The effectiveness of combined-cycle power plants hot startups simulating

Abstract

Activities aimed at substantiating the maneuverability characteristics of power-generating equipment installed at district heating power plants (DHPP) and especially at combined-cycle power plants (CCPPs) are quite topical for the modern conditions and involve calculations of thermally stressed state and analysis of the cyclic strength of steam path critical elements at different loading rates. Until recently, such problems have been solved in two possible ways: based on the results of tests carried out on operating equipment and using the mathematical models of heavily stressed parts of CCPP equipment. In this article, preference is given to the second way. The results of mathematical modeling represented as time dependences of the temperature state of equipment critical parts were taken as initial data for calculating their thermally stressed state and for analyzing their damageability according to the criterion of the equivalent operating hours. This criterion is an integral indicator characterizing the extent of damage accumulated in equipment parts and can be used for elaborating equipment maintenance programs. A dependence of the equivalent operating hours on the initial temperature of the metal of the high-pressure steam superheater’s outlet header, the component imposing the strongest limitations on the power unit loading rate, is obtained. It is shown that the number of equivalent operating hours of the CCPP steam circuit part equipment accumulated during hot startups does not have any essential effect on the equipment service life (heat-recovery steam generators, steam turbine, and steam lines).