CRITICAL CONDITIONS FOR CO2 HYDRATE FILMS TO REST ON SUBMARINE CO2 POND SURFACES - A MECHANISTIC STUDY

The stability of hydrate films formed at the horizontal interface betw een seawater and denser liquid CO2 under high pressures (greater than or similar to 35 MPa) is considered to have an insight into the feasib ility of the disposal/storage of liquid CO2 in the deep oceans. Hydrat e films formed at the interface (i.e., the surface of a liquid CO2 pon d on the seabed) may be denser than both liquid CO2 and seawater, may be denser than seawater but lighter than liquid CO2, or may be lighter than both liquids depending on the ambient pressure (i.e., the depth of the interface) and also on the fractional occupancy of hydrate crys talline cavities by CO2 molecules. The static force balance between th e gravitational forces and the interfacial tension force acting on eac h hydrate film is formulated, thereby predicting the critical conditio n beyond which the film may sink into the CO2 pond or buoy up into the sea, or it may be broken due to an internal stress.