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The requirement for SCR & SNCR (DeNOx)

For decades coal has been the fuel of choice for the majority of power stations around the world and also happens to be the most pollutant. The environmental regulation in Europe, China and India has stringent emission limits which coal fired power stations are finding it increasingly difficult and expensive to comply with and are therefore employing such systems as SCR and SNCR.


Selective catalytic reduction (SCR) systems are typically found on small and large boilers, gas turbines, diesel engines and even automobiles and have shown to reduce NOx by 70-95%. NOx are one of the primary pollutants generated in a fossil fuel combustion process, their presence in the atmosphere has a negative impact on the environment (smog, acid rain, reduced visibility) and human health (respiratory problems) therefore this very same NOx reducing technology is applied to power stations all around the world.

How it works

In the combustion process nitrogen reacts with oxygen in high temperature conditions to produce nitrogen oxides (NOx). Total NOx production is the sum of nitrogen monoxide NO and nitrogen dioxide NO2. Emission limits for NOx require plants to run DeNOx process in order to reduce NOx emissions below allowable limits.


The Nitrogen oxides concentration in the flue gas which can be effectively reduced by reacting them with ammonia water, or urea in high temperature. Ammonia/Urea reacts with both nitrogen monoxide NO and nitrogen dioxide NO2 to produce nitrogen N2 and water vapor H2O, and CO2 when Urea is used. SCR DeNOx installations are common for large coal fired power station, SNCR technology can often be found in small to mid-size incineration plants, and power stations utilising CFB boilers.

What we do

In order to control both SCR and SNCR systems, these processes require monitoring throughout. CODEL offer a range of products that can monitor both input and output gases, flow & dust emissions reliably and accurately using the very latest technology.

SNCR Process
SCR Process

Suitable Products

DCEM2100 Dual Pass Opacity / Dust monitor
VCEM5100 Gas Velocity Monitor
GCEM40 Single or multi-channel In-situ Flue Gas Analyser
GCEM40E Extractive Gas Analyser

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