A thermodynamic framework for modeling semiclathrate hydrate phase stability conditions in gas + tetra‐n‐butyl ammonium halide aqueous solution system

Abstract

To estimate the dissociation conditions of semiclathrate hydrates in gas + tetran-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-nbutylammonium 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.

Semi-clathrate hydrate phase stability conditions for methane + TetraButylAmmonium Bromide (TBAB)/TetraButylAmmonium Acetate (TBAA) + water system: Experimental measurements and thermodynamic modeling

“…Long et al [38] measured the hydrate phase stability conditions of CH 4 /CO 2 + TBAB + water systems in the P and T ranges of 0.54-14.57 MPa and 273.6-294.2 K, respectively. Alongside the experimental studies, various thermodynamic modeling studies on gas + ammoniumbased salts + water systems have been presented [39][40][41][42][43][44][45][46][47].…”