CO2 capture from power plants. Part II: A parametric study of the economical performance based on mono-ethanolamine

While the demand for reduction in CO2 emission is increasing, the cost of the CO2 capture processes remains a limiting factor for large-scale application. Reducing the cost of the capture system by improving the process and the solvent used must have a priority in order to apply this technology in the future. In this paper, a definition of the economic baseline for post-combustion CO2 capture from 600 MWe bituminous coal-fired power plant is described. The baseline capture process is based on 30% (by weight) aqueous solution of monoethanolamine (MEA). A process model has been developed previously using the Aspen Plus simulation programme where the baseline CO2-removal has been chosen to be 90%. The results from the process modelling have provided the required input data to the economic modelling. Depending on the baseline technical and economical results, an economical parameter study for a CO2 capture process based on absorption/desorption with MEA solutions was performed. Major capture cost reductions can be realized by optimizing the lean solvent loading, the amine solvent concentration, as well as the stripper operating pressure. A minimum CO2 avoided cost of € 33 tonne-1 CO2 was found for a lean solvent loading of 0.3 mol CO2/mol MEA, using a 40 wt.% MEA solution and a stripper operating pressure of 210 kPa. At these conditions 3.0 GJ/tonne CO2 of thermal energy was used for the solvent regeneration. This translates to a € 22 MWh-1 increase in the cost of electricity, compared to € 31.4 MWh-1 for the power plant without capture.