Measurement of the concentrations of volatile organic compounds within operating process units by open-path FTIR

摘要

Abstract: A field study was performed to evaluate the strengths and limitations of open-path FTIR for the measurement of volatile organic compounds within operating process units. The infrared measurement pathlengths of 100 to 300 meters traversed pipe alleys and pump rows within the units. Three different gas chromatographic-based measurements were made in parallel with the infrared measurements. This was done to provide a verification on the accuracy of the infrared measurements and to provide a cross comparison among the various gas chromatographic (GC) measurements. Measurements at plants found extremely low (sub-ppm) concentrations of organic compounds within the units tested. FTIR results were generally lower than those observed by the three GC methods. Open-path FTIR measurements appear to suffer from a number of limitations at this time including problems with background correction, high detection limits and the impact of meteorological conditions. Further refinements in the technology are required before it can provide high accuracy/precision measurements. At present, best applications might be for leak monitoring and alarming. !2