CEM Solutions – Industrial Emissions Monitoring

NOx and NH3 Monitoring

CEM Solutions – Industrial Emissions Monitoring

NOx and NH3 Monitoring in Industrial Processes

Nitrogen oxides that are created during combustion can be converted into nitrogen and water by adding ammonia or urea. Common methods for NOx reduction in power plants and waste incinerators are SNCR (selective non-catalytic reduction) and SCR (selective catalytic reduction).

SNCR works by injecting ammonia or urea into the combustion flue gases at high temperatures, in the region of 850 – 1150 degrees C. With this method NOx reductions of 30–70 % can be achieved. Benefits of SNCR are; ability to retrofit to existing systems, ease of installation & setup and lower cost of operation vs SCR.

With SCR, ammonia or urea reacts with NOx in the presence of a catalyst at between 200 400 degrees C. The catalyst speeds up the reaction leaving only nitrogen, water and trace levels of CO2. With this method NOx reductions of over 90% can be achieved.

Achieving the upper levels of NOx reductions can lead to emissions of ammonia, known as ammonia slip. This can be due to a range of factors such as over injection of ammonia into the exhaust gas, catalyst degradation and non-optimum process temperatures.

Monitoring Requirements

The industrial emissions directive (IED) combined seven previously existing directives such as LCPD, WID and SED. The aim of the IED is to achieve a high level protection of human health and the environment taken as whole by reducing harmful industrial emissions across the EU, in particular through better application of Best Available Techniques (BAT).

BAT Reference documents are published with an emphasis on BAT Conclusions and BAT AEL’s (Associated Emission Limits). Permits are then revised and compliance with BAT Conclusions achieved within 4 years of their publication.

The Dr Foedisch Multi-Component Analyser MCA 10

The MCA 10 can measure NOx (NO & NO2) and Ammonia to very low certified ranges compliant with IED requirements in one analyser.


The MCA 10 is a hot-wet infrared analyser using gas filter correlation and bi-frequency measuring methods to give class leading certified ranges.


  • Long operation times, high reliability
  • Modular system design with minimal consumables required
  • Pre-calibrated, immediately deployable
  • Zero point drift control
  • Remote diagnosis and system settings
  • Ability to integrate continuous TOC and Hg measurements


Operation of the system is carried out via a large touch screen display. This gives access and visualisation for live readings, trend data, diagnostics and system settings.