Bitumen Fractionation and Multicomponent Characterization of Solvent-Bitumen Systems

Date
2018-01-11
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Abstract
The phase behaviour and thermo-physical properties of solvent-bitumen systems are critical to design, optimize, and develop the solvent-based and solvent-aided recovery processes. This study presents experimental and modeling results on phase behaviour of light hydrocarbon solvents (methane, ethane, propane, and butane) and Athabasca bitumen fractions. In this work, a modified vacuum distillation system is developed to fractionate bitumen into four cuts. Boiling point distribution, density, viscosity, and molecular weight of each obtained cut are measured. Then, solvent solubility in each distillable bitumen fractions, density, and viscosity of liquid phase are measured using an in-house developed PVT apparatus at temperature and pressure ranges up to 190 oC and 6 MPa, respectively. A generalized solubility model is proposed in which the measured data of solvent solubility in bitumen cuts are used to develop the generalized binary interaction parameters between hydrocarbon solvents and each bitumen components. In this model, bitumen components are defined using the simulated distillation results and the binary interaction parameter correlation found for each solvent are used to calculate the solvent solubility in bitumen sample. Implementation of this model does not require measurements of solvent solubility in bitumen sample for tuning. The only input to this model is the boiling point distribution of the bitumen sample, which is obtained by simulated distillation test. Following the characterization of bitumen, solvent solubility in bitumen can be calculated using the generalized correlation of binary interaction parameter proposed in this study. The proposed generalized model showed promising results in prediction of the solubility of light hydrocarbon solvents in bitumen without need for extensive and costly solubility measurements. Another focus of this study is development of a method for characterization of heavy and extra heavy oils. The gel permeation chromatography (GPC) is combined with the simulated distillation (ASTM D7169) results and used to provide the molecular weight and boiling point distributions of very heavy and complex mixtures such as asphaltene and vacuum residue. The proposed model is properly validated and used to characterize the heaviest bitumen cut obtained by vacuum distillation.
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Keywords
Phase behaviour, Bitumen fractionation, k-value, Generalized model, Characterization methods, Solvent-aided recovery processes
Citation
Azinfar, B. (2018). Bitumen Fractionation and Multicomponent Characterization of Solvent-Bitumen Systems (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.