Modeling › Materials Behavior Under Severe Environments
In this thrust area, gas turbines and boiler operation is considered. Gas turbines in integrated gasification combined with cycle power plants burn a fuel gas (syngas, SG) in which the proportions of hydrocarbons, H2, CO, water vapor, and minor impurity levels may differ significantly from those in natural gas (NG). Such differences can yield changes in the temperature, pressure, and corrosive species that are experienced by critical components in the hot gas path, with important implications for the design, operation, and reliability of the turbine. For all fuel scenarios, the overall goal of IGCC plants is to produce maximum power at maximum efficiency, which typically translates to the use of the highest possible rotor inlet temperature (RIT). However, because advances in turbine technology to maximize RIT when burning NG have required that the advanced materials used for the critical hot section components are operated near their limits, changes in fuel characteristics that have the potential to modify the operating environment experienced by those components must be better understood to ensure that any possibly detrimental effects on the lifetime/reliability of the turbine can be assessed.
The evolution of pressure and temperature during boiler operation influence the processes that result in the failure and spallation/exfoliation of oxide scales formed on the steam-side of tubes used in power generation boilers. A comprehensive model was developed at ORNL for predicting the exfoliation of oxide scales based on available constitutive equations of the numerous contributing processes, including oxide growth, heat transfer, creep, elastic deformation, geometrical restraint – to name just few. In the exfoliation model, specific changes among boiler configuration and operating conditions, as well as differences in alloy properties and oxidation behavior, can be incorporated to enable the simulations of actual plant cycles, rather than to employ a data-fitting approach.
Contacts:
| SABAU, Adrian S. | sabaua@ornl.gov | 865.241.5145 |
| YIN, Hebi - Postdoc | yinh1@ornl.gov | 865.574.8849 |
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