shall support the stoker and its components from the boiler foundation or
boiler room floor. At the end of the grate the ash shall be discharged
into a bunker or pit as indicated. The bunker shall have a dust-tight
enclosure made of steel plates not less than 15.9 mm 5/8 inch thick,
properly protected with firebrick where exposed to the furnace and shall be
fitted with cast-iron, refractory-lined inspection and access doors, and
provisions for ash removal.
2.3.5
Burners
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NOTE: The designer must include all the required
data for proper design of the boiler. Delete all
references to coal and stokers where oil is the only
fuel to be utilized.
**************************************************************************
Where indicated and specified, each HTW generator shall be provided with
oil-fired burner or burners. The burner assembly and control systems shall
conform to NFPA 8501, UL 296, and UL 726, except as otherwise specified.
Supervised manual, semiautomatic, and fully automatic combustion safety
controls shall conform to NFPA 8501 and ASME CSD-1.
2.3.6
Fuel Oil Pumping and Heating Sets
An integrated, shop-fabricated oil pumping and heating set shall be
furnished and shall be duplex type, assuring 100 percent standby and the
oil shall be heated by medium temperature water. Two positive displacement
oil meters shall be provided. Each set shall include an electric oil
heater of sufficient capacity to heat the specified fuel oil to ignition
temperature at low generator load until enough HTW is generated to operate
the high temperature water-to-low temperature water (LTW) heat exchanger
and the LTW-to-oil heater. The electric heater shall be controlled by a
magnetic starter with a manually-operated ON-OFF switch in series with a
thermostatic control. When oil temperature is raised to proper level and
maintained by the LTW heater, the electric heater shall be disconnected
automatically by the thermostatic control. Fuel pumps shall be
electric-motor driven. Each pump shall have the capacity of not less than
[_____] L/second gpm at a discharge pressure of [_____] kPa psig with a
suction lift of 3 m 10 feet.
2.4
COMBUSTION CONTROL EQUIPMENT
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NOTE: Paragraphs describing inapplicable types of
combustion control equipment will be deleted. The
type of combustion control system specified for a
project will depend largely on the boiler capacity,
the fuel, initial cost, and cost of operation.
Basically, the types should be as follows (the
boiler capacities are expressed in Btuh and MW):
Type of Control
Coal (MW)
Oil (MW)
Positioning
0.879-15
0.870 - 12
Semimetering
7-21
7-19
Metering
7 and above
7-19 and above
Metering
20 and above
20 and above
with oxygen
SECTION 15555A
Page 34
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