Common methods for measuring NOx include sensor technologies based on chemiluminescence and electrochemical techniques. The electrochemical technique can not measure NO and NO2 at one time. Chemiluminescencs requires conversion of NO2 to NO for measurement of the NO2 content based on an assumed NO:NO2 ratio. In addition, measurements can be affected by the content of H2O and CO2.
Direct measurement of both NO and NO2 is the more precise way to measure Total NOx for Continuous Emissions Monitoring and measurement in the UV-region avoids the influence of H2O and CO2. System development based on UV Resonance Absorption Spectroscopy (UV-RAS) has been difficult in the past due to challenges in tuning the UV-lamp operation with its environment.
Pre-tuned NOx UV-Light Source from Heraeus
Now the Heraeus NOx Module overcomes this problem by offering a pre-tuned UV-light source in a stable environment, for easy integration as a Plug & Play Module into OEM UV-RAS systems. The Heraeus NOx Module has an integrated Electrodeless Discharge Lamp (EDL) and comes with the corresponding power supply combined in a compact box. The Nox-Module is designed for direct illumination of the measurement cell, so there is no additional optical connection needed.