Materials for the new power plant generation

Higher steam parameters in power plants enable energy conversion which is more efficient, with lower CO2 levels. The next generation of power plants is designed to withstand steam temperatures of over 700 °C. This is not possible when standard materials are used. For this reason, researchers at the Mannheim power plant are now testing thick-walled components made of nickel alloys. The high temperature material test track is designed to pave the way towards building a pilot plant.

Currently, coal-fired power plants with between 9 and 11 per cent Cr steels are designed for operating temperatures of up to 620 °C. By increasing the fresh steam temperature and other operating parameters, efficiency levels of over 50 per cent become possible. In order to achieve this increase in efficiency, the power plants must be designed to cope with higher operating temperatures. One option is to use nickel-based alloys.

New materials for efficient power plants

Until now, the boilers and turbines have usually been produced from iron-based materials. Materials of this kind can only be used to a limited extent with temperatures of over 600 °C. Nickel-based alloys can by contrast withstand higher flue gas and steam temperatures. Now a consortium is studying how nickel-based alloys change when subjected to loads typical of those present in power plants.

In the Mannheim power plant, this consortium is working with 29 partners from the scientific and industrial fields on the materials. The series of studies with thick-walled components in the high-temperature material test track (HWT II) has a budget of EUR 17.6 million. The German Federal Ministry of Economics and Technology is funding half the project. The technical association for power and heat generation, or VGB, and other third-party funders are contributing EUR 5.6 million. The project partners are providing EUR 3.5 million of their own funds. “This materials issue is of relevance for all energy providers and industry partners,” says Klaus Metzger, project manager at the Mannheim power plant.