Continuous Emission Monitoring of Tetrafluoromethane Using Quantum Cascade Lasers
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.
A Smorgasbord of measurements
Gas concentration measurements for process control, emissions monitoring and safety purposes are ubiquitous in refineries. The instrumentation is dominated by gas chromatographs, but over the past few years another technology has slowly found its way into many refineries: gas analysers based on tunable diode laser absorption spectroscopy (TDLAS). This article is the first of a […]
Hydrogen Sensor Based on Tunable Diode Laser Absorption Spectroscopy
A laser-based hydrogen (H2) sensor using wavelength modulation spectroscopy (WMS) was developed for the contactless measurement of molecular hydrogen. The sensor uses a distributed feedback (DFB) laser to target the H2 quadrupole absorption line at 2121.8 nm. The H2 absorption line exhibited weak collisional broadening and strong collisional narrowing effects. Both effects were investigated by […]