New advancement of high performance for a combined cycle power plant: Thermodynamic analysis

Abstract

A great amount of energy gets lost through the exhaust of simple, reheat and inter-cooling cycle. Sometimes, this energy is enough to run another cycle or can be used to heat the compressed air from the compressor to the combustion chamber which leads to an increase in the overall efficiency of the plant. Combined cycle is an alternative to utilize the lost energy. In this way, not only the efficiency of the plant increases but it also helps to reduce air pollution and global warming. This paper is a parametric analysis conducted in order to optimize the performance of combined cycle which involves the bypass valve. The result shows that gain in network output is about 45% when the temperature at the inlet of the turbine of topping cycle increases from 1000 K to 1400 K. The gain in net efficiency of the cycle is from 15% to 31% when the temperature at the inlet of the turbine of topping cycle increases from 1000 K to 1400 K. The bypass valve should be opened for small compression ratio and closed for high value of compression ratio. Keywords: Turbine inlet temperature, Compression ratio, Topping cycle, Combined cycle, Bypass valve