Analysis of parameters affecting the performance of gas turbines and combined cycle plants with vapor absorption inlet air cooling

The integration of an aqua-ammonia inlet air-cooling scheme to a cooled gas turbine-based combined cycle has been analyzed. The heat energy of the exhaust gas prior to the exit of the heat recovery steam generator has been chosen to power the inlet air-cooling system. Dual pressure reheat heat recovery steam generator is chosen as the combined cycle configuration. Air film cooling has been adopted as the cooling technique for gas turbine blades. A parametric study of the effect of compressor-pressure ratio, compressor inlet temperature, turbine inlet temperature, ambient relative humidity, and ambient temperature on performance parameters of plants has been carried out. It has been observed that vapor absorption inlet air cooling improves the efficiency of gas turbine by upto 7.48% and specific work by more than 18%, respectively. However, on the adoption of this scheme for combined cycles, the plant efficiency has been observed to be adversely affected, although the addition of absorption inlet air cooling results in an increase in plant output by more than 7%. The optimum value of compressor inlet temperature for maximum specific work output has been observed to be 25 degrees C for the chosen set of conditions. Further reduction of compressor inlet temperature below this optimum value has been observed to adversely affect plant efficiency. Copyright (c) 2013 John Wiley & Sons, Ltd.