Siemens Steam Turbine Technology for a 350 MW Power Plant with Highest Steam Conditions 600/620°C and 3DV{sup}TM Variable Reaction Blading

摘要

In 1999 worldwide population passed the 6 billion mark. According to estimations by the United Nations, the world population in 2020 will have grown to 8 billion. In those 20 years, the worldwide electric power consumption, however, will increase progressively by at least 50 per cent. Today, fossil fuels such as coal, gas, and oil account for 60 per cent of the electric power generation. This share is expected to rise to approximately 70 per cent by the year 2020. Coal represents 60 per cent of fossil fuel resources. Since it is expected to remain available at stable prices over the long term, current predictions indicate that it will remain a number one ranking fuel over the next several decades. Improving the efficiency of steam turbine power plants is therefore an important way of minimising emissions and costs of power generation. The fundamental options of efficiency improvement can be divided into increasing the main steam conditions and improving the process and component qualities. Siemens has a lot of experience in the field of power plants with supercritical steam conditions since in 1951 it built the first supercritical unit worldwide. The most recent examples of advanced steam power plants with highest steam conditions are "Schwarze Pumpe"/Germany (800 MW, 250 bar/544°C/562°C), "Niederauβem"/Germany (1000 MW, 265 bar/576°C/599°C), and "Isogo"/Japan (600 MW, 250 bar/600°C/610°C). The new Siemens 3DV{sup}TM blading concept with state-of-the-art three-dimensional airfoils and optimised aerodynamic bladepath design addresses the improvement of component quality. Based on this technology Siemens has developed steam turbines for further increased steam conditions. These turbines satisfy economical, environmental and long time operational requirements. This paper describes, as an example, a coal-fired 350 MW steam turbine with steam conditions of 280 bar/600°C/620°C. Focus is put on the most important features of the turbine.