WVU engineers solve corrosion problem in cutting-edge power plant technology

Postdoctoral researcher Lingfeng Zhou (WVU/Nathaniel Godwin).

Recently published research by West Virginia University engineers marks a big step forward in improving durability and performance of the solid oxide fuel cells that power plants can use to generate electricity.

Story by Micaela Morrissette, Research Writer 

Benjamin M. Statler College of Engineering and Mineral Resources

Postdoctoral researcher Lingfeng Zhou led the four-year study, which tested solutions for minimizing the amount of corrosive chromium gas that evaporates from solid oxide fuel cell components during power generation.

Two stainless steel alloys that could be used to manufacture certain parts of the fuel cells performed exceptionally well in Zhou’s tests.

Zhou explained that a solid oxide fuel cell is “a highly efficient energy conversion device that produces electricity directly from versatile fuels – from hydrogen to fossil fuels.

“The ceramics used in solid oxide fuel cells have to run at temperatures ranging from 500 to 1,000 degrees Celsius. The operating temperature is their largest disadvantage, but they offer high combined heat and power efficiency, long-term stability, fuel flexibility, low emissions and relatively low cost.

“Because of their high fuel-to-power conversion efficiency and minimal adverse influence on the environment, solid oxide fuel cells have the potential to be a platform for future power generation technologies – but they have to be able to last for at least 40,000 hours of operation with minimal degradation."

At sustained high temperatures, fuel cell components manufactured from metal alloys rich in iron and nickel can generate chromium gases, contaminating the environment and leading to deterioration of the fuel cells. To counteract that problem, Zhou’s team identified two recently developed stainless steel alloys that are cheap, oxidation resistant and, under conditions equivalent to those of a power plant in operation, form a protective layer of aluminum oxide that is “essentially free of voids or cracks.”

After the first 5,000-hour test cycle, those alloys still had not released detectable levels of corrosive chromium gas, which represents “excellent potential for the long-term,” according to Zhou. “Their aluminum oxide layer is immune to the effect of water vapor, thermodynamically stable and provides far superior protection in many industrial environments as compared to a conventional alloy.”

In September, the International Journal of Hydrogen Energy published the results of the study, which was supported by the U.S. Department of Energy.

WVU collaborators included Statler College researchers Wenyuan Li, assistant professor of chemical and biomedical engineering; Shanshan Hu, research assistant professor; Zhipeng Zeng, Yi Wang, Liang Ma (all postdoctoral students at WVU at the time of the study); and Xingbo Liu, professor and associate dean for research and the Statler engineering chair.

Zhou said, “Long-term operation without degradation is of great importance for solid oxide fuel cell stacks, and the next step is to apply these alloys in fuel cell industries.”

Citation: Alumina-forming austenitic stainless steel for high durability and chromium-evaporation minimized balance of plant components in solid oxide fuel cells

---