Recent development of steam turbines with high steam temperatures

Abstract

Power plants with high thermal efficiency are essential and indispensable in order to decrease the impact on the environments. In order to achieve this goal, enhancement of the steam conditions is the most fundamental and effective measure. Recent steam conditions in Japan range from 593 to 610 degree C owing to the technological development. There are many areas of technology for the realization of such steam conditions, for instance, material development, cooling design, steam path development, casing design, and so on. Not only the research and development but also accumulation of the operational results is of importance to achieve a breakthrough in turbine design. In this paper, recent development of steam turbines with high temperatures will be presented focusing on their design features including material selections. This paper also deals with further efforts targeting even higher steam conditions, which are promising for future development of steam turbine technology.