Extreme temperatures in gas turbines give rise to need for heat-resistant materials

Temperatures in the next generation of gas turbines are expected to reach as high as 3100 degrees Fahrenheit, heat so extreme it could literally vaporize components under high velocity steam.

The challenge for engineers is to create components that can withstand the high-temperature steam corrosion. If they can, gas turbines will run more efficiently, saving money and creating fewer greenhouse gases.

It’s a task bringing together GE Power and Clemson University engineers, who have launched a new research project with $600,000 from the U.S. Department of Energy.

The team is working to create a coating that would provide thermal and corrosion protection for components, including the turbine blades. The goal is to make a coating that will allow components to run nonstop for 32,000 hours, or more than 3.5 years.

Photo from left: Rajendra Bordia, Quan Li, Fei Peng, and Michelle Greenough are part of a Clemson University team working with GE Power to create new materials for next-generation gas turbines.

The research could have far-reaching effects. More than a third of the nation’s electricity came from natural gas in 2016, making it the leading source of energy, according to the U.S. Energy Information Administration.

Leading the research is Rajendra Bordia, who serves as principal investigator on the grant and is a professor and chair of Clemson’s Department of Materials Science and Engineering.

“Our goal is to work on the next generation of materials which will let these turbines operate at higher temperatures and thereby enable more efficient power generation systems,” Bordia said. “Everybody would like to get higher and higher efficiency so that for the same amount of fuel you can generate more and more power.”

Collaborators include John Delvaux, technical leader of high-temperature composites at GE Power in Greenville, and Fei Peng, an associate professor of materials science and engineering at Clemson.

Tony Mathis, president and chief executive officer of GE Aviation Military Systems, played a key role in making the collaboration possible by paving the way for Clemson, his alma mater, to take part in a consortium focused on ceramic matrix composites.

“The relationship is a result of Dr. Bordia’s personal efforts,” said Mathis, who has Bachelor of Science in mechanical engineering from Clemson. “Our ability to partner with universities on innovation has really just taken off. It really is starting to gain a ton of momentum.”

In gas turbines, air combines with natural gas or other fuels to spin a generator, producing electric current that travels through the electric grid to homes and businesses.

Turbine components are now made of metal alloys, Bordia said. But with the new coating, the underlying components could be made out of a material researchers call “silicon-carbide-based ceramic matrix composites,” or CMCs.

The CMC components would have advantages, such as low density and high strength, but if left uncoated, the turbine material could react with the steam very rapidly, Bordia said.

“The reaction product is a gas that just goes away,” he said. “Over time, the steam just eats up the component.”

To create the protective coating, researchers are planning to experiment with novel materials that can withstand the heat and steam and adhere to the CMC components.

GE Power is critically important to the research and was involved in writing the grant proposal that makes the project possible, Bordia said.

“Once we have developed a material system, GE is going to create a viable process to acquire these outcomes,” he said. “That part is a very critical task because it will transition it from our lab to something that can be implemented in the field.”

Delvaux said the research GE Power and Clemson are doing together help push the bounds of what is possible.

“We are developing high temperature components made from ceramic composites, with the aim of translating our research from the lab to the field,” he said. “This material operates under load at temperatures that melt most metals. The benefit is higher efficiency jet engines and power turbines that produce more power and less greenhouse gases, which is a good thing for the planet.”

Peng said that collaborating with Bordia brings together two key research groups in Clemson’s Department of Materials Science and Engineering.

“We have a lot of common interests, and we have different expertise,” Peng said. “This project gives us a unique opportunity to synergize our expertise to create new material that can have a great impact on increasing the power generation efficiency in gas-fired turbine generators.

“Due to the relevance of the project and the close collaboration with GE Power, this project will provide a unique learning opportunity for Clemson’s undergraduate students and research associates who will conduct the research.”

Anand Gramopadhye, dean of the College of Engineering, Computing and Applied Sciences, congratulated the GE Power and Clemson researchers on landing the grant.

“The research they are conducting is highly relevant to industry and the nation’s energy future,” he said. “Their project gives students an opportunity to participate in cutting-edge research that will uniquely prepare them for their careers. This is a well-deserved award.”