Clathrate hydrate for phase change cold storage: Simulation advances and potential applications

Production of CH4/C3H8 (85/15 vol%) Hydrate in a Lab-Scale Unstirred Reactor: Quantification of the Promoting Effect Due to the Addition of Propane to the Gas Mixture

“…The five polyhedral cavities are indicated with the nomenclature "n mi i ", where "ni" refers to the number of edges in the "i" face, while "mi" represents the number of faces having "ni" edges. Ordered as a function of their growing size, the five possible cavities are pentagonal dodecahedron (5 12 ), tetrakaidecahedron (5 12 6 2 ), hexakaidecahedron (5 12 6 4 ), irregular dodecahedron (4 3 5 6 6 3 ), and icosahedron (5 12 6 8 ).…”

“…The unit cell of sI includes two 5 12 and six 14-hedra; it is the most diffused in nature and is typical of guest molecules such as methane and carbon dioxide [8]. The cubic sII consists of sixteen 512 and eight 16-hedra and hosts molecules with a larger diameter, such as propane and butane.…”

“…The mechanism behind gas hydrate formation and dissociation can be advantageously exploited for several key applications, such as gas storage and transportation [10], the separation of gas mixtures into single species [11], cold storage [12], climate change mitigation [13], seawater desalination [14], and, more generally, waste water treatment [15], sludge dewatering [16,17], carbon dioxide capture and final disposal, and so on.…”

“…In greater detail, the maximum theoretical efficiency is lower than one due to the different molecular size of the two molecules. The unit cell of sI contains two different types of polyhedral cavity, the small 5 12 and the larger 5 12 6 2 . While methane can easily fit in both types of cavities, the molecule of carbon dioxide prefers the larger ones and, as a consequence, the replacement of methane in the small cavities is strongly hindered.…”

Rapid Growth of the CO2 Hydrate Induced by Mixing Trace Tetrafluoroethane

“…9 Due to the selective separation of CO 2 hydrate from mixed gas components and the high storage capacity of hydrate for guest molecules, CO 2 hydrate has become a new hydrate technology to capture and store CO 2 from fuel gas (CO 2 + H 2 ) and flue gas (CO 2 + N 2 ) and to reduce the CO 2 emission from power plants to the atmosphere. 10 In addition, due to the high gas storage density and large latent heat of phase transition of CO 2 hydrate, its application technology has also attracted extensive attention in the fields of CO 2 storage and transportation, 11 cold storage, 12,13 and seawater desalination. 14,15 However, the high operating pressure, slow hydrate formation kinetics, and low hydrate formation rate limit the industrial application of CO 2 hydrate technology.…”