Promotion mechanism for CO2 absorption into partially carbonated ammonia solutions

Chemical enhancement factors for CO2 absorption into partially carbonated N H3 solutions in a stirred-cell absorber Here experimentally determined over a wide range of carbonation ratio in this work. The results reveal that th e one-reaction promotion mechanism, which is traditionally used in the lite rature, has shortcomings in describing the effects of initial total ammonia concentration and carbonation ratio on absorption enhancement. A shuttle m echanism, by which NH3 and CO2 undergo an irreversible second-order reactio n in the interface region while the chemical equilibrium of multiple reacti ons prevails in the bulk region to liberate free NH3. is then proposed for the absorption enhancement. The calculation of the bulk-liquid compositions is made hy using the rigorous thermodynamic package in ASPEN PLUS simulato r, The chemical enhancement factors predicted by the present promotion mech anism are in good agreement with the experimental data available.