Analysis of the Dissolution of CH₄/CO₂-Mixtures into Liquid Water and the Subsequent Hydrate Formation via In Situ Raman Spectroscopy

• Main Authors: Zheng Li, Christine C. Holzammer, Andreas S. Braeuer
• Format: Article
• Language: English
• Published: MDPI AG 2020-02-01
• Series: Energies
• Subjects: gas hydrates; <i>in situ</i> raman spectroscopy; molar ratio; carbon dioxide; methane
• Online Access: https://www.mdpi.com/1996-1073/13/4/793

We report an experimental study for the investigation into the suitability of hydrate formation processes for the purification of methane (CH₄) from carbon dioxide (CO₂) at a sub-cooling temperature of 6 K and a pressure of 4 MPa. The experiments were conducted in a stirred batch reactor. Three different initial CH₄/CO₂ mixtures with methane fractions of 70.1 mol%, 50.3 mol%, and 28.5 mol% were tested. The separation efficiency was quantified by measuring in situ via Raman spectroscopy the ratios of CH₄/CO₂ in the gas mixture, the liquid water-rich phase before hydrate formation, and the solid hydrate phase after the onset of the hydrate formation. The results indicated that the main separation effect is obtained due to the preferential dissolution of CO₂ into the liquid water-rich phase before the onset of the hydrate formation.