In this communication, the prediction of gas hydrate formation conditions in the presence of sodium lignin sulfonate is predicted using two thermodynamic models. The first model employs the Peng-Robinson equation of state for the vapor phase, the UNIQUAC model for the activity coefficient of water, and Henry’s law constants for predicting gas solubility. In this model, sodium lignin sulfonate is treated as a molecule. The second model introduces an extended Peng-Robinson equation of state, tailored for electrolyte solutions, to calculate gas solubility and fugacity of components, with the activity coefficient of water set to unity. In this model, it is assumed that sodium lignin sulfonate and water undergo a reaction, resulting in the production of lignin sulfonic acid, sodium, and hydroxide ions. Both models are integrated with the van der Waals-Platteeuw theory to determine the conditions for gas hydrate formation. The results from the first model reveal that, for a given gas at different temperatures and sodium lignin sulfonate concentrations, the surfactant can exhibit inhibitory or promoting effects. Conversely, the second model suggests that, across all studied gases, an increase in sodium lignin sulfonate concentration corresponds to an elevation in hydrate formation pressure, signifying an improvement in inhibitory impact.

中文翻译：

---

木质素磺酸钠存在下形成笼形水合物


在本通讯中，使用两个热力学模型预测了木质素磺酸钠存在下的天然气水合物形成条件。第一个模型采用气相的 Peng-Robinson 状态方程、水活度系数的 UNIQUAC 模型以及预测气体溶解度的亨利定律常数。在此模型中，木质素磺酸钠被视为分子。第二个模型引入了针对电解质溶液定制的扩展彭-罗宾逊状态方程，用于计算气体溶解度和组分逸度，并将水的活度系数设置为 1。在此模型中，假设木质素磺酸钠和水发生反应，产生木质素磺酸、钠和氢氧根离子。这两个模型都与范德华-普拉特理论相结合，以确定天然气水合物形成的条件。第一个模型的结果表明，对于不同温度和木质素磺酸钠浓度下的给定气体，表面活性剂可以表现出抑制或促进作用。相反，第二个模型表明，在所有研究的气体中，木质素磺酸钠浓度的增加对应于水合物形成压力的升高，这意味着抑制作用的改善。