Natural gas hydrates are recognized as a crucial and sustainable energy resource. The formation, dissociation, and flow properties of CH4 hydrate from deep eutectic solvents (DESs) are investigated using a high-pressure rheometer. In this work, rheological experiments are performed using two DESs namely, tetrabutylammonium bromide + ethylene Glycol (TBAB + EG, DES1) and methyltriphenylphosphonium bromide + ethylene Glycol (MTPB + EG, DES2) at 1 wt% concentration, 274 K temperature and 8 MPa pressure. The hydrate formation starts around 1.7 h for DES1 and around 4 h for DES2. Pressure and viscosity of the slurry are analyzed while methane hydrate forms and dissociates. The pressure drop experienced during hydrate formation is roughly 1.4 MPa for DES1 and 1.7 MPa for DES2. Further, viscosity profiles are analyzed for both DESs with varying shear rate. The viscosity gradually decreases as the shear rate increases. At equilibrium conditions of pure CH4, a spike is observed during dissociation. The rheological data is further analyzed with Cross model to validate the shear-thinning behavior of methane hydrate.
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