Experiments on continuous chemical desorption of CO2-rich solutions

Abstract

The traditional thermal desorption is replaced by chemical desorption and the desorption tower is replaced by the reaction and precipitation tank to promote industrial application of chemical desorption. Monoethanolamine (MEA), N-methyldiethanolamine (MDEA), 2-amino-2-methyl-1-propanol (AMP) and potassium glycine (PG) were selected and the effects of temperature, CO2 loading, dosage of desorption agent and different calcium compounds on the desorption ratio were studied. The results indicated that desorption ratios of MEA, MDEA, AMP and PG were enhanced with increasing temperature, but the desorption ratio had a maximum at 40 °C in the case of MDEA. With increases of CO2 loading and the amount of Ca(OH)2, desorption ratios increased. The desorption ratios of four CO2-rich solutions with CaO were lower than that of Ca(OH)2, but the difference in desorption ratio decreased as reaction time increased. The desorption ratios of MEA, MDEA, AMP and PG were able to reach 84.3%,90.17%,88.71% and 92.22% in optimum operating conditions, which were higher than that of conventional thermal desorption and the optimum operating conditions were as follows: the reaction temperature is 40 °C, CO2 loading is 0.21 mol/L, Ca:C is 1:1 and the desorption agent is Ca(OH)2. This study has crucial significance for the application of chemical desorption.