The pre-combustion capture of CO 2 in an IGCC power plant employing the hydrate based gas separation (HBGS) process is a novel method currently receiving attention around the world. Tetra-n-butyl ammonium bromide (TBAB) is a promoter that has been shown to improve the efficiency of hydrate formation. In this study, the effect of temperature and pressure on 0.3 mol% TBAB solution is investigated. The induction time for the experiments conducted at 6.0MPa and 274.8K was found to be lower, while nucleation became increasingly random as temperature is increased and pressure is reduced. Total gas uptake and normalized rate of hydrate formation (NR 5 ) is also the highest for the experiments conducted at 6.0MPa and 274.8K. However, it was found that the hydrate phase CO 2 composition remains relatively constant at both reduced temperatures and pressures.