Carbonic Anhydrase (CA) is a key homogeneous catalyst to enhance mass transfer during amine-based CO2 absorption. It can promote CO2 hydration. Widger et al. (https://doi.org/10.1016/j.ijggc.2017.05.019) investigated the addition of a small amount of carbonic anhydrase. They first tested the solvent stability 125 °C, 135 °C, and 145 °C for 168 h. The solvents are MEA and A2P/AMP (results available in Fig. 6). Other properties of the solvents (viscosity, surface tension and surface elasticity) were also reported at different carbon loadings.
The influence of solvents with and without CA additive are reported at different carbon loadings (results are in Figure 9 of the paper). The addition of CA clearly enhanced mass transfer coefficient and CO2 removal rate (Figure 9 and 10). However, the increase of carbon loading reduced mass transfer coefficient (Figure 10). The difference between MEA and A2P/AMP are also available.
In addition, the authors estimated that the additive would be stable over 1500h after thermal stability test at 145 °C for 144 h.
Catalyst cost was also discussion in section 4.3 of the paper (https://doi.org/10.1016/j.ijggc.2017.05.019).