MIL-HDBK-1022A
to a temperature of 20 degrees F (11 degrees C) above the
fuel's pour point prior to pumping. Use one of the types of
heaters listed below.
8.10.2
Heating Medium. Use the appropriate heating medium
for the particular application based on temperature, pressure,
and availability. Saturated steam is the preferred heating
medium, but consider using hot oil, hot water, and electric
heating where steam is not available from existing sources.
8.10.3
Convection-Type. Use convection-type heaters
installed inside a storage tank and capable of passing through
a 36-inch (900 mm) diameter manhole with a capacity to raise
the temperature of a full tank of burner fuel oil
approximately 60 degrees F (33 degrees C) in 24 hours. The
appropriate Service Headquarters and/or DLA/DFSC will
determine if the capacity of the heater could be reduced if it
is not necessary to heat a full tank of fuel within 24 hours.
8.10.4
In-Line Type. In-line heaters consist of two
general types: tank suction and straight tube. All in-line
heaters are of the shell and tube construction. A tank
suction or suction in-line heater is installed inside the tank
on the tank issue line. The fuel oil enters the exchanger at
the end within the tank and exits at the opposite end outside
of the tank. The steam or other heating medium enters and
exits the exchanger at the end outside of the tank. A
straight tube or pipe in-line heater is installed directly
into the pipeline. The fuel oil enters the exchanger at one
end and exits from the other. The entry and exit points for
the steam side can vary. The following criteria applies to
in-line heaters:
a) Capable of heating fuel oil passing through them
from the ambient tank temperature to a minimum of 20 degrees F
(11 degrees C) above the fuel oil's pour point temperature at
required flow rate.
b) If installed in tanks, allow removal of heater
tube bundles without emptying the tank.
c) If multipass in-line heaters are used, do not
allow the oil temperature rise to exceed 30 degrees F
(17 degrees C) per pass.
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