NOx and O2 on the inlet to an SCR.

The gas stream contains ammonia, nitrogen oxides and in some cases sulfur dioxide . The NOx analyzer is a UV diode array process analyzer. Measuring the complete spectrum of the stream continuously and instantaneously.

The full spectrum  advantage
The figures below show the absorbance spectra of the DeNOx process stream components,. The absorbance features overlap, therefore, a full high resolution spectral analysis is essential. High accuracies at a relatively wide dynamic range can be achieved  due to the sharp absorbance features of the DeNOx stream component

The system uses an aspirator driven extractive sampling system with a heated umbilical sample line. The sample flows through the absorption cell and the oxygen sensor in series.   Long sample lines are avoided, minimizing the normal sample losses associated with sample adhesion to interior tubing walls.