Research Papers: Gas Turbines: Cycle Innovations

Evaluation of Property Methods for Modeling Direct-Supercritical CO2 Power Cycles

[+] Author and Article Information
Charles W. White

3168 Collins Ferry Road,
Morgantown, WV 26505
e-mail: CWWhite@keylogic.com

Nathan T. Weiland

National Energy Technology Laboratory,
626 Cochrans Mill Road,
Pittsburgh, PA 15236
e-mail: nathan.weiland@netl.doe.gov

Contributed by the Cycle Innovations Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received July 3, 2017; final manuscript received July 14, 2017; published online September 19, 2017. Editor: David Wisler.

J. Eng. Gas Turbines Power 140(1), 011701 (Sep 19, 2017) (9 pages) Paper No: GTP-17-1264; doi: 10.1115/1.4037665 History: Received July 03, 2017; Revised July 14, 2017

Direct supercritical carbon dioxide (sCO2) power cycles are an efficient and potentially cost-effective method of capturing CO2 from fossil-fueled power plants. These cycles combust natural gas or syngas with oxygen in a high pressure (200–300 bar), heavily diluted sCO2 environment. The cycle thermal efficiency is significantly impacted by the proximity of the operating conditions to the CO2 critical point (31 °C, 73.7 bar) as well as to the level of working fluid dilution by minor components, thus it is crucial to correctly model the appropriate thermophysical properties of these sCO2 mixtures. These properties are also important for determining how water is removed from the cycle and for accurate modeling of the heat exchange within the recuperator. This paper presents a quantitative evaluation of ten different property methods that can be used for modeling direct sCO2 cycles in Aspen Plus®. Reference fluid thermodynamic and transport properties (REFPROP) is used as the de facto standard for analyzing high-purity indirect sCO2 systems, however, the addition of impurities due to the open nature of the direct sCO2 cycle introduces uncertainty to the REFPROP predictions as well as species that REFPROP cannot model. Consequently, a series of comparative analyses were performed to identify the best physical property method for use in Aspen Plus® for direct-fired sCO2 cycles. These property methods are assessed against several mixture property measurements and offer a relative comparison to the accuracy obtained with REFPROP. The Lee–Kessler–Plocker equation of state (EOS) is recommended if REFPROP cannot be used.

Copyright © 2018 by ASME
Your Session has timed out. Please sign back in to continue.


