Cost Analysis of the Uky-Caer Transformative CO2 Capture System

U.S. DOE NETL has revised the published reference cases (RCs) used to compare CO₂ capture systems (CCSs). Differences between the RCs will be reviewed, emphasizing supercritical pulverized coal post combustion CO₂ capture, and the University of Kentucky Center for Applied Energy Research (UKy-CAER) CCS cost estimation method will be explained.

UKy-CAER takes a four-pronged approach to CCS. Details about how the synergistic effects of 1) mass transfer intensification; 2) two-stage solvent regeneration; 3) system integration and heat recovery; and 4) the use of an advanced solvent affect the cost of CCS will be presented. The UKy-CAER CCS employs several process intensification techniques for the absorber including partial CO₂ recirculation, temperature profile control, self-adjusting gas-liquid distribution, intercooling and bottom pump-around. Solvent regeneration is conducted in two stages. A split rich feed to the pressurized primary stripper, reduces the steam use and allows for a small column and the secondary air stripper, powered by recovered heat, works to reduce the steam requirement in the primary stripper, with higher rich loading, and provide an extra lean solvent to the absorber. The steam extracted to the CCS reboiler is desuperheated by heating a portion of the boiler feed water, reducing the exergy loss. An advanced solvent with an achievable regeneration energy of 900 BTU/lb CO₂ captured is assumed, with experimental results presented from the UKy-CAER small pilot CCS validating this assumption.

Additional equipment pertaining to the UKy-CAER CCS, being 20% of the bare erect cost, is well worth the extra capital when overall performance is considered. The cost of CO₂ capture with UKy-CAER CCS is $39/tonne (excluding transportation/storage), compared to the RC B12B cost of $58/tonne. Additionally, the equipment cost is lower by 13%, the auxiliary power load is lower by 4.7%, and an additional 26 MW of net power are generated.