyarsk Science Center of Siberian Branch of the Russian Academy of Sciences”, Krasnoyarsk 660036, Russia
3	Federal Research Center “Krasnoyarsk Science Center of Siberian Branch of the Russian Academy of Sciences”, Krasnoyarsk 660036, Russia
4	Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia

Funding (1)

Russian Science Foundation

21-13-00171 (121060300118-3)

The work demonstrates the results of the first experimental PFG NMR study in situ of the complex phase behavior of asphaltenes in the presence of high-pressure CO2. To perform the experiments, a series of sealed, thick-walled quartz capillaries were prepared with a mixture of CO2 and asphaltenes dissolved either in chloroform or benzene at different initial concentrations. Then, the temperature dependence of the diffusion coefficients of the asphaltene aggregates was measured for each sample after the mixture reached its equilibrium state, at which, in accordance with the solubility limit, only part of the initial asphaltenes remained dissolved. Despite quite low residual asphaltene concentrations in solution, experimental data clearly demonstrated the presence of aggregated structures (up to 70–80 wt %) attributed solely to nanoaggregates, with no signs of the presence of macroaggregates in the samples. Temperature dependencies of aggregate diffusivity clearly showed that the scenario, according to which the evolution of the asphaltene aggregates will develop, strongly depends on the initial asphaltene concentration, mass fraction of CO2 loaded into the system, and chemical nature of the solvent used. In particular, the most diluted asphaltene solution, expected to be the most resistive to the aggregation processes in a high-pressure CO2 environment, revealed the most pronounced aggregation-dependent translational dynamics as compared to those with a moderate initial asphaltene concentration. Contrarily, the concentrated asphaltene solution may not show drastic aggregation processes if the mass fraction of the CO2 loaded will not appear to be so high. Finally, the experimental results provide evidence that the temperature-triggered structural transformation of asphaltene aggregates due to the noncovalent bond breakup is not hindered under high-pressure CO2, but instead becomes more emphasized. The results obtained shed new light on asphaltene aggregate dynamics and brought new knowledge about the fundamental behavior of asphaltene in high-pressure CO2 conditions.

Morozov E.V. , Trukhan S.N. , Kozhevnikov I.V. , Peterson I.V. , Martyanov O.N.
Dynamics of Asphaltene Aggregates under High-Pressure CO2 Revealed by Pulsed-Field Gradient NMR
Energy and Fuels. 2023. V.37. N22. P.17215–17226. DOI: 10.1021/acs.energyfuels.3c02862 WOS Scopus РИНЦ ANCAN OpenAlex

Submitted:	Jul 31, 2023
Accepted:	Oct 20, 2023
Published online:	Nov 2, 2023
Published print:	Nov 16, 2023

Web of science:	WOS:001106320200001
Scopus:	2-s2.0-85178175215
Elibrary:	55926446
Chemical Abstracts:	2023:2256648
Chemical Abstracts (print):	185:71666
OpenAlex:	W4388296256

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