分时窄带CARS光谱技术在测量烯烃浓度方面的应用

Time-Sharing Narrowband CARS Spectroscopy in Olefin Concentration Measurement Applications

基于相干反斯托克斯拉曼散射(CARS)光谱技术机理,针对甲醇制烯烃(MTO)产物中多种组分烃类的探测需求,搭建了一套扫描式窄带CARS光谱实验装置。采用该装置对甲烷,乙烷,乙烯,丙烯分别进行CARS光谱扫描,获得了各分子的特征拉曼谱;并在相同实验条件下进行比对试验,得到不同分子特征峰处的CARS信号强度与目标气体浓度及其他背景气体之间的关系。通过建立简化模型对不同分子的CARS信号特征峰强度信息进行解析,提出了一种分时窄带CARS光谱探测多种拉曼活性气体浓度的方法,用于快速在线分析催化化工等领域中各类流体的组分。利用这种方法探测了甲烷,乙烯,丙烯的浓度,将实验误差控制在9%以内。

A scanning narrowband coherent anti-stokes Raman scattering（CARS）spectrometry was built up for the detection of the production of a variety of hydrocarbon components in the methanol to olefins（MTO）process.Methane,ethane,ethylene,propylene CARS spectra were scanned using this spectrometry;the characteristic Raman spectrum of each molecule was obtained.Under the same conditions,the relationships between CARS signal energy and different target molecules and other background gases were studied.A simplified model was established to simulate the CARS signal characteristic peak intensity contributed with different molecules,and the concentrations of Raman active molecules were calculated by this mode.This paper proposed a method of the on-line detection of Raman-active gas concentration by time-sharing narrowband CARS spectra.This method may have practical applications in the online analysis of catalytic chemical industry.The experimental error for the detection of the concentration of methanol,ethylene and propylene is less than 9%.