Dual frequency comb laser absorption spectroscopy in a 16 MW gas turbine exhaust

Abstract

We demonstrate the first frequency comb laser absorption spectroscopy in an industrial environment. Recent advancements in robust frequency comb design enabled installation of the sensor in an operating power plant, where we simultaneously measured temperature, H2O and CO2 concentration in the exhaust of a 16 MW stationary gas turbine. The frequency comb laser spectrometer probed 16,000 individual wavelengths of light spaced by 0.007 cm−1 (0.0014 nm) near 1440 nm, spanning 279 absorption features of H2O and 43 features of CO2. Fits to the measured absorption spectra yield simultaneous temperature, H2O and CO2 concentrations with between 10 and 60 second time resolution. Measurements over a 5 hour period tracked variations in the exhaust consistent with various changes to the gas turbine operation. Much larger wavelength ranges (200+ nm) and different time resolutions are possible depending on the desired precision by changing various settings on the same spectrometer. Overall, this work demonstrates the potential for frequency comb laser absorption spectroscopy in industrial combustion environments.