Abstract: The influential mechanism of inorganic salt for the solubility of natural gas is investigated.The solubility of natural gas in salt solution is less than that in pure water,which results from the consumption of free water and the decrease of the effective interspace due to the aquation of inorganic ions.The theoretical coordination models of water molecules with the inorganic ions are proposed.A mathematical relationship between the volume fraction of free water and the concentration of salt is established.Base on the work above,a more general model for calculating gas solubility is proposed,which can be applied to both pure water system and brines with any concentration.This model can be applied in the temperature range of 0-150℃ and pressure 0~60MPa.From this model,it can be verified that the classical Henry's law and the solvating model of gas in pure water are the two particular cases under low pressure or when the concentration of salt is equal to zero.

Key words: natural gas, brines, ground water, solubility, solvating mechanisms, Solvating model

摘要： 无机盐对气体溶解度影响的主要机制是:无机离子的水合作用减少了游离水的量和降低了溶液的有效间隙度,从而使气体在盐溶液中的溶解度比在纯水中低.提出水分子与盐离子的理论配位模型,建立了盐溶液中游离水体积分数与盐的质量浓度的数学关系.在此基础上推导出与亨利定律和气体在纯水中溶解度方程具有良好相溶性的,更具一般意义的关于气体溶解度的基本方程.该方程既适用于任何浓度的盐溶液,也适用于纯水体系;适用的温度和压力范围分别为0～150℃和0～60MPa.亨利定律和气体在纯水中溶解度公式仅是本文公式在低压和盐浓度为零时的两种特例.

关键词: 天然气, 地下水, 盐水, 溶解机理, 溶解度, 方程