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A thermodynamic framework for modeling semiclathrate hydrate phase stability conditions in gas + tetra‐n‐butyl ammonium halide aqueous solution system
Author(s) -
Parhizgar Hossein,
Javanmardi Jafar,
Mohammadi Amir H.,
Moshfeghian Mahmood,
Parvasi Payam
Publication year - 2018
Publication title -
asia‐pacific journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.348
H-Index - 35
eISSN - 1932-2143
pISSN - 1932-2135
DOI - 10.1002/apj.2199
Subject(s) - clathrate hydrate , chemistry , fugacity , halide , aqueous solution , dissociation (chemistry) , activity coefficient , hydrate , thermodynamics , ammonium fluoride , tetra , inorganic chemistry , ammonium bromide , bromide , pitzer equations , organic chemistry , pulmonary surfactant , biochemistry , physics , medicinal chemistry
Abstract To estimate the dissociation conditions of semiclathrate hydrates in gas + tetra‐n‐butyl ammonium halide aqueous solution systems, we introduce an extended thermodynamic framework, which was originally proposed by Javanmardi and colleagues for modeling of gas hydrate dissociation conditions in aqueous solutions of electrolytes (12 [1998] 219–222, Energy and Fuels). For evaluating the hydrate dissociation conditions, we apply the van der Waals–Platteuw theory. In addition, we incorporate the Peng–Robinson equation of state and the activity coefficient model of Pitzer and Mayorga to respectively calculate gas/vapor fugacity and tetra‐n‐butyl ammonium halide activity coefficient. Using this model, we have estimated the semiclathrate hydrate dissociation conditions in the systems of CH 4 , N 2 , or CO 2 + tetra‐n‐butylammonium bromide + water; CO 2 + tetra‐n‐butylammonium fluoride + water; and CH 4 or CO 2 + tetra‐n‐butylammonium chloride + water systems. The model results are found in satisfactory agreement with the selected experimental data collected from literature. Also, the average absolute temperature deviations for the studied systems are about 0.3 K.