Mathematical Modeling, Simulation, and Experimental Verification of CO2 Removal in a Turbulent Contact Absorber

A highly efficient technique of contaminant gas reduction, Turbulent Contact Absorber (TCA), is applied to CO2 removal from a typical flue gas. Aqueous K2CO3 sorbent was evaluated as a regenerable sorbent for CO2 from the flue gas. In order to identify the system, momentum and mass balance equations were written for the TCA tower. A flat plate falling film model was employed to simulate the TCA tower and the effect of turbulence was included in mass and momentum transfer coefficients. To check the accuracy of the model, a pilot scale TCA was built and operated. A Testo type gas analyzer was used to detect gas concentrations at the inlet and outlet of the rig. The model was validated successfully with pilot plant data. The effect of velocity and K2CO3 concentration on the TCA performance has also been carried out. It was found that the bed pressure drop increases linearly with gas velocity and then remains constant. An increase in the liquid flow rate increases liquid holdup, which leads to a rise in bed pressure drop. Higher turbulence within the TCA causes a velocity peak to shift from hypothetical gas-liquid interface towards the falling film plate. An increase of the K2CO3 concentration from 1.0 g mol/L to 2.0 g mol/L was found to give an increase in CO2 removal by about 4 %.