Diesel Hygroscopic
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Transcript of Diesel Hygroscopic
HOME ABOUT PROGRAM DIESEL 101 KNOWLEDGE CENTER CONTACT
Refuel Systems | Diesel 101 | Refuel Systems http://refuelsystems.com/en/Diesel_101
1 of 3 06/01/2011 07:48 AM
USLD FAQ's
(via CPPI)
DIESEL 101
FUEL CLEANLINESS
WHY TEST
CSA TESTING
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According to a
study performed
by the University
of Idaho in 1994,
it is estimated
that Low Sulfur
Diesel degrades
as much as 26%
in the first 28
days.
DIESEL 101 | REFUEL SYSTEMS
Diesel fuel is an organic compound that is used, not only
as a combustible, but also as a coolant and lubricant.
THE NATURE OF DIESEL
Made up of thousands of hydrocarbons, diesel fuel begins
to deteriorate as soon as it is produced. Today's ultra low
sulfer diesel fuel actually deteriorates at a faster rate
than traditional diesel fuel produced ten years ago due to
advances and changes in refining technology and
environmental requirements. This accelerated
degradation results in greater challenges when trying to
maintain fuel quality over time and can lead to
emergency/back-up generator failures.
Understanding how diesel fuel degrades and the factors
that contribute to its breakdown is essential to eliminating
single points of failure and protecting the critical
infrastructure on which we rely.
Equally important are the several factors that contribute to diesel fuel contamination.
These include:
Repolymerization and Oxidation
These are natural processes by which the diesel molecules lengthen and bond to produce
varnishes and insoluble gums. These particles then drop to the bottom of the tank to form
asphaltene (also known as diesel sludge).
Hygroscopicity
Low sulfer and ultra low sulfer diesel fuel is highly hygroscopic: it readily absorbs water
from moisture in the air. Water contamination in diesel fuel is of particular concern as it
can lead to the corrosion of steel components and the promotion of microbial growth.
Increased use of additives and the introduction of biodiesel, for the management of
mandated fuel sulphur reductions, have dramatically increased surfactant levels in diesel.
Surfactant levels are the measurement of the tenacity in which the emulsified water and
fuel molecules bond together. This change in fuel surfactancy has given rise to consistent
failures of congenital separation and coalescence media used to separate water from
diesel fuels.
Microbial Growth
Microbial growths that naturally occur in diesel can form a layer of organic debris that
adheres to the walls and bottom of the storage container as fuel ages. The growths survive
and flourish by living in or around the water line and feeding on the rich hydrocarbons
present in the asphaltene layer. Adding fresh fuel to a contaminated fuel supply
accelerates the development of these growths. Growths that break away from the sides
and float freely in the fuel can unexpectedly clog fuel lines or filters during emergencies.
These factors taken alone or together can interfere with the durability and performance of
back-up and emergency generators, and back-up systems as a whole
University of Idaho scientists have conducted tests to determine the timeline and
percentage of degradation of stored diesel fuel #2. The results of this testing indicated that
petroleum diesel fuel #2 degraded 26% after just 28 days of storage.
Just as hydrodesulphurization produced unforeseen side effects in diesel fuel lubricity,
Refuel Systems | Diesel 101 | Refuel Systems http://refuelsystems.com/en/Diesel_101
2 of 3 06/01/2011 07:48 AM
additives and biodiesel create a less obvious, but equally dangerous unintended outcome:
failure of existing fuel-water separators. In short, ULSD blends containing sufficient
lubricity additives to pass wear requirements, and ULSD blends containing biodiesel,
create conditions where commercial fuel-water separators fail to remove 40-100% of
fuel-entrained water. The insidious aspect of this side effect Is that there is no way for an
operator to know it is happening. - - Christine Stanfel - PhD - Ahlstrom Filtration - LLC
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Refuel Systems | Diesel 101 | Refuel Systems http://refuelsystems.com/en/Diesel_101
3 of 3 06/01/2011 07:48 AM