Neftyanaya Provintsiya 


Upgrading of ultra-viscous oil in sub- and supercritical aqueous fluid

R.R. Zakieva, N.Yu. Bashkirtseva



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This paper considers heavy oil aquathermolysis experiments in supercritical water conducted on reaction mixtures containing heavy oil, carbonaceous materials, and catalytically active rock-forming minerals.

The main characteristic feature of supercritical aquathermolysis products is increased content of paraffinic/naphthenic hydrocarbons: up to 76.2 wt% and 68.2 wt% for aquathermolysis products 4 and 5, respectively, compared to the original 40.8 wt%; whereas resin and aromatic fractions reduce. Aquathermolysis product 4 exhibits reduction of the aromatic and resin content from 13.7 to 4.1 wt% and from 37.8 to 13.1 wt%, respectively. Equidirectional change in the asphaltene content is also observed in aquathermolysis products: in experiments with hard coal (experiments 1 and 3) it has increased up to 9.9 and 9.2 wt%, respectively, compared to the original 7.7 wt%.

It has been demonstrated that aquathermolysis processes involve destruction of highmolecular-weight components and formation of normal and branched alkanes that have been absent in the original oil sample.

Resultant experimental data has been used to develop a process flow diagram of supercritical fluid technology for practical applications.

Key words:

ultra-viscous oil, asphaltene, aquathermolysis, oil upgrading, supercritical aqueous fluid


  1. Tumanyan B.P et al. Akvatermoliz neftey i prirodnykh bitumov: khimizm protsessa, katalizatory, perspektivy promyshlennoy realizatsii [Aquathermolyses of oil and natural bitumen: underlying chemistry, catalysts, potential for commercialization]. Uspekhi khimii, 2015, No. 84 (11), 1145 – 1175 pp. (in Russian)

  2. Desulfurization of hexyl sulfide and hexanethiol using supercritical water / Jimoon Kang [et al] // Journal of Supercritical Fluids. – 2019. – № 158. – P. 104734. (in English)

  3. Visbreaking of Heavy Oil under Supercritical Water Environment / Jun Liu [et al] // Industrial & Engineering Chemistry Research. – 2017. - №57 (3). (in English)

  4. Maity, S.K. Catalytic Aquathermolysis Used for Viscosity Reduction of Heavy Crude Oils: A Review / S.K. Maity, J. Ancheyta, G. Marroquın // Energy & Fuels. – 2010. – Vol. 24. – Р. 2809–2816. (in English)

  5. H. Machida. Green chemical processes with supercritical fluids: Properties, materials, separations and energy / H. Machida, M. Takesue, R.L. Smith // Journal of Supercritical Fluids/ – 2012. – Vol. 43. – Р. 2–1 (in English)


R.R. Zakieva, Kazan National Research Technological University

68, K. Marx st., Kazan, 420015, Russian Federation



N.Ju. Bashkirceva, Dr.Sc., Professor, Dean of Petroleum and Petrochemistry Faculty, Kazan National Research Technological University

68, K. Marx st., Kazan, 420015, Russian Federation


For citation:

R.R. Zakieva, N.Yu. Bashkirtseva Oblagorazhivanie sverhvjazkoj nefti v sub- i sverhkriticheskom vodnom fljuide [Upgrading of ultra-viscous oil in sub- and supercritical aqueous fluid]. Neftyanaya Provintsiya, No. 1(25), 2021. pp. 141-149. DOI (in Russian)


   © R.R. Zakieva, N.Yu. Bashkirtseva, 2021

       This is an open access article under the Creative Commons Attribution 4.0 License (