Guest gas enclathration in tetra-n-butyl ammonium chloride (TBAC) semiclathrates: Potential application to natural gas storage and CO2 capture

Enhanced clathrate hydrate formation kinetics at near ambient temperatures and moderate pressures: Application to natural gas storage

“…Thus, the choice of a thermodynamic promoter must provide significant impact on the operating and storage conditions albeit a penalty on the storage capacity of methane is inevitable. Many thermodynamic promoters have been reported and studied for methane hydrate formation [2,14,19,[36][37][38][39][40][41][42][43][44]. Though exhaustive literature is available on the hydrate phase equilibrium conditions for these different thermodynamic promoters, kinetic investigation studies using these promoters are relatively scarce.…”

Investigation of kinetics of tetrabutylammonium chloride (TBAC) + CH4 semiclathrate hydrate formation

“…Besides, it should be noted that this phenomenon was not the rst time to show up. In 2015, Kim et al 39,40 studied the spectra of (TBAC + CO 2 ) SCHs and (TBAC + CO 2 + N 2 ) SCHs, and the results showed that the addition of TBAC caused a slight shi of wavenumbers from 1275 cm À1 to 1272 cm À1 . Moreover, Hashimoto 50 provided the differences between HS-I SCHs and TS-I SCHs in Raman spectra in 2008.…”

“…4,[39][40][41] Kim et al presented the PXRD patterns of (TBAC + CO 2 ) SCHs and (TBAC + CO 2 + N 2 ) SCHs. 39,40 Oshima et al 41 studied crystallographic properties of (TBAB + TBAC) SCHs through PXRD measurement, and the result demonstrated that the double SCHs were formed with structure of tetragonal one (P4/mmm or P4/m) or orthorhombic one (Pmma) at different salt concentrations. However, these achievements of TBAC did not involve the formation kinetics which were important for hydrate-based applications.…”

Semiclathrate-based CO2 capture from flue gas mixtures: An experimental approach with thermodynamic and Raman spectroscopic analyses

“…In QAS semiclathrates, anions such as Br À , Cl À , and F À are involved in forming cage structures with the host water molecules, and tetra-n-butyl ammonium (TBA) cations are incorporated into the large cages. In addition, the QAS semiclathrates have small 5 12 cages which are left vacant and thus, can be used for capturing small-sized gas molecules [19,22,23,[25][26][27][28][31][32][33][34][35][36][37][38][39][40][41]. Due to their significant thermodynamic stability and guest gas enclathrating ability, QAS semiclathrates have been investigated as an alternative to gas hydrates for gas storage and separation [23,27,31,[42][43][44][45][46][47][48].…”

“…To avoid and overcome this concern, gas hydrate formation needs to be performed at much milder pressure and temperature conditions. Thus, extensive efforts have been undertaken to reduce hydrate equilibrium pressures or to enhance hydrate equilibrium temperatures by adding thermodynamic promoters to the system [10,12,[16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] Semiclathrates, which share many physical and chemical properties with gas hydrates, could be an attractive alternative to gas hydrates because in general, they can maintain their thermodynamic stability under atmospheric pressure conditions [19,[31][32][33][34][35][36][37][38][39]. In gas hydrates, the guest molecules are not physically bonded to host water lattices, whereas in semiclathrates, guest molecules can both take part in building the host water frameworks and occupy cages after breaking part of the cage structure.…”