Thermodynamic and molecular insights into natural gas dehydration using choline chloride-based deep eutectic solvents

Deep eutectic solvents (DESs) as promising green drying agents were first proposed to natural gas (NG) dehydration. In this work, choline chloride (ChCl)-based DESs were prepared using ChCl as hydrogen bond acceptor (HBA) and triethylene glycol (TEG), ethylene glycol (EG) or Urea as hydrogen bond donors (HBDs). To explore the potential application, methane (CH 4 ) dehydration experiment was conducted to verify the dehydration performance using prepared DESs. The thermodynamic properties were predicted by COSMO-RS model (Conductor-like screening model for real solvents). The quantum chemistry calculation was applied to understand the separation mechanism at the molecular level. The absorption performance of H 2 O in DESs depends on the weak interaction between Cl atom (or N and O atom) of ChCl and H atom of H 2 O as well as the free volume of DESs. Molecular dynamics (MD) simulation discloses the intermolecular interaction between HBA and HBD. This work makes the first multi-scale analysis on NG dehydration using DESs.