https://doi.org/10.1016/j.egypro.2017.03.1277
“The effect of the addition of tertiary amines (MDEA 2 M, DEAB 1.25 M) into 5M MEA on the cyclic capacity is
shown in Fig. 3. It is a plot of cyclic capacities against the amine mixtures, namely, 5 M MEA, 5 M MEA / 2 M
MDEA and 5 M MEA/ 1.25 M DEAB. The results show that the mixture of 5 M MEA/ 1.25 M DEAB provided the
highest cyclic capacity followed by 5 M MEA / 2 M MDEA and 5 M MEA. This is because of the higher desorption
rate of MEA/MDEA and MEA/DEAB compared to 5M MEA because of the involvement of tertiary amines in the
former two blends [10].
Comparing between 5 M MEA / 2 M MDEA and 5 M MEA/ 1.25 M DEAB, 5 M MEA/ 1.25 M DEAB has
higher cyclic capacity even though the total amine concentration in MEA/DEAB (6.25M) is lower than the total
amine concentration in MEA/MDEA (7M). This can be because of the more reactivity of DEAB towards desorption
compared to MDEA. In addition, from the chemical structure of DEAB in Figure 4, the methyl group acts as
electron donor to nitrogen atom. This makes nitrogen atom become more reactive [11]. With a constant column
height and liquid flow rate, MEA/DEAB has the ability to absorb more CO2. The rich amine came out from the
absorber in the MEA/DEAB system can reach up to 0.47 moleCO2/mole Amine, while the maximum is
approximately 0.42 mole CO2/mole Amine in MEA+MDEA system.”
