Manufacturers of boilers should be consulted to
determine if soot blowers are applicable for the
design contemplated. Small units are usually
manually cleaned.
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Where indicated, each boiler shall be provided with soot blowers using
[compressed air] [steam] as the blowing medium. The soot blower system
shall be the automatic sequencing and intermittent puff type. The soot
blower units shall be sequenced automatically using successive steps by
their controller, each step involving no more than a 70 kPa 10 psi drop in
air pressure at the receiver. After one unit is operated in successive
steps through its cycle, the controller shall shift the operation to the
second soot blower unit, and so on, until all units on that boiler have
been operated, after which the controller shall be shut down automatically
by the sequence controls. The soot blower heads shall have elements of
suitable material for the highest temperatures encountered in the boiler.
The sequence timer shall have provision for manual selection of the soot
blower units to be used. Soot blower system for oil fired boilers shall
conform to NFPA 85.
2.11.1.1
Air Compressor Unit
The air compressor unit shall conform to ASME PTC 10 except as specified
otherwise. Compressor speed shall not exceed 900 rpm. Motor speed shall
not exceed 1750 rpm. The service air requirements shall be as indicated
with receivers sized as indicated. The units shall be suitable for
heavy-duty service (soot blowing). The compressors shall be simplex type,
single-stage, double-acting, with water-jacketed cylinder, fitted with
intake and discharge valves of the lightweight feather, disc or plate type,
and shall be provided with necessary controls, water-cooled aftercooler,
moisture separator, drive, receiver, relief valves, and cooling water
controls as required. The compressor air intake shall be provided with an
air suction filter/silencer suitable for outdoor installation. The filter
shall have a collection efficiency of 99 percent of particles larger than
10 microns. The filter body and media shall withstand a pressure of 850
kPa 125 psi. The aftercooler shall be the shell-and-tube type designed for
air flow through the tubes with steel shell internal baffle plates. The
cooling capacity of the after cooler shall be sized for the total capacity
of the compressor. The moisture separator shall be provided with an
automatic water discharge trap and level gauge. Cooling water controls for
regulating compressor cylinder water temperature and after-cooler water
temperature shall be thermostatic valve type and shall be installed with a
three-valve bypass in the water outlet lines ahead of open sight drain
funnels. The compressor shall be equipped with adjustable, pressure type
unloader controls suitable for continuous compressor operation.
2.11.1.2
Air Receiver
The air receiver shall be a vertical type constructed in accordance with
ASME BPVC SEC VIII D1 for unfired pressure vessels for 1379 kPa 200 psi
working pressure, and shall be equipped with flanged inlet and outlet
connections, valved drain connection, minimum 150 mm 6 inch dial pressure
gauge, pop safety valves, and regulator connections.
2.11.2
Continuous Emissions Monitoring
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Emerging flue gas flow monitor technologies are
SECTION 15569A
Page 40
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