Materials of construction for steam temperatures of over 700 °c – kraftwerk forschung electricity production in usa


In order to realise steam power plants with higher efficiencies, designers require components that use appropriate materials of construction that can withstand fresh steam conditions of over 700 °C and pressures of up to 350 bar. New design concepts and joining and sealing techniques need to be investigated to deal with these conditions. arkla gas phone number This applies to boiler parts, steam turbines, valves and pipes, for example. Development cycles and costs can be significantly reduced using improved simulation tools. This also helps to reduce manufacturing costs.

There have been numerous attempts in the past to develop steels that withstand high steam temperatures of up to 650 °C. So far, none of these development projects have really been successful. Specialists do not believe that iron-based materials will be able to achieve any significant improvement on current temperature ratings. However, a new materials concept based on so-called nickel-base alloys is opening up new possibilities.

Nickel-base alloys are extremely resistant even at high temperatures. wholesale electricity prices by state This would allow for a significant increase in steam temperatures to over 700 °C. In turn, this would make efficiencies of over 50% possible in steam power plants in the future. It should also be taken into account that the increasing fraction of imported coal from various sources in the future will mean that the fuel quality will fluctuate to a greater extent. Power plant technology will have to be designed to be particularly flexible in order to achieve the highest possible efficiencies despite these fluctuations.

Corrosion-protection layers must also be developed in addition to suitable materials of construction. electricity images cartoon Applied materials research in this area is making use of institutional research being carried out by major research organisations with the support of COORETEC project funding (particularly with regard to the certification of materials). Development cycles and costs can be significantly reduced by improving simulation tools. This also helps to reduce manufacturing costs

Efficiencies of over 50% will be achievable by 2020. This will lead to possible CO 2 reductions of around 30% compared to the plants currently in service in Germany and reductions of 15% compared to those plants currently being constructed. The basis for these improvements will be provided by optimised process design and improved individual components with high component efficiencies, such as steam generators and steam turbines. The degree to which processes and components can be optimised ultimately depends on the resistance of the materials of construction and the stage of development of material technologies. Fuels with high moisture contents, such as domestic lignite, have not been able to achieve these efficiencies so far. However, pre-drying of coal in external coal-drying plants may make this possible in the future.

On the other hand, the co-combustion of biomass and substitute fuels with a sufficient fraction of biogenous material is advantageous as this further reduces CO 2 emissions. Moreover, these fuels can be used here with a significantly higher efficiency than would be the case with mono-combustion. gas city indiana newspaper In order to achieve optimal combustion, new monitoring methods for combustion and steam generation are necessary.

If new nickel-base materials are used for the high-temperature applications in place of the iron-based materials that have generally been used up to now, it will be possible to increase steam temperatures to over 700 °C in the future. Consideration was first given to power plants with a steam temperature of 700 °C back in the mid-1990s. gas x strips review These plans were grouped under the banner of the AD700 project, which was co-funded by the European Community’s 4th Framework Programme for Research. One of the most important findings of this project was that it established that 700 °C technology is economically viable.

Further research projects were also conducted in parallel, which were generally coordinated with activities under AD700. These include the German MARCKO DE2 and MARCKO 700 projects that were co-funded by the German Federal Ministry of Economics and Technology. In the past, superheater test facilities have been financed by participating industrial companies.

The COMTES700 project is being supported by the two MARCKO projects. gas definition science The European energy suppliers E.ON, RWE, EnBW, Vattenfall, EDF, Electrabel, Elsam, Energi E2 and PPC and the four manufacturers ALSTOM Power, Hitachi Power Europe, Burmeister & Wain Energy and Siemens are participating in COMTES700. At the same time, experiments are being conducted in a number of power plants to verify corrosion behaviour at high temperatures in a realistic flue gas atmosphere and to investigate the oxidation behaviour of the inner surface of pipes.

The NRWPP700 project – a detailed engineering study – was initiated in 2006 under the leadership of VGB PowerTech e.V., supported by the Federal State of North Rhine-Westphalia. Increased prices for raw materials – e.g. nickel – and the experience gathered in purchasing semi-finished products and in manufacturing components for COMTES700 have provided the impetus for a detailed examination of engineering design as part of the PP700 project.

New, resistant materials of construction will be necessary due to the rise in component temperatures of around 100 K in the superheater and in the steam reheater as part of the changeover to 700 °C steam turbines. Innovative austenites and nickel-base materials are the main candidates for use in superheaters at these increased temperatures. However, these materials still have to be certified. Ferritic/martensitic steels are particularly suitable for use in evaporators. The effect of ash deposits from the flue gas also has to be investigated.

Of particular interest is the issue of how deposits interact with the pipe materials under typical combustion and boiler-operation conditions in a 700 °C power plant. j gastrointest surg As in the case of 600 °C plants, programmes to investigate corrosion and fouling deposits as well as materials research and certification programmes will have to focus on 700 °C power plants.

The amount of knowledge available about 700 °C power plants is now sufficient enough to allow for the construction of a demonstration plant. However, the development potential has not yet been fully harnessed. Increasing steam conditions to over 700 °C is now considered to be technically feasible. Intensive work on this approach will continue. One of the goals of the ongoing research is to improve the composition of nickel-base materials so that steam temperatures of up to 800 °C will be possible.

Further verification work is to be carried out on 700 °C technology. For this purpose, a demonstration plant with an output of at least 500 MW is to be planned and constructed. Assuming that current research projects and those planned for the near future are successful, this plant could be realised by 2014. The groundwork for the detailed design of the demonstration power plant has been established by the PP700 pre-engineering study that was to be completed by the middle of 2008.