be present. The motor drivers shall be tested as specified in paragraph
entitled "Pumps, Valves, Motors." Two-fluid nozzle atomizer assemblies
shall be tested for proper atomization performance, plugging resistance and
wear resistance during actual flow of lime slurry and compressed air
through the nozzle, as required during operation. Submit information on the
categories general arrangement, foundation design, structural fabrication,
piping, erection, insulation, instrumentation, wiring, and electric motors.
Exterior ferrous metal surfaces of the spray dryer absorber systems
including, but not limited to, absorber vessels, holding bins, support
steel, manifolds, handrails and kickplate shall be properly cleaned and
shop primed, as specified. Mechanical and electrical component equipment,
such as atomizer machinery and control panels shall be provided with the
manufacturer's standard finishes. Ferrous surfaces which should not be
painted and are subject to corrosion shall be protected for the period
during shipment and storage with a suitable rust-preventative compound as
recommended by manufacturer.
2.7.1
Spray Dryer Absorber Vessel
The spray dryer vessel shall be cylindrical with a 60-degree conical bottom
section or with a trough-shaped bottom section with a minimum sideslope of
60 degrees above the horizontal. Provide replaceable wear plates, where
necessary. The absorber vessel shall be gas-tight and designed for a
transient condition (80 percent of yield strength) at internal pressures of
at least plus 4980 and minus 7470 Pa 20 and minus 30 inches water gage.
Stiffeners shall be of equal depth to provide a uniform surface to receive
insulation. The bottom section of the vessel shall be provided with hopper
heaters as specified in paragraph entitled "Fabric Filter Baghouse."
Heaters shall cover the bottom one-third of the hopper surface area.
Provide the hopper with poke holes, flanged discharge opening, mechanical
vibrators, strike plate and nuclear level switches, as specified in
paragraph entitled "Hoppers." A minimum of one access door on side of
vessel, as specified in paragraph entitled "Access," shall be provided for
access to the vessel interior for maintenance. Provide access doors with
external latches and tightening devices which will allow for gasket
shrinkage and yet produce a gas-tight seal. Doors shall be provided with
means for padlocking in the open position. Access shall be sufficient to
allow inspection of the vessel interior and removal and replacement of any
internal parts subject to erosion or corrosion.
2.7.2
Spray Dryer Atomizers
Each spray dryer sulfur dioxide absorber shall be provided with slurry
atomizers of the rotary or two-fluid nozzle type, as specified in the
following sections. Equip the spray dryer sulfur dioxide absorbers with
vanes, dampers, dispersers, and distributors required to ensure proper
contact of the flue gas with the atomized lime slurry. These devices shall
be designed to prevent maldistribution and short circuiting of flue gas and
localized abrasive impingement of fly ash on absorber internals. The gas
dispersers shall be designed to prevent the atomizer spray from impinging
on or wetting the vessel wall. Design the gas distribution devices to
provide contact between the gas and the atomized slurry as necessary to
maintain system performance throughout the gas flow range. Materials of
construction shall be suitable for use in the flue gas environment.
2.7.2.1
Rotary Atomizers
Provide a single slurry atomizer for each spray dryer absorber, complete
with electric motor drive, power transmission assembly, lubrication system,
SECTION 15864N
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