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Technical Reference

Fuel Filtration - Biodiesel Fuel

How should biodiesel be stored? How are fuel tanks cleaned?
Underground storage tanks are preferred to avoid If sediment is found then a vacuum truck should be used
temperature extremes. Above ground storage tanks with a scavenger device to effectively navigate around the
should be sheltered or painted with reflective paint. High tank and remove the contamination. Depending on the
temperatures during storage accelerate fuel degradation. severity of the contamination, an internal tank cleaning
Brass, bronze, copper, lead, tin and zinc may accelerate may be necessary to effectively remove contaminates. Tank
the oxidation of diesel and biodiesel fuel and potentially cleaning should take place one of two ways; (1) with
create sediments, gels or salts when reacted with some fuel the use of a high pressure hose with fuel, or (2) by
components. Acceptable storage materials include stainless physically scrubbing the inside of the tank. Both cleaning
steel, aluminum, Teflon® and most fiberglass. Lead solders, methods will use impingement cleaning, meaning all
zinc linings, copper pipes, brass regulators and copper surfaces are cleaned with either high pressure or physical
fittings should be avoided. scrubbing.

How do you check fuel tanks for Water and
Sediment? How can fuel filtration prevent problems

To ensure contaminants do not create fuel quality issues with biodiesel fuels?
it is important to remove them before they buildup. The When switching to biodiesel, some users have experienced
best way to check the tank is to retrieve a sample from the problems with premature fuel filter plugging. This is not
lowest point of the tank. For bulk storage tanks this can an issue at low level biodiesel blends but more commonly
be done with a bacon bomb or by drawing a sample off seen with blends of B20 or higher.
the lowest point of the tank. It is also a good idea to check
the on-board tanks; this can be done by drawing a sample Fuel filters are designed to remove water and particulate
from the lowest point with a sample kit. Every fuel system from fuel in order to protect the fuel system. They are
has the potential to experience problems so it is necessary designed to eventually plug. You may want to investigate
ENGINE LIQUID FILTRATION TECHNICAL REFERENCE
to check frequently for contamination. Every fuel system if you continue to have a change in the frequency of filter
should be inspected per federal, state and local regulations. changes.
In addition to those inspections it is necessary to look for
contamination. It is recommended that a storage tank be The Original Equipment Manufacturer (OEM) has
checked for water and sediment prior to each fuel delivery. specified filters for each fuel system to provide optimum
If the frequency of the deliveries is such that months go performance. When replacing the filters, it is strongly
by between them, then check the fuel tank at least once a recommended to continue to use the OEM filters or
month. If contamination is found, it should be removed the equivalent aftermarket filters. OEM is not the local
as soon as possible. Water should be removed either by mechanic. Check with the OEM headquarters.
draining water off the tank if it is equipped with a water
draw or with a vacuum truck. Whichever method is used, the Fuel filtration will be affected by multiple factors including:
removal should be done slowly so that free water can travel
to the low point in the tank. A visual inspection of the water Stability issues–A common symptom encountered
and fuel should be done at the same time and continued with degraded fuel is plugged filters. Solution—
until the fuel is clear and bright. proper housekeeping and the use of additives can
extend the shelf life of biodiesel fuel. Consult your
Why are fuel tanks checked for Microbial fuel supplier for proper recommendations and
testing.
Contamination?
Cold Flow – Biodiesel has a much higher cloud
It is necessary to test for microbial contamination because point/pour point than petroleum diesel fuel. Pure
the microbes can lead to filter and pump failures. It is biodiesel can start to cloud at 55°F and gel by 32°F.
recommended that fuel tanks be tested for microbial Make sure proper cold flow is being requested for
contamination twice a year, preferably in the fall and spring. the desired region of operation.
To test for microbial contamination, obtain a quart sample
from the tank bottom. Contact your fuel distributor about Water Separation – Water is present in fuel and
performing a microbial test. Many fuel distributors perform therefore many fuel systems require a method of
this test for a fee or can give a referral to a reputable lab water removal before it reaches the fuel injectors.
that can perform testing. The costs associated with routine Be sure to drain water separators daily to ensure
testing is a small price to pay in relation to the cost of fuel in optimum performance.
the fuel tank, the cost to have vehicles go down due to filter Cleaning/Solvent Effects – Biodiesel (B100) is an
plugging and the cost of biocide used to treat microbial excellent solvent for cleaning any hydrocarbon
contamination deposits that may have formed in the fuel system.
After switching to biodiesel it is expected that fuel
filters may plug quickly to begin with and then
return to a normal change interval after the fuel
system is cleaned.

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