CO₂Capture from Simulated Fuel Gas Mixtures Using Semiclathrate Hydrates Formed by Quaternary Ammonium Salts

Abstract

In order to investigate the feasibility of semiclathrate hydrate-based precombustion CO2 capture, thermodynamic, kinetic, and spectroscopic studies were undertaken on the semiclathrate hydrates formed from a fuel gas mixture of H2 (60%) + CO2 (40%) in the presence of quaternary ammonium salts (QASs) such as tetra-n-butylammonium bromide (TBAB) and fluoride (TBAF). The inclusion of QASs demonstrated significantly stabilized hydrate dissociation conditions. This effect was greater for TBAF than TBAB. However, due to the presence of dodecahedral cages that are partially filled with water molecules, TBAF showed a relatively lower gas uptake than TBAB. From the stability condition measurements and compositional analyses, it was found that with only one step of semiclathrate hydrate formation with the fuel gas mixture from the IGCC plants, 95% CO2 can be enriched in the semiclathrate hydrate phase at room temperature. The enclathration of both CO2 and H2 in the cages of the QAS semiclathrate hydrates and the structural transition that results from the inclusion of QASs were confirmed through Raman and (1)H NMR measurements. The experimental results obtained in this study provide the physicochemical background required for understanding selective partitioning and distributions of guest gases in the QAS semiclathrate hydrates and for investigating the feasibility of a semiclathrate hydrate-based precombustion CO2 capture process.

Accurate measurement of phase equilibria and dissociation enthalpies of HFC-134a hydrates in the presence of NaCl for potential application in desalination

“…Gas hydrates have been utilized in various fields: from exploitation of naturally occurring gas hydrates, natural gas storage and transportation, carbon dioxide capture and sequestration, to desalination [3][4][5][6][7][8][9][10]. Among their various applications, hydrate-based desalination has recently attracted significant attention because the need for desalination is increasing due to water shortages and the sources for desalination are not limited to seawater.…”

Hydrate-based CO2 capture and CH4 purification from simulated biogas with synergic additives based on gas solvent

“…While in the case of the simulated biogas mixture hydrate formed with TBAB-DMSO, the peak at 1286 cm À1 was observed shift to 1278 cm À1 except that the peak at 1381 cm À1 was the same position as that of the THF-DMSO case. It is well known that Raman peaks at 1278 cm À1 and 1381 cm À1 should correspond to CO 2 occupies both 5 12 6 2 and 5 12 6 3 cages of the semiclathrate hydrate framework [14,49,51]. It should be noted that the relative intensity of peak splitting at 1307 cm À1 and 1326 cm À1 are likely corresponding to a change in the structural environment of the alkyl groups and can be attributed to CH 2 -bending modes in this spectral region [52].…”

Chitosan as a Natural Polymer for Heterogeneous Catalysts Support: A Short Review on Its Applications

“…Quaternary ammonium salts, such as Bu4NBr, Et4NBr, are currently in use for industrial preparation of cyclic carbonates [50], and therefore have attracted much scientific attention in the development of heterogeneous catalysts for these applications. Recent studies also revealed the use semi-clathrate hydrates in the presence of quaternary ammonia salts of TBAB for CO2 capture up to 95% [51,52].…”