NOX Reduction

Plants with flue gas installations are facing increasingly strict emission standards. New environmental permits, European regulations, and emission targets are pushing businesses to reduce nitrogen oxide (NOX) emissions.

The Callens Group helps industrial companies reduce NOX emissions with technically feasible solutions that seamlessly fit into their existing production process. From combustion process optimization to flue gas aftertreatment, we develop an integrated approach that lowers emissions without losing sight of your installation’s continuity and energy efficiency.

Discuss your NOX challenge

When is investing in NOX reduction the right move?

NOX reduction becomes relevant when nitrogen oxide (NOX) emissions are a point of concern within your production process, or when stricter emission requirements call for modifications to your installation. This can be the case for new investments, the optimization of existing combustion installations, or environmental permitting.

The Callens Group helps you select the most suitable NOX reduction technology based on your combustion process, target emission values, and the technical parameters of your installation. We always look for the optimal balance between emission reduction, energy efficiency, investment cost, and operational reliability.

Applications:

  • Complying with stricter NOX emission limits or environmental permit conditions.
  • Reducing emissions from existing boiler installations or thermal oxidizers.
  • Designing a new combustion installation in line with the applicable emission standards.
  • Expanding or renovating an existing installation with stricter regulations in mind.
  • Achieving very low NOX emissions through flue gas aftertreatment.
  • Optimizing the combustion process without compromising production continuity.
  • Developing a future-ready installation prepared for further tightening of emission legislation.
Callen Rookgasrecirculatie SCR

Which type of NOX reduction solution is the best?

The most suitable solution will depend on your combustion installation, flue gas temperature, emission targets, available space, and investment planning.

Some installations can already lower their NOX emissions by optimizing the combustion process. In other cases, additional flue gas treatment is required to achieve the desired emission values.

That is why the Callens Group engineers always analyze the complete combustion process. Based on that analysis, we determine which technology, or combination of technologies, delivers the greatest technical, environmental, and economic value.

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Your challengePossible solution
You want to limit NOx formation during combustion.Internal flue gas recirculation system
Additional reduction without major boiler modifications.External flue gas recirculation system
Achieving very low emission values.SCR
A compact solution with limited investment cost.SNCR
New boiler or retrofit project.Optimized boiler design
Combining multiple technologies.Integrated NOx reduction strategy
SOLUTIONS

The Callens Group offers a broad range of NOX reduction solutions

There are several technologies to reduce nitrogen oxide emissions. Depending on the combustion process, target emission values, and technical possibilities, the Callens Group selects the solution that best suits your installation. This may range from primary measures, such as flue gas recirculation and an optimized boiler design, to flue gas aftertreatment using SCR or SNCR which all allow us to achieve the required emission reduction while keeping a strong focus on efficiency and operational reliability.

Callen Rookgasrecirculatie SCR 2

Flue gas recirculation

Lowers the flame temperature by returning part of the flue gases to the combustion zone, either through internal flue gas recirculation or by recirculating them externally. As a result, less thermal NOX is formed.

More about our flue gas recirculation
Callen Rookgasnabehandeling

Flue gas aftertreatment (SCR & SNCR)

When combustion process optimization is not enough, flue gas aftertreatment removes nitrogen oxides from the flue gases through Selective Catalytic Reduction (SCR) or Selective Non-Catalytic Reduction (SNCR). Depending on the installation and the required emission reduction, the Callens Group selects the most suitable technology.

More about flue gas aftertreatment (SCR & SNCR)
Callen O Ptimum Rookgasnabehandeling 1

Optimized boiler design

By optimizing the combustion chamber, burner configuration, and air supply, NOX formation can already be significantly reduced at source.

More about optimized boiler design

Less NOX. More operational reliability.
Discover which NOX reduction technology best suits your installation.

Discuss your NOX challenge
USPs

Why choose NOX reduction by the Callens Group?

An NOX reduction project delivers the greatest value when emission reduction, energy efficiency, and process continuity are perfectly aligned. With our industrial process expertise and years of experience, we develop solutions that not only reduce emissions but also preserve the performance of your installation.

