Boiler Aero-Shield™ minimizes fouling and erosion problems.

Press Release Summary:

Aero-Shield™ improves boiler performance in situations where excessive fouling and tube erosion exists in various heat transfer areas. Fit snugly around boiler tube, product has flat, wedge-like, aerodynamic shape that improves flue-gas flow patterns and heat transfer while reducing fouling. Custom-designed for each application, this flue gas flow control redistribution device reduces maintenance as well as cleaning for downstream heating surface tubes.

Original Press Release:

Valmet Introduces Aero-Shield(TM), Engineering Solution to Boiler Fouling and Erosion Problems

Charlotte, NC – Valmet (formerly Metso Power), the global engineering and technology company and market leader in boiler tube shields, announces the release of a new product designed to improve boiler performance in situations where there is excessive fouling and tube erosion in various heat transfer areas. Called Aero-Shield™, the product fits snugly around a boiler tube, protecting it from erosion and corrosion. With its flat, wedge-like aerodynamic shape, the Aero-Shield™ improves flue-gas flow patterns. The result is a reduction in fouling and improved heat transfer.

The Aero-Shield is a proven technology, with seven years in development and four years of successful operation in over 20 units.

Solid-waste-fired boilers are particularly prone to excessive fouling in convection pass areas, especially in boilers where the flue-gas flow path makes sharp, 180° and 90° turns, potentially resulting in uneven gas flow distribution. The Aero-Shield™ functions as a flue-gas flow-control redistribution device, enabling less maintenance and cleaning for downstream heating surface tubes.

Following a full evaluation of a given scenario, Valmet’s engineering staff custom-designs the Aero-Shields™ to address the identified problem. The process includes modeling the existing boiler thermal and Computational Fluid Dynamics (CFD) of the problematic area.

Aero-Shields™ were developed in the mid-2000s for the energy-from-waste (EfW) market by Covanta Energy, a world-leading sustainable waste management and renewable energy company. In close cooperation with Valmet, the Aero-Shield™ was subjected to extensive field-testing in Covanta-operated EfW facilities. Engineering studies and field tests have demonstrated that Aero-Shields™:

  • Reduce fouling and slagging
  • Increase heat transfer up to 25% yielding higher boiler efficiency
  • Increase service life for boiler pressure parts
  • Increase service life for boiler parts downstream of the Aero-Shields™
  • Reduce damage to regular tube shields located downstream of the Aero-Shields™, resulting in cost savings in downtime and labor for maintenance.

Field tests were performed by using a variety of alloys and thicknesses in order to identify materials that functioned well without being cost-prohibitive. Based on these tests, several different materials were developed for the Aero-Shield™ applications.

“We believe that we have good data to prove the effectiveness of Aero-Shields™ in many different situations where performance and component life were compromised,” says Jarkko Hyvarinen, Aero-Shield Product Manager, Valmet. “However, before recommending Aero-Shields™ in a particular situation, Valmet will complete an Engineering study that includes a CFD analysis and thermal modeling to generate the best solution.”

Valmet has been granted exclusive global rights to design, manufacture and sell the Aero-Shield™. Covanta Energy Inc. owns the patent.

About Valmet
Valmet is a global supplier of technology and services to customers in the process industries, including mining, construction, pulp and paper, power, and oil gas. Our 30,000 professionals based in over 50 countries deliver sustainability and profitability to customers worldwide. Expect results.

For information on the Aero-Shield™, tube shields and all Valmet products, please visit For inquiries, please call Valmet 704-541-1453 or send an email to

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