Amino acid salts for CO2 capture at flue gas temperatures

• To develop novel absorbents for CO2 capture at high temperatures.
• To determine the physical properties of the novel absorbents at high temperatures.
• To determine the CO2 solubility of the novel absorbents at high temperatures.
• To investigate the CO2 kinetics of the novel absorbents at high temperatures.
• To model the absorption reaction rate of the novel absorbent at high temperatures.

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 2–6 M taurate solution were determined over the temperature range of 293–353 K. 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 4 M taurate at 353 K is similar in magnitude to the KG of 7 m monoethanolamine (MEA) at 313 K. 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 7 m MEA solution. The reaction rate constant of taurate carbamate formation in this work agrees well with published values.