Development requirements for absorption processes for effective CO2 capture from power plants

Effective commercial liquid absorption technology currently applicable for CO2 capture from power plant flue gases uses a conventional chemical solvent, MEA(monoethanolamine), which was developed over 60 years ago as general non selective solvent to remove acid gases from natural gas streams. The application to CO2 capture from almost atmospheric pressure flue gases required modification of the technology on account of the oxygen content to incorporate inhibitors to resist solvent degradation and equipment corrosion, as well as upstream treatment of the flue gases to remove both SOx and NOx present. The solvent strength used by such processes is relatively low in comparison with high strength modern chemical solvents. The resultant effect is large equipment and high regeneration energy requirements which is a parasitic load on the power plant. Using current technology for CO2 capture from flue gas derived from conventional pulverized coal fired power stations increases the nameplate capacity with a consequential increase of 50% in electricity prices. The development requirements to replace the current available technology were identified by sensitivity analysis as higher solution concentration which results in smaller equipment size and a lower thermal regeneration energy demand and consequential reduction in the overall power plant nameplate capacity.