Effect of solvent concentration using modelled HFMC

The effect of solvent concentration on the CO2 removal efficiency of MDEA + KLys, MDEA and MEA solutions is shown in Fig. 8.

Fig 8

Fig. 8. Effect of solvent concentration on the CO2 removal efficiency (gas flow rate = 6L/hrC0=1400ppm, solvent flow rate = 1.5L/hrTgas=298K)

It can be observed in Fig. 8 that with increasing solvent concentration, the CO2 removal efficiency of all solutions significantly increases except for the MDEA + KLys that increases slightly. This could be considered as an additional advantage of MDEA + KLys solution compared to MDEA and MEA, where lower concentrations can be used which will result in lower viscosity, corrosion rate along with operational costs associated with CO2 capture process. As expected, the CO2 removal efficiency increases with increasing solvent concentration, which could be attributed to the availability of more molecules to react with CO2. However, for MDEA + KLys solution with high KLys concentrations, a solid product is formed and leads to a decrease in CO2 absorption capacity. This is one of the main challenges associated with amino acid salts where precipitation occurs, especially at high concentrations (Garg et al., 2017). MDEA + KLys solution showed better CO2 removal efficiency (∼96%) compared to MEA (∼80%) and MDEA (∼78%) under similar conditions.

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