(687b) Design and Techno-Economic Analysis of a Carbon Capture and Storage By Mineralization (CCSM) Process Using NaOH As an Alkaline Feedstock

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 AspenPlus^TM. 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

References

[1] R.
R. Chandran and D. T. Chin, Electrochimica Acta, 1986, 31, 39.

[2] G.
Heddle, H. Herzog, and M. Klett, "The economics of CO2 storage," Massachusetts
Institute of Technology, Laboratory for Energy and the Environment, 2003.