Excimer UV Fluorescence
Our ATOM INSTRUMENT™ Excimer UV Fluorescence (EUVF) Technology is the principal technology used in our online and elemental analyzers for total sulfur and total nitrogen measurement. The Excimer UV Fluorescence (EUVF) Technology provides high reliability and confidence of analytical results, reduces operational and maintenance costs, meets today’s emission standards, and delivers outstanding analytical performance to meet the challenges of future emission requirements.
The UV Fluorescence method is the most simple and practical low-level sulfur analytical technique. It has been widely used and proven over many years of use in industrial settings. This method involves injection of a sample into a high-temperature oxidation furnace, converting all hydrocarbons into water (H2O) and carbon dioxide (CO2). Total sulfur contained in molecular-bound hydrocarbon species is oxidized at temperatures in excess of 1000°C into sulfur dioxide (SO2) by the reaction: R-SH + O2 → SO2 + CO2 + H2O
The furnace effluent containing these combustion byproducts is directed into a detection chamber where it is excited by high-energy, short-wavelength emission from the excimer source. The UV photons from the excitation source, transfer energy into the SO2 molecule and raise its energy level to create an excited singlet state. These excited molecules rapidly decay back to their lower energy ground state releasing the absorbed energy as a secondary emission known as fluorescence.
SO2 + hν → SO2* → SO2 + hν’
Fluorescence emission is optically filtered to remove undesired wavelengths from excitation source and background scatter within the detector chamber. Detection of filtered fluorescence emission is accomplished using a Photomultiplier Tube and amplified by proprietary high sensitivity electronics.
Calibration and validation routines are seamlessly incorporated into the analyzer’s operation software. The analyzer has a very fast response time to process changes (within 1 cycle), ensuring proper process monitoring with fast moving processes. The sample injection system design is simplified resulting in greater reliability and lower maintenance, for example, the sample valve only actuates once per cycle increasing lifetime. Finally, the analyzer results are insensitive to sample buildup or interference from oxygenates present in the sample stream.
Our Excimer UV Fluorescence Technology is much less sensitive to interference from molecular-bound nitrogen, which can significantly affect the accuracy of sulfur measurement depending on the composition of the analyzed samples.