This paper presents a method for assessing the degree of approaching the paper output of the Clausius-Rankine cycle to the Carnot cycle. The computations to illustrate its use were performed for parameters characteristic of the current state of development of condensing power plants as well as in accordance with predicted trends for their further enhancing. Moreover there are presented computations of energy dissipation in the machines and devices working in such a cycle.
The paper presents the results of the numerical analyses for the steam turbine rotor, dedicated for the newly-designed 900 MW steam unit with supercritical steam parameters (650 °C, 30.0 MPa). Basing on the design calculations, an optimal design solution was determined. Review of the available literature on materials for turbine rotors with supercritical steam parameters was done. Then the start-ups of the turbine were simulated. Thermal and strength states were analyzed. As a result, an optimal start-up characteristic was obtained.
The paper presents a thermal-economic analysis of a 900 MW coal-fired power unit for ultra-supercritical parameters with internal steam reheat. The subject of the study was the cycle proposed as the "initial thermal cycle structure" during the completion of the project "Advanced Technologies for Energy Generation" with the steam parameters of 650/670 °C/30 MPa. Two configurations of internal reheat were analysed: with a four- and seven-section exchanger. The effect of reheat on the operation of the power unit under a partial load was also analysed, and preliminary calculations of the heat exchange area of the internal reheat were made.
This article describes the validation of a supercritical steam cycle. The cycle model was created with the commercial program GateCycle and validated using in-house code of the Institute of Power Engineering and Turbomachinery. The Institute's in-house code has been used extensively for industrial power plants calculations with good results. In the first step of the validation process, assumptions were made about the live steam temperature and pressure, net power, characteristic quantities for high- and low-pressure regenerative heat exchangers and pressure losses in heat exchangers. These assumptions were then used to develop a steam cycle model in Gate-Cycle and a model based on the code developed in-house at the Institute of Power Engineering and Turbomachinery. Properties, such as thermodynamic parameters at characteristic points of the steam cycle, net power values and efficiencies, heat provided to the steam cycle and heat taken from the steam cycle, were compared. The last step of the analysis was calculation of relative errors of compared values. The method used for relative error calculations is presented in the paper. The assigned relative errors are very slight, generally not exceeding 0.1%. Based on our analysis, it can be concluded that using the GateCycle software for calculations of supercritical power plants is possible.
The paper presents a thermal-economic analysis of different variants of a hard coal-fired 900 MW ultra-supercritical power unit. The aim of the study was to determine the effect of the parameters of live and reheated steam on the basic thermodynamic and economic indices of the thermal cycle. The subject of the study was the cycle configuration proposed as the "initial thermal cycle structure" during the completion of the project "Advanced Technologies for Energy Generation" with the live and reheated steam parameters of 650/670 °C. At the same time, a new concept of a thermal cycle for ultra-supercritical parameters with live and reheated steam temperature of 700/720 °C was suggested. The analysis of the ultra-supercritical unit concerned a variant with a single and double steam reheat. All solutions presented in the paper were subject to a detailed thermodynamic analysis, as well as an economic one which also included CO2emissions charges. The conducted economic analysis made it possible to determine the maximum value of investment expenditures at which given solutions are profitable.