Critical review of mutual diffusion coefficient measurements for liquid solvent + bitumen/heavy oil mixtures

Ghanavati, Mohsen; Abedi, Jalal

doi:10.1002/cjce.22000

Cited by 14 publications

(13 citation statements)

References 31 publications

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“…However, one can see from Table that there was a clear remarkable declining trend for the apparent molecular diffusion coefficients as the bitumen concentration and subsequently mixture viscosity increased. This observed trend clearly contradicts the counterintuitive trends found by some researchers, such as Oballa and Butler, and the absence of concentration dependency by Zhang and Shaw as discussed in Ghanavati et al…”

Section: Resultscontrasting

confidence: 65%

“…. However, in other techniques, the molecular diffusion coefficient cannot be considered as a constant for the designed experiments and, thus, the analysis would be more complex and demanding, introducing unwanted errors in the concentration dependency trends . Therefore, the results demonstrated here are free from inherent analysis error involved in other analysis techniques and can be considered as the actual physical behavior of the system.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, the solvent‐bitumen mass‐transfer phenomenon has been investigated more thoroughly in modeling and experimental studies. A critical review of available literature in liquid solvent + bitumen/heavy oil systems has been presented by Ghanavati et al The limited mutual diffusion coefficient data of liquid solvent + bitumen/heavy oil systems reported in the literature suffer from experimental limitations and analysis procedure difficulties that make their interpretation puzzling. Moreover, when solvent is placed on top of bitumen/heavy oil in a stagnant diffusion cell, asphaltene precipitates at the interface, forming a barrier that hinders the diffusion process.…”

Section: Introductionmentioning

confidence: 99%

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Application of taylor dispersion technique to measure mutual diffusion coefficient in hexane + bitumen system

Ghanavati

Abedi

2014

AIChE Journal

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A novel approach with fewer technical and analytic limitations in liquid solvent-bitumen diffusion studies is used in this article. The Taylor dispersion technique was selected for its convenient short run time experiments and reliable data analysis to find mutual diffusion coefficients in a hexane 1 bitumen mixture. For the first time, the infinite-dilution molecular diffusion coefficients of bitumen in hexane were measured in both the presence and relative absence of asphaltene particles in the solution at atmospheric pressure and temperatures of 303.15, 310.15, and 317.15 K. The polydisperse nature of bitumen was clearly revealed. Results were compared with common predictive tools. Also, the asphaltene surface charge in the hexane precipitating solvent was demonstrated. Through concentration dependency investigations at atmospheric pressure and 303.15 K, it was determined that the mutual diffusion coefficients monotonically decrease as the viscosity of mixture increases within the studied 0-34% volumetric concentration of bitumen. The Taylor dispersion technique shows great potential for diffusion studies of liquid solvent-bitumen systems.

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Section: Resultscontrasting

confidence: 65%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Application of taylor dispersion technique to measure mutual diffusion coefficient in hexane + bitumen system

Ghanavati

Abedi

2014

AIChE Journal

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“…It should be noted these values are in solvent finite dilution. A comprehensive survey of liquid molecular diffusion in literature was reviewed by Ghanavati et al (2014a). Using Equation 11, the concentration distribution was developed for various systems.…”

Section: Solvent Diffusionmentioning

confidence: 99%

Dissolution and Mobilization of Bitumen at Pore Scale

2015

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Steam injection, in various forms, has been commercially successful for in situ recovery from the oil sands. One of the recovery methods being tested -with an aim to reduce steam requirement -involves the injection of a suitable solvent, by itself, or in combination with steam. Solvents are being utilized at a pilot scale in both cyclic steam stimulation (CSS) and steam-assisted gravity drainage (SAGD) processes. The present study examines the mixing of a solvent with bitumen at the pore scale, using an analytical model with typical field data.The convective diffusion equation is solved for a spherical geometry, and applied to a drop of bitumen is a pore space. Calculations are done for a number of solvents, viz. pentane, and hexane. The rate of bitumen dissolution is determined for both static and dynamic conditions, for a number of velocities corresponding to typical field injection rates. The diffusion coefficients are taken from the latest laboratory data reported. Calculations are also done for heating of the bitumen (without solvent) for the same conditions. The resulting bitumen viscosity is compared as a function of time, for both solvent injection and heating.Results show that the time of solution of a bitumen drop in the solvent is of the order of days. The time varies with the type of solvent (largest for pentane), and the injection velocity. The times to attain the same viscosity by solvent injection in one case, and conduction heating in the other, respectively, differ by orders of magnitude. The significance of this finding for field application of solvents is discussed.The outcome of this research will improve our understanding about solvent diffusion and dispersion process for bitumen in porous media. This will help us to modify the current modelling approach to capture more realistic mass transfer and solvent/bitumen interaction in porous media.

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“…Yet, most of these solutions incorporate various simplifying assumptions that might limit their applicability or impose significant error in the calculation of the diffusivity constant. Consistency of the methods of measurement and the approaches implemented to analyze the collected data (i.e., parameter estimation method) has been a challenge …”

Section: Introductionmentioning

confidence: 99%

Measurements of Molecular Diffusion Coefficient and Solubility of Dimethyl Ether in Bitumen at T = (323.15–383.15 K) and P = (0.69–2.76 MPa)

2019

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We report the first comprehensive data set on the molecular diffusion coefficient of dimethyl ether (DME) in bitumen at a temperature range of 70–110 °C and pressures up to 2.76 MPa. A new experimental setup was introduced that allows accurate and reliable measurements of equilibrium solubility and molecular diffusion coefficient of gases in liquids at high pressures and temperatures. The experimental data on diffusional mass transfer of dimethyl ether (DME) into the bitumen is utilized to estimate the molecular diffusion coefficient while taking the liquid swelling into account. The results show that the molecular diffusion coefficient of DME is in the range of ∼0.2–2 × 10–9 m2/s depending on the operating conditions and viscosity of the mixture. The measured data find applications in the design and optimization of solvent-aided thermal recovery of bitumen and heavy oil.

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Critical review of mutual diffusion coefficient measurements for liquid solvent + bitumen/heavy oil mixtures

Cited by 14 publications

References 31 publications

Application of taylor dispersion technique to measure mutual diffusion coefficient in hexane + bitumen system

Application of taylor dispersion technique to measure mutual diffusion coefficient in hexane + bitumen system

Dissolution and Mobilization of Bitumen at Pore Scale

Measurements of Molecular Diffusion Coefficient and Solubility of Dimethyl Ether in Bitumen at T = (323.15–383.15 K) and P = (0.69–2.76 MPa)

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