Font Size: a A A

O2 And Co Sensing Based On Tunable Diode Laser Absorption Spectroscopy

Posted on:2011-01-25Degree:MasterType:Thesis
Country:ChinaCandidate:C X ZhangFull Text:PDF
GTID:2198330332476051Subject:Engineering Thermal Physics
Abstract/Summary:PDF Full Text Request
Gas sensing based on Tunable Diode Laser Absorption Spectroscopy (TDLAS) with fast response, results are accurate, the system is stable and simple, is suitable for real-time on-line measurement. At the same time using non-contact laser measurement method does not affect the measured environment, it is more responsive to the real situation of the tested gas. With rapid development in recent years, tunable diode laser is more stable in performance and cheaper in prices. Therefore, tunable diode laser absorption spectroscopy has been widely used in gas emissions on-line monitoring.In this paper, based on TDLAS technology, cheap tunable diode laser is used for gas sensing.in near infrared bond. In industrial production process, O2 concentration and temperature measurement has great significance. In the paper, O2 absorption lines near 760nm are used for concentration and temperature measurement. Take advantage of temperature distribution, using two absorption lines locate at 760.07nm and 760.09nm, we can remove the impact of O2 in the air without N2 purging. For temperature measurement, using the O2 absorption lines locate at 759.86nm and 760.44nm through special optical designing, we can remove the impact of O2 in the air without N2 purging. Temperature and concentration of O2 are measured at the same time. CO concentration real-time monitoring in process combustion has great significance for improving combustion efficiency and controlling emissions of combustion. CO absorption line located at 2302.12nm is selected for measuring by direct absorption and wavelength modulation methods.The results show that, for O2 concentration measurement, from5% -100% the relative error between measurement and calibration is below 7.01%, the minimum detection is 0.3%-m in 500K by theory calculation. For O2 temperature and concentration measurement at the same time, from 400K-1000K the relative error between measurement and calibration is below 6%, the minimum detection is 0.5%-m in 500K by theory calculation. The detected limits meet the needs of industrial environment. Measurement results are accurate and reliable, measurement system is simple and feasible. For CO concentration measurement by direct absorption method, from1%-9% the relative error between measurement and calibration is below 5%, the minimum detection is 60ppm-m in 1000K by theory calculation. For CO concentration measurement by wavelength modulation, from1%-9% the relative error between measurement and calibration is below 3%, the minimum detection is 20ppm-m in 1000K by theory calculation. The detected limits meet the needs of combustion environment.
Keywords/Search Tags:tunable laser absorption spectroscopy (TDLAS), concentration measurement, temperature measurement, wavelength modulation
PDF Full Text Request
Related items