Experimental research on chemical desorption based on CO2-rich absorption solutions

Although CO2 capture by chemical absorption can achieve highly efficient removal of CO2 from flue gas, the energy consumption of absorbent regeneration is high, and the CO2 after desorption need to be compressed, transported and sequestrated. To reduce energy consumption and sequestrate CO2 at low cost, an CO2 desorption process was developed, in which the CO2-rich solutions was regenerated and CO2 was sequestrated in the form of CaCO3. Five kinds of CO2-rich solutions, monoethanolamine (MEA), methyldiethanolamine (MDEA), potassium glycinate (PG), MDEA/MEA and MDEA/PG were investigated by adding calcium hydroxide. The optimum reaction condition, which CO2 loading was 0.621 mol/L and Ca(OH)2 dosage was 1:1 for desorption of CO2-rich solution, was determined. And the effects of three parameters (time, temperature and stirring rate) on CO2 desorption rate were further analyzed. The optimum reaction temperature for the amine absorbents and the amino acid salt solvents were 20 degrees C and 50 degrees C, respectively. The optimum reaction time and standing time were 30 min, respectively, and the optimum stirring rate was 800 r/min. MEA exhibited the highest desorption rate (85.31%) among the five solutions. In addition, the results of multicycle-cycle experiments showed that the MEA lean solution desorbed by chemical desorption still had excellent absorption capacity. Compared with the conventional thermal desorption process, the chemical desorption process had great advantages for CO2-rich solutions regeneration and did not require further treatment of CO2.

Automated summary

A study on the chemical desorption of CO2 to sequester it again found the optimal reaction conditions and analyzed the effects of time, temperature, and stirring rate on the desorption efficiency of CO2. MEA exhibited the highest desorption rate among the five solutions, and multiple-cycle experiments showed its excellent absorption capacity.