TM 5-810-15
energize-to-trip. The energize-to-trip philosophy is
Regardless of the level of automation incorporated
more desirable since it reduces nuisance trips, is
into the burner controls, the system logic must
operable on loss of power, and is more reliable.
insure that the operator commands are performed
(3) Flame detection and management. Stoker
in the correct sequence with intervention only when
fired boilers do not utilize flame detection or flame
required to prevent a hazardous condition.
management. Pulverized coal and gas/oil fired
Pulverized coal burner controls must provide the
systems do require flame detection, which is the
proper sequential logic to completely supervise
key to proper flame management. The basic re-
burner startup and operation including coal feeders,
quirements of flame detectors are detection of the
pulverizers, air registers, ignitors, and flame
high energy zone of a burner flame, ability to
detectors. Gas/oil burner controls must provide the
distinguish between ignitor and main flames, and
proper sequential logic to completely supervise
discrimination between the source flame, adjacent
burner startup and operation including gas/oil fuel
flames, and background radiation. Ultraviolet (UV)
valves, air registers, ignitors and flame detectors.
detectors are suited for flame detection of gas or
The ACFB boiler includes utilizing a main gas
light oil ignitor and main gas flames. Infrared (IR)
burner or gas lances and ignitor system to warm the
detectors are used for pulverized coal flames. Self
boiler and bed temperature above minimum
checking or redundant detectors should be used to
required for solid fuel firing. This burner operation
ensure reliability. Location of the flame detectors is
is identical to a gas/oil burner operation. The
critical to proper flame management and must be
ACFB boiler does not have a main fuel burner;
given careful consideration. Flame detection
however, the introduction of fuel is completely
systems will be on-off type based on the presence
supervised to provide the proper sequence for
or absence of flame.
purge, ignitors, warm-up burners, flame detection,
(4) Burner controls. Burner controls are the
coal feeders, sorbent feeders and bed temperature
permissives, interlocks, and sequential logic which
monitoring. Note the bed temperature monitor
are required for safe startup and operation of
insures that adequate temperature is present to
pulverized coal, ACFB and gas/oil burners. Burner
ignite the solid fuel. Adequate bed temperature
controls range from manual to fully automatic.
9-12
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