Absorption Kinetics of CO2 in Aqueous Ammonia with High Load and Salinity

Abstract

In order to improve the absorption efficiency of carbon dioxide (CO2) in the process of inorganic ammonia carbon capture, it is critical to find out the factors inhibiting CO2 absorption. In this work, the mass transfer flux of CO2 is measured by a multi-column wetted wall reactor. The results indicated that the boundary concentration of NH3 under the conditions of chemical reaction is 1.01527 kmol·m-3. The contribution of CO2 concentration in the liquid film to the reaction rate is found to be less than that of NH3. The carbonization degree is only related to pH and has nothing to do with the initial concentration of NH3. The decrease of absorption efficiency is related to the H+ activity coefficient rather than the change of the diffusion coefficient. A flux prediction model with high load and salinity is presented subsequently. Furthermore, the two important regulation indexes are the pH and NH4HCO3 saturation.