Oil dispersed nickel-based catalyst for catalytic upgrading of heavy oil using supercritical water

• Published in: Fuel (Guildford) 2022-04, Vol.313, p.122702, Article 122702
• Main Authors: Djimasbe, Richard, Varfolomeev, Mikhail A., Al-Muntaser, Ameen A., Yuan, Chengdong, Feoktistov, Dmitriy A., Suwaid, Muneer A., Kirgizov, Alexey J., Davletshin, Rustam R., Zinnatullin, Almaz L., Fatou, Saar D., Galeev, Ranel I., Rakhmatullin, Ilfat Z., Kwofie, Michael, Klochkov, Vladimir V., Prochukhan, Konstantin Yu
• Format: Article
• Language: English
• Subjects: Alkanes; Alkylation; Aromatic compounds; Aromaticity; Asphaltenes; Catalysts; Catalytic activity; Catalytic upgrading; Chemical analysis; Contamination; Dispersion; Heavy metals; Heavy oil; Isomerization; Magnetic resonance spectroscopy; Nickel; Nickel sulfide; Nickel-based catalyst; NMR; NMR spectroscopy; Nuclear magnetic resonance; Oil; Oil pollution; Oil-dispersed catalyst; Optical microscopes; Resins; Spectrum analysis; Supercritical water; Upgrading; Viscosity; Visual observation; Wastewater; Wastewater pollution; Wastewater treatment; Water pollution; Water splitting; Yield
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2021.122702

[Display omitted] •Ni-stearate significantly improved heavy oil upgrading performance in SCW.•NinSm, NiO, and Ni(OH)2 were in-situ formed as electrocatalyst for water splitting.•These Ni compounds as catalysts promoted isomerization and hydrogenation.•Using catalyst significantly reduced asphaltenes up to 98% in 60 mins.•Using catalyst yielded less contaminated wastewater and is environmentally friendly. Upgrading of heavy oil using supercritical water (SCW) has attracted a lot of attention recently due to the unique properties of SCW to act as hydrogen donor source and good solvent for organic matters. In this study, nickel-based oil-dispersed catalyst was used to intensify heavy oil upgrading in SCW. Its catalytic activity on upgrading performance and its influence on environment (from the point of the contamination of wastewater obtained after SCW treatments) were assessed. The result revealed that Ni-based catalysts increased the yield of upgraded oil to 89.73% from 81.99%, while reduced the yield of gases and coke to 8% and 2.27% from 14.92% and 3.09%, respectively. With catalysts, the heavy oil (API gravity 14° and viscosity 2073 mPa·s) was upgraded to light oil (API gravity 26.10° and viscosity 19.8 mPa·s) with a higher H/C ratio and lower content of S, N, and metals. Moreover, an obvious change in the composition and structure of upgraded oil was found, including a significant decrease in resins and asphaltenes content with an increase in saturate content; an increase in C7-C20 alkanes content with a decrease in C21-C30 alkanes; a significant conversion of poly-aromatics into di-aromatics; a decrease in the mean chain length (MCL), aromaticity factor (FCA), aromatic (Car carbons), and secondary + quaternary group (Csq) with an increase in primary group (−CH3, Cp) and tertiary group (Ct) in the structure of resins and asphaltenes, etc., proved by SARA analysis, elemental analysis, FTIR spectra, GC, GC–MS, and 13C NMR spectroscopy. In addition, we found that waste water was less contaminated by oil and paramagnetic ions, confirmed by visual observation, scanning optical microscope, and low-field NMR measurements. All these significant improvements in upgrading performance resulted from the in-situ transformation of oil-dispersed Ni-based catalysts into Ni3S2; Ni9S8; NiS; NiO; and Ni[OH]2 in oil environment. These in-situ formed active phases of Ni acted as electro-catalysts for water splitting reactions to promote the participation of water in upgrad