Ethylene Separation via Hydrate Formation in W/O Emulsions

An hybrid absorption-hydration method was adopted to recover C2H4 from C2H4/CH4 binary gas mixtures and the hydrate formation conditions of C2H4/CH4 mixtures was studied experimentally in diesel in water (w/o) emulsions. Span 20 at a concentration of 1.0 wt% in the aqueous phase was added to form water in diesel emulsions before hydrate formation and then hydrate in diesel slurry was separated after hydrate formation. The influences of initial gas-liquid volume ratio (53–142), pressure (3.4–5.4 MPa), temperature (274.15–278.15 K), water cuts (10–30 vol%), and the mole fraction of C2H4 in feed gas (13.19–80.44 mol%) upon the C2H4 separation efficiency were systematically investigated. The experimental results show that ethylene can be enriched in hydrate slurry phase with high separation factor (S) and recovery ratio (R). Most hydrate formation finished in 20 min, after that, the hydrate formation rate became very slow. The conclusion is useful for determining the suitable operation conditions when adopting an absorption-hydration method to separate C2H4/CH4.