Equilibrium Conditions of Carbon Dioxide and Ethane Gas Hydrate in the Presence of Binary Mixtures of Methanol and Sodium Chloride
Date
2014-04-03
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Abstract
For oil and gas production operations, in which the possibility of gas hydrate formation exists, methanol is used extensively to thermodynamically inhibit gas hydrate formation. In cases where sea water, or brine, are also produced along with the natural gas the dissolved salt will also thermodynamically inhibit gas hydrate formation. Thus, having quantitative information on the inhibiting effect of the mixed solution of methanol and NaCl can allow operators to fine tune the amount of methanol that needs to be added to a given stream.
In the current study, the three-phase equilibrium conditions of carbon dioxide and ethane gas hydrate formation, in the presence of mixtures of sodium chloride and aqueous methanol solutions, were experimentally determined. The experimental data were obtained in a sapphire variable volume cell by using the isothermal pressure search method. With each gas, the hydrates were formed in three different aqueous solutions of methanol and sodium chloride. The three solutions that were used were 5% methanol/10% NaCl, 10% methanol/10% NaCl and 10% methanol/5% NaCl. The experimental temperature ranged from 267.57 to 273.01 K and the experimental pressure ranged from 0.7 to 3.0 MPa. As expected, it was found that the pressure required to form the hydrates in the mixed inhibitor solution was greater than the pressure required to form the hydrates in pure water. However, it was also noted that the solutions had a greater inhibiting effect on the formation of carbon dioxide hydrates than on the formation of ethane hydrates. Finally, the experimental data was used to test the correlating capability of the equation of state of Clarke and Bishnoi (2004). It was seen that the equation of state was able to successfully correlate the experimental data.
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Engineering--Petroleum
Citation
Alqahtani, F. (2014). Equilibrium Conditions of Carbon Dioxide and Ethane Gas Hydrate in the Presence of Binary Mixtures of Methanol and Sodium Chloride (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/25930