Search

A new signal processing algorithm tailored for in-situ applications combines multivariate analysis and hmable diode laser absorption spectroscopy. The principle and the application to the spectra separation of tetrafluoromethane and its interferants is demonstrated.

Recent developments in quantum cascade lasers have enabled the development of new sensors for in-situ applications that have so far only been possible with extractive systems. In this work, a sensor is presented using a unique Wavelength Modulation Spectroscopy approach to measure tetrafluoromethane, a strong greenhouse gas. The sensor was characterized in a laboratory environment indicating a long-term detection limit of 20 ppb·m and a short-term value of well below 10 ppb·m. To demonstrate the feasibility of the sensor in a real-world environment, it was installed at an Alcoa aluminum smelter. A co-located Fourier Transform Infrared Spectrometer allowed direct comparison measurements of both systems. General agreement between the two methods was observed, leading to the conclusion that the developed in-situ quantum cascade laser based sensor has the potential to continuously measure tetrafluoromethane at aluminum smelters.

Gas analyzers for industrial applications must have high reliability and require little maintenance. Analyzers for in situ measurements using tuneable diode laser spectroscopy in the near infrared have proven to meet these requirements. A brief description of the measurement principle and the LaserGas II analyzer is given. Some examples of practical industrial applications where this measurement technique is superior to most other techniques are presented