Study on Hydrate Formation and Foam Stability in a Liquefied Natural Gas–High Expansion Foam System

In the process of high expansion foam inhibiting liquefied natural gas (LNG) leakage evaporation, LNG and water in foam will generate hydrates in a normal pressure environment. In order to study the absorption effect of hydrate on LNG vapor, a hydrate formation device in an LNG–foam system was designed. The gas content experiment of hydrate was carried out to evaluate the inhibition effect of hydrate absorption on LNG evaporation, which provides a basis for improving the stability time of hydrate and reducing the escape rate of natural gas. Tetrahydrofuran (THF) will aggravate the foam drainage rupture, thereby weakening the stability of the foam. On the basis of adding a hydrate thermodynamic promoter, nanoparticles were added to enhance the stability of foam. The experimental results show that the foam half-life of 1 wt % THF and 0.5 wt % hydrophilic SiO2 nanoparticles is the longest, which is 1.7 times higher than that without additives. The gas absorption of hydrate formed in the compound system accounts for 57.5% of LNG evaporation gas, which is more than 4 times that without additives.