As CO°©2 capture technologies are approaching the commercialization stage, storage of the large amounts of CO2 expected from the capture has emerged as a major problem. The conventional large scale storage method of injecting CO2 into strata or ocean bears some critical problems such as adverse effects on the environment and potential leakage to atmosphere. For that reasons, the approach of carbon capture and storage by mineralization (CCSM) is getting much attention as it converts CO2 into chemically more stable mineral carbonates, e.g., calcium carbonate (CaCO3), magnesium carbonate (MgCO3), which are also valuable industrial raw materials. In this work, a CCSM process using sodium hydroxide (NaOH) as an alkaline feedstock is designed by integrating the well-known chlor-alkali process with a CO2 absorption process. In the designed process, NaOH solution made from electro-chemical reactions within the chlor-alkali process is transported to the CO2 absorption process for capture and conversion of CO2 (in flue gas emitted from a pulverized coal power plant) into sodium bicarbonate (NaHCO3) and sodium carbonate (Na2CO3). The designed process should overcome the insufficient alkalinity supply and slow carbonation rate problems which are the main challenges in the existing CCSM processes. In particular, the designed process is suitable for our native country of Korea in consideration of the low electricity price and high accessibility to brine. First, the designed process is implemented in the commercial process simulator of AspenPlusTM. Second, a techno-economic analysis of the designed process is carried out for a comparison with the standard carbon capture and storage (CCS) approach using the MEA absorption and injection into ocean, which is most close to commercial operation. Economics of the designed process are analyzed in terms of cost of CO2 avoidance ($/ton CO2). Finally, a sensitivity analysis is performed to find influential parameters of the designed process with respect to overall economic performance.
Figure 1 Schematic diagram of the designed CCSM process
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 G. Heddle, H. Herzog, and M. Klett, "The economics of CO2 storage," Massachusetts Institute of Technology, Laboratory for Energy and the Environment, 2003.