(3)
Emergency stop
2.12
ASH HANDLING SYSTEM (PNEUMATIC)
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NOTE: Choose this article and its paragraphs and
subparagraphs or the above article entitled "Ash
Handling System (Mechanical)" and its paragraphs and
subparagraphs.
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2.12.1
System Requirements
Provide a complete integrated, pneumatic, automatic sequencing, ash
handling system with air intakes, material intakes, ash doors and
enclosures, iron alloy conveyor line, fittings, rotary slide gates, primary
and secondary materials separators, tertiary bag filter, [steam exhauster,]
[electric motor driven positive displacement blower (mechanical
exhauster),] [air washer,] silo vent filter, ash silo, rotary ash
conditioner, and any other equipment that may be necessary for a complete
pneumatic ash handling system. Provide related electrical work required to
operate the ash handling system. Design system so that the ash silo is
never placed under a partial vacuum.
2.12.2
System Type
System shall be of the intermittent vacuum type, whereby the vacuum is
interrupted permitting periodic discharge of collected materials into the
silo on a programmed time cycle. System shall have sufficient air velocity
to pick up ash that may be deposited in the pipe.
2.12.3
Hoppers
System shall receive, and on a sequenced basis convey to the ash silo, ash
from the stoker fired boiler ash storage hoppers, siftings hoppers, soot
hoppers, baghouse hoppers, and other pollution control equipment hoppers.
Convey from only one pickup point at a time.
2.12.4
Discharge
Discharge ash into the ash storage silo in a dry condition. Arrange silo
equipment for disposal of conditioned ash to trucks. Operation shall be as
nearly dustless as possible.
2.12.5
Maximum Noise Level
The noise level of the operation shall not exceed 85 decibels sound
pressure level 1.52 meters 5 feet from the equipment in any direction.
2.12.6
Ash Storage Hopper
Provide a dry storage hopper for each boiler to receive and store bottom
ash as it is discharged from the traveling grate. Hopper shall be
compatible with the grate ash discharge enclosure as specified under
paragraph entitled "Coal Stokers" and shall have a net volume to receive
and store material for an 8 hour period at maximum boiler output. Size
hopper for mean ash level for one meter 3 feet below the step floor with
ash density of 640 kg per cubic meter 40 pounds per cubic foot for
volumetric sizing.
SECTION 15502N
Page 130
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