High-sensitive monitoring of carbon monoxide in industry flue gases using tunable diode lasers

Carbon monoxide (CO) is a very important gas generated in the industrial process; therefore to implement CO concentration on-line monitoring is a key factor for industrial process control. Tunable diode laser absorption spectroscopy (TDLAS) is a high sensitive, high selective and fast trace gas detection technique. With the features of tunability and narrow linewidth of distributed feedback (DFB) laser and by precisely tuning its wavelength to a single isolated absorption line of the gas, TDLAS technique can be utilized to accurately perform online gas concentration monitoring with very high sensitivity. In this paper, a system for online monitoring of CO concentration is developed by our group employing TDLAS technique. The experimental results are present and discussed in this report. The characteristics of the system are: the sensitivity, 10ppm; detection accuracy, 0.02%; long term stability, 1%.