Gas turbine selection for feedwater repowering

  • Marcin Wolowicz Warsaw University of Technology
  • Krzysztof Badyda Warsaw University of Technology


The paper presents the concept of using hot exhaust gases from gas turbines with different power output to heatup feedwater in a supercritical power plant unit. The gas turbine is connected to the system, bypassing a highpressure regenerative heat exchanger. The benefits of this solution are discussed and the factors to be taken intoaccount are listed. The criteria to be met by the gas turbine to ensure safe and optimal connection to the steamsystem are discussed. A reference unit model with 800 MW electric power (an existing super-critical power unit inPoland—Belchatow II) was created and presented in a previous paper by the same authors. This model was latersupplemented with a gas turbine (three different models with different levels of power production are taken intoconsideration). The system with a gas turbine enjoys greater power and efficiency over the steam cycle alone. Thepower increase is due to the extra power generated by the gas turbine and the higher output of the steam systemcaused by increasing the steam flow through the turbine (closed extraction to the "bypassed" high-pressure heatexchanger). System power is changed linearly with the steam flow and reaches the nominal point 40..50% higherthan without an added gas turbine (depending on gas turbine power and efficiency). The efficiency characteristicsof the whole system are flatter, with higher values.


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How to Cite
WOLOWICZ, Marcin; BADYDA, Krzysztof. Gas turbine selection for feedwater repowering. Journal of Power Technologies, [S.l.], v. 95, n. 4, p. 302--308, dec. 2015. ISSN 2083-4195. Available at: <>. Date accessed: 26 july 2021.
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