Printing parts for gas turbines is about to get easy

It worked before, so why not try something similar again? After engineers at E.ON Energy Projects and Siemens Energy had installed 3D-printed burners in a gas turbine in an ultra-modern combined cycle power station at a potash plant in Philippsthal in the German state of Hesse, they were impressed with the turbine’s operating parameters.

So when in early 2020 Siemens Energy offered to add newly designed, additively manufactured guiding vanes and heat shields to this power machine, E.ON Energy Projects was ready to intensify the cooperation: “After Vladimir showed us the additively manufactured components in Finspång and suggested another cooperation, the manager of the additively manufactured burner project, Niklas Lange, and I were quickly convinced to take the 3D-printing with gas turbines even further”, says Tobias Müller, project manager at E.ON Energy Projects.

“We were convinced that precision and durability of the 3D printed parts shouldn’t pose an incalculable risk. Moreover, based on our prior experience, we knew we could rely on the Siemens Energy Team. So my biggest challenge then was to align all things in a way so that this technology would be approved for a commercially base load operated, highly available industrial gas turbine.

Thanks to the good cooperation with our customer K+S and the insurance company we were able to sign all documents within a short timeframe – and today the turbine, thanks to its new 3D-printed parts, works as well as it did when we commissioned it over eleven years ago.”

Additive Manufacturing (AM) is revolutionizing the development and production of components not just in the automotive and aerospace industries but also in the energy sector. Since curbing the greenhouse effect has become a decisive factor in energy policy worldwide, it is necessary to push the manufacturing of gas turbines beyond the limits of conventional production, increasing efficiency and enabling using more and more hydrogen and biofuels.

This is where 3D-metal-printing comes in. It allows precise improvement of parts through tailored design. For that reason, turbines with printed parts have higher efficiency, use less fuel for the same output, and consequently produce less emissions. Greenhouse emissions can be reduced even further if these parts are designed especially for hydrogen or biofuels. All of this comes on top of AM production being more sustainable, as it uses less power and has higher material utilization.

In addition, AM accelerates rapid prototyping, which shortens the design and market introduction of new components. “We are experts for additively manufacturing these parts”, says Vladimir Navrotsky, Technology and Innovation Manager at Siemens Energy. “But we need a partner like E.ON to know that it works reliably in the field.”

Obviously, the idea is not to print a whole gas turbine – AM is still very expensive. That’s why it’s the complex high-value parts, namely those exposed to a high-temperature environment using internal air cooling, that are prime candidates for being printed – such as burners, guide vanes or heat shields.

For example, the standard burner in Philippsthal used to have 13 individual parts. In 2018, Navrotsky’s team in Finspång managed to manufacture it in one solid piece with complex fuel channels under its surface. It’s similar with the guide vanes for Stage 2 of the Philippsthal-turbine, also AM manufactured in Finspång, Sweden, and installed in summer 2020.

In order to improve their aerodynamic performance, they had to be produced with a thin trailing edge. “This helped with the cooling of the vane. But what helped even more in this regard, were in-wall cooling channels. Both these channels and the thin trailing edge could only be achieved with the help of AM”, says Navrotsky. The consequence: cooling air consumption is significantly reduced.

Alternatively, with the amount of cooling air staying the same, the temperature of the part could be lowered even further and therefore extend the turbine’s vanes lifespan. Either way, the turbine’s performance is improved.

The performance measurements done on-site confirmed the guide vanes use 25 percent  less cooling air and improve turbine efficiency by 0,5 percent. In the second half of 2021, Siemens and E.ON Energy Projects plan to install additional 3D-printed guide vanes for Stage 1 with in-wall cooling. “In the end, by implementing AM designed components we expect significant engine efficiency improvements”, says Navrotsky.

Product improvements are obviously not the only way to decrease emissions. Better planning, targeted inspections, maintenance and optimization of operations also help. Another way of pushing decarbonization are alternative fuels such as hydrogen – and here AM can be of service, too.

For example, in 2019 Siemens sold two gas turbines to Braskem in Brazil, Latin America’s largest petrochemical company. Their special feature: AM-burners optimized for burning hydrogen. In 2023, these gas turbines will run with 60 percent hydrogen by volume, leading to a reduction of over 6 percent in CO2 emissions.

But obviously, it’s not just the reduction in emissions what’s attractive about hydrogen. With renewable power becoming more and more dominant in our energy mix, power supply fluctuates a lot more. Hydrogen can store power when it’s abundant and feed it back into the grid when there is a shortage – especially since gas turbines are very flexible with short ramp-up times.

And since many industrial processes produce hydrogen as a side product, this often can be employed at low-cost. Even more, today Siemens is committed to gradually increasing the hydrogen capability of its gas turbines to 100 percent  by 2030. “Gas turbines capable of running solely on hydrogen may prove to be the missing link to establishing a green and sustainable energy sector”, say Navrotsky. “For that, you need specialized components that AM provides”, says Navrotsky.

And you need cooperation between partners like E.ON Energy Projects and Siemens Energy, which goes far beyond a normal supplier-client-relationship. “We offer bespoke on-site power and heat supply solutions for clients in high energy consuming industries, optimized to their needs”, says Müller. “Increasing efficiency and reducing emissions are always  very important goals for us. And in this special case we needed a reliable partner – like Siemens Energy.”

For Siemens, this cooperation gives them the opportunity to evaluate their innovative parts under real life conditions. And since the gas turbines are fitted with sensors throughout, the data can also be used to develop even more powerful, environmentally friendly, and durable components in the future – including those using hydrogen and other biofuels. “Additive Manufacturing for high value components in the energy sector is about to become a mature technology” says Navrotsky. “It’s the future, we cannot do without.”

May 10, 2021

Hubertus Breuer is an independent journalist specializing on technology reporting. He lives and works in Munich, Germany. 

Combined picture and video credits: Siemens Energy, EON energy projects