Experimental study on CO₂ absorption and regeneration of aqueous sodium glycinate solutions

Absorption of CO₂ with amines has been extensively studied in recent years because of environmental concern of greenhouse effect. The investigation of CO₂ absorption by aqueous sodium glycinate (SG) solution with different concentrations (1.0-4.0 mole SG·L^-1) was conducted in a double stirred-cell absorber, and the regeneration performance of SG aqueous solution after CO₂ absorption by means of heating was studied. The relationships between the absorption rate, absorption capacity, absorption load and absorption time, the influence of absorption temperature on absorption rate, and the absorption performance difference between SG aqueous solution and several other commonly used aqueous alkanolamine solutions were discussed. The results indicate that the CO₂ absorption rate of SG aqueous solution is higher than that of the other commonly used aqueous alkanolamine solutions, and that the influence of absorption temperature on the absorption rate of SG aqueous solution is significant. The SG aqueous solution with higher concentration has higher absorption capacity, whereas lower absorption load. The regeneration efficiency of the used SG aqueous solution increases from 80.0% to 92.6% with the increase of regeneration temperature from 363 K to 403 K; and the most suitable regeneration temperature and time were found as 383-388 K and 76-82 min respectively.