Selective Catalytic Reduction

Selective Catalytic Reduction

  • Industry's only totally integrated system
  • Reduces NOx by up to 95%, down to 1 ppm
  • Ammonia reacts with NOx to form harmless nitrogen and water
  • CFD modeling used to optimize every system
  • Works with Firetube, IWT, HRSG, and retrofit boilers


Selective Catalytic Reduction (SCR) is a post-flue gas treatment that is capable of reducing NOx emissions from a wide variety of boiler systems. SCR is one of the most effective ways of reducing NOx in a flue gas stream, with reductions up to 95%.


SCR is one of the most effective ways to reduce NOx emissions in a flue gas stream. It decreases NOx emissions by as much as 95%, down to 2 ppm without retrofitting the burner.

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  • Applications
  • Designed specifically for your application, with both installation-ready and freestanding stacks available
  • Three types of reduced agent systems are availalbe: Anhydrous Ammonia, Aqueous Ammonia and Urea
  • Single integrated control system operates the boiler, burner and SCR
  • Catalyst bed geometry is optimized and the highest quality corrugated catalyst is used with vanadium, titanium or tungsten oxides as active agents
  • A custom heat recovery system allows flue gas temperatures to be optimized, resulting in the most effective reduction of NOx emissions. Recovering the waste heat of the flue gas with an economizer increases the efficiency of the boiler.
  • Completely integrated from the ammonia injection grid to the exhaust stack system, including all ladders, platforms and piping


SCR uses ammonia as a reducing agent, which is introduced into the flue gas stream. This mixture then comes in contact with a catalyst, selectively transforming the NOx into harmless nitrogen and water. With the addition of SCR, NOx emissions can be reduced down to 1 ppm. It’s a viable option to help meet current or future environmental regulations or your company’s sustainability goal. Cleaver-Brooks is the only manufacturer that can offer a complete SCR system integrated with your boiler. That means a single-source solution with a streamlined engineering process and better value, as well as a better system with more flexibility to meet the needs of your application. Cleaver-Brooks manufactures every major component of the boiler system, which enables us to provide an optimal solution for your needs. We use Computational Fluid Dynamics (CFD) and other advanced modeling software to ensure flawless design. Equipment integration allows precise adjustment to the boiler, burner, and controls, resulting in the most cost-effective and efficient SCR system.


Industrial Watertube Boilers →

From 10,000 to 1,000,000+ lb/hr including the Steam-Ready line, custom watertubes, OSSG boilers, and elevated D-style.

Firetube Boilers →

Integrated and engineered solutions

Boiler Exhaust Solutions →

The highest quality installation-ready and engineered freestanding stacks.

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