https://doi.org/10.3390/pr9122184
“When the CO2 partial pressure of flue gas is 10 kPa and the pressure of the desorption tower is 2.2 bar, the influence of concentration on reboiler energy consumption is studied, and the studied concentration range is 10–40 wt.%. Since the measured concentration of the CO2 solubility data of the HEPZ solution used for regression modeling was up to 30 wt.%, the highest solution concentration applicable to the HEPZ thermodynamic model is also 30 wt.%. The concentrations studied for HEPZ were 5, 15 and 30 wt.%. When the concentration of PZ is too high, crystals will be precipitated and the solubility of anhydrous PZ at 20 °C is 14 wt.% PZ, which corresponds to 1.9 m PZ [32]. Therefore, problems will exist during plant start-up, operation and shutdown. The relationship between its concentration and energy consumption will no longer be studied. Figure 3 shows the relationship between the concentration of MEA, HEPZ, DMEA, 1-MPZ, AMP aqueous solution and energy consumption.”
“Figure 3. When the CO2 partial pressure of flue gas is 10 kPa, and the pressure of the desorption tower is 2.2 bar, the influence of the concentration of aqueous amine solutions on energy consumption for: (a) MEA, (b) DMEA, (c) 1-MPZ, (d) AMP and (e) HEPZ, is shown.”
“It can be seen from Figure 3 that as the concentration of the MEA aqueous solution increases, Qabs increases and L/G of the absorption tower decreases, so Qcon and QT decrease. The sum of the three kinds of heat, Qreb, decreases, and the magnitude of the decrease becomes smaller as the concentration increases. The concentration of DMEA aqueous solution increases from 10 to 30 wt.%, Qabs is basically unchanged, L/G decreases, so Qcon and QT decrease, and Qreb decreases. When it rises from 30 to 40 wt.%, L/G increases, Qcon and QT also increase, while Qabs is unchanged, so Qreb increases, and the optimal concentration of DMEA is 30 wt.%. As the concentration of 1-MPZ increases, Qreb decreases. The optimal concentration of 1-MPZ is 40 wt.%. The effect of the concentration of AMP on energy consumption is the same as that of MEA. As for HEPZ, the reboiler energy consumption is significantly lower than that of other solvents, and the proportion of Qcon is the lowest, which does not change much with the concentration. Due to the large MW of HEPZ, the L/G difference of HEPZ solutions with different concentrations is significant, and Qcon and QT decrease significantly with the increase of the concentration.”