Regular solution model for asphaltene precipitation from bitumens and solvents

Microcalorimetry Study of the Adsorption of Asphaltenes and Asphaltene Model Compounds at the Liquid–Solid Surface

“…For instance, asphaltenes are known to stabilize water-in-oil emulsions by forming a rigid and mechanically strong gel-like "skin" at the liquid-liquid interface that hinders coalescence and retards film drainage 3,4,5,6,7,8 . Asphaltenes are also known to precipitate and, under certain conditions, create deposit layers that in some cases result in plug formation 9,10,11,12 . This is perhaps one of the most undesirable problems encountered in oil production that leads to flow assurance issues and evidently, increases in operational costs.…”

Life, data, and everything

“…Following careful measurements and results interpretation, Yarranton's group is continuously working on the transference of this knowledge into useful technology for process calculations. This careful, painstaking work shows its value when used to model thermodynamic equilibrium of bitumens when contacted with hydrocarbon solvents [1]. The results are slowly making headway into process simulations.…”

Thermodynamic modelling of asphaltene precipitation and related phenomena

“…This is the case of Wang and Buckley [103], where a correlation with the refractive index of non-polar species is used to estimate the solubility parameter of the oil [103], reducing the uncertainty of the model. In the work of Yarranton et al [104][105][106], the bitumen or heavy oil is considered to consist of the SARA (saturates, aromatics, resins and asphaltenes) pseudocomponents, the solubility parameters of which are obtained from a correlation with enthalpy of vaporisation and molar volume data. Oil phases consisting of both asphaltene and non-asphaltene components are also assumed in the work of Mohammadi and Richon [107].…”

“…In particular, a number of authors [104][105][106][115][116][117][118][119] have developed thermodynamic models based on the Scott-Magat polymer theory [120,121], where the heterogeneous structure and polydispersity in the asphaltene molecular weight is taken into account in the model. Although there is recent practical evidence from sulphur analysis and speciation of reservoir crude oils that there are circumstances where polydispersity can be ignored at the molecular [73] and nanoaggregate/cluster [72] levels, polydisperse models have been developed to account for size and molecular weight distributions of aggregates due to asphaltene self-aggregation [115,119,122,123].…”

“…The first application of this type of model to study precipitation of an asphaltene fraction characterised by a molecular-weight distribution is that of Kawanaka et al [122] in which a gamma distribution is arbitrarily chosen [122]; the variance of the distribution is treated as an adjustable parameter. Although gamma distribution functions have been a common choice [105,106,115,124], Schultz-Zimm distribution functions [104] and fractal distribution functions [119,123] have also been suggested. A comparison between these different distribution functions is made in the study of Manshad and Edalat [117], where the use of a fractal distribution function leads to best agreement with experimental data.…”