Searching for synergy between alcohol and salt to produce more potent and environmentally benign gas hydrate inhibitors

Gas hydrates formation is a primary complication in the oil and gas industry. The most universal gas hydrate prevention agents are thermodynamic inhibitors. The most prominent is methanol (MeOH), which has high toxicity and evaporation losses. We experimentally studied the methane hydrate phase equilibria to systematically explore the synergism of MeOH and MgCl2. The new data extend the range of inhibitor concentrations and equilibrium temperatures studied for magnesium chloride systems. The higher the concentration of the components, the more potent the synergy. Parameters to quantify the synergism are proposed. The data were complemented by ice-freezing temperature measurements. The results indicate that the inhibitory properties of MeOH can be improved and consumption reduced by using its combinations with MgCl2 due to the superior salt' anti-hydrate activity and the synergistic effect. Partial replacement of the toxic MeOH with the safer and non -volatile MgCl2 could also reduce inhibitor losses and minimize environmental impact.