Modelling the hydrate formation condition for sour gas and mixtures

In order to improve the predicting ability of hydrate formation condition for sour gas contained systems, the dissolution of gas in water and hydrolytic reaction equilibrium existing in aqueous phase was taken into account and two concepts, i.e., the true compositions and apparent compositions of aqueous phase, were introduced. And then the approach to determine the true compositions including ionic components was given and the modified method to calculate the component fugacity of aqueous phase was developed by introducing Debye–Huckel electrostatic contribution term. The new method coupled with Chen–Guo model was successfully used to predict the thermodynamics property of hydrates for carbon dioxide and hydrogen sulfide pure gases, binary, and ternary sour gas mixtures in pure water systems. The calculation precision is superior to that of original Chen–Guo model and CSMHYD hydrate software.