Kinetic study of carbon dioxide absorption with aqueous potassium carbonate promoted by arginine

The absorption of carbon dioxide (CO 2 ) into aqueous 35   wt.% equivalent potassium carbonate (K 2 CO 3 ) solution was performed using a wetted wall column at temperatures from 313   K to 343   K. Effect of arginine concentrations on absorption rates of CO 2 into carbonate solutions was investigated and the second-order rate constant k 1 was obtained using two-film model. Preliminary screening results showed that arginine was an effective promoter in aqueous K 2 CO 3 solution for CO 2 capture. The reaction of CO 2 with arginine is described using zwitterionic mechanism. The overall reaction kinetic constant k ov strongly increased with the increase of arginine concentration and absorption temperature under the investigated range. Based on the pseudo-first-order regime, the reaction rate parameters were obtained from the kinetic measurements and k 1 was determined as 33,641 and 85,367   L   mol −1   s −1 at 315   K and 325   K, respectively with activation energy of 71.9   kJ   mol −1 . The overall reaction rate for CO 2 absorption into promoted K 2 CO 3 were described as the following equation: - r CO 2 = 2.58 × 10 16 exp - 8645 T C Arg + 4.32 × 10 13 exp - 6666 T C OH - C CO 2 $-r_{{\text{CO}}_2}=\left(2.58\times {10}^{16}\exp \left(-\frac{8645}{T}\right)C_{\text{Arg}}+4.32\times {10}^{13}\exp \left(-\frac{6666}{T}\right)C_{{\text{OH}}^{-}}\right)C_{{\text{CO}}_2}$ .