shall be divided into a minimum of flue modules. The maximum air-to-cloth
ratio excluding one module for cleaning and one module for maintenance
shall be 4.0 for pulse-jet units or 2.25 including the reverse gas volume,
for reverse gas units with the spray dryer operating at the design gas flow
specified in paragraph entitled "Expected Flue Gas Conditions."
Calculation of air-to-cloth ratio for reverse gas fabric filter baghouses
shall exclude thimble, ring, and cuff area covered by bags. Pulse-jet
fabric filter baghouses, if provided, shall be designed for off-line
cleaning during normal operation with the capability for on-line cleaning
when required. Reverse gas fabric filter baghouses shall provide a maximum
of three-bag reach. Reverse gas bag cleaning systems shall provide a
minimum of 9 liter per second per square meter 1.75 cubic feet per minute
per square foot of fabric to be cleaned.
Hopper capacity shall allow
for a minimum of ten hours storage at maximum fly ash and absorber product
material loading. Hopper design capacity shall be based on a fly ash
density of [_____] kilogram per cubic meter pounds per cubic feet. Hopper
design strength shall be based on fly ash density of [_____] kg per cubic
meter pound per cubic feet plus the support of 454 kg 1,000 pounds of ash
handling equipment per hopper. Structural design shall be based on the
assumption that the hopper is full of ash up to the bottom of the bags for
pulse-jet units or up to the tube sheet for reverse gas units. Fabric
filter baghouse structural design temperature range: [_____] to [_____]
degrees C degrees F.
2.6.4
Lime Slurry Preparation System
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NOTE: Design slaker enclosure with adequate access
area around feeders, slakers, and grit removal
equipment to perform required maintenance.
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A single lime slurry preparation system shall serve all spray dryer
absorbers. The lime feed bin shall be sized to store at least the quantity
of lime required for 72 hours operation of two steam generators at the
maximum sulfur dioxide rate specified and at the guaranteed stoichiometry.
The minimum storage volume shall be [_____] cubic meter feet. Provide the
bin with two conical hoppers. The lime feed bin shall be capable of
receiving lime either directly from self-unloading blower trucks or from a
remote silo and pneumatic conveying system to be provided by the
Contractor. Lime shall be slaked with detention or paste-type slakers.
Two full-capacity lime feeders and slakers shall be provided. Each lime
feeder and slaker shall be sized to provide 110 percent of the slurry
quantity required during operation of 2 steam generators at the maximum
sulfur dioxide rate specified. The turndown capability from this design
capacity shall be at least 10 to one. The lime slurry preparation system
shall provide 100 percent installed spare capacity feeders, slakers, and
grit removal equipment. The lime slurry system will operate with one
equipment train in operation and one as backup. The FGD system control
panel in the steam plant control room shall provide complete operational
monitoring of and alarm annunciation for each equipment train. Capability
for emergency shutdown of the lime slurry preparation system shall be
provided at the FGD system control panel. Failure of the operating
equipment train to respond to the automatic start signal from the low tank
level switch shall be alarmed in the control room. The slurry tank storage
capacity between the low and low-low levels shall be sufficient to allow
time for the control room operator to dispatch operations personnel to the
lime slurry preparation system to start-up the backup train and to provide
slurry to the tank before the low-low level is reached. Enclosed feeders
SECTION 15864N
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