Abstract In the current study, the effect of tetra-n-butyl ammonium bromide (TBAB) and cyclohexane mixture on CH4 semi-clathrate hydrate formation was studied. Semi-clathrate dissociation conditions for CH4 + TBAB + cyclohexane + water were investigated at different concentrations of TBAB (0.05, 0.10, and 0.15) mass fraction in the presence of cyclohexane at the pressure and temperature ranges of 1–8 MPa and 275.1–295 K, respectively. In addition, a thermodynamic model was suggested to predict the phase equilibria of our system, which is divided into four phases, where the van der Waals–Platteeuw Solid Solution Theory has been used to predict the hydrate phase. For gas phase, The SRK equation of state was applied. For oil phase, the cyclohexane activity coefficient in the organic phase was calculated by the non-random two-liquid model (NRTL). Finally, to determine the activity coefficient of the electrolyte species in the aqueous phase, the semi-empirical electrolyte NRTL (eNRTL) activity model was used. The results showed that the proposed model has an acceptable agreement with the experimental semi-clathrate hydrate dissociation data with an approximately average absolute relative deviation of 5.4%.

中文翻译：

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在环己烷 (CH) 和四正丁基溴化铵 (TBAB) 混合物存在下 CH4 半笼形水合物相平衡的热力学建模和实验测量

摘要 在目前的研究中，研究了四正丁基溴化铵(TBAB) 和环己烷混合物对CH4 半包合物水合物形成的影响。在 1–8 MPa 和 275.1–295 的压力和温度范围内，在环己烷存在下，在不同浓度的 TBAB（0.05、0.10 和 0.15）质量分数下研究了 CH4 + TBAB + 环己烷 + 水的半包合物解离条件K，分别。此外，建议使用热力学模型来预测我们系统的相平衡，该系统分为四个相，其中范德瓦尔斯-普拉蒂乌固溶体理论已用于预测水合物相。对于气相，应用 SRK 状态方程。对于油相，有机相中的环己烷活度系数通过非随机两液模型（NRTL）计算。最后，为了确定水相中电解质物质的活性系数，使用了半经验电解质 NRTL (eNRTL) 活性模型。结果表明，所提出的模型与实验半笼形水合物解离数据具有可接受的一致性，平均绝对相对偏差约为5.4%。