## Abstract

The p-T phase envelopes of four binary and two ternary mixtures of carbon dioxide (CO_{2}), nitrogen (N_{2}) and hydrogen (H_{2}) have been reported at temperatures between 252 and 304K. The compositions of the binary mixtures are x_{N2}=0.0201 and 0.0399 for CO_{2}+N_{2} and x_{H2}=0.0300 and 0.0499 for CO_{2}+H_{2}, respectively. For the two ternary mixtures of CO_{2}+N_{2}+H_{2}, the compositions are x_{N2}=0.020, x_{H2}=0.030 and x_{N2}=0.040, x_{H2}=0.030. The experimental data show that the bubble-point pressures of the CO_{2}-permanent gas mixtures increase substantially when adding only several percent (mole fraction) of N_{2}, H_{2} or both in CO_{2}. H_{2} has the largest effect on the bubble-point pressure. For a mixture with 5% H_{2} in CO_{2}, the bubble-point pressure reaches 10.1MPa at 288.15K, corresponding to an increase of 99% from the vapour pressure of pure CO_{2}. These vapour-liquid-equilibrium data have also been compared to those predicted using the GERG-2004 and Peng-Robinson (PR) equations of state. Between the two models, the PR equation of state gives the smaller deviations (2.5-4.2%) for the bubble-point lines of CO_{2}+H_{2} when using temperature-dependent binary interaction parameters, while both models show excellent agreement (0.4-2.8%) between the experimental and predicted data for CO_{2}+N_{2}. We also successfully model the CO_{2}+H_{2} data using molecular simulation.

Original language | English |
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Pages (from-to) | 68-81 |

Number of pages | 14 |

Journal | International Journal of Greenhouse Gas Control |

Volume | 41 |

DOIs | |

Publication status | Published - 1 Oct 2015 |

## Keywords

- Carbon capture and storage
- Carbon dioxide
- Equation of state
- Hydrogen
- Molecular simulation
- Nitrogen
- Vapour-liquid equilibrium

## ASJC Scopus subject areas

- Pollution
- Energy (all)
- Management, Monitoring, Policy and Law
- Industrial and Manufacturing Engineering

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