Post-combustion carbon capture from coal fired plants - solvent scrubbing (Davidson, 07-2007)

The potential use of solvents for carbon dioxide capture from the flue gas from coal fired power plants is reviewed. After an introduction to solvent absorption of CO2, the use of alkanolamine solvents, particularly monoethanaloamine (MEA) is considered. The degradation of solvents in the flue gas environment and the consequent corrosion problems associated with the degradation products is then examined. The energy consumption for regeneration of the solvents is a key feature in determining the overall costs of solvent scrubbing. There is considerable research on alternative solvents to MEA which have higher capacity for CO2 capture and lower energy consumption among other attributes. The design of the absorption contractors which facilitate the contact and interaction of the gas and liquid phases can also contribute to lowering the energy consumption of the overall process. Techno-economic studies, process modelling and simulation are also reviewed. Some details of existing demonstration and pilot plants and current national and international R&D programmes are given. Finally, the potential environmental aspects of the solvent scrubbing processes are briefly examined.