Comparative evaluation of different combined cycle configurations having simple gas turbine, steam turbine and ammonia water turbine
Abstract Gas/steam combined cycles have been increasingly used in power plants due to better energy utilization for getting better performance from them as compared to Brayton cycle based gas turbine plant or the Rankine cycle based steam turbine plant individually. However, there exists ample scope for further improvement in the performance of combined cycles through variations in their arrangements. The present study deals with the thermodynamic analysis of different combined cycle power plant configurations having the simple gas turbine with closed loop cooling of gas turbine blades and varying arrangements in the bottoming cycle. The variation in the bottoming cycle relies upon the effective utilization of energy available in the topping cycle. The bottoming cycle considered uses steam cycle or ammonia water cycle or its combination. The comparison of eight different combined cycle configurations considered in this study reveals that, the work output is maximum for simple gas turbine with bottoming cycle having reheat ammonia water turbine and steam turbine, with an output of 638 kJ/kg of air, first and second law efficiency of 54.95% and 57.87% respectively for ammonia mass fraction of 0.7. The exergy loss is found to be maximum for the combustion chamber followed by heat recovery vapor generator.
Energy