Technical Features and Long-term Operating Experience of Mitsubishi Advanced M 501 G Gas Turbine

Abstract

The combined cycle power plant is recognized as one of the best thermal power plants for its high efficiency and cleanliness. Under these circumstances. Mitsubishi Heavy Industries, Ltd.(MHI) developed large, heavy-duty 1, 200C class M 701 D (for 50Hz utility) gas turbine and 1, 400C class M 501 F (for 60Hz)/M 701 F (for 50Hz) gas turbines. Their high efficiency and reliability for combined cycle applications have been proven in field operations. Based on the fact that the combined cycle efficiency is highly dependent on the gas firing temperature, MHI has newly developed the 1, 500C class M 501 G (for 60Hz)/M 701 G (for 50Hz), which is called “G” series, gas turbines.Development of the “G” series gas turbine was started in early 1990' s and the design was based on the following concepts, which give excellent performance and high reliability to the “G” series.Firstly, proven features from the “F” series are kept. Secondly, the most advanced technologies in aerodynamic design, heat transfer design and new materials for the “G” series are introduced. Thirdly, our conventional design criteria in industrial gas turbines are applied. Fourthly, NOx and the metal temperature remains at the same level as the “F” series by applying steam-cooled combustors even though the turbine inlet temperature is increased. Finally, special measurements and verification tests are carried out before commercial operation to secure their high reliability.The trial operation of the M 501 G was conducted in 1997 in the combined cycle verification plant in MHI Takasago. Japan. It was successful and the commercial operation was started in June 1997. Since then, the detail inspections were conducted and the condition of each component was quite sound. Therefore, the availability. defined as the actual power supply hours over demanded power supply hours excluding scheduled shutdown such as periodical inspection, during the commercial operation was 98.6%.The trial operation of the M 701 G was conducted in October 1998 in the domestic utility company. After completion of plant tests, the commercial operation was started in July 1999. The availability during commercial operation is 100%.This paper describes the technical features and up-to-date operating status of the M 501 G combined cycle power plant in MHI Takasago.