Development and operating experiences of the 510G, `1500degC class` gas turbine; 1500degC kyu gas turbine 501G no kaihatsu to jissho unten ni tsuite

The above-mentioned gas turbine developed by Mitsubishi Heavy Industries, Ltd., is described. For this turbine, a 17-stage axial flow compressor is designed, which incorporates the technologies of MCA (multiple circular arc) blades and CDA (controlled diffusion airfoil). As for the combustor, a recovery type steam cooling system is adopted for the first time in the world, which necessitates no cooling air. The heat that the steam collects while cooling the combustor is recovered at the steam cycle side, and this enhances the overall thermal efficiency of the plant. The turbine is a high-load, high-performance 4-stage axial flow type that can deal with an increase in load ensuing from a rise in the inlet temperature. The stator vanes are built of a Ni-base superalloy MGA2400 which is an improved-weldability version of Ni-base alloys known to be poor in weldability. The facility used for the long-term reliability verification test of the turbine is a multiaxial combined plant capable of a gas turbine output of 225MW and a steam turbine output of 105MW. The outcome of the test reveals a high availability of 99.9% in a 1557-hour operation. 5 refs., 12 figs., 3 tabs.