Equilibrium Hydrate Formation Conditions for the Mixtures of CO₂ + H₂ + Tetrabutyl Ammonium Bromide

Abstract

The equilibrium hydrate formation conditions for the gas mixture of CO 2 and H 2 with tetrabutyl ammonium bromide (TBAB) are measured. The data show that TBAB can reduce the gas hydrate formation pressure as an additive with the mole fraction of (0.14, 0.21, 0.29, 0.50, 1.00, and 2.67) %. The experiments were carried out in the temperature range of (274.05 to 288.55) K and the pressure range of (0.25 to 7.26) MPa. The equilibrium hydrate formation pressure of the CO 2 + H 2 + TBAB mixture is remarkably lower than that of the CO 2 + H 2 mixture at the same temperature and decreases with the increase in the concentration of TBAB. In addition, to avoid the formation of pure TBAB hydrate, in which there are no CO 2 or H 2 , for the above gas mixture, the formation conditions of the pure TBAB hydrate with TBAB mole fraction from (0.14 to 2.67) % were also measured.

Equilibrium Conditions for Semiclathrate Hydrates Formed with CO2, N2, or CH4 in the Presence of Tri-n-butylphosphine Oxide

“…Unlike ordinary hydrates having well defined structures (Structure I, Structure II, and Structure H), SCHs have diverse structures and have hydrogen-bonding interaction between guests and hosts molecules, which is much stronger than the van der Waals force in ordinary hydrates 5 SCHs have drawn increasingly more interest from researchers for their potential applications in hydrogen storage 8 , carbon dioxide storage 9 , and gas separation [10][11][12][13][14] . The thermodynamic data of SCHs are limited, and the majority of them are for TBAB 8,[15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] . More phase equilibrium data on SCHs are needed for acquiring in-depth knowledge of gas hydrate formation, optimizing the thermodynamic models, and developing effective gas processing technologies.…”

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

“…Despite these advantages, a commercially viable hydrate-based CO 2 separation process has been challenging due to it must satisfy the following factors [41][42][43][44]: (1) Moderate operating condition; (2) high selectivity of CO 2 ; (3) rapid hydrate formation rate; and (4) excellent gas storage capability. For the first factor, some outstanding thermodynamic additives such as tetrahydrofuran (THF) [27], Tetra-b-utyl ammonium/phosphonium salts [17,20,26] and cyclopentane (CP) [28,45] have been proved. For instance, when the simulated landfill gas hydrate formed with 0.0234 mol fraction tetra-n-butyl ammonium bromide (TBAB), the equilibrium hydrate formation pressure could reduce by approximately 90% [17], it is very close to the realistic temperature and pressure condition for separation operating.…”

Effects of Promoter on the Formation of Gas Hydrate from Blast Furnace Gas

“…완벽한 clathrate를 이루지 않고 semi-clathrate를 형성하는 TBAB (Tetra-n-butyl ammonium bromide), TBAC(Tetra-n-butyl ammonium chloride), TBAF(Tetra-n-butyl ammonium fluoride) 등을 통칭하는 TBAX와 TBPB(tetra-n-butyl phosphonium bromide) 등이 있다 [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] 3. 결과 및 고찰 Table 2에 Gas hydrate dissociation pressure for , N 2 + water system [44]; , BFG model gas + water system; and , CO 2 + water system [45].…”