Comparison of different equations of state in a model based on VdW–P for prediction of CO2 hydrate formation pressure in Lw-H-V phase and a new correlation to degrade error of the model

• A model based on VdW–P model was implemented for prediction of hydrate formation pressure of CO2.
• Effects of different equations of state on predicted hydrate formation pressure for CO2 were studied.
• A new correlation to improve the results was presented then tested with experimental data.

Carbon dioxide plays a significant role in global warming. Formation of carbon dioxide hydrate is one of the several ways to remove this gas from the atmosphere. In order to attain a proper process design, pressure and temperature of the hydrate formation should be estimated.The empirical correlations, charts and thermodynamic model scan be used to predict these conditions.In this work, a model based on van der Waals–Platteeuw for prediction of hydrate formation conditions of CO2which uses four different equations of state, PR, RK, PT and ALS in Lw-H-V phase and in temperature range of 271.6 K–283.2 K is used and the results are brought out in order to compare with each other and with experimental data reported in the literature.Among PR, PT, RK and ALS equations of state, PR with total AADP of 2.52% shows better results than other equations of state.For the model based on VdW–P which uses PR as an equation of state a correlation is presented in order to reduce the amount of error which appears at high temperatures. This correlation reduces the amount of AADP for temperatures of hydrate formation higher than 280.44 K from 4.42 % to 1.04%.

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