WVU Engineering Professor Develops Protective Coatings for Gas Turbine Blades

Xingbo Liu, Statler chair of engineering, conducts research at his WVU lab. Photo courtesy of WVU/Paige Nesbit.

An engineer at West Virginia University (WVU) (Morgantown, West Virginia, USA) is leading a research project to develop new, cutting-edge coatings for the blades of turbines used in large-scale power generation. It is anticipated that this new coating could potentially help make hydrogen a predominant global fuel source, particularly for power plants. 

Developed by Xingbo Liu, professor in the Department of Mechanical and Aerospace Engineering at WVU, the new protective coating will be able to withstand the extreme heat and corrosion of hydrogen combustion but work with the principles and technologies of existing natural gas turbines. 

This research, which is already been deemed promising enough to receive early investment from business, could potentially play a critical role in transforming the energy industry in West Virginia by enabling energy operators to provide clean power based on existing resources—in this case, the state’s power generating plants and natural gas reserves. 

Liu’s project has received a $2 million grant from the U.S. Department of Energy (DOE), which was geared toward decarbonizing the U.S. power and industrial sectors, advancing clean energy manufacturing, and improving America’s economic competitiveness. 

“There are several ways to turn a turbine and generate power,” says Liu, who also serves as associate dean for research and endowed chair and engineering at WVU’s Benjamin M. Statler College of Engineering and Mineral Resources. “All the most popular ways today use heat. Today, in about two-thirds of turbines, we burn coal or we burn natural gas to turn a turbine, with coal contributing about 20% and gas about 40% of the total power we generate in the U.S. Less often, we use a nuclear reaction to heat water and generate steam.” 

After nuclear energy, Liu adds, hydropower is the most common source of electricity, with other clean energies such as wind and solar bringing up the rear. One of the primary benefits of hydropower is that it produces no carbon dioxide or other byproduct—when hydrogen react with oxygen and combusts, it produces only water in the form of steam, which in turn can spin turbine blades to produce electricity. 

While hydrogen has been widely seen as a leading clean energy fuel since the 1970s, using it to replace fossil fuels entirely as a power source is still fairly unrealistic. Rather, Liu’s team is focused on a more immediate goal: a turbine that uses a blend of both hydrogen and natural gas as fuel. 

“The principle of a turbine that runs on hydrogen is the same as a turbine powered by natural gas, but with hydrogen the combustion characteristics are different from gas,” Liu says. “Hydrogen combustion has two unique characteristics. One is that the reaction produced is pure steam, which can be very corrosive. The other is the temperature. Combustion is really hot and combustion temperatures are sometimes even higher than the melting point of the metal component.” 

The hottest part of any turbine is the blades, which is why Liu’s research is focused on creating coatings that will keep a turbine’s blades from corroding, oxidizing, or even melting when hydrogen fuel is added to natural gas. 

“People use coatings all the time as simple as nonstick cookware or coatings on eyeglass lenses,” Liu says. “In the case of turbines, there have been two different kinds of coatings. One is called the environmental barrier coating, where you protect your component from the corrosive environment. And the other coating is a thermal barrier coating. It’s a heat insulator, like the oven mitt you wear when you cook. Most of our research is around the thermal barrier coating.” 

Liu’s study, “High-Entropy Alloy-based Coating to protect Critical Components in Hydrogen Turbine Power System,” focuses specifically on coatings that are made from a mix of different elements. 

“Typically, the materials we are using today have one major element, such as copper or aluminum,” Liu says. “It’s not pure aluminum, it’s an aluminum alloy, but the majority of the alloy is aluminum. With a high-entropy alloy, we don’t have one major element, it’s a bunch of things together, and each one of them has a similar composition. It’s basically a stew, and that gives us some unique properties that we think have hope for this application.” 

Source: WVUToday, https://wvutoday.wvu.edu.