Enhancement of CO2 capture through hydrate formation: the effect of tetrahydrofuran (THF) and tertiary amine solutions

Abstract

Global climate change and global warming due to elevated CO2 atmospheric concentrations have become a major global concern. For this reason, the separation and capture of CO2 from industrial effluence is an important research focus. The CO2-based hydrate formation process has received close attention in the field of carbon capture due to its efficiency in selectively separating CO2 from pre- and post-combustion gas mixtures. In this work, a set of experiments was conducted in the presence of the two tertiary amines, triisopropanolamine (TIPA) or triethanolamine (TEA) combined with THF to evaluate their effectiveness in CO2 selectivity during hydrate formation and in decreasing the operational pressure required for the process. These experiments were aimed at observing whether the presence of amines supports/depresses the hydrate formation. In addition, they were also aimed at comparing the carbon-selective separation efficiency of the systems with and without amines through hydrate formation. It was observed that TEA discouraged hydrate formation. However, the addition of TIPA in the presence of THF at an operational pressure of 3.5 MPa improved initial gas loading as well as CO2 selective separation from the gas mixture. This contributed to an increase of 65% in the capture of CO2 from the gas mixture. When the same experiment was carried out at a lower pressure of 1.5 MPa, CO2 selectivity was also observed to have increased. However, the induction time was observed to be considerably longer compared to the previous case.