Parametric optimization of the thermodynamic cycle design for supercritical steam power plants

•An original methodology for the design of supra-critical power plants is proposed.•Best reheating steam pressure and configuration of preheating system is found.•A technical and economical multi-objective optimization is made.•The Pareto frontier shows different possible configurations and reheat pressures. The paper presents an original methodology and model for the optimal design of power plants with supra-critical steam turbine cycle. By applying a thermodynamic analysis, the method finds the best configuration of the preheating system, the steam extractions from the turbine and the reheating steam pressure, for different main steam parameters and different high-pressure turbine configurations. A multistep optimization is made in the paper for a fixed fuel input. First, a parametric optimization of a given scheme, without restrictions was performed. Secondly, a technical parametric optimization with restrictions and the definition of the scheme is realized. Finally, a multi-objective optimization with the consideration of two criteria is made: a technical criterion (the thermal cycle net efficiency) and an economical one (the specific investment in the power plant’s equipment). The multi-objective optimum values for each studied case are obtained. The results from the Pareto frontier show that the technical optimum tends to the highest values of reheat pressure, while the economic one tends to the lowest values of reheat pressure. The results are in line with appropriate data from the literature.