Comparative pyrolysis kinetics of heavy oil and its SARA fractions using distributed activation energy model

The pyrolysis behaviors of Qingdao vacuum residue(QD-VR)and its SARA(saturates,aromatics,reins,and asphaltenes)fractions were evaluated by thermo-gravimetric with mass spectrometer(TG-MS).The pyrolysis kinetics were determined by Friedman,one-parallel and four-parallel distributed activation energy model(DAEM),respectively.The results indicated that the pyrolysis behavior of QD-VR was similar to that of aromatics.For saturates,the release of H_(2),CH_(4),CO,and CO_(2) occurred in 80-400℃,while the temperature range for QD-VR and other fractions is 200-800℃.The average activation energy(Ea)via Friedman method was 179.72 kJ/mol and increased with the conversion ratio.One-parallel Gaussian DAEM was more suitable to describe the pyrolysis process of the single SARA fractions,while four-parallel Gaussian DAEM was more suitable to describe the pyrolysis process of heavy oil.Furthermore,comparing the weighted E_(a) from one-parallel(227.64 kJ/mol)and four-parallel Gaussian DAEM(204.63 kJ/mol),the results suggested that during pyrolysis process of heavy oil,there was an interaction between the SARA fractions,which could reduce the E_(a) of heavy oil pyrolysis.Specifically,during heavy oil pyrolysis,resins and asphaltenes could increase the E_(a) of saturates and aromatics,while saturates and aromatics could decrease the E_(a) of resins and asphaltenes.

Selection of Extraction Solvents for Bitumen from Indonesian Oil Sands through Solubility Parameters

Indonesian oil sands were systematically separated to investigate their basic composition.The extraction effects of the solvents with different Hilderbrand solubility parameters(HSPs)on the bitumen of Indonesian oil sands were compared.Furthermore,the Hansen solubility combination parameter(HSCP)and Teas triangle were used to explore rules in the separation of oil sands bitumen via solvent extraction.Finally,the saturates,aromatics,resins,and asphaltenes(SARA)fractions of the bitumen from Indonesian oil sands were analyzed.The results showed that the Indonesian oil sands were oil-wet with a bitumen content of 24.93%.The solvent extraction for bitumen could be accurately and conveniently selected based on the solubility parameter.When the HSPs of the extraction solvent were around 18–19 and the HSCPs were closer to a certain range(δ_(d)=17.5–18.0,δ_(p)=1–3.5,and δ_(h)=2–6),the extraction effect of bitumen from Indonesian oil sands improved,and the primary component affecting the extraction rate of bitumen were asphaltenes.