Think small: NETL's nanotechnology research explores how energy applications can benefit from the nanoscale.  

A Little Bit about Nanotechnology
Anyone who has ever dammed a stream knows that the more stones you stack, the more effectively you ward off the flowing water. In other words, the thicker the blockade, the more substantial the protection. So, the builder searches for the biggest, heaviest river rocks to pile into a backyard version of the Hoover Dam. Several stacks later, the builder has amassed a fortress to stop the flow of water, with maybe a few trickles sneaking in among the cracks. Now, imagine that instead of the massive, heavy bulwark that took all morning to construct, the builder could have compressed the unwieldy ramparts into a lighter, thinner layer and still maintained the same level of protection—something like replacing the behemoth barricade with a sturdy sheet of acrylic glass. This is the basic idea of nanotechnology. 

Heavy, bulky barriers are okay for dams and castles, but many modern applications, particularly in energy technology, require more sophistication. Weight and bulk can interfere with the way equipment operates, wearing out components and reducing efficiency. In addition, many applications may be space limited. 

What if the builder could take those same river rocks and shrink them down? Imagine that they are still stackable and strong enough to hold back the water. Imagine the dam was actually composed of tiny river rocks, one hundred times smaller than their bulk counterparts. With smaller materials, the builder could make several layers of barricade in less space than the original, leaving him/her with a bigger pool on the other side. The builder could even have multiple layers in less space than the one original, providing better blockage for the occasional trickle. With this new, smaller material, the builder is able to accomplish his purpose more effectively and with less bulk.  

Scaling down to the atomic or molecular level, thousands of times smaller than the width of a human hair, is nanoscale. Nanomaterials are used to add strength to composite materials that must be lightweight. Adding nanoparticles to certain materials increases strength and durability while keeping the material light. Because the nanoparticles are so small, thousands can fill the space of a non-nano structure. 

Nanotechnology is benefitting many areas of our daily lives including information technology, medicine, transportation, and energy. It’s providing discoveries and solving problems that would otherwise be insurmountable.

    Turbines are at the heart of the power generation industry. View video [WMV-2.8MB]

Smaller Scale, Bigger Problem
Nanoparticles are more than just a diminutive of their “regular” sized counterparts. The study and development of nanotechnologies involves the understanding and control of matter at the atomic or molecular level, and at this small scale the fundamental behaviors of things change. For example, bond strengths between particles are different. Rather than simply scaling down a known formula to nano size, a new formula must be developed. Nano-sized particles can also fit in between the protons and neutrons of regular sized particles, affecting how all these particles react and bond. The problem is similar to what physicists experience when jumping from quantum physics to astrophysics. Gravity is the dominating force in astrophysics in dealing with large matter (similar to the effect of gravity upon an elephant versus a ladybug), whereas quantum physics is tied to electricity and magnetism, which have a greater effect on small matter. So far, no system exists that can combine equations from one realm to the other—with different dominating forces at work, there is no way to simply scale up or down. Because the fundamental properties of matter can be changed and rearranged at the nanoscale, work at this level carries its own set of rules.

  Erosion-resistant nanocoatings are making gas turbine engines more efficient, reducing cost and saving fuel.  

Understanding how the nano “system” works and how researchers can use it to our best advantage is what the study of nanotechnology is all about. Nano-sized particles could revolutionize fields such as medicine and energy. For example, nanoparticles are currently being developed to deliver chemotherapeutic agents directly to tumor cells without damaging surrounding normal cells. In the energy sector, nanotechnology could make more efficient scrubbers to remove SOx and NOx or provide quicker, more cost-effective filters to purify water—and the applications are truly limitless. 

The U.S. Department of Energy (DOE)’s Office of Energy Efficiency and Renewable Energy (EERE) is conducting research to realize the promise of nanotechnology. Under EERE’s Industrial Technologies Program, DOE is funding the projects that will improve production and manufacturing techniques for nanomaterials and nano-enabled products so that these innovations can move beyond the laboratory scale and into practical applications. NETL’s Project Management Center manages the projects selected under this program.

In 2008, DOE announced its Nanomanufacturing for Energy Efficiency Research Call, which was geared toward “quick-win” nanomanufacturing projects with a realistic path to commercialization in 3–5 years. Now the labors conducted under the selected projects are coming to fruition. One project selected under this research call is now nearing commercialization and making great improvements in the turbine arena.

