标题： 二氧化碳在水中的溶解度：关于水合物成核的一些有用结果 显示英文标题

标题： Solubility of carbon dioxide in water: some useful results for hydrate nucleation

摘要： In this paper, the solubility of carbon dioxide (CO$_{2}$) in water along the isobar of 400 bar is determined by computer simulations using the well-known TIP4P/Ice force field for water and TraPPE model for CO$_{2}$. In particular, the solubility of CO$_{2}$ in water when in contact with the CO$_{2}$ liquid phase, and the solubility of CO$_{2}$ in water when in contact with the hydrate have been determined. The solubility of CO$_{2}$ in a liquid-liquid system decreases as temperature increases. The solubility of CO$_{2}$ in a hydrate-liquid system increases with temperature. 两条曲线在某个温度下相交，该温度决定了400巴下的水合物的解离温度（$T_{3}$）。 我们比较了预测结果与之前工作中使用直接共存技术获得的 $T_{3}$。 两种方法的结果一致，我们建议使用相同的色散相互作用截断距离，将 $T_{3}$的值设为290(2)K。 我们还提出了一种新颖且替代的方法，用于评估等压下水合物形成时化学位的变化。 新方法基于CO$_{2}$溶解度曲线的使用，当水溶液与水合物相接触时。 它严格考虑了CO$_{2}$水溶液的非理想性，提供了可靠的成核驱动力值，并与其他热力学方法得到的结果一致。 结果表明，在相同过冷度下，甲烷水合物的水合物成核驱动力比二氧化碳水合物更大。 我们还分析和讨论了色散相互作用的截断距离以及CO$_{2}$的占据率对水合物成核驱动力的影响。 显示英文摘要

摘要： In this paper, the solubility of carbon dioxide (CO$_{2}$) in water along the isobar of 400 bar is determined by computer simulations using the well-known TIP4P/Ice force field for water and TraPPE model for CO$_{2}$. In particular, the solubility of CO$_{2}$ in water when in contact with the CO$_{2}$ liquid phase, and the solubility of CO$_{2}$ in water when in contact with the hydrate have been determined. The solubility of CO$_{2}$ in a liquid-liquid system decreases as temperature increases. The solubility of CO$_{2}$ in a hydrate-liquid system increases with temperature. The two curves intersect at a certain temperature that determines the dissociation temperature of the hydrate at 400 bar ($T_{3}$). We compare the predictions with the $T_{3}$ obtained using the direct coexistence technique in a previous work. The results of both methods agree and we suggest 290(2)K as the value of $T_{3}$ for this system using the same cutoff distance for dispersive interactions. We also propose a novel and alternative route to evaluate the change in chemical potential for the formation of hydrate along the isobar. The new approach is based on the use of the solubility curve of CO$_{2}$ when the aqueous solution is in contact with the hydrate phase. It considers rigorously the non-ideality of the aqueous solution of CO$_{2}$, providing reliable values for driving force for nucleation of hydrates in good agreement with other thermodynamic routes used. It is shown that the driving force for hydrate nucleation at 400 bar is larger for the methane hydrate than for the carbon dioxide hydrate when compared at the same supercooling. We have also analyzed and discussed the effect of the cutoff distance of the dispersive interactions and the occupancy of CO$_{2}$ on the driving force for nucleation of the hydrate.