IEAGHG, 2015, Oxy-Combustion Turbine Power Plants, International Energy Agency Greenhouse Gas, Cheltenham, UK.
Allam, R. J. , Palmer, M. R. , Brown, G. W., Jr. , Fetvedt, J. , Freed, D. , Nomoto, H. , Itoh, M. , Okita, N. , and Jones, C., Jr. , 2013, “ High Efficiency and Low Cost of Electricity Generation From Fossil Fuels While Eliminating Atmospheric Emissions, Including Carbon Dioxide,” Energy Procedia, 37, pp. 1135–1149. [CrossRef]
Allam, R. J. , Fetvedt, J. E. , Forrest, B. A. , and Freed, D. A. , 2014, “ The Oxy-Fuel, Supercritical CO2 Allam Cycle: New Cycle Developments to Produce Even Lower-Cost Electricity From Fossil Fuels Without Atmospheric Emissions,” ASME Paper No. GT2014-26952.
Weiland, N. , Shelton, W. , White, C. , and Gray, D. , 2016, “ Performance Baseline for Direct-Fired sCO2 Cycles,” Fifth International Supercritical CO2 Power Cycles Symposium, San Antonio, TX, Mar. 29–31, Paper No. NETL-PUB-20257. http://sco2symposium.com/www2/sco2/papers2016/OxyFuel/103paper.pdf
Lu, X. , Forrest, B. , Martin, S. , Fetvedt, J. , McGroddy, M. , and Freed, D. , 2016, “ Integration and Optimization of Coal Gasification Systems With a Near Zero Emissions Supercritical Carbon Dioxide Power Cycle,” ASME Paper No. GT2016-58066.
EPRI, 2014, “ Performance and Economic Evaluation of Supercritical CO2 Power Cycle Coal Gasification Plant,” Electric Power Research Institute, Palo Alto, CA, Report No. 3002003734. https://www.epri.com/#/pages/product/000000003002003734/
Span, R. , and Wagner, W. , 1996, “ A New Equation of State for Carbon Dioxide Covering the Fluid Region From the Triple-Point Temperature to 100 K at Pressures Up To 800 MPa,” J. Phys. Chem. Ref. Data, 25(6), pp. 1509–1596. [CrossRef]
Zhao, Q. , Mecheri, M. , Neveux, T. , Privat, R. , and Jaubert, J.-N. , 2016, “ Thermodynamic Model Investigation for Supercritical CO2 Brayton Cycle for Coal-Fired Power Plant Application,” Fifth International Supercritical CO2 Power Cycles Symposium, San Antonio, TX, Mar. 29–31, Paper No. 93. https://www.researchgate.net/publication/318701302_Thermodynamic_model_investigation_for_supercritical_CO2_Brayton_cycle_in_coal_fired_power_plant_application
NIST, 2007, “ NIST Reference Fluid Thermodynamic and Transport Properties—REFPROP,” National Institute of Standards and Technology, Gaithersburg, MD, NIST Standard Reference Database 23. https://www.nist.gov/sites/default/files/documents/srd/REFPROP9.PDF
NETL, 2013, “ CO2 Compressor Simulation User Manual,” Carbon Capture Simulation Initiative, National Energy Technology Laboratory, Morgantown, WV.
Hume, S. , 2017, EPRI, private communication.
Green, D. W. , 2008, Perry's Chemical Engineers' Handbook, 8th ed., McGraw-Hill, New York.
Baltadjiev, N. Z. D. , 2012, “ An Investigation of Real Gas Effects in Supercritical CO2 Compressors,” M.S. thesis, Massachusetts Institute of Technology, Cambridge, MA. https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0ahUKEwiUhPnygvLVAhXkzIMKHXUEBcIQFgg3MAE&url=https%3A%2F%2Fdspace.mit.edu%2Fbitstream%2Fhandle%2F1721.1%2F77101%2F824780783-MIT.pdf%3Fsequence%3D2&usg=AFQjCNHoZ2B3mjVszt51x2i4y2ffgmYM6w


Grahic Jump Location
Fig. 1

Block flow diagram of a simplified direct sCO2 cycle

Grahic Jump Location
Fig. 2

Comparison of LK-PLOCK calculations to saturated CO2 vapor and liquid-specific volume data

Grahic Jump Location
Fig. 3

Relative errors of property methods in calculating saturated vapor (upper) and liquid (lower) CO2 specific volumes

Grahic Jump Location
Fig. 4

Pure saturated CO2 vapor and liquid molar volume evaluation

Grahic Jump Location
Fig. 5

Relative error (bubble area) in superheated CO2 molar volume. Solid bubbles are positive deviations from REFPROP, and empty bubbles are negative deviations.

Grahic Jump Location
Fig. 6

Data used for property assessment of CO2:H2O binary mixture [10]

Grahic Jump Location
Fig. 7

CO2:H2O binary property evaluation

Grahic Jump Location
Fig. 8

Relative differences in key performance variables from REFPROP. Numbered variables defined in Table 5.

Grahic Jump Location
Fig. 9

Calculated versus experimental data for REFPROP

Grahic Jump Location
Fig. 10

Calculated versus experimental data for LK-PLOCK

Grahic Jump Location
Fig. 11

Calculated versus experimental data for PR-BM

Grahic Jump Location
Fig. 12

Calculated versus experimental data for BWRS

Grahic Jump Location
Fig. 13

Calculated versus experimental data for BWR-LS

Grahic Jump Location
Fig. 14

Calculated versus experimental data for SRK

Grahic Jump Location
Fig. 15

Calculated versus experimental data for RK-SOAVE

Grahic Jump Location
Fig. 16

Calculated versus experimental data for SR-POLAR

Grahic Jump Location
Fig. 17

Calculated versus experimental data for GRAYSON

Grahic Jump Location
Fig. 18

Calculated versus experimental data for PC-SAFT




Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In