Asphaltenes formation during thermal conversion of deasphalted oil

Joy H. Tannous, Arno de Klerk

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)


New asphaltenes are formed during the thermal conversion of heavy oil. When new asphaltenes are formed from deasphalted oil, it erodes the conversion advantage provided by solvent deasphalting prior to visbreaking. The postulate that asphaltenes formation is caused by free radical addition reactions was evaluated. Indene was employed to exacerbate asphaltenes formation during thermal conversion of deasphalted oil at 400 °C. Evidence was provided that indene was involved in addition reactions with itself and with deasphalted oil to produce new n-pentane insoluble material. Whether indene induced increase asphaltenes formation, or whether it formed addition products with the deasphalted oil was not resolved. Self-reaction of indene at 400 °C resulted in extensive formation of n-pentane insoluble material. Formation of n-pentane insoluble material was reduced in mixtures with indane and naphthalene. Using these model systems the presence and nature of addition products was determined. The reported thermal conversion of indene was consistent with reaction chemistry based on molecule-induced homolysis, free radical addition, and propagation / termination by hydrogen transfer. The prevalence of addition reactions and the importance of hydrogen transfer reactions were highlighted, which have implications for modelling reaction chemistry describing thermal conversion of heavy oil.

Original languageEnglish
Article number115786
Publication statusPublished - Nov 1 2019
Externally publishedYes


  • Asphaltenes
  • Deasphalted oil
  • Free radical addition
  • Hydrogen disproportionation
  • Molecule-induced homolysis
  • Visbreaking

ASJC Scopus subject areas

  • General Chemical Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Organic Chemistry


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