Optimization of turbine pressures in a net-zero supercritical Allam cycle

Yousef Haseli, Greg F. Naterer

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


The Allam cycle is an innovative clean power cycle that reduces environmental pollution associated with fossil fuel-based power production by capturing the generated carbon dioxide. Numerical simulation of the cycle performance has been reported in past studies. This article develops a new method to predict and optimize the thermal efficiency of the cycle. Optimization of the cycle efficiency is performed with a thermodynamic model with respect to the turbine inlet and exhaust pressures at a fixed turbine inlet temperature (TIT). A criterion is established for the maximum efficiency which subsequently relates the turbine inlet and outlet pressures, exit pressure of the CO2 compressor, and minimum cycle temperature. Using a previously developed process model, it is shown that the turbine cooling flow rate has a negligible impact on the optimum turbine pressures although it reduces the cycle efficiency by 2–3%. The process model is also used to assess the accuracy of the present method over a wide range of turbine inlet pressures and a CO2 compressor exhaust pressure (pCO2e) of 60 and 80 bar. The average percentage error is found to be −1.6 ± 0.3% for TIT = 1431 K, pCO2e = 80 bar and 1.3 ± 0.3% for TIT = 1331 K, pCO2e = 60 bar. The methodology developed in this paper improves the understanding of relationships between the key process parameters of the Allam cycle at the condition of maximum efficiency.

Original languageEnglish
Article number136639
JournalJournal of Cleaner Production
StatePublished - May 10 2023


  • Efficiency optimization
  • Supercritical power cycle
  • Thermodynamic modeling
  • Turbine pressure ratio


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