In Parts I, II, and III, the Hu-Lee-Sum (HLS) correlation was demonstrated to be a robust method for determining the hydrate suppression temperatures for structure I and II hydrates containing inorganic salts and organic inhibitors. Here, Part IV introduces two different approaches to estimate the water activity for systems containing inhibitors: ice melting point and activity coefficient models. The ice melting point is translated into the water activity changes, which can then be directly used for the hydrate suppression temperatures. The great benefit of this method is its applicability to any inhibited systems with unknown compositions of inhibitors. The activity coefficient model is based on widely available models. These methods for determining the water activity allow for a simple yet reliable prediction of hydrate suppression temperatures for inhibited systems, which advocate for their use in place of the more traditional methods known to be less reliable and less accurate.

中文翻译：

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抑制系统的气体水合物抑制温度的普遍相关性：IV。水分活度

在第 I、II 和 III 部分中，Hu-Lee-Sum (HLS) 相关性被证明是确定含有无机盐和有机抑制剂的结构 I 和 II 水合物的水合物抑制温度的可靠方法。在此，第四部分介绍了两种不同的方法来估计含有抑制剂的系统的水活度：冰熔点和活度系数模型。冰的熔点被转化为水活度的变化，然后可以直接用于水合物抑制温度。这种方法的最大好处是它适用于任何含有未知抑制剂组成的抑制系统。活度系数模型基于广泛使用的模型。