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An analytical method of estimating diffusion coefficients of gases in liquids from pressure decay tests
Author(s) -
Yang Zehao,
Bryant Steven,
Dong Mingzhe,
Hassanzadeh Hassan
Publication year - 2019
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.16408
Subject(s) - diffusion , exponential function , thermodynamics , mathematics , measure (data warehouse) , statistical physics , physics , computer science , mathematical analysis , database
We present an exact solution of quasi‐equilibrium model, based on pressure decay technique, to measure diffusion coefficient. The results of the quasi‐equilibrium model are compared with the traditional equilibrium model and it was found that the latter is only a special case of former one. We provide new approximate solution to estimate diffusion coefficient that is more convenient to use, compared with the previously reported approaches. It also reveals that our solution is capable of taking into account greater portion of the collected pressure decay test data and is more accurate. Based on the developed solution, estimation approaches, including linear method and exponential method, are presented and applied to analyze synthetic and experimental pressure‐decay data. The quasi‐equilibrium model is also compared with the traditional equilibrium model. The results reveal that analysis of the test data using equilibrium model may introduce large error in estimation of diffusion coefficient. © 2018 American Institute of Chemical Engineers AIChE J , 65: 434–445, 2019