Improvement in CO2 absorption and reduction of absorbent loss in aqueous NH3/triethanolamine/2-amino-2-methyl-1-propanol blends

Changes in the CO2 absorption rates and capacities of the absorbent 2-amino-2-methyl-1-propanol (AMP), blended with NH3 and other additives, were investigated toward performance improvement. The NH3-blended absorbent removed CO2 more efficiently than the AMP absorbent alone. However, absorbent loss through NH3 evaporation was observed under these conditions. A second absorbent, the tertiary amine triethanolamine (TEA), which has a low vapor pressure, was selected and blended with the NH3/AMP system to reduce NH3 evaporation. Its effects on NH3 loss and the absorption rate and capacity of the NH3/AMP system were investigated, and the optimum blending ratios were determined. In addition, the absorbent blend at the optimum blending ratio was compared to AMP alone and the commercially available absorbent monoethanolamine at the same weight ratio. The thermal stabilities of the absorbents, under conditions used in the CO2 absorption process, were compared by thermogravimetric analysis.