Experimental investigation of hydrate formation in a high pressure cell and comparison of the results with thermodynamic models

Natural gas is rapidly growing in global importance both as a primary energy source and a feedstock for downstream industry. Natural gas produced from reservoirs, usually coexist with formation water. At the proper conditions of pressure and temperature, coexistence of water with the small size molecules in natural gas, may lead to gas hydrate formation. Gas hydrates are solid crystalline compounds stabilized by the inclusion of suitably sized gas molecules inside cavities formed by water molecules through hydrogen bonding. Good thermodynamic models have been developed to predict hydrate dissociation conditions, but due to some uncertainties still the experimental study of this phenomenon is needed. In this study, an experimental test rig has been designed and installed for the measurement of hydrate dissociation conditions. Measurements can be made for pressures up to 50 MPa for different gas samples in the presence of pure water and inhibitors. To check the validity of the results obtained from this test rig, the hydrate dissociation temperature for a nitrogen gas sample has been measured for a pressure of 17.971 MPa (2607.25 psia). The measured data is compared with the predictions of three well known thermodynamic models. The results show that there is a good agreement between measured data and the predictions.