New alloys aim to boost hydrogen turbine efficiency

In 1884, marine engineer Charles Parson used coal to energy his groundbreaking invention, the multi-stage steam turbine, to supply electrical energy. This technological revolution marked a brand new daybreak of energy era and consumption around the globe. At present, humanity’s growing electrical energy and energy wants require extra environment friendly generators and environmentally pleasant fuels.

To satisfy the vitality wants of the close to future by breakthrough supplies expertise, engineers at Texas A&M purpose to develop a supplies system for gas turbines that may function utilizing hydrogen fuel as a substitute of pure gasoline. It will embody high-performance alloys, protecting coatings and cooling methods.

“The United States has set an ambitious goal to decarbonize energy by 2035,” stated Dr. Don Lipkin, professor within the materials science and engineering division and principal investigator on the grant.

“We need materials solutions for advanced gas turbines that are both cleaner and more efficient; that is, the turbines can work at much hotter temperatures and use hydrogen gas instead of natural gas so as not to produce carbon dioxide.”

Generators convert mechanical energy to electrical vitality. Inside these machines, blades connect to a central shaft. When these blades rotate, just like the blades of a fan, the shaft spins, turning a generator and producing electrical energy. In Parson’s turbine, the blades had been set in movement by the steam produced by coal-heated water.

Within the Nineteen Thirties, coal-fired power plants slowly began to shift to pure gasoline to enhance energy manufacturing effectivity and cut back carbon dioxide emissions. In gasoline generators, the stress from ignited compressed gasoline turns the blades to supply electrical energy as a substitute of steam.

The objectives for the following era of superior generators are to be much more environment friendly and substitute pure gasoline with hydrogen, which has a minimal carbon footprint. Nonetheless, these objectives open two different cans of worms.

“Very efficient turbines need to operate at much higher temperatures, around 3000 Fahrenheit or more, and we need materials solutions for advanced turbines that can operate in these hotter regimes,” stated Lipkin.

“The other problem is that when you burn hydrogen in air, you make more steam than when burning natural gas. Most turbine materials will show signs of accelerated distress when exposed to high temperatures and very wet environments.”

The supplies used to make generators are superalloys which might be composed of predominantly nickel and cobalt, with small portions of different components, similar to chromium, aluminum, tungsten, molybdenum and niobium.

The principle drawback with nickel-based superalloys is that they start to soften at 2400 F. Therefore, engineers are investigating a brand new class of supplies system known as refractory excessive entropy alloys (RHEAs), a lot of which have melting temperatures above 3500 F.

Below Part 1 of the Advanced Research Projects Agency-Energy (ARPA)-E’s ULTIMATE programTexas A&M supplies scientist Dr. Raymundo Arróyave recognized promising various promising RHEAs.

“To solve this seemingly impossible problem, we make use of advanced alloy design tools pioneered in our groups,” stated Arróyave who’s co-principal investigator on this undertaking together with Dr. Ibrahim Karaman. “The discovery of new alloys capable of withstanding these extreme environments is akin to finding a needle in a multi-dimensional haystack.”

Within the subsequent step, Lipkin and his workforce will check if RHEAs with tailor-made coatings developed by the A&M workforce can concurrently tolerate excessive temperatures, oxidation and moisture. They’re creating an experimental set-up carefully resembling the most well liked portion of a hydrogen-fired gasoline turbine.

Merely put, extremely pressurized hydrogen and air shall be squeezed by small rocket-nozzle formed tubes and ignited. This course of generates sizzling, high-velocity gasoline and steam that exit the nozzle at supersonic speeds and impinge on the RHEA coupons.

The workforce will examine the resilience of the RHEA supplies system—together with the substrate alloy, oxidation-resistant coating and thermal barrier coating—in a simulated hydrogen gasoline turbine atmosphere with and with out cooling.

“One way we can meet our carbon reduction goals in the energy sector is to keep our overall energy generation infrastructure intact but switch to burning hydrogen as the fuel, as opposed to natural gas,” stated Lipkin.

“No one solution is going to work for all of the energy infrastructure in the US; it’s going to be a mix of renewables and non-renewables.”