Material challenges in industrial gas turbines

Industrial gas turbines find their use in a variety of different applications, such as in simple cycle for power generation and mechanical drive or combined cycles for power generation and district heating. The gas turbine is normally run on natural gas, but can also be run on liquid fuels. The ever increasing demand for higher efficiency in power generation, in combination with expected lower life cycle costs, adds a real challenge for the development of gas turbines. Also Materials Technology is facing many of those challenges. The drive for better fuel flexibility, including possibility to run on heavy fuels, and also renewables, requires better understanding, and be able to cope with highly corrosive elements, present in the fuel, or ingested via air intake. Hot corrosion has attended a lot of interest in the past, and will continue to do so. Another life limiting factor is the combination of increased firing temperatures, and the driver to lower the amount of cooling air used. This sets high demands on alloys in the hot components with good oxidation resistance, in combination with good creep and cyclic properties. The ever increasing temperatures also require advanced oxidation protection coatings, as well as thermal barrier coatings. The expected service conditions for industrial gas turbines, lead to particular interest in the mechanical properties in high temperature materials, for mechanical integrity calculations.