Technical and Economical Effectiveness of Modernization 370 MW Power Unit Repowered by Gas Turbine with their Modernization to Cogeneration
This chapter presents thermodynamic and economic analysis of electric power unit with the rated capacity of 370 MW operating in a combined-cycle, which is repowered by a gas turbine in a parallel system with dual-pressure heat recovery steam generator and concurrently working in a cogeneration for steam feeding from extractions A2 and A3 in the steam turbine and LP-IP crossoverpipe. These calculations apply the mathematical model of the unit presented in Chap. 3 and Stodola-Flügel turbine passage equations for the steam turbine from Chap. 4, which illustrate the variable concentration of steam stream passing through it as a result of repowering the unit by a gas turbine and variable steam extraction for district heating purposes. In the exemplary calculations referred to an assumption is made about the value of a thermal power and its qualitative regulation as presented in Chap. 6. The economic analysis applies the methodology in Chap. 2.