Re: [MV] Diesel Fuel

From: Jim Allen (jimallen@onlinecol.com)
Date: Sat Nov 11 2000 - 09:58:17 PST


Regarding the storage of diesel fuel, I said. Upon reflection, it appears
that I may have been overly optimistic in my information. I said:

>>1) Diesel fuel has a maximum storage life of 1 year. Sta-Bil, a fuel
>>additive that keeps fuel fresh in storage, will help diesel fuel also.

Chris replied;

>Actually, diesel fuel will keep indefinately by itself, however algae will
>start to grow in the fuel and cause it to break down. If you have old diesel
>fuel, you should run it through a filter before using it. Also, if your
>diesel vehicle sits a lot, it is advisable to add an algaecide to the fuel.

I respond:

My information differs. Here is but one treatise on diesel fuel storage. If
you do a concerted web search you can find others. My 1 year figure comes
from a booklet by Chevron (though they didn't mention sotorage conditions)
and information from the Petroleum Institute. Apparantly, much deponds on
HOW the fuel is stored. Using a fuel stabilizer and renewing it annually,
one source says that 5 years is possible. If I had a seldom used rig, I
would add a fuel stabilizer. Read below.

PETROLEUM and ENVIRONMENTAL ENGINEERING SERVICES
P.O. Box 4911 San Luis Obispo, CA 93403
FAX/Phone (805) 543-8648

LIFE EXPECTANCY OF STORED DIESEL FUEL

>From The Desk Of:
MASOUD MEHDIZADEH, Ph.D.

Life expectancy of stored diesel fuel is limited. Depending on the amount
of contaminates, sooner or later stored diesel fuel will deteriorate. Of
the many contributing causes there are three main factors responsible for
the deterioration of stored diesel oil/fuel. These factors include:
oxidation,
microorganism growth and corrosion.

In the case of oxidation, oxygen reacts with the hydrocarbon molecules in
the fuel. Oxidation causes discoloration, formation of particulate, water
and gum. Oxygen is introduced to stored diesel fuel through tank
ventilation, refueling and can even be entrapped during the refining
process.

In the case of microorganism growth, bacteria and fungi will gather at the
fuel water interface in the storage tank. They consume the diesel fuel and
produce acid and water as a bi-product. Again, air is a contributing source
for these contaminates. Emulsified water in the diesel fuel will accelerate
this process.

Corrosion is caused by microbial growth, water and voltage potential
through storage tank walls. Corrosion destroys storage tank walls and
releases metals back into the stored fuel. This action will accelerate the
oxidation reaction.

Conducted studies have confirmed the effects of some of the factors
discussed above. 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 was that the petroleum diesel fuel #2
degraded 26% after 28
days of storage.

Nitrogen compounds will effect the storage stability of hydrocarbon fuels
in a variety of ways depending on the type and concentration of the
nitrogen compound, the chemical make up of the fuel, presence of other
trace materials and storage conditions. Studies conducted by Frankenfeld
et.al. under
accelerated storage conditions have proved that sediments are formed. The
formation of these sediments are even more in the presence of water and
dissolved oxygen.



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