Structure and Activity Relationships for CO2 Regeneration from Aqueous Amine Based Absorbents

A study to determine the structure and activity relationships of various amine based CO2 absorbents was performed in which, the desorption of CO2 from saturated absorbent at 80 C and atmospheric pressure was measured to assess the initial desorption rate and desorption capacities at pseudo equilibrium. Evaluation of desorption capacity at 80 C will give a better understanding for more energy efficient and lower circulation rate absorbent for CO2 absorption process. Results showed that an increase in chain length between the amine and different functional groups in the absorbent structure up to four carbon, result in an increase in initial desorption rate, also increase in the desorption capacity at pseudo equilibrium in most absorbents. Steric hindrance effect was noticed when side chain with an alkyl group was present at α –carbon to amine group in the structure. Increase in the number of amine group in absorbent structure, results in higher desorption capacity that reaches up to 75 % of CO2 is desorbed. Aromatic amines substituted with an amine group by a side chain at the cyclic ring shows an increase in desorption capacity at pseudo equilibrium.