Updating the parameters of existing model for prediction of gas hydrate formation conditions in aqueous electrolyte solutions

Gas hydrates are solid crystalline compounds similar to ice which belong to the clathrate category. Gas hydrates are basically combinations of light gases such as methane, ethane or carbon dioxidewith water molecules under certain temperature and pressure conditions. Blockage of oil and gas transmission lines due to the gas hydrate formation is a destructive experience in the petrochemical industry. This phenomenon, however, can be considered as a potential method for the separation and storage of Greenhouse gases such as carbon dioxide. Therefore, prediction of phase boundary of gas hydrate is essential to achieve this purpose. In 1999, gashydrate formation conditions in the presence of electrolytes using the Assberg-Petersen model to calculate water activity was predicted. In the present work, the parameters of this model were optimized again after updating the CH4, C2H6, C3H8 and CO2 hydrate data in the presence of electrolytes, NaCl_KCl_CaCl2. The calculated average absolute errors, AAD, are 0.12 K for CO2,0.18 K for CH4, 0.50 K for C2H6 and 0.10 K for C3H8. As it is obvious, the predicted values are in good agreement with experimental data.