US builds first hydrogen-powered turbines with superalloys that can withstand temperatures of 3,500°F

In 1884, marine engineer Charles Parson used coal to power his groundbreaking invention, the multistage steam turbine, to generate electricity.

This technological revolution marked a new beginning in power generation and consumption worldwide.

Today, humanity’s increasing demand for electricity and electricity requires more efficient turbines and environmentally friendly fuels.

Texas A&M engineers have received funding from the Department of Energy to develop breakthrough materials technologies to meet future energy needs.

Manufacture of hydrogen-powered gas turbines

The goal of this grant is to develop a material system for gas turbines that can run on hydrogen instead of natural gas.

These include high-performance alloys, protective coatings and cooling systems.

“The United States has set the ambitious goal of decarbonizing energy by 2035,” said Dr. Don Lipkin, professor in the Department of Materials Science and Engineering and principal investigator on the grant.

“We need material solutions for advanced gas turbines that are both cleaner and more efficient; This means the turbines can operate at much higher temperatures and use hydrogen gas instead of natural gas to avoid producing carbon dioxide.”

Next generation turbines

Turbines convert mechanical energy into electrical energy. In these machines, the blades are attached to a central shaft.

When these blades rotate, like the blades of a fan, the shaft rotates, turning a generator and producing electricity.

In Parsons’ turbine, the blades were driven by the steam produced by water heated with coal.

In the 1930s, coal-fired power plants slowly began converting to natural gas to improve electricity production efficiency and reduce carbon dioxide emissions.

In gas turbines, the pressure of ignited compressed gas turns the blades to produce electricity instead of steam.

The goals of the next generation of advanced turbines are to become even more efficient and replace natural gas with hydrogen, which has a minimal carbon footprint.

Use of high temperature alloys

However, these goals open two more cans of worms.

“Very efficient turbines need to operate at much higher temperatures, around 3,000 Fahrenheit or more, and we need materials solutions for advanced turbines that can operate in these hotter environments,” Lipkin said.

“The other problem is that burning hydrogen in air produces more steam than burning natural gas. Most turbine materials show signs of accelerated degradation when exposed to high temperatures and very humid environments.”

Turbines are made of superalloys, predominantly nickel and cobalt, with small amounts of other elements such as chromium, aluminum, tungsten, molybdenum and niobium.

The main problem with nickel-based superalloys is that they start melting at 2400F.

So engineers are studying a new class of materials called high-entropy refractory alloys (RHEAs), many of which have melting temperatures above 3,500 F.

Advanced alloy design

As part of Phase 1 of the Advanced Research Projects Agency-Energy (ARPA)-E ULTIMATE program, materials scientist Dr. Raymundo Arróyave of Texas A&M several promising RHEAs.

“To solve this seemingly impossible problem, we use advanced alloy design tools developed in our groups,” said Arróyave, together with Dr. Ibrahim Karaman lead researcher in this project.

“Discovering new alloys that can withstand these extreme environments is like finding a needle in a multidimensional haystack.”

In the next step, Lipkin and his team will test whether RHEAs can withstand high temperatures, oxidation and moisture simultaneously with custom coatings developed by the A&M team.

They create an experimental setup that is very similar to the hottest part of a hydrogen-powered gas turbine.

To put it simply, hydrogen and air are forced through small rocket nozzle-shaped tubes under high pressure and ignited.

This process produces hot, high-velocity gas and steam that exit the nozzle at supersonic speeds and affect the RHEA coupons.

The team will examine the resilience of the RHEA material system – including the substrate alloy, oxidation-resistant coating and thermal barrier layer – in a simulated hydrogen gas turbine environment with and without cooling.

“One way to achieve our carbon reduction goals in the energy sector is to keep all of our energy production infrastructure intact, but switch to burning hydrogen as a fuel instead of natural gas,” Lipkin said.

“No single solution will work for the entire U.S. energy infrastructure; It will be a mix of renewable and non-renewable energy.”