Stability boundaries of gas hydrates helped by methane—structure-H hydrates of methylcyclohexane and cis-1,2-dimethylcyclohexane

Static Formation and Dissociation of Methane+Methylcyclohexane Hydrate for Gas Hydrate Production and Regasification

“…Through gradual bath heating [29] (process (iii) in Fig. 2a)), the partial hydrate decomposition reveals that part of the sI hydrate coexists with sH hydrate during the CH 4 +MCH hydrate formation process (ii) [30]. However, the amount of sI hydrate cannot be confirmed because there may be phase transition to sH hydrate.…”

“…2b) gradually decreases to the phase equilibrium boundary of sI CH 4 hydrate, consequently the formation slows down. The following heating process (iii) indicates that most of the initially formed sI hydrate has transformed to sH hydrate [30], since sI hydrate tends to become thermodynamically unstable as preswww.cet-journal.com (Fig. 2c), the formation rates are much slower compared to those under higher pressures.…”

Large pressure depression of methane hydrate by adding 1,1-dimethylcyclohexane

“…Some chemicals, e.g. neohexane (Mehta and Sloan, 1993;Thomas and Behar, 1994;Hütz and Engle zos, 1996;Ohmura et al, 2003), methylcyclohexane (Mehta and Sloan, 1994a;Mooijer-van den Heuvel et al, 2000;Sun et al, 2002;Nakamura et al, 2003), 2,2,3-trimethylbutane (Thomas and Behar, 1994;Mehta and Sloan, 1994b) and pinacolone (Ohmura et al, 2003) have been investigated as a candidate for additives. All of them show a large pressure depression from the equilibrium pressure of pure methane (as a representative of natural-gas) hydrate system.…”

Icosahedron cage occupancy of structure-H hydrate helped by Xe -1,1-, cis -1,2-, trans-1,2-, and cis-1,4-dimethylcyclohexanes

“…In our previous studies, we have investigated whether seven DMCH stereo isomers can generate the s-H hydrate in the presence of methane (Nakamura et al, 2003(Nakamura et al, , 2004aThomas and Behar, 1994). The 1,1-DMCH, cis-1,2-DMCH and cis-1,4-DMCH generate the s-H hydrate in the presence of methane, while the other DMCH stereo isomers cannot generate it.…”