Studies on Reduced Inlet Temperature of Compressor and Water Injection to Enhance the Thermal Efficiency of Gas Turbine

Abstract

Burning of hydrocarbons and recovering the thermal energy through gas turbines and producing useful work is a widely used method of thermal power generation. In simple Brayton cycle the amount of work needed for compression is high. It affects net useful work and efficiency of the cycle. Inter cooling is used as a method for reducing compressor work. Studies on inter cooling with water injection will give an idea of how the efficiency varies as a function of temperature, pressure and amount of water injected. We cannot lower the inlet temperature of air to compressor indefinitely; as it affects the net useful work and efficiency in the form of cooling work. The conversion efficiency increases with increase in temperature at inlet of turbines.  However, consideration on the material properties often places limitations on the highest temperature which can be used in operation. Also for reducing the NO_X production during combustion, the inlet temperature should be controlled.  The inlet temperature can be controlled by managing the excess air used or by injecting water into the combustion chamber. This paper theoretically analyses the variation of thermal efficiency of gas turbine cycle for different configurations of operations.