Comparison of Different Amine Solvents for the Absorption of CO₂

Abstract

For the capture of CO2 the most promising method is chemical absorption in aqueous amine solutions. The most common solvent recycled in the absorber-stripper system is aqueous monoethanolamine (MEA). However other amines such as diethanolamine (DEA) and methyldiethanolamine (MDEA) are also considered as potential suitable solvents. The reduction by 85 % of the CO2 emission of a coal fired power plant is studied by simulation with a professional flow-sheet simulator. The simulation is done in two steps: first in open loop without recycling the lean solvent and wash water, then in closed loop. The influence of the most important operational parameters is studied. The optimal values where the desorption energy is minimal are determined for the temperature, flow rate and composition (CO2 and amine content) of the cold lean solvent, for the stripper: top pressure, location of the feed stage(s). The heat duties of all heat exchangers are also compared for the three different solvents.