Amino acid salts for CO2 capture at flue gas temperatures

Abstract

The amino acid salt potassium taurate has potential for use as a high-temperature absorbent for post-combustion CO2 capture, because of its low volatility and high absorption rate. In this study, the densities and viscosities of 2–6M taurate solution were determined over the temperature range of 293–353K. We found that the CO2 solubility of taurate solutions, measured using a stirred-cell reactor, is comparable to that of alkanolamines at high temperatures. The absorption rate of CO2 into CO2-free and CO2-loaded taurate solutions was determined using a wetted-wall column. The KG of 4M taurate at 353K is similar in magnitude to the KG of 7m monoethanolamine (MEA) at 313K. We also found that the KG of taurate decreased with increased CO2 loading, although the KG values of taurate solutions are still comparable to CO2-loaded 7m MEA solution. The reaction rate constant of taurate carbamate formation in this work agrees well with published values.