Abstract
This paper reviews and integrates the latest energy-efficiency improvement techniques to recently developed superalloys and coatings for enhancing power output and profitability in today’s industrial gas turbines (GTs). It has been shown that the retrofitting of inlet air cooling and steam injected gas technology technologies in simple turbines can boost power output from 30 to 48.25 MW and improve generation efficiency from 29.9% to 33.4%. It has been reviewed that for improving efficiency of power plants beyond 60%, it is important to use higher turbine inlet temperature (TIT) in combined cycle gas turbine by applying single-crystal nickel-based superalloys and thermal barrier coating involving closed-loop steam cooling. It has been shown that an increase of the TIT by 56°C can result in increased revenue of US$8
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kW to the manufacturer of the original rating, provided the GT is sold for US$200
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kW. In view of the latest development in GT technology, which enables them to be operated at TIT = 1,600°C, it is recommended to develop superalloys based on higher-melting temperatures (Mo-based superalloys). A new chart for increasing power output has been developed so as to enable the GT designers to manufacture GT engines with enhanced profitability.