June 2013 • 31
Fuel Quality
As the energy industry’s
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WE GO BEYOND
THE NUMBERS
FOR YOU.
New Fuels Bring New Challenges
Corrosion in ULSD dispensers has been reported nationwide
DISTILLATE FUELS ARE MORE STRESSED AND
complex than the fuels that marketers sold
just a few decades ago, and expert treat-
ment is needed to ensure the high quality
that customers expect. That’s the diagnosis
delivered at the recent Atlantic Region
Energy Expo by Mark Stellmach, President
of Fuel Management Services Inc.
Stellmach said that petroleum products
became considerably less stable as refiners
began using catalytic cracking widely in
the 1970s to stretch the output of a barrel
of crude oil. “Straight-run fuel was hardy
and stable and could remain in storage for
a long time. Cracked fuels are more fragile
and chemically active,” he explained.
New variables were added with desul-
furization of distillates and the blending in
of biofuels such as ethanol and biodiesel.
Low-sulfur fuels are more challenging to
store and maintain than high-sulfur fuels,
but there are also positive attributes, par-
ticularly reduced air pollution. “Ultra-low
sulfur diesel is the fuel we use that we’ll
need to compete with natural gas and to
survive,” he said.
A DIFFERENT FUEL
Refiners apply high pressure tem-
peratures in the presence of catalysts to
desulfurize the fuel. “It’s a different fuel,”
Stellmach said. ULSD shows less resistance
to microbial growth than high-sulfur fuels
do. “With so much sulfur removed, the fuel
loses its natural ability to keep fungus and
bacteria from growing,” he said.
Some marketers of ULSD for on-road
use have experienced trouble with corro-
sion in dispensing systems. “Accelerated
corrosion of dispensing equipment has
become an issue nationally,” Stellmach
said, and marketers need to take proactive
steps to prevent such problems.
ULSD has a greater affinity for moisture
than high-sulfur diesel, and it’s important
to keep water from entering ULSD tanks.
“ULSD carries water along for the ride,” and
the water collects on fuel-wetted surfaces
where it becomes the electrolyte allowing
corrosion to occur. “Good housekeeping is
more important than ever,” he added.
ETHANOL TO BLAME?
Stellmach said there are indications that
cross-contamination of ethanol might be
introducing water into ULSD equipment
and hastening corrosion, but more studies
are needed to determine the exact causes of
the problem.
ULSD also has higher solvency than high-
sulfur fuels and less resistance to microbial
growth, which means it is more susceptible to
microbial growth and more likely to release
sludge from tank walls and floors.
To date, there are few if any reports of
corrosion in heating oil tanks that store
ultra-low sulfur heating oil, but Stellmach
recommends marketers take extra care in
making sure the problems are not repeated
as heating oil dealers transition to reduced-
sulfur fuels.
As traditional heating oil is replaced by
ultra-low sulfur fuel and biodiesel blends,
dealers are experiencing unprecedented
change to the product. “With good handling
and maintenance procedures and practices,
we’ll experience all the good the new fuels
have to offer,” he said.
PREVENTATIVE MAINTENANCE
Stellmach,
whose company sells
UltraGuard
™
heating oil treatment, recom-
mends a preventative maintenance regimen
for ultra-low sulfur distillates that includes
periodic testing for microbes, treatment
with biocide as needed and treatment with
a fuel inhibitor. The fuel inhibitor should
prevent corrosion, provide demulsification,
disperse organics and discourage microbial
growth, he said.
He also recommends that retailers use
a laboratory to perform spot tests on fuel
from suppliers. The lab should test for sta-
bility, water content, particulate, microbial
life, organic and inorganic contamination,
and cold flow performance.
