PEFTEC 2017 - Abstract

Abstract Title: Diesel Fuels and Additives - Interference-free Determination of Total Sulfur with the patented MPO Technology
Abstract Type: Poster
Session Choice: Analytical Techniques: Elemental Analysis and Speciation
Presenter Name: Dr Olga Weisheit
Co-authors:Dr Angela Gröbel
Company/Organisation: Analytik Jena AG
Country: Germany

Abstract Information :

The fast and trustable quantification of sulfur contents is an integral part of the process and quality control in refineries. The most reliable and flexible method to do this is the thermal decomposition with a subsequent UV-fluorescence detection of the formed SO2.

Independent of the sulfur content, the majority of samples can be analyzed with excellent results in shortest time. However, for some samples quantitative-deviating measurement results can occur depending on their composition (e.g. cetane improver such as amyl nitrate, 2-ethylhexyl nitrate etc.).This behavior is originated by the positive cross-sensitivity of UV-fluorescence detection to NO, which fluoresces in the same wavelength range as SO2, but with a significantly lower intensity. Depending on the nitrogen content present in the sample, the applied process parameters, and the used hardware, this can lead to more or less significant interferences. The effect ranges between 0.6 - 2.0 ppm "false" too high TS reading per 100 ppm Nitrogen content.

This is a serious problem, considering the fact that many fuels classified as sulfur-free already have an "actual" TS content close to the statutory limit value of 10 ppm. The sulfur content determined can exceed the specified threshold easily, if nitrogen-containing cetane improvers are used. Thus the fuel does no longer comply with the requirements, a costly "after treatment" is needed. However, this unnecessary effort can be avoided by using matrix-independant techniques like the patented MPO - Micro Plasm Optimization, an enhancement of the classic UV-fluorescence. In real-time interfering components are converted into harmless species, no additional auxiliary materials (e.g. catalysts), no extension of analysis time due to multiple injection, or matrix separation by trap-and-release approaches is required. Results are gained as fast as usual.