Fewer emissions, greater operational reliability
Compliance with stricter emission standards
Tailored to your installation

Partnering with the Callens Group means carefully considered emission reduction

Stricter emission standards call for carefully considered choices. Not every installation faces the same challenges, and not every NOX reduction technology is suitable for every process. That is why the Callens Group always starts with an analysis of your installation and combustion process. Based on that insight, we develop a tailored solution that achieves the required emission reduction, with maximum attention to efficiency, reliability, and production continuity.

With the Callens Group, you get one point of contact for your entire NOX reduction project: from the initial analysis through installation, including service and maintenance. That keeps the project clear and reduces the need for separate coordination between multiple parties.

The Callens Group is not tied to one brand, manufacturer, or technology. That means that we can select the solution that is technically and economically best suited to each project. Our engineers analyze factors such as the combustion process, flue gas composition, required emission limits, available space, and impact on your production process. This gives you a solution that is tailored to your installation and emission targets.

With more than 120 service and maintenance specialists, the Callens Group has one of the largest service teams in the market. Preventive maintenance, periodic inspections, fast interventions, remote monitoring, and an extensive stock of spare parts help keep your NOX reduction installation operating reliably and in line with the specified emission values.

The Department of Technology is the Callens Group’s innovation center. Here, new developments in NOX reduction are assessed for their technical feasibility and added value to industrial applications. Only proven technologies ultimately make their way to our customers.

With 13 locations across Belgium, the Netherlands, and France, we combine the advantages of an international group with the proximity of local teams. This allows us to respond quickly, stay closely involved, and support our customers for the long term.

Ready to structurally reduce your NOX emissions?

Do you want to comply with stricter emission standards or prepare your combustion installation for future regulations? Our specialists will be happy to assess which NOX reduction technology best suits your production environment.

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“Effective NOX reduction starts with insight into the complete combustion process, not by choosing one individual technology.”

Projects involving NOX reduction

Callens Warmtepomp 3
Thermal technology Industrial heat pumps Electrification +1

Industrial heat pumps reduce CO₂ emissions

Capacity4.2 MW
Energy source100% electricity
Cargill Haubourdin E boiler 20 MW 30 T ZW
Thermal technology Electrification Electrode boilers +2

Combination of e-boiler and gas boiler modernizes starch factory

Capacitye-boiler: 20 MW 
gas boiler: 20 MW
Working pressure35 barg
FAQ

Questions?
We have the answers.

There are several technologies to reduce nitrogen oxide (NOX) emissions. The most suitable solution will depend on factors such as the combustion process, target emission values, the existing installation, and the available space. The Callens Group analyzes these parameters and selects the technology, or combination of technologies, that offers the greatest technical and economic added value.

Want to know which technology best suits your installation? Discuss your NOX challenge with our specialists.

Both SCR (Selective Catalytic Reduction) and SNCR (Selective Non-Catalytic Reduction) reduce NOX emissions through a chemical reduction process. The difference lies in the application. SCR uses a catalyst and achieves very low emission values, while SNCR works without a catalyst and can be a technically and economically attractive solution to certain applications. The most suitable technology will depend on the installation, process conditions, and required emission reduction.

Flue gas recirculation is particularly suitable when NOX formation needs to be limited during the combustion process itself. By returning part of the flue gases to the combustion chamber, the flame temperature drops and the formation of thermal NOX is reduced. Depending on the installation, internal or external flue gas recirculation may be an option, potentially in combination with other NOX reduction technologies.

Discuss the possibilities for your installation with our experts.

In many cases, existing combustion installations can be optimized without full replacement. Depending on the technical possibilities, the solution may involve an adapted boiler design, flue gas recirculation, SCR, SNCR, or a combination of different technologies. The Callens Group assesses which solution best suits the existing installation and the desired emission targets.

Contact our specialists for an analysis of your installation.

The choice of NOX reduction technology will depend on several factors, including flue gas temperature, fuel type, the combustion installation, required emission limit values, and available space. That is why the Callens Group first performs a thorough analysis of the complete combustion process. Based on that analysis, we develop a solution that optimally combines emission reduction, energy efficiency, and operational reliability.

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