Electric Boilers Flashcards
Electric boilers
a) require tall stacks for pollution dispersal
b) tend not to be very compact
c) require sootblowers when fuel is coal
d) have energy conversion efficiencies close to 100%
e) are not as safe as other boilers
d) have energy conversion efficiencies close to 100%
A main disadvantage of an electric boiler is
a) they are not very compact
b) furnace refractory tends to be high maintenance item
c) vibration requires special footings
d) input energy cost is high
e) energy transfer efficiency is low
d) input energy cost is high
An advantage of an electric boiler is, that it
a) has a high steaming rate
b) can be operated at high pressures and temperatures
c) produces very dry steam
d) has a high efficiency of energy transfer from the
electricity to the boiler water
e) does not require an operator
d) has a high efficiency of energy transfer from the
electricity to the boiler water
An advantage of an electric boiler is that it
a) is silent in operation
b) can rapidly produce steam
c) can produce steam at very high pressures
d) requires only one blow-off valve
e) does not require a sight glass
a) is silent in operation
Most electric boilers are limited in pressure to about
2100 kPa due to the effect of high temperature on the
a) steam space
b) submerged area
c) boiler fittings
d) vessel structure
e) elements or electrodes
e) elements or electrodes
A boiler which incorporates a basket and a basket drain valve is the a) steam generator b) immersion boiler c) Sterling boiler d) electrode boiler e) thermal flood boiler
d) electrode boiler
Operating voltage for an electrode boiler may be as high as
a) 30,000 volts
b) 16,000 volts
c) 5,000 volts
d) 550 volts
e) 240 volts
b) 16,000 volts
Electrode boiler capacities can be as high as
a) 16,000 kW
b) 30,000 kW
c) 1,200 kPa
d) 1,200 kW
e) 30,000 kPa
b) 30,000 kW
The electrode type boiler
a) cannot have a varying load
b) must operate at very constant pressure
c) utilizes bundles of electric elements
d) requires water which conducts electricity
e) will produce hydrogen by electrolysis of water
d) requires water which conducts electricity
The steam produced by an electrode type boiler depends on
a) the voltage supplied to the elements
b) the level of water in the basket
c) the number of heating elements engaged
d) the number of baffles
e) the amperage supplied to the elements
b) the level of water in the basket
The amount of current passed through the water of an electrode
boiler depends on
a) the depth of the electrodes in the water
b) the control valve setting
c) the steam pressure in the boiler
d) the water quality
e) the water temperature
a) the depth of the electrodes in the water
One disadvantage of an electric boiler is that it
a) requires alternating current
b) requires DC power
c) has no chimney
d) is not very efficient
e) is very expensive to operate
e) is very expensive to operate
A \_\_\_\_\_\_\_\_\_\_ is not required on an electrode electric type boiler. a) safety valve b) gauge glass c) blow-off valve d) low water cut-off e) pressure gauge
d) low water cut-off
An immersion electric boiler capacity can be as high as
a) 1,500 kW
b) 2,100 kW
c) 30,000 kW
d) 16,000 kW
e) 5,000 kW
a) 1,500 kW
Immersion boiler tube bundles
a) act to conduct current through the water
b) can be easily removed from the unit for maintenance
purposes
c) cannot be used to regulate steaming capacity
d) have very low electrical resistance
e) operate at only one voltage
b) can be easily removed from the unit for maintenance
purposes
