28
LMS Issue 3 | 2014
Materials Science/Analysis
Getting Ready for Take-off
F
uel system icing inhibitors (FSII) are
added to jet fuel to prevent freezing
of the water content at flight altitude.
Their concentration in water and therefore their freezing point correlates with
the refractive index.
Jet fuel contains up to 30ppm water.
The outside temperature at flight altitude
is below -50°C, so icing of water in jet fuel
must be inhibited. Frozen water in jet
fuel may cause blocking of the fuel feed
system. In aviation, the addition of a FSII
to jet fuel is mandatory, depending on
flight route, altitude, season and aircraft.
FSII, like Diethylene Glycol Monomethyl Ether (DiEGME), have to be
added to jet fuel in a final concentration
of 0.10 - 0.15% v/v. To analyse absolute
FSII content in jet fuels, ASTM standards require the use of refractometry
for measuring water extracts. The preconfigured scale, FSII ASTM D 5006,
in Anton Paar´s Abbemat refractometer
will automatically adjust the prism and
the sample to 20°C with an accuracy of up
to ±0.03°C. Compared to other methods
used for DiEGME determination, the
advantage of refractive index determination lies in the rapid sample preparation
and measurement.
Abbemat refractometers analyse the
refractive index with a highly precise
accuracy of up to 0.00002nD, therewith
meeting the required repeatability for
FSII detection within 0.005 volume %.
This is specified in the application note
available online. ⚛
Anton Paar Southern Africa (Pty) Ltd
Contact: Andre van Zyl
Tel: 011-021-5165/6/7
Email: [email protected]
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A
gilent Technologies Inc. recently
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The 7900 ICP-MS is a complete
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