Measurement and Modeling of CO2 Solubility in Natural and Synthetic Formation Brines for CO2 Sequestration

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• 作者：Haining Zhao ; Robert Dilmore ; Douglas E. Allen ; Sheila W. Hedges ; Yee Soong ; Serguei N. Lvov
• 刊名：Environmental Science & Technology
• 出版年：2015
• 出版时间：February 3, 2015
• 年：2015
• 卷：49
• 期：3
• 页码：1972-1980
• 全文大小：449K
• ISSN：1520-5851

文摘

CO₂ solubility data in the natural formation brine, synthetic formation brine, and synthetic NaCl+CaCl₂ brine were collected at the pressures from 100 to 200 bar, temperatures from 323 to 423 K. Experimental results demonstrate that the CO₂ solubility in the synthetic formation brines can be reliably represented by that in the synthetic NaCl+CaCl₂ brines. We extended our previously developed model (PSUCO2) to calculate CO₂ solubility in aqueous mixed-salt solution by using the additivity rule of the Setschenow coefficients of the individual ions (Na⁺, Ca²⁺, Mg²⁺, K⁺, Cl^{鈥?/sup>, and SO₄2鈥?/sup>). Comparisons with previously published models against the experimental data reveal a clear improvement of the proposed PSUCO2 model. Additionally, the path of the maximum gradient of the CO₂ solubility contours divides the P-T diagram into two distinct regions: in Region I, the CO₂ solubility in the aqueous phase decreases monotonically in response to increased temperature; in region II, the behavior of the CO₂ solubility is the opposite of that in Region I as the temperature increases.}