ECN publication
EDGAR CO2 purity: type and quantities of impurities related to CO2 point source and capture technology: a Literature study
Published by: Publication date:
ECN Biomass & Energy Efficiency 4-3-2013
ECN report number: Document type:
ECN-E--12-054 ECN publication
Number of pages: Full text:
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This study provides an in-depth description of CO2 stream quality that is to expected in a Carbon Capture and Storage (CCS) context, such that needs for development of appropriate infrastructure may be anticipated. The summary of literature data shows that composition of CO2 gaseous streams vary significantly as a function of CO2 point source such like power plants flue gas, fuel gas, land-fill gas and digester gas streams and also depend strongly upon the recovery technology to be used. In general, it clearly appears that plant economics eventually govern the impurity level that will be actually found in the CO2 stream. While CO2 purity higher than 97% may be reached with most of the first generation solvent scrubbing systems, the use of less energy intensive 2nd generation capture technologies such as solid sorbents and membrane separation unit may induce higher impurities levels in CO2, while decreasing the energy requirement for CO2 separation. As a result the report also addresses the conditioning technologies that are available or need to be developed for removal of traces elements such as mercury, volatile compounds and other condensable compounds, as complementary cleaning technology to CO2 capture technologies. Finally the report tentatively establishes a relation between current pipeline specifications which may actually impose most of the criteria on CO2 quality specifications and the proven separation performances of available CO2 capture technologies. If post-combustion capture on power plant flue gas is to dominate CO2 capture technology in the future, as a result of the possibility of retro-fitting existing power plants, main contaminants will be nitrogen and oxygen and concerns about poisonous or harmful contaminant are not of concern. However, if CO2 capture from industry is to be implanted sulphur contaminants, fuel contaminants and CO contaminant must be taken into account and adequately abated.

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