May sediments affect the inhibiting properties of NaCl on CH4 and CO2 hydrates formation? an experimental report

The equilibria of methane and carbon dioxide clathrate hydrates were measured in presence a pure-quartz porous sand, with without NaCl. Two different salt concentrations tested: 0.030 0.037 wt%. Results compared phase equilibrium data already present literature for these species. Despite salt, the medium was found to promote process, mainly increased surface/volume ratio improved heat transfer. In sand affected process differently as function temperature: at values higher than 3 – 5 °C, it promoted while lower this range, but still greater ice-point, acted an inhibitor. However, results can be considered true only temperatures above ice point. Due similarity water hydrates, Raman microscale measurements performed gather information about influence sediments, temperature on OH-stretching vibrations water. obtained allowed clarify how addition NaCl, or sediments liquid water, under conditions (15 °C −15 °C), influenced hydrogen bonds. Specifically, changes vibrations, when correlated NaCl concentrations, demonstrated that partially inhibited effects probably due hydrophilic interactions silanol groups sediments. SEM showed morphological experimental conditions.