Effect of graphite nanoparticles on CO2 hydrate phase equilibrium

• Hydrate formation conditions in nanofluids was discussed in the article.
• An improved method was used to determine the hydrate formation conditions.
• A model was proposed to predict the conditions of hydrate formation.

Stepwise heating method was used to determine the hydrate phase equilibrium in the water containing graphite nanoparticles. The results show that, compared with deionized water at a given temperature, a significant upward shift of the formation pressure of the CO2 hydrate formed in graphite nanoparticles suspensions was observed, but the phase equilibrium curves of CO2 hydrate formation in the different graphite nanoparticles concentrations were basically consistent. In this regard, graphite nanoparticles have a negative effect on the gas hydrate formation. In addition, an improved hydrate thermodynamic model was proposed to predict the hydrate equilibrium conditions under the system of graphite nanoparticles suspensions. The results show that the maximum average deviation of pressure predicted by model is 3.39, but the minimum average deviation is 2.21. It indicates that the data of the model prediction was good agreements with the data obtained from experiments.