Semi-batch experimental study on CO2 absorption characteristic of aqueous ammonia

Absorption characteristics of CO2 into aqueous ammonia are the key factors to achieve simultaneous removal of pollutants from coal-fired flue gas by ammonia scrubbing. An experimental study with asemi-continuous flow reactor was conducted to investigate the CO2 absorption characteristic of aqueous ammonia solutions. Pure CO2 was chosen in order to avoid the effect by the other gas components in this paper. The effect on solution CO2 loading and CO2 absorption capacity, which is caused by ammonia concentration, CO2 inlet velocity and temperature, has been given. Furthermore, the effect on absorption characteristic and slippery characteristics of ammonia caused by additives is also covered. The experiment results show that, with increase of ammonia concentration, the solution CO2 loading increases while the CO2 absorption capacity decreases. Both the above two parameters decrease with the increase of CO2 inlet velocity, but the total reaction rate acts reversely. When the temperature reaches 15 °C or 35 °C, the absorption characteristic can reach the extreme points. Adding AMP into ammonia can enhance the absorption of CO2, and control the slippery of ammonia in the absorption process. What’ s more, 3% is a better choice for addition concentration.