Partial Carbon Capture by Absorption Cycle for Reduced Specific Capture Cost

Artikel i vetenskaplig tidskrift, 2018

For a sustainable-energy system, the industrial carbon emission should be zero or close to it. The partial capture of CO2, i.e., capturing only a share of the CO2, is discussed as an option for initiating the transition toward the decarbonization of industry by reducing the CO2 mitigation cost at industrial sites. This work models two approaches to achieving partial capture based on amine absorption: (1) capturing 90% CO2 from a split stream of the flue gas or (2) capturing less CO2 (≪90%) from the total flue-gas flow. A techno-economic analysis is carried out that considers scale, CO2 concentration, and process configurations (absorber intercooling and rich solvent splitting) when comparing the cost of partial capture to full capture, i.e., capturing close to all CO2 from the entire gas. Besides lowering absolute costs, the study shows that partial capture from CO2-rich gases may also lower specific cost (€ per tonne of CO2 captured) compared to full capture, despite the economy of scale, during certain market conditions. Operating expenditures, especially the cost of steam, are found to be dominating cost factors for partial capture, even for capture down to 200 000 tonnes per year.