Measurements and Correlation of Physical Solubility of Carbon Dioxide in (Monoethanolamine + Water) by a Modified Technique

A modified experimental technique for measuring the physical solubility of CO 2 in monoethanolamine (MEA) aqueous solutions using the “N 2 O analogy” method is proposed in this work. The modified technique employs a scaled spiral glass tube with a small drop of mercury as a eudiometer as an alternative to a three-branch U-tube setup to keep the system pressure constant and measure the volume of a drop of absorbed gas at constant temperature. The results were in good agreement with literature values, suggesting that the technique is feasible and reliable. Compared with the three-branch U-tube setup, the new technique is easy to operate and more sensitive and accurate. The physical solubility of CO 2 in aqueous MEA solutions over the full range of concentrations was measured using this modified technique over the temperature range from 298.15 to 323.15 K under a constant ambient pressure. Wang et al.’s model ( Chem. Eng. J. 1992, 48, 31−40) was used to correlate the data, and the results showed that the model is good for predicting the behavior of the (monoethanolamine + water) system.