Fig. 4: Properties of the active ice in gas hydrate formation.
From: Enhanced formation of methane hydrate from active ice with high gas uptake
a Cumulative gas uptake of methane hydrate formed in a cycle test for the active ice. Methane hydrate was formed at 272.65 K and initial pressure of 6.0 MPa; the hydrate dissociation to active ice was conducted at 272.65 K and atmospheric pressure. b Cumulative gas uptake in a preservation test for the active ice; the active ice was preserved at 268.15 K for varying durations and then used for methane hydrate formation at 272.65 K and initial pressure of 6.0 MPa. c Cumulative gas uptake of methane hydrate formed in the active ice at constant pressure of 3.0 MPa and 272. 65 K. d Cumulative gas uptake of methane hydrate formed in active ices that compressed to different loosening coefficients; the temperature and the initial pressure for hydrate formation were 272.65 K and 6.0 MPa, respectively. e Photo of the methane hydrate formed in the compressed active ice with loosening coefficient of 1.55, showing no wall−climbing effect during formation. f Cumulative methane uptake of another three activate ices at 272.65 K and initial pressure of 6.0 MPa. Active ice 2: the ice dissociated from CO2 − SDS hydrate; active ice 3: ice powder of 600-ppm SDS solution, with particle size of 180 ~ 250 μm; active ice 4: natural snow mixed with 0.1 wt% SDS.
