FUEL OIL HEATERS
Alstrom Fuel Oil Heaters serve two major purposes:
to make fuel oil pumpable and to provide the requested atomization in the burner. Fuel oil has a high viscosity and when stored at
the ambient temperature cannot be pumped. The first step is to preheat the
fuel oil inside the storage tank, reduce its visc
osity
, and then dispense it by means of pump suction.
"VSF" and
"ATL" tank suction heaters
are used in underground storage tanks, while
"SSF" heaters apply to
aboveground tanks. The oil leaving the tank is heated to 110-120°F. Before
fuel oil flows to the burner, it receives additional heating. The required
fuel oil temperature depends upon the burner design and the grade of fuel
oil. Usually, burner manufacturers specify the temperature best suited for
their burners. Fuel oil No. 6 is heated to 160°F in horizontal rotary
burners, 220°F in steam atomizing burners, and 250°F in mechanical atomizing
burners. Alstrom "HST,"
"ST",
"HDT", and
"DT" fuel oil heaters are
designed for this purpose. For the majority of applications, the electric
heater is used for startup. Once the boiler provides sufficient steam
pressure or water temperature, the electric heater assumes a standby
function. Combination Steam-Electric Fuel Oil Heater
"ASE" combines the steam tube
bundle and the electrical sheath into one unit, thereby creating a simple,
compact, labor-saving package. The properly designed fuel oil preheater
provides the necessary fuel oil atomization, resulting in complete
combustion and efficient, trouble-free burner maintenance.
"Hermetic Safe Guard" Preheaters Series
"HDT"
These
unique "Hermetic Safe Guard" tube-within-a-tube
oil preheaters provide absolute, positive boiler
protection in the event of an oil leak. The
inner tube contains water or steam, while the
outer tubes are surrounded by the fuel oil. The
space between the two tubes is connected to the
rear safety chamber. Should an oil leak occur,
the oil goes into the safety chamber and becomes
visible in the Alstrom Visual Indicator. This
oil preheater is required by the New York City
Board of Standards and Appeals as well as by New
York, Michigan, and Oregon states. The heaters
consist of a carbon steel shell, a tubesheet, a
manufactured head, and stainless steel tubes TIG-welded
to the tubesheet. If the heating medium is
liquid, then the number of tube passes is
selected to provide the requested velocity of
liquid. As the fuel oil crosses the staggered
tubes, baffles control its direction and
velocity. Since pressure drop on the tube side
and shell side is limited, optimization of the
heater's design is required.
"Safe Guard" Preheaters
Series "DT"
Alstrom Multipass "Safe Guard" Preheaters Series "DT" are used for
preheating fuel oil with steam or boiler water. The "DT" preheater features
a tube-within-a-tube. The inner tube contains the oil, while the outer tube
is surrounded by the boiler water or steam. The space between the two tubes
contains heat transfer solution and is charged in the factory. Should an oil
leak occur, the oil goes into the rear safety chamber and becomes visible in
the Alstrom Visual Indicator. The multipass design allows the selection of
2, 4, or 6 tube passes for maximal fuel oil velocity in the tubes within the
permitted pressure drop. When boiler water is the heating medium, the low
shell side pressure drop increases performance on a gravity circulation
hook-up by increasing boiler flow rate, allowing the heater to keep its full
rating.
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