Advertisement

Thermal Engineering

, Volume 64, Issue 4, pp 295–300 | Cite as

Influence of the reheat temperature on the efficiency of the wet-steam turbines of thermal power plants that operate under variable conditions

Steam Turbine, Gas Turbine, Steam-Gas Plants and Accessory Equipment

Abstract

A brief analysis of the existing methods for controlling the operating conditions of the turbine units that operate at variable loads is presented. In practice, the outdated rule of operation is most frequently used that states that the higher the parameters of the live and reheat steam and the lower the condenser pressure are, the higher is the efficiency of the turbine unit. However, in the technical literature, there is sufficiently substantiated evidence that this approach is not always correct, especially under low loads. This applies to both the regulation of the initial and final pressure and reheat temperature t r. In the article, particular stress is laid on the controllable parameter t r, the effect of which in the operational practices, according to the results of the analysis, is underestimated. The causes are considered that constrain more effective use of reheat temperature t r as a process variable. The results of field trials to investigate the influence of t r on the efficiency of turbine units of various capacities, viz., of 210, 250, 300, and 325 MW, during operation at varying loads are presented. It is shown that a decrease in t r to an optimal value of 10–30°C, depending on the load and the condenser pressure, increases the thermal efficiency by 1–2%. The following general pattern has been set: the lower the load, the lower the optimal reheat temperature. The main causes and factors that result in more efficient use of the heat phase transition in the steam path of the low-pressure cylinder and increased efficiency of the unit under rational choice of the reheat temperature are studied.

Keywords

steam turbine variable operating conditions reheat nonequilibrium efficiency 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    A. A. Tarelin and V. P. Sklyarov, “Working out measures to increase efficiency of the low-pressure section of the K-300-240 turbine in energy market conditions,” Nauka Innovatsiï 3 (3), 30–35 (2007).CrossRefGoogle Scholar
  2. 2.
    A. A. Tarelin, V. P. Sklyarov, G. K. Voronovskii, T. I. Shvedova, A. V. Medvedovskii, and A. Yu. Kozlokov, “Influence of the industrial superheat temperature on the power of T-250/300-240 turbine unit,” Probl. Mashinostr. 10, 5–8 (2007).Google Scholar
  3. 3.
    A. A. Tarelin, V. P. Sklyarov, A. Yu. Maistrenko, and A. V. Kosyachkov, “Improving the efficiency of steam turbine units working in off-design modes,” Vost.-Evr. Zh. Peredovykh Tekhnol., No. 2/7, 4–8 (2009).Google Scholar
  4. 4.
    V. A. Ivanov, Operating Modes of Large Steam Turbine Units (Energoatomizdat, Leningrad, 1986) [in Russian].Google Scholar
  5. 5.
    L. B. Zusmanovich and V. I. Fedorov, “Determining the optimal amount of condensing water flow on an 800MW generating unit,” Teploenergetika, No. 2, 27–30 (1984).Google Scholar
  6. 6.
    L. I. Degtyarev, “The erosion of turbine blades,” Sov. Kotloturbostr., No. 4, 4–11 (1938).Google Scholar
  7. 7.
    Yu. I. Daskal, “Deposition of the highly dispersed moisture in turbine arrays,” Izv. Vyssh. Uchebn. Zaved., Energ., No. 12, 81–83 (1983).Google Scholar
  8. 8.
    A. A. Tarelin, V. P. Sklyarov, and V. P. Kryzhenko, “Features of measuring the volumetric density of charges in the wet steam flow in a turbine,” Probl. Mashinostr. 3 (1–2), 11–16 (2000).Google Scholar
  9. 9.
    A. A. Tarelin and V. P. Sklyarov, Electrophysical Phenomena and Nonequilibrium Processes in Steam Turbines (Energotekh, St. Petersburg, 2012) [in Russian], in Ser. Problems of Power Engineering, Vol.9.Google Scholar
  10. 10.
    A. A. Tarelin, “Electrization of a wet steam flow and its influence on reliability and efficiency of turbines,” Therm. Eng. 61, 790–796 (2014). doi 10.1134/S004060151411010XCrossRefGoogle Scholar
  11. 11.
    V. I. Reznik, B. M. Shleifer, and S. I. Zaraiskii, “Some problems of the intermediate superheating adjustment of steam,” Teploenergetika, No. 3, 15–19 (1977).Google Scholar
  12. 12.
    E. I. Benenson, G. D. Barinberg, and V. I. Vodichev, “Influence of the external separation and intermediate superheating of steam on the thermal efficiency of the district heating saturated steam turbines,” Teploenergetika, No. 7, 38–42 (1979).Google Scholar
  13. 13.
    V. A. Ivanov, G. I. Levchenko, and N. A. Sorokin, “Adjustment of the electric power of combined cycle power plants operating in thermal mode by changing the steam superheat temperature,” Teploenergetika, No. 3, 12–15 (1988).Google Scholar
  14. 14.
    A. A. Tarelin and V. P. Sklyarov, “Increasing the turbine unit efficiency of Ukraine’s thermal and combined cycle power plants with consideration of the conditions of power market,” Visn. Khark. Politekh. Inst., Ser.: Energ. Teplotekh. Protsesi Ustatkuvannya, No. 12, 17–23 (2013).Google Scholar
  15. 15.
    I. I. Kirillov and R. M. Yablonik, The Fundamentals of the Theory of Wet-Steam Turbines (Mashinostroenie, Leningrad, 1968) [in Russian].Google Scholar

Copyright information

© Pleiades Publishing, Inc. 2017

Authors and Affiliations

  1. 1.Podhornyi Institute of Mechanical EngineeringNational Academy of Sciences of UkraineKharkivUkraine

Personalised recommendations