Spatial Resolved Characterization of Coke in Spent Hydroprocessing Catalysts by Raman Microscopy

摘要

Laser Raman Spectroscopy (LRS) has been reported in the past as a sensitive method of studying coke formed on catalysts (1, 2). Recent developments have made LRS a, even more powerful, user-friendly tool for the spectroscopic characterization of materials. These developments include automated data acquisition, process control of the analysis and the application of glass fiber light conductors combined with optical microscopy. In addition, the development of various new laser light sources like UV (λ = 257 nm), green (λ = 532 nm) and near infrared (λ = 785 nm) allow new options (optimizations) for typical analytical problem in the technique. For instance, in using an UV source the major drawback of LRS in the characterization of coke deposits, the high level of fluorescence, can be circumvented as shown by Li and Stair (3).