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The photograph shows PG field personnel during servicing work on one of the low-pressure rotors.
Dec. 8, 2003 -- Older power plants can be better matched to conditions in the liberalized power market by implementing customized modernization packages. At the Mehrum hard coal-fired power plant in Germany, Siemens Power Generation (PG) made a key contribution toward increasing the net efficiency of the 25-year-old plant by two percentage points to 40.5 percent.
The gain in efficiency was achieved primarily by modernizing the steam turbine. The unit's gross capacity is now 750 MW. Depending on load, approximately an additional 76,500 tons of coal would be needed annually in a non-modernized power plant to attain an increase in power output of 38 MW.
"The results of these upgrades have far exceeded our expectations. That applies both to the increase in power output and to the plant's profitability," stressed Bernhard Michels, Managing Director and Technical Manager of Kraftwerk Mehrum GmbH, after the plant had gone back on line. The environment also will benefit from the plant modernization.
According to the operator, CO2 emissions will drop by as much as 200,000 tons per annum, which represents a major contribution toward achieving the targets established in the Kyoto Protocol. The Mehrum plant is jointly operated by E.ON Kraftwerke, Hanover-based Enercity and BS Energy headquartered in Braunschweig.
As part of the turbine upgrade Siemens PG fitted the high-, intermediate- and two low-pressure cylinders with new stationary and moving blades of three-dimensional design. In addition to the new blading, the exhaust cross section of the two low-pressure cylinders was increased from 6.3 to 8 m2 to reduce exhaust losses. The large final-stage blades of the low-pressure turbines are free-standing without connecting elements, therefore a high-performance material was especially developed by Siemens PG for this purpose.
The upgrade program also included optimization of the turbine's admission and exhaust areas. As a result of these measures turbine efficiency increased by 3.8 percentage points. The turbine's I&C system also was upgraded accordingly. The installation was conducted by approximately 100 people in parallel with the power plant's scheduled major inspection and overhaul.
Nowadays, upgrade measures are not only intended to bring degraded components back to their original condition. They are also intended to increase the operating economy of the entire plant. All measures are planned in close cooperation with customers and specially geared to their needs. The basis for each modernization concept is precise knowledge of the plant's condition, which is obtained using on-line diagnostics systems. With the aid of these systems it is possible to establish the current condition of plant sections and forecast the future course of events. Based on this data, service and modernization measures can be planned well in advance and bundled in terms of the time frame to save costs.
The Power Generation Group (PG) of Siemens AG is a company in the international power generation sector. In fiscal 2003 (which ended September 30), Siemens PG posted sales amounting to approximately EUR 7 billion and received new orders totaling EUR 7.3 billion. Group profit amounted to EUR 1.171 million. On September 30, 2003, PG had a workforce of 30,300 worldwide.
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