کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4698270 1637540 2016 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Ab initio thermodynamics of magnesium carbonates and hydrates in water-saturated supercritical CO2 and CO2-rich regions
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات ژئوشیمی و پترولوژی
پیش نمایش صفحه اول مقاله
Ab initio thermodynamics of magnesium carbonates and hydrates in water-saturated supercritical CO2 and CO2-rich regions
چکیده انگلیسی

ab initio Thermodynamics is used to determine how free energies of magnesium carbonates and hydrates in a CO2-rich environment change with water concentration across a range temperature and pressure relevant to geochemistry and carbon sequestration (275 K to 375 K and pCO2 of 1 to 210 bar). The methodology is based on first principles density-functional theory (DFT) calculations of the total energies and vibrational entropy of periclase, magnesite, brucite, nesquehonite, and hydromagnesite coupled to the experimental chemical potentials of CO2 and H2O. The impact of water in supercritical CO2 (scCO2), even though less than 1% at saturation, is found to have a significant impact on the stability of hydrated carbonate minerals. Hydromagnesite and nesquehonite are found to be more thermodynamically stable than periclase and brucite in water-saturated scCO2 and hence may be expected to result kinetically from carbonation of these minerals during CO2 sequestration. Under dehydrating conditions nesquehonite destabilizes rapidly, whereas hydromagnesite is much more likely to persist in a CO2-rich environment, consistent with the observations that hydromagnesite is widespread in nature and nesquehonite is relatively rare.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Geology - Volume 434, 15 September 2016, Pages 1–11
نویسندگان
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