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Three types of contamination effect diesel - Water,
solid inorganic and microbial.
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Water is removed and kept at a minimum by
draining tanks and having a water separator before or included with
the fuel filter.
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Solid inorganic contaminates are kept to minimum
by the fuel filter.
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Microbial
contamination - Bacteria, yeasts and fungus is eliminated by fitting
a De-Bug Unit before the primary fuel filter. The fuel delivered to
the engine and the also the fuel returned to the tank is free of
bugs.
Twenty-seven (27) individual species
of bugs can occur in diesel fuel:
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Bacteria
utilise
hydrocarbons and reproduce 'asexually' by binary fission;
swelling in size as they feed, they then separate into two
cells. In this way microbes double their numbers every 20
minutes, one spore becomes 262,144 in 6 hours. Typical
bacteria known to utilise hydrocarbons are Pseudomonas
aeruginosa, other Pseudomonas species, Flavobacterium spp.,
Acinetobacter spp., Alcaligenes spp., Micrococcus spp.,
Arthobacter spp., Corynebacterium spp., Brevibacterium spp.,
Klebsiella app.
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Yeast
bud
onto the parent cell, then eventually separate. Reproduction
takes several hours and yeast prefer acidy environments. Typical
yeasts growing on hydrocarbons are Candida spp., Saccharomyces
spp., Torula spp., Torulopsis spp., Hansenula spp.
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Fungus
grow in
the form of branched hyphae, a few microns in diameter, forming
thick, tough, intertwined mycelial mats at fuel/water
interfaces. Typical moulds which degrade hydrocarbons are
Penicillium spp., Aspergillus spp., Fusarium spp., Monilia spp.,
Botrytis spp, Cunninghammella spp., Scopulariopsis spp.,
Cladisporium resinae, Hormonicus resinae.
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Sulphate Reducing
Bacteria (SRB) are a specific
group of bacteria utilizing simple carbon, not hydrocarbons, and
require the activity of other microbes in a consortium. SRB
produce hydrogen sulphide. SRB are also directly involved with
many microbial corrosion reactions and can cause sulphide
souring of stored distillate products.
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Restricted fuel flow,
uneven atomization and
incomplete combustion caused by slime build up in the fuel lines,
filters and injector needles.
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Cylinders
develop cool spots causing uneven
wear to the rings and cylinder bores. Acids and gums can eventually
leach into the lubricating oil, causing corrosion of the crank
components.
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Some
species create acids
that remove ions from the atomic structure of metals: this is the main
cause of corrosion in fuel tanks, lines, pumps and injectors.
The presence
of bugs in fuel has a definite effect on the quality of diesel and are
responsible for increasing operating costs.
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Increase
fuel burn
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Increase
maintenance required on filters, fuel pumps and injectors
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Increase exhaust
smoke
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Increase equipment running
costs
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Decrease power
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Decrease reliability
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Decrease service life of all fuel system
components
By fitting a De-Bug Clean Fuel Unit all diesel
bugs
eliminated
Simply
by running the engine or a recirculation pump, the fuel is kept
clean and fresh.
Savings
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