Studies of CO₂Hydrate Formation and Dissolution

Sequestering waste CO 2 in the deep ocean as a gas, liquid, or hydrate has been variously proposed ( 1−3 ). We describe experiments producing CO 2 hydrate that may eventually assist in developing methodology for large-scale creation of this ice-like substance. We produced a simple and inexpensive system for conducting high-pressure experimentation. We established the minimum ratio of CO 2 to water (both deionized water and seawater) needed to produce stable traces of hydrate. We suggested an explanation for the differences observed in forming hydrate from the two media. We demonstrated that hydrate decomposed when exposed to an intermittent flow of water. We proposed a model of pathways involved in forming CO 2 hydrate. Previous reports on hydrate formation have emphasized pressure−temperature relationships and ef fects thereon. Our experimentation focused on the amount of CO 2 in all phases inside the pressure chamber (designated as Υ-CO 2 ). The minimum Υ-CO 2 needed for producing hydrate varied with pressure. Hydrate became unstable and decomposed in intermittently flowing water. Our approach has yielded new information regarding requirements for hydrate formation and the potential for dissolution in the deep ocean