The Effect of Stadis 450 on MSEP Rating and Coalescence Technical Basis of Re-Doping Turbine Fuels With Stadis 450
Abstract
The use of filter/coalescers at airports and terminals requires that the fuel be free from additives and contaminants which might reduce the effective service life of these elements. The Microseparometer (MSEP) is one test which is commonly used to ensure that the fuel is free from surfactants. However, experience has shown that the use of Stadis 450 often significantly lowers MSEP rating while not affecting coalescer performance. This has caused problems in situations where re-doping with Stadis 450 to improve the fuel conductivity is needed. In some cases, the MSEP rating due to previous additions of Stadis 450 precludes re-doping without reducing the MSEP to below commonly accepted ratings. This study was undertaken to determine whether there was a correlation between the MSEP rating due to Stadis 450 addition and coalescer deactivation. Examination of data from field experience, the United States Air Force service tests, and other literature confirmed the hypothesis that Stadis 450 did not adversely affect coalescer performance commensurate with the drop in MSEP rating often seen. A substantial experimental evidence from single element tests similar comparing coalescer performance when ASA-3 was used to those tests when Stadis 450 was used showed slightly better effluent water levels when Stadis 450 was used (3.9 ppm for ASA-3 vs. 2.9 ppm), while the average value of MSEP differed markedly (88.7 for ASA-3 vs. 63 for Stadis 450). As a result of this study, it was concluded that the customary minimum MSEP of 70 can be relaxed when a drop in rating is specifically due to the addition of Stadis 450. The data indicate that Stadis 450 will not disarm coalescers even though MSEP may be low. However, there is a need to maintain control over chance contamination which may occur during fuel handling and distribution which could have a deleterious effect on coalescence.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1999
- Accession Number
- ADA373482