firing for extended periods in the low fire mode
overheating, due to waterside deposits
varying the water level above the crown sheet
carrying excessive alkalinity in the boiler water
第1题:
A bypass line provided around a waste heat auxiliary boiler in a diesel engine exhaust system, may be used to avoid boiler ______.
A.corrosion at low engine loads
B.erosion at high engine loads
C.overload at high engine loads
D.scaling at all exhaust temperatures
第2题:
concentrations of calcium sulfate in the boiler water
fuel oil in the feed water
improper treatment of the feed water with calcium sulfate
excessive feed water alkalinity
第3题:
A.water-tube
B.fire-tube
C.exhaust gas
D.composite
第4题:
operating the boiler at less than normal water level
installing fins on the firesides of water-tubes
increasing the amount of excess air to the burners
treating the boiler water with chemical oxygen scavengers
第5题:
will be modulated in proportion
will be modulated in proportion and integral
will be modulated in proportion and differential
will not be modulated at all
第6题:
A firebox explosion in an automatically fired auxiliary boiler may be the result of ______.
A.excessive purging before lighting off
B.insufficient trail for ignition period
C.a faulty transformer in the ignition circuit
D.insufficient purging before lighting off
第7题:
yellowish flame
golden yellow flame
white flame
brilliant white flame
第8题:
If the feed pump for an auxiliary boiler fails to deliver the feed water to the boiler, the cause may be ______.
A.high steam pressure in the boiler
B.abnormally high feed-water temperature
C.abnormally high boiler water temperature
D.steam demand exceeding feed pump capacity
第9题:
relight the boiler immediately to prevent loss of steam pressure
relight the fire off the brickwork as the bricks are cherry red
purge the furnace of any combustible gases before attempting to relight the fire
speed up the feed pump to prevent dry firing when the burner flame is reestablished
第10题:
increased heat transfer
fireside erosion
high steam demand
overheated tubes