New absorption liquids for the removal of CO2 from dilute gas streams using membrane contactors

Abstract

A new absorption liquid based on amino acid salts has been studied for CO2 removal in membrane gas-liquid contactors. Unlike conventional gas treating solvents like aqueous alkanolamines solutions, the new absorption liquid does not wet polyoleÿn microporous membranes. The wetting characteristics of aqueous alkanolamines and amino acid salt solutions for a hydrophobic membrane was studied by measuring the surface tension of the liquid and the breakthrough pressure of the liquid into the pores of the membrane. The dependence of the breakthrough pressure on surface tension follows the Laplace-Young equation. The performance of the new absorption liquid in the removal of CO2 was studied in a single ÿber membrane contactor over a wide range of partial pressures of CO2 in the gas phase and amino acid salt concentrations in the liquid. A numerical model to describe the mass transfer accompanied by multiple chemical reactions occurring during the absorption of CO2 in the liquid owing through the hollow ÿber was developed. The numerical model gives a good prediction of the CO2 absorption ux across the membrane for the absorption of CO2 in the aqueous amino acid salt solutions owing through the hollow ÿber.

Hollow fiber membrane contactor absorption of CO2 from the flue gas: Review and perspective

“…Boributh et al (2011a) investigated three membrane lengths of 0.25, 0.5 and 0.7m, and reported that using the length of 0.7m, the CO 2 removal rate increased by 15.27% and 3.58% in comparison with other two modules, respectively. Also, Kumar et al (2002) observed the impact of the fiber length on the absorption flux to validate the numerical models with experiments. In order to investigate on the absorption and desorption characteristics of membrane gas absorption and traditional separation methods, an experiment system of CO 2 separation in a HFMC is proposed and depicted in Figure 3.…”

Highly Selective Amino Acid Salt Solutions as Absorption Liquid for CO2 Capture in Gas–Liquid Membrane Contactors

“…Amino acids have the same functionality as alkanol amines (e.g. MEA), but in contrast to alkanol amines solutions, they are expected to have a higher oxidative stability [35,37] and a better resistance to degradation. [38] In addition, they can be made nonvolatile by adding a salt functionality, which significantly reduces the liquid loss and energy consumption associated to that.…”

“…The performance of CO 2 absorption using the amino acid salt solutions was always superior to MEA and MDEA under the same operating conditions. Kumar et al [37] studied the wetting characteristics of polyolefin membranes using an amino acid salt solution (potassium salt of taurine). In comparison to aqueous alkanol amine solutions, the amino acid salt solution does not wet the polyolefin microporous membranes.…”

“…In comparison to aqueous alkanol amine solutions, the amino acid salt solution does not wet the polyolefin microporous membranes. Furthermore Kumar et al [37] carried out CO 2 absorption experiments with a single fiber membrane contactor as absorber. With both increasing liquid flow rate and increasing partial pressure, an increase in CO 2 flux could be observed.…”

Advances in Liquid Absorbents for CO2 Capture: A Review

“…42 The wetting characteristic for the new solution was studied by measuring the surface tension of the liquid and the breakthrough pressure of the liquid into the membrane pores, and it was found that the new liquid does not wet the polypropylene membrane, while having good reactivity towards CO 2 .…”