Intensified methane hydrate formation from active ice in wide temperate range

The ice powder with unfrozen surfactant solution layer (active ice) is efficient in intensifying gas hydrate formation, however, only in a narrow temperature range. To broaden the temperature range, the effects of gas injection mode, gas pressure and temperature, and particle size on the hydrate formation in the active ice were investigated. The results suggested that continuous gas injection enhanced hydrate formation by producing more unfrozen solution layer at low temperatures; the hydrate formation rate and the gas uptake increased with the increase of gas pressure, while increased with the increase of gas temperature only at low ice temperatures; increasing the gas temperature is more effective in smaller ice particles. The suitable temperature range for fast hydrate formation in the active ice was broadened to 273.15 ∼ 266.15 K from 273.15 ∼ 271.65 K. This study improves the feasibility of hydrate-based gas storage or separation via the active ice.