Ethylene Separation via Hydrate Formation in W/O Emulsions

An hybrid absorption-hydration method was adopted to recover C 2 H 4 from C 2 H 4 /CH 4 binary gas mixtures and the hydrate formation conditions of C 2 H 4 /CH 4 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 C 2 H 4 in feed gas (13.19–80.44 mol%) upon the C 2 H 4 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 C 2 H 4 /CH 4 .