基于高温还原及差分吸收光谱监测烟气汞的实验研究

Research on Flue Gas Mercury Based on High Temperature Reduction and Differential Absorption Spectroscopy

高温还原法在不需要催化剂的条件下可将烟气排放中的二价汞转化为零价汞,便于进行烟气总汞的监测。运用差分吸收光谱法(DOAS)反演出烟气汞浓度,与没有加高温装置的测量结果作对比,验证高温设备的适用性,并配比不同浓度的零价汞和二价汞进行混合实验。在传统的DOAS算法基础上,研究遗传算法、傅里叶变换滤波及积分面积法对烟气汞浓度的影响。实验结果表明:传统算法具有偶然性,整体误差大;傅里叶变换反演出的浓度误差较大;积分面积法较遗传算法误差偏低,整体波动也小,反演出的偏差最小为0.55%,适合用于反演低浓度排放的烟气汞测量。

By means of high-temperature reduction method, the oxidized mercury will be reduced to elemental mercury without any catalyst, which is convenient for the monitoring of mercury in flue gas. Using differential optical absorption spectroscopy （DOAS） to inversion the concentrations of mercury, and then comparing that with the outcome resulted from experiment without the high-temperature device to verify the applicability of high temperature equipment, and to carry out experiments mixed with different concentrations of the elemental mercury and mercury oxidation. By probing into the impact of genetic algorithm, FFT and the integral area method on the concentration of mercury in flue gas based on the traditional DOAS algorithm, it＇ s turned out that the traditional algorithm is of contingency with a comparatively large overall error, while the Fourier transform inversion error is too large, the algorithm of integral area inversion has a lower error and a stable volatility than genetic algorithm and integral area inversion error minimum of 0. 55%. The volatility of genetic algorithm is also not as stable as that of integral area inversion, which demonstrates that the integral area inversion is the most applicable for the inversion of low concentration of mercury.