Experimental measurements of phase equilibria conditions for methane hydrates containing methanol/ethylene glycol and NH4Cl solutions

Abstract

In this study, we performed experiments to obtain phase equilibrium data for methane hydrates in the presence of ammonium chloride (NH4Cl) and methanol/ethylene glycol (MeOH/MEG), for which there is currently no data. The measured three-phase (liquid–hydrate–vapor, L–HV) equilibrium data for methane hydrates containing MeOH/MEG and NH4Cl solutions in a temperature range 264–281 K and a pressure range 4–12 MPa may be useful in engineering applications. In addition, the hydrate inhibition performance of our aqueous inhibitor systems can be summarized as follows: (10 wt% NH4Cl + 20 wt% MeOH/MEG) > (5 wt% NH4Cl + 20 wt% MeOH/MEG) > (10 wt% NH4Cl + 10 wt% MeOH/MEG) > (5 wt% NH4Cl + 10 wt% MeOH/MEG). The dissociation enthalpies of methane hydrates containing the mixed inhibitor solutions were also calculated using the Clausius–Clapeyron equation, and the predicted values matched the experimental values well.