Fig. 1. Experimental system
1: Nitrogen source; 2: PTFE tube; 3: CS200 flow control valve; 4: BTX standard fluid; 5: Silicone hose; 6: BT100-2J precision peristaltic pump; 7: Atomizer; 8: Mixing gas chamber; 9: Heating device; 10: Filter; 11: Ultraviolet enhanced xenon light source; 12: Absorption cell; 13: Exhaust gas outflow end; 14: Data acquisition system; 15: PC data processing system; 16: Waste liquid recovery tank; 17:Shell

Fig. 2. Schematic of smooth denoising

Fig. 3. Schematic of Wavelet transform denoising

Fig. 4. Comparison of benzene absorption cross-section

Fig. 5. Comparison of filtering effect

Fig. 6. Absorbance of gaseous benzene

Fig. 7. Benzene fitting curve

Fig. 8. Differential absorbance curve of benzene

Fig. 9. BTX mixed concentration inversion process
(a): BTX differential absorbance; (b): BTX differential absorbance and xylene differential absorbance;(c): Differential absorbance of benzene and toluene; (d) Differential absorbance of benzene

Table 1. Inversion results of gaseous benzene based on integrated area method and least square method

Table 2. BTX mixed gas ratio (mg·m^-3)

Table 3. Inversion results of different concentrations mixed gases (mg·m^-3)