Abstract
Phase equilibrium conditions of semiclathrate hydrate incorporating tetra-w-butylammonium bromide, hereafter TBAB, and CO_2 were experimentally measured. Several previous studies on CO_2 separation technology using semiclathrate hydrates have been carried out and they reported the possibility of applications in industries such as steel-making and power plants. To contribute this technology, we examined thermodynamic properties of TBAB + CO_2 hydrates. Semiclathrate hydrates have a property that the dissociation temperature varies depending on composition of the aqueous solution of ionic salts such as TBAB. The dissociation temperatures of TBAB + CO2 hydrates were measured in the range of mass fraction of TBAB (0.05, 0.10, 0.15, 0.20, 0.25, and 0.30) under the C02 pressure maintained at 0.3 MPa. The measurement uncertainties were ±0.05 K for temperature, ±3.2 kPa for pressure and ±5.0.10^<-4> for mass fraction. Experimental results show that all of the dissociation temperatures of TBAB + CO_2 hydrates are higher than those of TBAB hydrates formed without CO_2.
