基于可调谐半导体激光吸收光谱技术,选用2-3μm附近的R(30)吸收谱线,利用波长调制技术分别对高温管式炉炉中标定的CO/N2气体和自制燃油炉燃烧烟气中CO体积分数进行测量.引入激光强度影响系数Tr(t)对实验结果进行修正,以排除激光强度变化所造成的干扰.结果表明,实验验证了R(30)谱线在1200K以下,随着温度的上升谱线强度上升,更有利于高温下CO测量.测量CO体积分数变化趋势与燃烧工况相符,并且与其他测量仪器所测结果一致,谱线R(30)应用于工业现场中燃烧环境下的CO测量具有一定的可行性.
In situ measurements of CO concentration using 2.3 μm diode laser were received by scanned wavelength modulation with second-harmonic signal in the controlled laboratory environment of a high temperature tube furnace and in the combustion environment of a homemade oil burning furnace. In order to eliminate the interference caused by laser intensity change, the laser intensity influence coefficient Tr (t)is introduced to modify the measurement results. These experiments demonstrate that the line strength of R (30)will increase with the rise of combustion temperature (less than 1 200 K), which is favorable for the measurement of CO concentration at high temperature. The results show that the change of measured CO concentration agrees with the combustion conditions and the measurement result by traditional method. Those experiments also demonstrate the feasibility of applying spectral line R (30) to the in situ measurement of CO concentration in industrial combustion environment.