Abstract Inorganic salts can thermodynamically inhibit gas hydrate formation. However, some inorganic salts at low concentration can act as a kinetic hydrate promoter. The mechanism of kinetic hydrate promotion in the presence of low concentration of inorganic salts is still unknown. This paper presents an experimental study into methane hydrate formation in an impeller-agitated vessel in the presence of sodium halides and alkali metal chlorides at low concentrations. It is shown that alkali metal chlorides and sodium halides at low concentration can reduce the induction time and kinetically promote gas hydrate formation. It has been proposed that bubbles form inside the agitated vessel as a result of the gas pocket break-up. Simulated gas pocket break-up studies show a smaller gas bubble formation in the salts solution with low concentrations in comparison with in the pure water. The small bubbles formation leads to an increase in the gas-water interface area and gas hold-up of the vessel. Consequently, there will be an increase in the mass transfer for gas hydration formation. In addition, the strength of hydrogen bonds at the gas/water interface affect the gas dissolution rate into the aqueous phase. Ions that have more affinity for the interface order water molecules weakly and improve the gas hydrate formation. Bubbles zeta potential measurements also confirm the ion-specific effect of the applied salts at the gas-water interface. Ultimately, gas-water interfacial area and ion-specific effect play critical roles in the gas hydrate formation.

中文翻译：

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低盐浓度条件下天然气水合物形成动力学与表面离子分布之间的联系

摘要 无机盐可以在热力学上抑制天然气水合物的形成。然而，一些低浓度的无机盐可以作为动力水合物促进剂。在低浓度无机盐的存在下，动力学促进水合物的机制仍然未知。本文介绍了在低浓度卤化钠和碱金属氯化物存在下，在叶轮搅拌容器中形成甲烷水合物的实验研究。结果表明，低浓度的碱金属氯化物和卤化钠可以减少诱导时间并在动力学上促进天然气水合物的形成。已经提出由于气泡破裂而在搅拌容器内形成气泡。模拟气袋破裂研究表明，与纯水中相比，在低浓度盐溶液中形成的气泡较小。小气泡的形成导致气水界面面积和容器的气体滞留量增加。因此，气体水合形成的传质将增加。此外，气/水界面处氢键的强度影响气体溶解到水相中的速度。对界面具有更大亲和力的离子对水分子的排序较弱，并改善了天然气水合物的形成。气泡 zeta 电位测量也证实了在气-水界面应用盐的离子特异性效应。最终，气水界面面积和离子特异性效应在天然气水合物的形成中起关键作用。