2.
Effects of Internal Corrosion.
a. Decreased Throughput. As a buildup of material (wax, mill scale) on the inter of the pipeline occurs
there is a decrease in the quantity of products received through the pipeline compared to the past.
b. Increased Maintenance. As a decrease in volume takes place, action to compensate by increasing the
discharge pressure may be taken. (If there is an action, there is a counter action). With the increase in pump
discharge, there will be an increase maintenance requirement to both the pumps as well as the pipeline.
c. Possible Product Contamination. The presence of water, heat, and solids will effect the product,
causing loss of property and possibly microbiologically growth
3.
Methods of Preventing Corrosion.
a. Remove Water.
Fuel as it is discharged should always be issued through a filter/separator to
eliminate water and solids.
b. Remove Oxygen. Fuel can be passed through an air eliminator where pockets of air can be
eliminated. To remove oxygen requires the fuel be heated and is not a process employed in the military.
c. Use Inhibitors. The inhibitors form a thin protective film on the pipes, pumps, tanks, and other metal
surface with which it comes in contact. There are two types of inhibitors available but only one that is used in
military pipeline systems. The inhibitors are water-soluble and oil-soluble.
(1) Water-soluble inhibitor. The water-soluble inhibitor is not used in the military system as it would
be removed when the fuel is passed through the filter/separator thereby not eliminating corrosion.
(2) Oil-soluble inhibitors. The oil-soluble inhibitor is used when required. (Reference MIL-HDBK-
200G, para 7.3.7.2.) Products such as motor gasoline and diesel fuel have the inhibitor added by the
manufacturer; only jet fuel does not have it added. If laboratory test shows a need for an inhibitor, the quantity
required can be injected along with the product into the pipeline.
(a) The inhibitor is effective in preventing corrosion on clean metal, will prevent further
corrosion on an already corroded metal, and will remove rust and mill scale to a small degree.
(b) The oil-soluble inhibitor can be passed through a filter/separator without removal of the
inhibitor.
d. Use Internal Coating (TEFLON). The addition of a coating to the pipe interior is expensive. For the
military, it is not a procedure we would use; whereas in some commercial industry (chemical, steam) service, it
can be economical. An advantage of this type of material is its corrosive resistance. Only where the material has
been damaged is corrosion subject to occur.
e. Use nonmetallic Pipe. Material of plastic, fiberglass, and graphite as well as other materials
developed in the future may be used where they can meet the pressure and type of service requirements (hot and
arctic cold). These types of material are noncorrosive.
QM5200
15-2
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