Investigation of Kinetic Hydrate Inhibition Using a High Pressure Micro Differential Scanning Calorimeter

Abstract

Methane hydrate formation and decomposition were investigated in the presence of the kinetic inhibitor (Luvicap EG) and synergist (polyethylene oxide; PEO) using a high pressure micro-differential scanning calorimeter (HP-μDSC) with both temperature ramping and isothermal temperature programs. These investigations were performed using small samples in four different capillary tubes in the calorimeter cell. When the isothermal method was employed, it was found that Luvicap EG significantly delays the hydrate nucleation time as compared to water. The results obtained from the ramping method demonstrated that in the presence of Luvicap EG hydrate nucleation temperature was reduced. However, the presence of Luvicap EG promoted the extent of hydrate formation once nucleation had occurred. The addition of a small amount of PEO enhanced the nucleation inhibition capability of Luvicap EG further and decreased the promotion of hydrate growth. Additionally, hydrate formed in the presence of inhibitor decomposed at higher temperatures compared to pure water, indicating that while hydrate formation is initially inhibited; once hydrates form, they are more stable in the presence of inhibitor. Overall, this method proved a viable experimental technique, especially in the case of screening expensive and rarely available materials, such as biologically based inhibitors, before scale up.