Tunable Diode Laser for Gasmet CX-4000

In the past, Continuous Emissions Monitoring Systems have relied on different types of technologies for measurement of criteria pollutants like SO2, CO, NOx, HCl, O2, TOC. What this hasmeant fromthe end user point of view is that there are multiple analysers to maintain and calibrate. This has in turn often lead to high investment & maintenance costs.

Gasmet Technologies set out the change this when the project for the new

Tunable Diode Laser (TDL)module was started. The goal was to incorporate the whole assembly inside the enclosure of Gasmet Cx-4000 FTIR gas analyser. The end result is a single analyser which is capable of measuring H2O, CO2, CO, NO, NO2, N2O, SO2, HCl, HF, NH3, TOC, O2 and many others.

This TDL module for Cx-4000 features a Vertical Cavity Surface Emitting Laser (VCSEL), which are known for their long lifetime. Also, there’s very little concern of interference from other gases, since the VCSEL utilises a part of the spectrum where O2 absorption band is virtually interference free fromother gases. Finally, the VCSEL laser uses the same gold coated sample cell which withstands very high concentrations of H2O and corrosive gases, such as HCl and SO2.

The O2 measurement results are stored on the hard-drive of an Industrial Computer along with other measurement results (no additional analog input is needed). Fromthe computer the results can be transmitted to DCS or DAHS for compensation calculations with various different outputs (analog & digital).