The Next Generation of Hydrate Prediction: An Overview

The van der Waals and Platteeuw hydrate equation of state, coupled with the classical thermodynamic equation for hydrates, has been used in the prediction of hydrate formation for over 40 years. The standard state used in these equations is a hypothetical empty hydrate lattice. In part I of this series, we proposed an alternative derivation of these equations using a different standard state. The new hydrate equations were shown to be simpler to use. In part II of this series, we proposed an aqueous phase model tailored specifically for the presence of hydrate inhibitors such as salts and methanol in the aqueous phase. Part III provides a prescription for the incorporation of the new hydrate and aqueous phase models into a multi-phase Gibbs energy minimization program (CSMGem). Part IV compares predictions from the CSMGem program with four other commercially available programs. In this paper, we give a brief overview of each of the papers in the series, discussing the non-ideal solid solution hydrate model, incorporation of all fugacity models using the Gibbs energy minimization technique, and overall results of the CSMGem program.