Investigation of Steam Injection Effect and Exergy Analysis on ABC Gas Turbine Cycle

An air bottoming cycle (ABC) was proposed in the 1980 decade as an alternative for the conventional steam bottoming cycle. Now this cycle is being applied as a compact and simple bottoming cycle. In the gas-air heat exchanger, thermal energy of topping cycle exhaust is transferred to bottoming cycle. In fact, exhaust of topping cycle is using as a heat source for bottoming cycle. Nevertheless, lower efficiency than combined steam turbine cycles makes ABC not customary. On the other hand, attempt to increase efficiency in gas turbine was leading to wet cycles. Steam was entering in the middle parts of the cycle (between compressor and turbine).Very low additional compressor consuming work and increasing in turbine work is the main reason for higher efficiency of steam injection cycle in compare with simple cycle. In this paper, steam injection in ABC is investigated. We use both cycle benefits (steam injection and ABC).In fact, our innovation is using combination of air bottoming and wet cycles for heat recovery purpose. In this research, exergy analysis and performance improving are investigated in ABC gas turbine cycle with steam injection by using a series of computer code. In the model steam or water is injected in discharged of bottoming compressor. Corrosion reduction (in comparison with wet cycles) , performance improvement of ABC gas turbine and reducing undesirable effect of ambient temperature on efficiency of combined ABC cycle are the advantages of using this method.