Nucleation of Methane Hydrate from Water and Aqueous Solutions of Malonic Acid in Glass Cells with Varying Surface Hydrophilicity

The work investigated the nucleation of methane hydrate from pure water and a 2 wt % aqueous solution of malonic acid. The experiments were conducted in glass vials with typical or increased surface hydrophilicity. To increase the surface hydrophilicity, treatment with a sulfochromic mixture followed by boiling in water was used. It has been shown that faster nucleation (shorter induction period) occurs on more hydrophobic walls. The induction period for 2 wt % solutions of malonic acid increases significantly, with this effect pronouncing more for the hydrophilized vials’ walls. The paper discusses possible reasons for such evolution. For malonic acid solutions in glass cells, visual observations have shown that hydrate nucleation preferably occurs not at the three-phase solution–glass–gas contact line but at the solution–glass interface.