摘要
获得CO2在地下咸水中的溶解度是CO2地质储存研究中亟待解决的问题,然而不同离子对CO2溶解度的影响却鲜有文献提及。为了填补实验数据的空缺,本研究设计了一套高压条件下CO2溶解度测量装置,克服了传统高压釜取样不便和实验重现性差的缺点;通过测定纯水中CO2的溶解度验证了实验装置和方法的精准性;测定了地质埋存条件下0.1 mol/L、0.2 mol/L和0.5 mol/L Ca Cl2、Mg Cl2溶液中CO2的溶解度。与文献结果不同,实验发现Ca2+对超临界CO2溶解度的影响小于Mg2+,并且CO2在两种溶液中的溶解度差异会受到温度和压力的影响。在本实验范围内,不同离子溶液中溶解度的最大差别高达18.53%,而几乎所有CO2溶解度模型文献都没有提及此变化。最后对溶解度随温度、压力以及离子种类变化的现象进行了理论分析。
The solubility of CO2 in the formation brines is a key issue in the studies of C02 geological storage. However, there are few data published for the effect of different ions on the solubility of CO2. In order to fill the gap of the experimental studies, the effect of Ca2＋ and Mg2＋ on the solubility of CO2 is explored in this research. A new apparatus was devised to measure the solubility of CO2 , which overcomes the inconvenience of sampling and the poor reproducibility of the traditional autoclave. In order to validate the accuracy of the new apparatus, several experiments measuring the solubility of CO2 in pure water were conducted. The solubility of C02 in aqueous CaC12 and MgC12 solutions of O. 1 mol/L, O. 2 mol/L and O. 5 mol/L was measured with the temperature ranging from 40°C to 70°C and the pressure from the standard atmosphere to 20 MPa. Under the supercritical state of CO2, with the increasing ion concentrations, this difference begins to show obvious regularity, that is, the effect of Ca2＋ on the solubility of C02 is weaker than Mg2＋ Within the experimental ranges of the temperature and pressure, the biggest difference resulting from these two spices of solutions reaches 18.53% , while almost all the models neglect that difference. Theoretical analysis of this trend was conducted. The impact of different ions on the solubility is mainly attributed to the ＂ salting-out effect＂. The impact of temperature, pressure and ions on the solubility was also analyzed.
出处
《水文地质工程地质》
CAS
CSCD
北大核心
2015年第5期22-28,共7页
Hydrogeology & Engineering Geology
基金
国家自然科学基金资助项目(41272387)
关键词
CO2溶解度
地质储存
地下咸水
PR方程
超临界
CO_2 solubility
geological storage
formation brine
Peng-Robinson equation of state
supercritical state
