Distillation Raman process monitoring

Distillations are perfect candidates for Raman process monitoring since many potential fluorescent or interfering species are reduced or removed. The Institut Francais du Petrole holds two relevant patents discussing the use of Raman spectroscopy to control the separation of aromatics by adsorption on simulated moving beds and the separation of isomers, particularly aromatic hydrocarbons with 8-10 carbon atoms such as para-xylene and orffio-xylene.67 68... 

Distillation column monitoring was one of the first reports of using on-line Raman spectroscopy in real time for process analysis. This application used FT Raman coupled to a remote sample cell with optical fibers [27] to determine the bottoms product of a solvent recovery column. The system was linked to a control... 

In addition. Cooper et al. [91] discussed the use of a Raman analyzer to provide feedback and feed-forward data on a number of chemical manufacturing processes originating from crude oil, where several of the production steps involved a distillation separation again, in these examples, the Raman analyzer was positioned at the outlet to the distillation tower. They claim from their work that a Raman analyzer would be useful for monitoring and controlling aromatic extraction, liquid paraffin aromatization, and the production of cumene, cyclohexane from benzene, ethylbenzene, xylene isomers, dimethyl terphthalate, and styrene. It should also be noted that in all these processes, at least one and in several cases multiple distillation columns are involved. 

---