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BOLETÍN DE LA SOCIEDAD GEOLÓGICA MEXICANA http://dx.doi.org/10.18268/BSGM2009v61n3a3 |
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Modelo teórico para el cálculo de las solubilidades mutuas entre gases no–polares y agua con sales disueltas. Parte 1: Desarrollo de ecuaciones termodinámicas
Theoretical model to calculate mutual solubilities between non–polar gases and brines. Part 1: Development of thermodynamic equations
Renee J. Pérez1, Robert A. Heidemann2, Eduardo González–Partida3
1ExxonMobil Upstream Research Company 3120 Buffalo Speedway, Houston, TX 77098.
2 Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Drive Calgary, Alberta, Canada T2N1N4.
3 Centro de Geociencias, Universidad Nacional Autónoma de México, Campus Juriquilla, Boulevard Juriquilla 3001, 76230 Juriquilla, Querétaro, México.
* This email address is being protected from spambots. You need JavaScript enabled to view it..
Abstract
We propose a thermodynamic model for the equilibrium of non–polar gases, water and aqueous sodium chloride solutions valid to high pressures, high temperatures, and to high ionic strength solutions. The model couples Henry's Law and an equation of state to reproduce experimental data in the aqueous phase and the gas–rich fuid phases. The standard state chemical potential of the solute in brines is related to the standard state chemical potential of the solute in pure water through a salting–out or Setschenov coefficient. The salting–out coeffcients are obtained from experimental data. The model reproduces all crucial phenomena, including three phase equilibrium, at temperatures below the critical temperature of water. The modeling approach cannot account for gas–gas equilibrium phenomena that occur in the vicinity of the water critical point, nor for the hydrate–vapor–liquid equilibrium near the melting point of water.
Key words: Gases, brines, solubility, thermodynamics, water.
