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Optimization and performance evaluation of equations of state for supercritical CO2-rich mixtures for application in the NET Power cycle

Year: 2025
Type: article
Abstract: In this paper the interaction parameters of six equations of state (EoS) were calibrated from density and phase equilibrium experimental data of supercritical CO 2 -rich mixtures. The Peng-Robinson (PR), Soave-Redlich-Kwong (SRK), Lee-Kesler-Plöcker (LKP), Benedict-Webb-Rubin-Starling (BWRS), perturbed chain SAFT (PC-SAFT) and Cubic-Plus-Association (CPA) EoSs were considered. As a novelty, the pressure, temperature and composition ranges for calibration were (1 – 49) MPa, (293.18 – 423.15) K, and (72.6 – 99.8) % mol CO 2 , which are close to those found in the innovative oxy-combustion NET Power cycle, particularizing the optimization of the EoSs for application in this power cycle. The performance of the EoSs, including the GERG-2008 EoS, was assessed in an isentropic compression process from 7.4 MPa to 30 MPa. The LKP EoS reported the lowest average deviation, 2.03 %, in modeling the bubble and dew lines of the supercritical CO 2 – H 2 O mixture. The GERG-2008 EoS was the most reliable model capturing the density of the supercritical CO 2 -rich mixtures, reporting an average deviation of 1.34 %. Therefore, the combination GERG-2008 + LKP is recommended for NET Power cycle modeling purposes. Only the CPA and GERG-2008 models captured the liquid-like properties of the CO 2 -rich mixture during the compression. This resulted in a specific compression work of 33.02 kJ kg −1 for GERG-2008, while the PR, SRK, LKP, and PC-SAFT EoSs reported a value up to 1.54, 1.65, 1.53, and 1.70 times higher. • Equations of state were optimized for application in the novel NET Power cycle. • LKP EoS captured the CO 2 - H 2 O bubble and dew lines with the lowest error, 2.03 %. • GERG-2008 captured the density of the sCO 2 mixtures with the lowest error, 1.34 %. • The GERG-2008 specific work was 32.91 kJ kg −1 , up to 1.71 lower than other EoSs.
DOI: 10.1016/j.supflu.2025.106693
Language: English
Open Access status: hybrid
Estimated APC paid: $3,910
OpenAlex ID: W4411201042
FWCI: 2.595
Cites: 60
Cited by: 11
Related to: 10