Fluorescence Noise Eliminating Fiber-Enhanced Raman Spectroscopy for Simultaneous and Multiprocess Analysis of...

C₂H₂ and H₂, as important chemical and energy raw materials, can be produced effectively and environmentally friendly by the partial oxidation (POX) of CH₄. Simultaneous analysis of intermediate gas compositions in the multiprocess (cracking, recovery, degassing, etc) of POX can regulate product generation and improve production efficiency. To overcome the disadvantage of common gas chromatography, we propose a fluorescence noise eliminating fiber-enhanced Raman spectroscopy (FNEFERS) technique for simultaneous and multiprocess analysis of the POX process, in which the fluorescence noise eliminating (FNE) method can effectively eliminate the horizontal and vertical spatial noise to ensure ppm level limits of detection (LOD). The vibration modes of gas compositions related to each POX process such as cracked gas, synthesis gas, and product acetylene are analyzed. Meanwhile, the composition of three-process intermediate sample gases from Sinopec Chongqing SVW Chemical Co., Ltd is quantitatively and qualitatively analyzed simultaneously, along with the ppm level LODs (H₂: 11.2 ppm, C₂H₂: 3.1 ppm, CO₂: 9.4 ppm, C₂H₄: 4.8 ppm, CH₄: 1.5 ppm, CO: 17.9 ppm, allene: 1.5 ppm, methyl acetylene: 2.6 ppm, 1,3-butadiene: 2.8 ppm) with a laser power of 180 mW, exposure time of 30 s, and accuracy of higher than 95.2%. This study fully demonstrates the ability of FNEFERS to replace gas chromatography to achieve simultaneous and multiprocess analysis of intermediate compositions for C₂H₂ and H₂ production and to monitor other chemical and energy production processes.