Solubility of n-alkanes in supercritical CO2 at diverse temperature and pressure
Poor solubility of heavy hydrocarbons in CO 2 has limited the application of CO 2 -EOR (enhanced oil recovery) in modern oil recovery industry to some extent. Therefore, it is crucial to investigate the solubility regularity of different hydrocarbons in supercritical carbon dioxide (scCO 2 ) in the first place. In this paper, our objective is to explore the solubility of n -alkanes (C 6 H 14 –C 18 H 38 ) in scCO 2 . To measure cloud point pressures, the experiment utilizes high-pressure view chamber, and results for accuracy and repeatability of the experimental method and instrument are evidently positive. Then, cloud point pressures for n -alkanes from 318 K to 343 K show a proximately linear and positive correlation with the temperature; they also increase with expanding chain length of n -alkanes. In addition, the result of x (molar fraction of n -alkane at cloud point pressure) indicates that x has a positive correlation with the pressure at identical temperature, and when pressure is constant, temperature increase will reduce x . Finally, relationship studies between density of CO 2 and x reveal that, density of CO 2 has a positive influence on the solubility of n -alkane, and the Chrastil model corrects ln ρ and ln S data. The measured data align with the Chrastil model, with a maximum AARD value of 9.85%.
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