Cost 522 - Power Generation into the 21st Century; Advanced Steam Power Plant

摘要

"Advanced Steam Power Plant" is one of three working groups within the frame of COST 522. Its main aim is to develop and evaluate ferritic steels for applications under steam conditions up to 650°C. Today's state of the art for large fossil-fired steam turbines comprises live steam conditions of up to 610°C/300bar and re-heat temperatures of up to 630°C. These ultra super critical steam parameters significantly increase the plant efficiency, and at the same time, reduce the fuel consumption, thereby reducing the emissions of CO_2. In order to maintain high operational flexibility of such large plant, the thick-walled components should be manufactured from ferritic materials. Rotors, casings, bolts, tubes/pipes and waterwalls are considered the critical components for investigation. The class of the 9-12% Cr steels is currently used for these critical components in the most advanced plants. Significant effort to increase the application temperature of these steels was focussed within the European COST 501 programme and led to improved materials for 600°C application for forged and cast components and for pipework. These improved materials are already successfully applied in a number of advanced European power plants. The 9-12% Cr steels still offer some further potential regarding their creep strength although the oxidation resistance must be carefully taken into consideration when temperatures up to 650°C are targeted. A large number of new ferritic-martensitic compositions, which have been designed on the basis of the positive experience from the previous activity as well as on the results obtained with advanced thermodynamic calculation tools are under investigation in the new COST 522 programme. Full size cast and forged components have been manufactured from the most promising compositions and will be evaluated by mechanical testing.