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On the determination of diffusivities of volatile hydrocarbons in semi‐solid bitumen
Author(s) -
Tang Joseph S.
Publication year - 2001
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450790126
Subject(s) - hexane , limiting , toluene , asphalt , solvent , diffusion , chemistry , dispersion (optics) , residual , chromatography , analytical chemistry (journal) , thermodynamics , materials science , organic chemistry , composite material , mechanical engineering , physics , optics , algorithm , computer science , engineering
Residual volatile hydrocarbons in bitumen constitute a potential source of air pollution. Diffusivities of volatile components in bitumen are needed to assess the extent of environmental damages that could result from bitumen spill or working loss of vapour to the atmosphere. Knowledge of solvent dispersion is also required in the recovery of viscous bitumen by solvent displacement. This paper discussed the de‐coupled transfer model developed by Tang and Zhang and its limiting solution. Fu and Phillips' diffusion data were re‐interpreted based on the limiting solution with delay time correction. The diffusion coefficients of hexane iso‐hexane, cyclo‐hexane and toluene at 25°C were found to be 8.6 × 10 −8 cm 2 /s, 6.3 × 10 −8 cm 2 /s, 2.4 × 10 −8 cm 2 /s and 6.8 × 10 −8 cm 2 /s, respectively. Improper use of the limiting solution could lead to 25% over‐estimates of diffusion coefficients.