Laser-based gas analysers to measure H2S

SpectraSensors Inc has announced the release of three new products designed specifically to improve process efficiency in refineries and chemical plants. Using tunable diode lasers and Herriott cell technology, SpectraSensors offers a pioneering solution without tradeoffs - fast, repeatable and reliable H2S measurement coupled with operational simplicity and low maintenance costs. SpectraSensors employs proprietary tunable diode laser (TDL) technology that was spun out of NASA's Jet Propulsion Laboratory in 1999.

The company claims that its SS Series analysers use robust TDL that emit near-infrared light at wavelengths absorbed by the gas being measured. The IR light passes through the gas sample and is measured by a solid-state detector. As the laser wavelength is tuned across a specific wavelength, energy is absorbed, reducing the amount of light arriving at the detector. The fraction of light that is absorbed, as the laser is tuned across the line, is directly proportional to the concentration of the target gas. Because the laser is tuned across the line four times each second it can be used for fast, accurate measurements and control of process parameters independent of contamination or laser intensity.