Prediction of Hydrate Formation Temperatures in Salt–Alcohol Inhibitor Systems Using an Improved Activity Model

Hydrate formation severely affects offshore petroleum operations. Accurate prediction of hydrate formation temperature is crucial for developing prevention and control strategies. This work proposes an improved activity coefficient model for salt–alcohol inhibitor systems. Alcohol–water interactions are described using the UNIFAC-Dortmund model, while salt effects are represented by the Bromley model. The combined activity coefficient is coupled with a multiphase flash calculation and the van der Waals–Platteeuw (vdW–P) framework to predict hydrate equilibria. The model is validated for pure CH4, CH4–CO2 mixtures, and CH4–C2H6–C3H8 blends under various inhibitor conditions. Prediction accuracy was evaluated using the average absolute deviation (AAD) and average absolute relative deviation (AARD). The results show good agreement with experimental data and demonstrate higher accuracy compared with previous models.