Ryotaro Magoshi

Development of Advanced USC Technologies for 700°C Class High Temperature Steam Turbines

Global warming due to increased CO2 levels in the atmosphere and resource saving have been the focus of world attention in the past decades. Efforts to improve generating efficiency by increasing the turbine inlet steam temperature and pressure in large capacity fossil-fuel and combined-cycle power plants are being made together with efforts to improve the internal efficiency. Most of MHI’s modern steam turbines, including the combined cycle plants, have a 600°C class USC inlet steam conditions. 700°C class Advanced USC (A-USC) technology is one of the remarkable technologies being developed to reduce CO2 emissions, and one, which was chosen by Japan’s ‘Cool Earth - Innovative Energy Technology Program’, which was launched in 2008 to contribute to substantial reductions in CO2 emissions. Major Japanese manufacturers of boilers and turbines joined forces with research institutes to bring the project to reality. This paper illustrates the features and benefits of A-USC technologies for MHI’s 700°C class high temperature steam turbines, including cycle design, conceptual design (structure and alloy), and the development of candidate materials.Copyright

Development of Welded Rotors for High-Temperature Steam Turbines

Steam turbine plants face strict market demand for high-temperature operation, streamlining, and shortened delivery times. The welded rotor enables streamlining through the use of material most appropriate for high to low-temperature parts. The use of materials will also enable a shift to larger capacity and shorter delivery times. The hetero-material welded rotor consisting of 2.25CrMoV, 9%Cr, and 3.5NiCrMoV steel was developed to meet these demands and verified at Takasago combined cycle plant. The plant has been conducting commercial and proving operations on the rotors. In this paper the authors introduce verification of work execution, strength, thermal stability, inspection for the welded rotor, and actual machine commercial operation.© 2005 ASME