exhauster
unit tangentially, avoiding direct impingement on the nozzle.
Provide a
unit capable of producing a vacuum of at least 40.56 kPa 12
inches of
mercury column at shutoff and not requiring more than [0.32]
[0.44] kg
of steam per second at 690 kPa (gage) [2500] [3500] pounds of
steam per
hour at 100 psig.
2.12.16
Steam Condenser, Air Washer and Silencer
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NOTE: The steam exhauster system requires 0.32 kg
2500 pounds of steam per second hour for a 150 mm 6
inch system (8 to 23 Mg9 to 25 tons per hour) and
0.44 kg 3500 pounds of steam per second hour for an
200 mm 8 inch system (13.6 to 31.75 Mg15 to 35 tons
per hour) and approximately 1.89 L/s 30 gpm of water
to the air washer. A steam condenser, air washer
and silencer should be used when the steam exhauster
is used and should not be used when a mechanical
exhauster is specified.
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Provide a double stage cyclone type steam condenser, which also extracts
the remaining solids from the steam-air system. Construct steam condenser
body of hard metal castings not less than 16 mm 5/8 inch thick suitable for
this special service except that the inlet connector shall be not less than
19 mm 3/4 inch thick. Castings shall have a Brinell hardness of not less
than 250. Other metal used in the condenser shall be at least 6 mm 1/4 inch
thick steel with the top not less than 13 mm 1/2 inch thick steel plate.
Provide drain connection not less than 76 mm 3 inches and water connection
not less than 38 mm 1 1/2 inches. Provide silencer as required for quiet
operation.
2.12.17
Ash Storage Silo
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NOTE: Use enclosures for silo roof and unloader in
climates where protection of equipment and personnel
from the weather is desired.
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[_____] meters feet in diameter with [_____] meters feet high walls with a
live bottom and flyash storage capacity of not less than [_____] Mg tons,
based on ash bulk density of 640 kg per cubic meter 40 pounds per cubic foot
for volumetric sizing. Structural joints shall be dusttight and
watertight. Provide columns, beams, bracing, and other structural members
as required for complete erection of silo and accessories. Live storage
capacity shall allow for 20 degree angle of repose from silo outlet.
Height of silo storage shall not be more than twice the diameter. Provide
a minimum of one meter 3 feet of freeboard above the ash level. The design
of the support steel shall be approved by the ash system supplier. Design
silo in accordance with the Uniform Building Code. The design shall take
into account seismic load, wind load, snow load, equipment loads and an ash
bulk density of 1120 kg per cubic meter 70 pounds per cubic foot. Ash silo
support shall be free standing and shall be of sufficient height to allow
gravity discharge of ash through the rotary ash conditioner to a [truck]
[railroad car].
Provide access stair tower with intermediate platforms at
3.66 meters 12 foot intervals for access to ash conditioner level, silo
floor level and silo roof level. Platforms from adjacent structures with
stair access may be provided in lieu of the stair tower, but ladders with
SECTION 15502N
Page 138
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