Hydrate phase equilibrium of hydrogen-natural gas blends: Experimental study and thermodynamic modeling

Blending hydrogen (H-2) into natural gas pipelines has become an effective way to transport H-2 on a large scale. Due to the difference in properties between H-2 and natural gas, the natural gas hydrate (NGH) phase equilibrium will be changed after blending H-2, which influences the flow assurance in pipelines. In this work, hydrate phase equilibrium for CH4 + H-2 , CH4 + C2H6 + H-2 , and CH4 + C2H6 + C3H8 + H-2 multicomponent systems had been measured at a temperature range from 274.24 K to 289.59 K by the isochoric pressure-search method. The results show the inhibition effect on CH4 hydrate formation of blending H-2 to 20% is a little better than the 5.0 wt.%CH3OH solution. In addition, the Chen-Guo model was adopted to predict hydrogen-natural gas blends (HNGB) hydrates formation conditions, and model results have a good agreement with the experimental data. Average enthalpies of HNGB hydrates dissociation were also calculated utilizing the Clausius-Clapeyron equation, which was in the range of 68.02 kJ/mol and 90.17 kJ/mol. These studies provide basic data for flow assurance when transporting HNGB in pipelines. (C) 2022 Elsevier B.V. All rights reserved.