changeout of atomizers while the steam generators are on-line. Air
compressors shall be as specified in this paragraph. Nozzles shall be the
internal mixing type so that the compressed air and the lime slurry are
mixed internally to the nozzle orifice, resulting in the atomization of the
slurry. Internal surfaces of the nozzle which are subject to wear shall be
made of a suitable abrasion-resistant material and shall be easily
replaceable. Atomizer operation shall be monitored remotely in the steam
plant control room and locally in the absorber penthouse. Provide
instrumentation, controls, and alarms, as necessary, to ensure proper
operation of the atomizers. Slurry flow and pressure and air flow and
pressure in each atomizer feed line shall be monitored continuously.
Provide flow and pressure switches to indicate nozzle flow malfunction.
Control system shall automatically isolate any malfunctioning atomizer and
provide alarm annunciation in steam plant control room. Sufficient control
interlocks shall be furnished to assure that air flow to nozzle commences
first and terminates last relative to slurry flow during atomizer start-up
and shutdown. Atomizers shall be designed so that normal maintenance can
be performed by plant maintenance personnel who have been trained, as
specified in paragraph entitled "Operator Training Program." The dedicated
air compressor system provided with FGD systems utilizing two fluid-nozzle
atomization shall be complete with two air compressors, one operating and
one backup, and necessary controls and accessories required for automatic
operation. Each compressor shall be sized to provide at least 120 percent
of the maximum atomization air flow and pressure required. [As an
alternative to the preceding specified arrangement, individual air
compressors may be provided for each spray dryer absorber. Each unit shall
be sized to provide at least 120 percent of the maximum atomization air
flow and pressure required for operation of one spray dryer, and with all
[_____] units connected together, so that the unit normally dedicated to
the spray dryer for the idle boiler provides the required backup.] [For
either arrangement], [the] following features shall be provided: The air
compressors and all controls and accessories specified herein shall be
located inside an enclosure to provide an environment suitable for
compressor operation. Provide the structural and miscellaneous steel for
framing of the enclosure. Instrumentation and controls shall provide both,
local and remote monitoring, alarm annunciation, and automatic transfer to
backup unit in the event of failure of the operating unit.
2.7.2.3
Spare Equipment
One complete spare atomizer assembly shall be provided for every two
installed assemblies. Spare atomizer assemblies shall require only the
connection of lime slurry and air feed lines to allow insertion and
operation in place of a malfunctioning assembly. In addition, provide
spare nozzle wearing surface component parts, and other atomizer component
parts as required for one year's operation. Provide two complete sets of
tools required for disassembly and assembly of atomizer units.
2.7.3
Monorail and Hoist
Provide permanent hoist and monorail system for each spray dryer absorber,
as required, to install and remove atomizers. Monorail and hoist system
shall conform to NFPA 70. Monorail shall extend beyond edge of absorber
with sufficient clearance to allow lowering of atomizer assembly to ground
level and raising from ground level. Hoisting system shall be designed in
accordance with MMA MH27.1 and HMI 100. Provide wire rope electric hoist
with motor-operated trolley. Rope drum shall be sized for full lift from
ground level. Hoist capacity shall be 150 percent of heaviest piece of
equipment to be lifted during atomizer installation or removal or 908
SECTION 15864N
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