Influence of CO2 partial pressure on mass transfer

https://doi.org/10.1039/C7RA01352C

“Increasing the CO₂ partial pressure in the gas feed to the absorber column has two effects on K_GCO2a_V. First, increasing the CO₂ partial pressure can lead to an increase of the partial pressure gradient⁸³ because of the consummation of more actively free-amine molecules and, as a result, a decrease of K_GCO2a_V can occur (according to eqn (2)). Second, increasing the CO₂ partial pressure can intensify the gas flow turbulence in the absorber column and, as a result, increase K_GCO2a_V.⁸⁴ In the above-mentioned reviewed works, researchers showed that by increasing the CO₂ partial pressure in the gas feed, K_GCO2a_V decreased. This effect shows that amine solutions, especially those which have higher reaction kinetic constant values (such as MEA or PZ), have good performance under lower partial pressure than under higher partial pressure.^85,86 This effect indicates that amine solutions have a high CO₂ removal efficiency in a lower partial pressure of CO₂ in the gas feed. This occurrence shows that the liquid phase resistance dominates the mass transfer performance of absorption into amine solutions.⁸⁷“