A Case Study of Mixed Gas-Steam Cycle GT: LM6000 Class Aeroderivative Gas Turbine
Many ideas were proposed to aim the generation thermal efficiency up to 60%, such as “Steam-Cooled H-Tech. Combined Cycle”, “Methanol Conversion Regenerative Gas Turbine”, “Kalina Cycle” etc. The target thermal efficiency of 60% based upon LHV, could be also attained, when applying mixed gas-steam cycle like ISTIG and/or GAS3D for advanced aeroderivative gas turbines, which comprise of multiple shafts with overall pressure ratio more than 50, and TIT more than 2600 F (1700 K). It might be meaningful to evaluate existing aeroderivative gas turbines like LM6000 etc. by applying such a improving concept, as the more advanced gas turbines to be derived from GE90, PW4000, and Trent800 are not available to date for land applications. The intercooled ICAD GT of 77 MW was adopted as a base engine, and it was derived that the water /steam-injected WI/GAS3D GT version could produce 106 MW with 56% thermal efficiency, and it must be emphasized that the power curve in variation with ambient temperature is very flat than conventional GT plants.