Viscosity Mixing Rules for Bitumen at 1–10 wt % Solvent Dilution When Only Viscosity and Density Are Known

Abstract

Viscosity is an important parameter to assess heavy oil and bitumen upgrading operations, such as bitumen dilution to meet pipeline viscosity specification limits. In conceptual design studies that involve blending of high-and low-viscosity materials, the experimental measurement of viscosity is impractical; therefore, such studies employ mixing rules to estimate mixture viscosity. Mixing rules for conceptual design evaluations where limited or no information apart from the viscosity and density of the bitumen and solvents is available were of interest. This study determined which viscosity mixing rules could be used with such limited input, what the predictive errors were, whether the performance of those mixing rules were measurably affected by changes in chemical composition, and if mixing rules could be applied at the <10 wt % solvent concentration in bitumen. Binary mixtures of 1−10 wt % of six different solvents (1-methylnaphthalene, decahydronaphthalene, 1,2,3,4-tetrahydronaphthalene, butylcyclohexane, butylbenzene, and n-decane) and Athabasca bitumen were prepared, and their viscosity, density, and refractive index were measured at 303, 313, and 333 K (30, 40, and 60 °C) and atmospheric pressure. The performance of mixing rules in predicting these properties for the binary mixtures at low solvent concentration was evaluated. It was found that the simple mixing rule, log [log (ν m + 0.7)] = Σw i log [log (ν i + 0.7)], and that by Miadonye et al. (Petrol. Sci. Technol. 2000, 18, 1−14) consistently gave the better viscosity estimation with an absolute average relative deviation (AARD) of around 30%. Within this uncertainty, there was no evidence indicating that the mixing rules could not be used for viscosity prediction of bitumen−solvent mixtures at low dilution levels. The mixing rules appeared not to be affected by the chemical nature of the solvent, and if it had an effect, it was of the same order or less than the uncertainty of viscosity prediction.

Hydrothermal Treatment of Bitumen Froth: Impact of Mineral Solids and Water on Bitumen Properties

“…In the literature, various theoretical models are available to predict the viscosity of different mixtures such as suspensions, bitumen–organic solvent mixtures, and water-in-oil (W/O) emulsions. − Some of these models were used to correct the measured viscosity of the contaminated bitumen in this study. Their corresponding equations and assumptions based on which these equations are applicable can be found in Section S5 (Tables S4 and S5) of the Supporting Information.…”

Visbreaking of Bitumen Froth: Influence of Minerals, Water, and Solvent on the Physicochemical Changes in the Bitumen Phase

“…For viscosity correction, the mixing rule proposed by Miadonye et al was used in this study. It was reported that for solvent concentrations ranging from 1 to 10 wt %, this mixing rule consistently provided the best viscosity estimation with an absolute average relative deviation (AARD) that varied in the range 0%–35%, depending on the solvent used . In the same study, it was also observed that viscosity overestimation increased with solvent content and that within the uncertainty of the estimation, there was no effect of the chemical nature of the solvent on viscosity prediction.…”

Viscosity–Temperature Relationship and Binary Viscosity Mixing Rules for Fast Pyrolysis and Hydrothermal Liquefaction Oil Blends

“…The calibration of the equipment was verified using a DKD (100 000 BW) certified viscosity standard at atmospheric pressure and temperatures up to 100 °C. Details on the instrument calibration can be found in ref 30.…”