Kinetic Modelling and Simulation of Carbon Dioxide Absorption into Aqueous Ammonia Solution

Nowadays, the amount of greenhouse gases in the atmosphere is nearly on the verge of alarming and one of the main components which is of highest the abundance is carbon dioxide (CO2). Therefore, it is imperative that its emission be reduced. Through absorption, alkanolamines have been widely focused on as the solvent to absorb CO2. However, it is found that using normal alkanolamines has its disadvantages, hence aqueous ammonia solution was found to be a possible replacement. It works effectively and also economically for the absorption of CO2. This paper studies the kinetic modelling of CO2 absorption into aqueous ammonia solution in order to better understand the chemical and physical kinetics and hydrodynamic properties of the absorption of CO2 in aqueous ammonia solution. This was done by simulating the developed model using Matlab. Using the work done by Rinker et al., the reaction rate kinetics were modelled and then simulated in order to calculate the apparent rate coefficient, kapp, which is then compared to that of Diethanolamine (DEA) since DEA is one of the more common amine solution used to absorb CO2 due to its quicker reaction. The results indicate that ammonia is greater as compared to DEA in terms of the kapp where a lower temperature is required in order to obtain the same kapp with that of DEA and the kinetics of the reaction is encouraging for ammonia until temperatures approaching 310 K.