Flue Gas Treatment (SCR & SNCR)

Q: When is SCR the best choice?

SCR is especially valuable when very low NOX emission values must be achieved or when future emission standards require maximum reduction. The technology delivers the highest reduction rates and is often used on larger industrial installations.Wondering which flue gas treatment solution is right for your installation? Our experts are happy to explore the options with you.

When combustion process optimizations are not enough to achieve the required emission values, flue gas treatment offers an effective solution. Through a chemical reduction process, nitrogen oxides (NO_X) are removed from the flue gases, making even the strictest emission standards achievable.

The Callens Group designs and builds flue gas treatment systems tailored to your production process. Based on an analysis of your installation, our engineers determine whether Selective Catalytic Reduction (SCR) or Selective Non-Catalytic Reduction (SNCR) is the most suitable technology. This allows us to combine maximum emission reduction with reliable, energy-efficient operation.

Discuss your flue gas treatment project

When is flue gas treatment the right choice?

Flue gas treatment becomes relevant when an optimized combustion process alone is not enough to achieve the required NO_X emission values. This technology is especially suited for installations that must comply with very strict limit values.

The Callens Group examines which type of flue gas treatment best suits your installation. To do so, we analyze factors such as flue gas temperature, flue gas composition, required emission reductions and available space.

Why choose flue gas treatment?

To achieve very low NO_X emission values.
To comply with the strictest environmental permits.
To upgrade existing installations to meet new emission standards.
To combine emission reduction with high operational reliability.
To implement a future-proof solution.

Which type of flue gas treatment is the most suitable solution?

SCR and SNCR share the same goal: removing nitrogen oxides from flue gases. Yet the two technologies differ significantly in their field of application. The optimal choice will depend on the required emission limit values, the flue gas temperature, the type of combustion installation, the available installation space and the operational conditions of your production process.

That is why the Callens Group does not start from one standard technology, but from a thorough analysis of your entire flue gas path. Our engineers map out the flue gas composition, temperature profiles, flow rates, fuel, operating hours and future emission targets. Based on that, we determine which technology, or which combination of technologies, delivers the required NO_X reduction with maximum operational reliability, optimized energy consumption and the lowest total cost of ownership.

Our analysis starts from the following questions:

Which NO_X emission values does your installation need to achieve today and in the future?
What flue gas temperature is available for an efficient SCR or SNCR system?
Which fuel is used, and how does it affect flue gas composition?
How much space is available to integrate a flue gas treatment system?
Which capital and operating costs deliver the best return over the full service life?
Can flue gas treatment be combined with source-control measures such as flue gas recirculation or an adapted boiler design?

Once all these parameters are clear, we select the technology that best suits your installation and emission targets.

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Your challenge	Most suitable solution
Achieving very low NO_X emissions	SCR
Compact solution with limited capital expenditure	SNCR
Maximum emission reduction on large installations	SCR
Retrofit of an existing installation	SCR or SNCR (after analysis)
Meeting the ever more stringent emission standards	SCR
Uncertainty about the best technology	Analysis by the Callens Group

SCR or SNCR?

SCR	SNCR
Works with a catalyst	Works without a catalyst
Very high NO_X reduction	Good NO_X reduction
Suitable for very strict emission standards	Suitable for less stringent emission limit values
Higher capital expenditure	Lower capital expenditure
Maximum performance	More compact installation

BENEFITS

Benefits of
flue gas treatment

When very low emission values are required, flue gas treatment is one of the most efficient technologies to sustainably remove nitrogen oxides from flue gases.

Very high NO_X reduction

With SCR or SNCR, even the strictest emission limit values can be achieved.

Maximum operational reliability

Every installation is designed with continuity and ease of maintenance in mind.

Suitable for existing installations

SCR and SNCR can often be integrated into existing flue gas installations.

Cost-effective long-term investment

The selected technology combines emission reduction with an optimal total cost of ownership.

Fully
customized

The technology is tailored to your process, flue gas composition and emission targets.

Ready for stricter emission standards

Your installation is prepared for a further tightening of the emission standards.

“Maximizing energy efficiency does not start with choosing a technology. It starts with mapping your specific environment and goals.”

FAQ

Questions?
We have the answers.

SCR stands for Selective Catalytic Reduction and uses a catalyst to remove nitrogen oxides from the flue gases, resulting in very high reduction rates. SNCR stands for Selective Non-Catalytic Reduction and works without a catalyst by injecting a reducing agent directly into the flue gases. The most suitable technology will depend on the required emission values, flue gas temperature and the characteristics of your installation.

SCR is especially valuable when very low NO_X emission values must be achieved or when future emission standards require maximum reduction. The technology delivers the highest reduction rates and is often used on larger industrial installations.

Wondering which flue gas treatment solution is right for your installation? Our experts are happy to explore the options with you.

Yes. The Callens Group take care of flue gas treatment projects from A to Z. We analyze your flue gas installation, select the most suitable technology, handle the engineering, delivery, installation and commissioning, and continue to provide service and maintenance after handover. That gives you one single point of contact throughout the entire process.

You can find more information about the different steps in our workflow here.

Yes. In many projects, flue gas recirculation is the first step in limiting NO_X formation at source. When additional emission reduction is needed, this technology can be combined with SCR or SNCR. The Callens Group determines which combination achieves the required emission values with the highest energy efficiency and the lowest total cost.

Find out which combination best fits your installation. Talk it through with our experts.

Our engineers analyze factors including flue gas temperature, flue gas composition, fuel type, required emission limit values, available space and operating conditions. Based on that analysis, we recommend the technology that combines the highest emission reduction with maximum reliability and an optimal total cost of ownership.

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