Three-Phase Equilibrium Conditions of TiAAB Semiclathrates Formed from N2, CO2, and Their Mixtures

A variable-volume reactor was used for measuring the solid-vapor-liquid equilibrium conditions of semiclathrates formed in an aqueous solution of tetra-iso-amyl ammonium bromide (TiAAB). The TiAAB semiclathrates were formed from pure CO2, pure N-2, and three mixtures of CO2 (1) + N-2 (2), which had cylinder compositions of x(1) = 0.78, x(1) = 0.52, and x(1) = 0.21. The experimental temperatures ranged from (302 to 307) K, the experimental pressures ranged from (220 to 2115) kPa, and the concentration of TiAAB in solution was constant at a mass fraction of W-TiAAB = 0.1403. For all of the gases used in the present study, it was found that, at a given pressure, the minimum temperature required to form TiAAB semiclathrates is significantly higher than that required for forming both gas hydrates or tetrabutyl ammonium bromide (TBAB) semiclathrates from the same gases.