| Three kinds of blended absorbents were investigated on bench-scale experimental bench according to absorption rate and regeneration grade to select a reasonable additive concentration. The results show that, among methyldiethanolamine(MDEA) and piperazine(PZ) mixtures, comparing MDEA∶PZ=1∶0 .4 (m∶m) with MDEA∶PZ=1∶0 .2(m∶m),the absorption rate is increased by about 70% at 0 .2 mol·mol-1.When regeneration lasting for 40 min, regeneration grade of blended absorbents with PZ concentration of 0 .2,0 .4,and 0 .8 is decreased to 83 .06％,77 .77％ and 76 .67％ respectively while 91 .04% for PZ concentration of 0. MDEA∶PZ=1∶0 .4(m∶m) is a suitable ratio for MDEA/PZ mixtures as absorption and regeneration properties of the blended absorbents are all improved. The aqueous blends with 10％ primary amines and 2% tertiary amines could keep high CO2 absorption rate, and lower regeneration energy consumption. Adding 2% 2-Amino-2-methyl-1-propanol (AMP) to 10% diethanolamine (DEA), the blended amine solvents have an advantage in absorption and regeneration properties over other DEA/AMP mixtures. Blended solvents, which consist of a mixture of primary amines with a small amount of tertiary amines, have the highest absorption rate among the three. And mixed absorbents of secondary amines and a small amount of sterically hindered amines have the best regeneration property. To combine absorption and regeneration properties, blends with medium activator addition to tertiary amines are competitive. |
