Ranking of kinetic hydrate inhibitors using a high pressure differential scanning calorimeter

A High Pressure Differential Scanning Calorimeter (HP-µDSC) was used to characterize the kinetic inhibition performance of several kinetic hydrate inhibitors (KHIs) up to 390 bar (39 MPa) of model natural gas. A novel protocol was devised to increase the spread between effective KHIs to obtain their performance ranking. The natural gas used in the study was a mixture of 90 mol% methane and 10 mol% propane. Linear cooling ramps at a constant cooling rate of 0.5 K/min were used under isobaric conditions. Both the formation temperature of natural gas hydrate during a linear cooling ramp and the amount of hydrate formed were used for comprehensive analysis. The second method was based on the growth inhibition of natural gas hydrates and opened a new possibility that only several repeat measurements may be sufficient for fast screening of good KHIs. The results showed that HP-µDSC is a promising tool for the evaluation of kinetic inhibition performance of KHIs that can only be obtained in minute quantities.