We present an exact solution of quasi‐equilibrium model, based on pressure decay technique, to measure diffusion coefficient. The results of the quasi‐equilibrium model are compared with the traditional equilibrium model and it was found that the latter is only a special case of former one. We provide new approximate solution to estimate diffusion coefficient that is more convenient to use, compared with the previously reported approaches. It also reveals that our solution is capable of taking into account greater portion of the collected pressure decay test data and is more accurate. Based on the developed solution, estimation approaches, including linear method and exponential method, are presented and applied to analyze synthetic and experimental pressure‐decay data. The quasi‐equilibrium model is also compared with the traditional equilibrium model. The results reveal that analysis of the test data using equilibrium model may introduce large error in estimation of diffusion coefficient. © 2018 American Institute of Chemical Engineers AIChE J, 65: 434–445, 2019

中文翻译：

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通过压力衰减测试估算液体中气体扩散系数的一种分析方法

我们提出了一种基于压力衰减技术的准平衡模型的精确解，以测量扩散系数。将准平衡模型的结果与传统的平衡模型进行比较，发现后者只是前者的一种特殊情况。与以前报道的方法相比，我们提供了一种新的近似解来估计扩散系数，使用起来更加方便。这也表明我们的解决方案能够考虑到收集到的更大的压力衰减测试数据中的大部分，并且更加准确。基于开发的解决方案，提出了包括线性方法和指数方法在内的估计方法，并将其应用于分析合成和实验压力衰减数据。准平衡模型也与传统的平衡模型进行了比较。结果表明，使用平衡模型对测试数据进行分析可能会在扩散系数的估计中引入较大的误差。©2018美国化学工程师学会AIChE J，65：434–445，2019