Why the Dosing System Is Critical to SCR Performance

Why the Dosing System Is Critical to SCR Performance – and How NOxMASTER™ Delivers Long-Term Reliability

Selective Catalytic Reduction (SCR) technology is widely recognised as one of the most effective solutions for reducing NOx emissions from combustion sources such as gas engines, turbines, and Diesel Generators. While the catalyst often receives most of the attention in SCR systems, the dosing system plays an equally critical role in ensuring consistent performance, efficiency, and reliability.

The Role of the Dosing System in an SCR

In any SCR system, the dosing system is responsible for precisely injecting the reagent (typically aqueous ammonia or urea) into the exhaust gas stream. Accurate dosing is essential for two key reasons:

• Effective NOx reduction: The correct amount of reagent must be introduced to react with NOx across the catalyst.
• Avoiding ammonia slip: Overdosing can lead to unreacted ammonia passing through the system.

However, dosing systems can face a common operational challenge: injector fouling and clogging.

The Common Problem: Injector Blockage

In many SCR installations, injectors are exposed to harsh exhaust environments. Over time, deposits, crystallisation, or particulate contamination can lead to blocked or partially obstructed injectors. This can result in:

• Reduced dosing accuracy
• Poor NOx reduction performance
• Increased maintenance requirements
• System downtime

For operators, this means higher operational costs and reduced confidence in emissions compliance.

The NOxMASTER™ Solution: Compressed Air Assisted Dosing

The NOxMASTER™ SCR system has been designed to address this issue directly through its compressed air-assisted dosing system.

By using compressed air to support reagent injection, the system provides several key benefits:

• Improved atomisation of the reagent into the exhaust gas stream
• Continuous cleaning of the injector tip, preventing deposit build-up
• Stable and precise dosing across the full operating range

This air-assisted approach significantly reduces the risk of injector clogging, even under demanding operating conditions or during frequent load changes.

Confidence Built on Reliability

Because the NOxMASTER™ dosing system actively prevents injector fouling, the SCR injectors maintain consistent performance throughout the life of the system.

This level of reliability allows us to do something many SCR suppliers cannot:

We confidently offer a lifetime guarantee on our SCR injectors.

For plant operators and project developers, this means:

• Reduced maintenance requirements
• Improved system availability
• Long-term operational confidence
• Lower total cost of ownership

A Smarter Approach to Emissions Control

Reliable emissions compliance depends on more than just a high-quality catalyst. It requires precise, dependable dosing technology that performs consistently over many years of operation.

With its compressed air-assisted dosing system, NOxMASTER™ SCR ensures optimal reagent injection while eliminating one of the most common causes of SCR maintenance issues.

The result is a robust, high-performance solution designed for the long term - backed by our lifetime SCR injector guarantee.

If you would like to learn more about the NOxMASTER™ SCR system or discuss your emissions abatement requirements, please feel free to contact our team. +44 (0) 1342 713743 | www.noxmaster.co.uk