On the Efficiency of Heat and Electric Power Plants Based on Combined-Cycle Plants with Overexpansion of the Working Fluid in the Gas Turbine and Injection of Steam into the Gas Path

Abstract

The subject of the study is a steam-gas (combined-cycle) contact plant with overexpansion of the working fluid inside the gas turbine and a hot-water recovery boiler. A special feature of the design is that dry saturated steam is used for injection and a regenerator serves as the mixing point. A hot-water recovery boiler is also installed to reduce heat loss into the environment. The study was carried out using the software package, System for Automated Calculation of the Parameters of Gas-Turbine Plants and Combined-Cycle Steam-Gas Plants. Results of variant parametric optimization of the working fluids of the plant performed according to a given design are presented. An additional increase in the useful power of the steam plant is due to the use of the regenerator as a steam superheater. In this case, the efficiency reaches 46.43% and the capacity of the hot-water recovery boiler, 4.7 MW. The method of mathematical simulation based on graph theory is used to verify the correctness of calculations.