Yongwon Seo

The methane (CH4) - carbon dioxide (CO2) swapping phenomenon in naturally occurring gas hydrates is regarded as an attractive method of CO2 sequestration and CH4 recovery. In this study, a high pressure microdifferential scanning calorimeter (HP μ-DSC) was used to monitor and quantify the CH4 - CO2 replacement in the gas hydrate structure. The HP μ-DSC provided reliable measurements of the hydrate dissociation equilibrium and hydrate heat of dissociation for the pure and mixed gas hydrates. The

Hydrate phase equilibria for the binary CH 4 + water and CO 2 + water mixtures in silica gel pores of nominal diameters 6.0, 15.0, and 30.0 nm were measured and compared with the calculated results based on van der Waals and Platteeuw model. At a specified temperature, three phase H−L W −V equilibrium curves of pore hydrates were shifted to the higher pressure region depending on pore sizes when compared with those of bulk hydrates. The activities of water in porous silica gels were expressed wi

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 TB

This study aims to examine the thermodynamic feasibility of separating sulfur hexafluoride (SF(6)), which is widely used in various industrial fields and is one of the most potent greenhouse gases, from gas mixtures using gas hydrate formation. The key process variables of hydrate phase equilibria, pressure-composition diagram, formation kinetics, and structure identification of the mixed gas hydrates, were closely investigated to verify the overall concept of this hydrate-based SF(6) separation

In this study, guest gas enclathration behavior in semiclathrates of tetra-n-butylammonium bromide (TBAB) was closely investigated through phase equilibrium measurement and spectroscopic analysis. The three-phase equilibria of semiclathrate (H), liquid water (L(W)), and vapor (V) for the ternary CH(4) + TBAB + water and CO(2) + TBAB + water mixtures with various TBAB concentrations were experimentally measured to determine the stability conditions of the double TBAB semiclathrates. Equilibrium d

Semiclathrate hydrate phase equilibria for N 2 + TBAB (tetra- n -butylammonium bromide) + water mixtures were measured in the temperature range of (280 to 290) K and in the pressure range of (4.0 to 9.2) MPa at TBAB, w (weight fraction) = 0.05, 0.20, 0.40, and 0.60. Also, semiclathrate hydrate phase equilibria for N 2 + TBAF (tetra- n -butylammonium fluoride) + water mixtures were measured in the temperature range of (293 to 302) K and in the pressure range of (2.0 to 9.7) MPa at TBAF, w = 0.10,