    Gas turbine compressor blades are easily affected by pollutants, water droplets, and other particles in the air. These erosive agents damage a turbine engine's performance and hinder efficiency.

The Whirr of Success.
Nanotechnology has the potential to benefit nearly every facet of our lives, and energy is one application that most of us use daily. Applying nanotechnology to improve energy processes could therefore impact us in very meaningful ways. Turbines are behind many of the energy applications upon which we’ve come to depend. Not only are they the workhorses of the power industry, they propel the transportation sector as well. A new erosion-resistant nanocoating developed with NETL funding and being commercialized through MDS-Coatings Technologies Corporation (MCT), with assistance from NETL’s Office of Research and Development, is benefitting both of these sectors in significant ways. 

Selected under the Nanomanufacturing Process Development area, the project “Erosion-Resistant Nanocoatings for Improved Energy Efficiency in Gas Turbines” is improving engine fuel efficiencies, leading to less fuel consumed and reducing environmental impact of industrial processes.

Despite their force and power, the compressor blades of a gas turbine are surprisingly delicate. Pollutants, sand, and even water droplets in the atmosphere can damage a blade and reduce efficiency and negatively impact a gas turbine engine’s performance. As jet planes travel through the air, their compressor blades are attacked by water droplets, dust, and even volcanic ash, all of which are erosive agents. Eroded blades must be replaced, which is an expensive and time consuming operation. But blades that are operating sub-optimally do not function efficiently, resulting in increased fuel consumption and decreased engine power. 

Coating the blades with a protective barrier is a good option to prevent erosion. Coatings are cheaper and easier to apply than replacing a blade, which saves time and money. Such coatings must be lightweight so they don’t disturb the operation of the turbine, and they must be strong to withstand the erosive agents and provide tough, long lasting protection. Using nanotechnology, engineers are able to coat a compressor blade with multiple layers—more than would be possible with non-nano coatings—and provide a cost-effective, impenetrable layer to the blades of industrial gas and commercial aviation turbines. The erosion-resistant nanocoatings are so thin that they impact neither the weight nor dimensions of the coated components.

  Erosion-resistant nanocoatings are helping the commercial airline industry save fuel and maintenance costs.      

In the transportation sector, the protective coatings developed under this project are translating erosion protection into fuel savings, reduced operational costs, and extended part life. Erosion is detrimental to a commercial gas turbine engine’s performance, increasing fuel consumption and carbon emissions. To put this into perspective, consider that just a 1 percent loss in compressor performance for a U.S. commercial carrier equates to millions of gallons of fuel consumed annually. Protective coatings also allow the compressor airfoils to maintain their proper geometric shape and to continue operating for an additional life cycle versus either being repaired or replaced with costly new compressor airfoils.    

In the energy sector, the novel erosion-resistant nanocoatings are making strides as well. Gas turbines can be made more efficient under certain conditions such as inlet fogging. In this process, a fine mist of water is applied at the engine’s intake and the higher density mist is ingested into the engine’s compression section. The greater density of this “inlet fog” allows the compressor to increase the compressor’s overall pressure ratio. With higher pressure, the engine puts out more power without combusting more fuel. The result? Greater power and lower emissions without consuming more fuel. It may sound like a win-win situation, but inlet fogging does have a major drawback: like the compressor airfoils of a jet engine, industrial turbine compressor airfoils can experience erosion from the impact of small water droplets in the inlet fog. However, applying nanocoatings protects the blades against water droplet erosion and enables the use of inlet fogging to enhance a gas turbine engine’s power output.

The nanocoatings developed under this project have demonstrated great potential in extending the lives of turbine engine compressor blades in both the industrial energy and commercial aviation transportation sectors. With these nanocoatings, gas turbine engines will be able to operate at or near peak efficiency for longer periods of time. The technology could save the U.S. commercial air fleet more than 3 million barrels of oil annually and allow power generation companies to employ processes that can significantly increase their energy production without consuming additional fossil fuels and lower emissions of greenhouse gases. As research expands our understanding of nanotechnology, we’re sure to benefit from its application for years to come.