TDLAS Monitoring of Carbon Dioxide with Temperature Compensation in Power Plant Exhausts

Abstract

Featured Application: Applying to complex industrial environment, TDLAS monitoring with temperature compensation can come handy.Abstract: Temperature variations of flue gas have an effect on carbon dioxide (CO 2 ) emissions monitoring. This paper demonstrates accurate CO 2 concentration measurement using tunable diode laser absorption spectroscopy (TDLAS) with temperature compensation methods. A distributed feedback diode laser at 1579 nm was chosen as the laser source for CO 2 measurements. A modeled flue gas was made referring to CO 2 concentrations of 10-20% and temperatures of 298-338 K in the exhaust of a power plant. Two temperature compensation methods based on direct absorption (DA) and wavelength modulation (WMS) are presented to improve the accuracy of the concentration measurement. The relative standard deviations of DA and WMS measurements of concentration were reduced from 0.84% and 0.35% to 0.42% and 0.31%, respectively. Our experimental results have validated the rationality of temperature compensations and can be further applied for high-precision measurement of gas concentrations in industrial emission monitoring.

State-of-the-Art Laser Gas Sensing Technologies

“…All the above review papers presented a full discussion with regard to the related technical field of gas sensing. The remaining papers report on the technical research of gas detection based on direct laser absorption spectroscopy [19][20][21][22][23][24][25]. The target analytes were acetylene (C 2 H 2 ) [19], methane (CH 4 ) [20], oxygen (O 2 ) [21], and 13 CO 2 / 12 CO 2 isotopic ratio [22].…”

“…The target analytes were acetylene (C 2 H 2 ) [19], methane (CH 4 ) [20], oxygen (O 2 ) [21], and 13 CO 2 / 12 CO 2 isotopic ratio [22]. The corresponding sensors were used for the monitoring of power plant exhausts [23] and vision imaging [24].…”

A Method for Correcting the Interference of Overlapping Absorption Lines Using Second Harmonic Spectral Reconstruction

“…Trace gas detection based on infrared absorption spectroscopy is widely applied in exploration geochemistry, medical diagnosis, and industrial analysis fields due to its advantages of high selectivity and high sensitivity [1][2][3][4][5]. Overlap may occur between adjacent absorption lines since the linewidths of absorption lines are widened by molecular collision, doppler shift, and the measurement instrument [6][7][8].…”

Quartz-Enhanced Photoacoustic Detection of Ethane in the Near-IR Exploiting a Highly Performant Spectrophone

“…2020, 10, 2447 2 of 11 molecular species and operating in a wide range of pressures and temperatures, as well as in harsh environments. Extreme working conditions combined with life-threatening risks, such as intoxication and poisoning of the operators, triggered many remote sensing solutions like the employment of unmanned aerial vehicle (UAVs) [8][9][10].Laser based spectroscopic techniques guarantee a high detection selectivity because of the narrow linewidths characterizing the laser source employed in the visible to the terahertz range, capable of exciting the target molecules while not being absorbed by the gas matrix [11][12][13][14]. The spectral purity of the excitation source, combined with wavelength/amplitude modulation approaches and the efficiency of the optical detection techniques result in reaching detection sensitivity levels as low as parts per quadrillion [15][16][17].Depending on the specific application, these unique characteristics can make laser-based sensors more suitable solutions for remote, fast, selective and sensitive trace gas detections relying on UAVs compared to electrochemical and semiconductor sensors.…”

“…Laser based spectroscopic techniques guarantee a high detection selectivity because of the narrow linewidths characterizing the laser source employed in the visible to the terahertz range, capable of exciting the target molecules while not being absorbed by the gas matrix [11][12][13][14]. The spectral purity of the excitation source, combined with wavelength/amplitude modulation approaches and the efficiency of the optical detection techniques result in reaching detection sensitivity levels as low as parts per quadrillion [15][16][17].…”